I’d guess possibly a valve seat issue. Maybe a burnt valve. Regardless it’s a win that you knew something wasn’t right, and you dug in to see what was going on. A lot of other shops would’ve just given the car back to the customer. Excellent video Kiwi, and thanks for showing us that there are some people that still care about the quality of their work and do it the right way.
If it was a burnt valve the sound would be coming from the intake (intake valve bad) or out the exhaust. Up the guide into the valve cover? That is odd.
@@kiwiclassicsandcustoms9160 I'd have to guess at a damaged valve - maybe with the stem bent just a touch - letting the compression out. If the bend is high enough in the stem, it could have damaged the guide also, giving us that noise around the valve spring. My only concern here is that it hasn't pushed the seal off - or at least, not enough to let oil in and give us that classic puff of blue smoke on startup. It's gunna be interesting to see who's guess hits closest to the truth. 👍
seems a logical assumption except why would the gases force their was out around the valve stem when the least path of resistance would be the exhaust port........
@@kiwiclassicsandcustoms9160 Good question. I know you will figure it out. You were right about the initial performance. Or the lack of it. Should have been a lot snappier. Still a valve issue I think. For some reason. Looking forward to the answer to this one.
The coolant was not changed since build completion, safe to say, little to no "other" maintenance was completed. Behind Door #1, Burned valve from running the lash to tight.
The old 2.02" 'X' heads used to be prone to cracking between the two valves. The T/A uses a 'J' casting with 2.02' valves like the 71' 360 but it had the smaller 1.88 intake. In either case, the old dollar bill trick on the exhaust pipe will verify a burned valve. If the dollar gets sucked into the pipe its a burned valve. If not, it's a ring. Or, if you check the compression and squirt oil into the cylinder, the compression will rise if it's a ring and stay the same if it's the valve. I am sure you know this, just my 2 cents worth. Good luck with the project.
It kind of sounds like it has a cracked head. if the valve guides have been replaced (or worse, knurled) that might be the source. I can't wait to see the repair and cause!.
Glad you found it, could be something cheap yet until you know for certain. One time a squirrel built a nest inside the air cleaner on a 360 I had in my plow truck over the winter. Vacuumed out all I could. Fired it up and blew some walnut shells out of the pipes. Thought it was fine but just like your example it was down on power and pull. Reworked the carb, little better, noticed what you were finding the same way, only with the valve cover off. Pulled the head which I didn’t want to do but after three days I finally found what you guys found in less time. In my case, a piece of walnut shell perfectly sized and shaped had jammed not allowing the valve to seal all the way on one cylinder. Hopefully it is not a burned valve, I know you will get to the bottom of it, you guys are good, way to find the problem so fast.
@@kiwiclassicsandcustoms9160 yup, i was tending a crack or hole type deal.At least we not asuming kiwi doesn't kno his job like a lot of commenters seem to think
I would still pressurize the cylinder before pulling the head off. A continuous flow of air will be easier to pinpoint, and it is possible that the problem is not in the head and the compression is leaking into the crankcase, and the sound just happens to be coming through the oil drain holes in the head.
Of course you drove it, felt it, heard it and then said naaaa let’s actually fix this sucker. Good for you man seriously some people would just run it and say ehhh it’s old or what ever
I've seen that before. You can hear that uneven "galloping" sound when turning it over, which is caused by the difference in compression between one or more cylinders. Could be a valve not closing all the way, bad valve stem seal, stuck rings, or a few other things, especially with an engine that has sat for a really long time. In that engine it is obviously valve related. I specifically remember one case where a guy started up an engine that had sat for a really long time. A valve completely stuck open (commonly called a "dropped valve") and cracked the piston. A lot of bad things can happen to engines (and any other mechanical device designed to move) when it sits for a long time without moving. Most people say you should not start a stored vehicle. To me that is totally wrong. It should be started and warmed up on a regular basis. It should also be maintained on a regular basis, including oil and coolant changes. I've seen engines completely destroyed because the rings were literally welded to the bores by rust, and when someone tried to turn it over, it gouged the crap out of the cylinder walls. I would recommend completely rebuilding both heads on that engine.
I could hear it during the test drive video, I thought it was an exhaust leak. at first I thought the valve issue was a cracked valve, where the valve head meets the stem. Explains why when the stem is in the closed position the valve face doesnt meet the valve seat and loss of compression but on second thought it's around the valve guide/seal. So probably too tight lash may have caused Bent valve that wrecked the guide and seal. Won't find out till you pull the head.
Sometimes the mic will pick up things the ear can’t and vice versa. At first I wondered why he didn’t comment on that. Sounded pretty horrid on this end.
3 guesses, 1) the valve is slightly bent, causing it not to seat well, 2) the valve is burnt, 3) the valve contacted the piston from the tight adjustment, and the force cracked the valve guide. It could also be a combination of any of these. As much as I regret to say on such a beautiful car, you will no doubt have to remove that head at least, to pinpoint it.
Do you have a rear-looking Borescope? Also (probably doesn't matter since the head has to come off anyway) but you could fire it up in dim light; you should see the blue combustion flame from wherever the breech is. The only thing I can think of that doesn't spell cracked head is if the exhaust from that one port is completely blocked, burning the valve and leaving nowhere else but the guide to chuff through
It's still an absolute gorgeous car. Actually reading the title of the last video I was afraid you are going to find some -major- rust issues. But it seems to be absolutely perfect from what I could see. So I am very glad (for your customer) that it's "just" an engine issue. Sure that's a bummer but its's not like finding a metric ton of bondo and rust in and on the chassis (like usual). Thanks for the upload!😊
Thanks for the update. It's the shame what it is. Pray the head is okay. Pity to see that kind of issue.😢 She's still beauty for sure. There are times that an internal engine problem isn't caught until... I can't see that that restoration is done that bad but I've had engines fail when least expected due to a very minor issue. Truly a shame that it happened here.
Possibly a sodium filled exhaust valve (hollow valve head and stem) which has failed. Once the sodium has disappeared the valve will overheat and fail very quickly and in some cases gasses exit the combustion chamber via the hollow valve centre. The sound which you detected could be this very leak.
Quite the mystery, and brain teaser! But, at least he's got a professional on it. Must be weird problem month! My neighbor came to me in desperation after dealing with a problem on his Lexus is. A local parts store (big box, I won't mention who because they made good in the end) scanned it for him. Of course they told him it was a bad upstream 02 sensor, (typical) and sold him one, with the socket to fit it. After playing hell replacing it, it helped for a day, then it started running crappy again, falling flat on it's face anything over half throttle. They scanned it again and said it was his MAF sensor and sold him one. That helped for about an hour, then back to where it was. I told him scanning simply reads failure codes and he'd probably have to take it to a shop and have it diagnosed through the process of elimination with some resistance testing. But, I gave it a quick look, and went for a ride with him. It was idling weird and inconsistent with the check engine light going on and off. He mentioned he'd had the battery replaced at said part store and the problem started shortly after that. So, I went back under the hood for a look. I noticed it right away when I looked at the battery! The battery is located on the passenger side, back by the firewall, like my Lexus. Probwhy I didn't spot it the first time. I asked, did you replace the positive battery terminal? He said, they noticed it was corroded when they replaced the battery and sold him another and replaced it when they replaced the battery. They replaced the factory steel terminal with a pos Chinese lead one! I drove him to a different parts store, got a steel one, replaced it, problem solved. He threw the old 02 sensor and MAF sensor away. We went back to the first parts store where I spoke to the manager and explained that they had created the problem. He gave them back the lead terminal and they refunded him on the parts the sold(conned him into buying) him. I bet that computer didn't know whether to shit or go blind! 😂 Anyway, good luck with that head, I hope it isn't cracked!
Listening to the audio from your road test I wasn't sure if it was just how the mic was picking up the side exit exhaust but it sounded like an exhaust manifold leak or possibly your bad/burnt valve?
The 2 comments are good possibilities but to come up the spring means the guide is gone and if someone did bronze wall bushings it could have trashed on. Lucky she didnt drop a valve on test ride. Tare down time. Good call kiwi. ❤
Could be a bent valve and, get ready coolant could have rotted a hole into an over ported intake runner. I want to say porting near push rods you have to be careful, bronze guides can shift also. I like to glue them with red lock tight, graphite grease works good on intake valve stems as it stays and counters unleaded fuel not lubing the valve stem. Or "get ready for this one"back in the early '70's Chrysler was going thru dark times. It was not uncommon for them to leave lots of casting clay in the blocks, this mixed with coolant would make an abrasive slurry that may have worn a hole under the spring from the coolant flowing. I have cleaned gobs of casting clay out from behind rotted freeze plugs in early '70's blocks?
@TheGforcead very true but engines have had the coolant left in them for over 20yrs without issues so let's lean on the dark times or guide failure but nevertheless I can't wait to see how this shakes out. 50yrs of engine building this is very odd.
its puzzling it would seem to be coming up around the valve stem but why would it push out with such pressure when its got the exhaust port to escape though easily..... path of least resistance and all that........
Possibly blown headgsket on the valley side i had a Windsor blow a headgasket externally towards the exhaust manifold side sounded like a chopper yet had no oil leaks or water leaks blew the steel ring of the gasket love ur videos Kiwi from Australia
I did have a spark plug on my gtx that you could blow through, weirdest thing so I kept it to show others. Sounded like an exhaust leak kinda. Anyway I await the diag it's a nice car almost too nice to drive on the street
I've had a similar sound when an exhaust valve was split on a 948cc A-series engine, but it could also be a burnt seat, something caught between the valve and the seat or a slightly bent valve even. The A35's engine with the split valve - not certain why the valve cracked / split, but I have heard it can happen when a valve gets too hot or has been burnt for a few thousand miles. Maybe running lean on one cylinder? Mismatched spark plug that's too hot? On the A35, the valve had split all the way from the lip to the stem and there was a 2mm gap at the lip, so she'd been burnt for a while. I don't always hear the hiss around the seat of a burnt valve, but there was a definite hiss like that Challenger's #1 exhaust valve from the one that was split. A bit of a tell-tale sign that something was amiss with the sound the starter made on cranking the engine over - the stumble on one cylinder. Good catch, my friend! ...and in Typical Kiwi Fashion, near enough isn't good enough and it needs to be RIGHT before the customer gets it back. I admire that ethic as it's one of my own and seldom found nowadays. Taking a bit of pride in your work and ensuring your good reputation by going the extra mile to ensure the long-term enjoyment your customer has with their vehicle by spotting an issue and correcting it before it gets worse and potentially costs more to repair. Good on ya, mate! All the best
Kiwi, given the noise up through the guide, I'd be tempted to pull that exhaust manifold loose, then try your test again. If it's a plugged port/manifold making the guide the path of least resistance, that should change it enough to hear.
Cylinder head is toast... coolant leak from poor maintanence led to overheating/ hot spots in the heads.Hissing that loud is caused by cracks in the valve seat....spring can be good valve can be good guide can be good..but that loud of a hiss/ compression leak sounds like its going right past the seat through cracks in the head casting chamber itself...probably has cracks in both heads..time to remove and magnaflux
From the back of bleachers: I'm going to with cracked head. It makes no sense if you're losing half your compression past the valve or valve seat - it'll go out the exhaust port, not by the stem/guide, path of least resistance and all that. I'd be looking around the spark plug hole between the valves for a possible crack into the valve guide. Weirder things have happened. How was oil consumption with the crankcase pressurized? Noticeable?
Quite a head scratcher eh Kiwi. I think you might have to bite the bullet on this one. Disassembly required mate. Can't wait for the update. Cheers buddy.
So a crazy thought, the valve broke and plugged the exhaust port. The only place left for the compression to escape is through the guide. Sure it's thinking outside the box and no one has ever encountered such a thing but hey ya never know. This is think tank level consulting work! ;)
Considering the quality of the rest of the car, it would be hard to believe that the machine work would have been skimped on. But maybe a knurled guide with the valve wiggle specs just barely within spec (or perhaps unchecked and overlooked) along with the tight lash keeping the valve from seating very tightly thus causing a burnt valve/seat.
I encountered this once on a 305 Chevy. It was a cracked head and the crack went from next to the valve seat up around the exhaust port then continuing along the valve guide.
Burnt valve from too tighter clearance. Good to see you have plenty of work on now you have started working on cars other than Fords lol. And the update will now be part 3... bourbon after work no during. 😁🇬🇸🤘
Great review Kiwi do those mufflers with that 180degree direction change restrict the exhaust flow and limit the hp ? Burnt valve is my guess on #1 cylinder. Looking forward to seeing what you find out
Burnt valve and compression slipping by a loose valve guide? That's my guess. Surprised it wasn't pushing oil out of like the breather or PCV system somewhere if that is the issue. Could also maybe be a head gasket blown on the inside of the lifter valley, maybe, but that's probably a bit of a stretch. She is a pretty sweet ride, hope y'all get to the bottom of the mystery soon! Take care Kiwi, and hey Uncle Tony!
At first when I heard it had been leaking coolant I thought the performance maybe be caused it to overheat and blow a head gasket causing it to stutter down low. Then maybe a burnt or otherwise damaged valve. Beautiful car, a spell with "doctor kiwi" should make it feel a lot better. Looking forward to seeing the antidote to her feeling unwell.
What a cliff hanger! That would have to be a big hole for air to come out around the valve guide as well as go out the exhaust with the valve open. It would be super weird for the valve to be sealed and the air to come around it in some way. I'm doubting *all* of the air is coming out there but a good bit is for sure so maybe a very roached guide and burnt valve/seat? Once you pull that head I'd guess the problem is obvious.
The only way that could happen is if the compressed air has nowhere to go. It is either escaping through a crack or hole in the head while the piston is coming up to make compression or you heave a plugged header tube and a bad valve seal. If the piston is on a compression stroke, it's a crack or hole by where the sound is. if the piston is coming up to push the exhaust out, then there is a rag or something in the header tube/exhaust manifold port, for that cylinder. Maybe a bent/crushed header tube. So it cooked the valve seal. When running and the exhaust valve opens to let out the very hot burnt exhaust, and the tube is blocked, it makes compression and the least path of resistance is the valve seal. Or if it was ported to much and blew through a thin wall.
Maybe the compression is going out the exhaust, but the manifold has to be off to hear it? Kinda like the valve cover does. Cracked valve seat or cracked valve guide? Cracked head? Small block Mopar heads are notorious for cracking between the valves, but it rarely causes an issue.
Odd problem. I guess the exhaust manifold being on mutes the leakoff much like the valve cover? Valve guide must have gone elliptical... lets blame unleaded gas?
@@kiwiclassicsandcustoms9160 - I think it's a crack that is next to the guide. The valve is closed on compression stroke so it's sealed from the exhaust port, and the crack is in the chamber and up through the casting to the valve cover area.
Seems like the valve guide would need to be pretty loose to do that. What's weird is pressure follows the path of least resistance, so that guid has to be real loose, or there's resistance where it shouldn't be. Be interesting to see how it turns out.
Nice trick Kiwi, getting 2 videos by leaving us hanging on these last few mins. :) (of course I am joking, sometimes making innocent little jokes don't always come across when typed) I am looking forward to the diagnosing & resolving the issue(s).
What seems strange is that we can hear the cranking rpm drop and an additional load on the starter when that cylinder is in compression cycle. Cam lobe worn off? Take rough measurements on valve/rocker travel.
That seems like a good theory but the leaking compression is coming out around the valve stem area not out the exhaust port where a bent would leak it to ...
Whatever it is. Hopefully it doesn't require replacing the head. That's an all original car. That would suck. Especially if it was caused by the engine builder. If the valve lash was that much too tight. I'm afraid of what else they could've done wrong. I don't build engines. But when I work on things I'm not 100% familiar with, I look up the specs. Doesn't seem as if that was done here. Good luck Kiwi. And good luck to the owner too. Sounds like you might need it
On AAR/TA, it's mechanical rockers with HYDRAULIC lifters. If the valve "lash" adjustment is 0.100" too tight", whatever that means to him, he could have bent a pushrod, or possibly hurt the cam. I'm not sure if you can see #1 exhaust cam lobe, because it's at the extreme front, but I'd certainly try to look down the oil drain back hole in the left head and look at the cam lobes. If the valve "lash" adjustment is that far off, I'd also be making absolutely sure the rocker shafts were not installed upside down or something silly like that. I've seen that done, and that can do a LOT of damage.
All the noise is at the valve but how do we know its not pushing into the manifold too? Just wondering. I can imagine a blocked ex port somehow (not really) but I agree with the burnt seat and or valve...
Nothing found underneath when on the rack so I really expected that some jackass hit you during the test drive ! Phew ! lol. Whatever is revealed that the issue is at least it’s just a mechanical issue from my standpoint. Such a beautiful T/A ! Take care
The only way compression can escape the cyl at the top is through the valve. Maybe degree the cam before removing the head? I say it is either valve timing, bent, or not sealing when it is TDC! Definitely not great. Since it is not engine wide, anticipate a valve issue.
The exhaust port / header pipe must be blocked ( with what , or how I don’t know ) . The low compression is because that cylinder is unable to pump ( get air in ) efficiently with a blocked header . The gas escaping around into the valve guide is because that has become the “ path of least resistance “ . It’s being pushed up the guide because it can’t exit through the header
@@kiwiclassicsandcustoms9160 yeah, bit of a mystery. Perhaps only some is getting out. A large crack from the combustion chamber to a valve is pretty rare.
Probably the reason why you had a gasket pushed out on the wet side. Leaking compression into the water side of things, pushed out a head gasket maybe?
Ahhh, possible valve guide cracked from a bent valve pushing compression into the water jacket and out around the seal area? things that make you go hmmmm
You don't see many T/A's this color, which makes it extra sharp and unique. Perhaps a bent valve or cracked seat going up thru the guide, but the hiss usually means a poor valve sealing. Either way, the head needs to be pulled.
With the clinder at TDC pressurize the cylinder then listen t see if the leak is coming back through the intake or out the exhaust pipe. Not that it's going to really matter now anyway because you know the head has to come off. The valve is probably warped.
I’ve heard that sound a bunch of times on Harley’s with blown head gaskets but I don’t think that applies here. I’m Waiting anxiously to see what is the result. I’m suspect about the tight valve lash. Burned valve combined with bad guide? Is there carbon tracking inside the valve cover?
Smoked the exhaust valve and seat from the lash being way to tight. At least it is serviceable and not a cracked head. You do good work and appear to really care about the cars and owners.
It may have been a "mis-speak" but if the valves were truly 100/1000 (0.100") too tight, there is likely a bent valve. Surprised there's not a LOT of damage in multiple cylinders. Perhaps it was 0.010" too tight?
I’d guess possibly a valve seat issue. Maybe a burnt valve.
Regardless it’s a win that you knew something wasn’t right, and you dug in to see what was going on. A lot of other shops would’ve just given the car back to the customer.
Excellent video Kiwi, and thanks for showing us that there are some people that still care about the quality of their work and do it the right way.
Thanks man!!! And thanks for watching!!
If it was a burnt valve the sound would be coming from the intake (intake valve bad) or out the exhaust. Up the guide into the valve cover? That is odd.
@@hotpuppy1 you're correct, for that sound to be coming up the stem makes no sense and yet it is or at least sounds like it is......🤔
@@kiwiclassicsandcustoms9160 I'd have to guess at a damaged valve - maybe with the stem bent just a touch - letting the compression out. If the bend is high enough in the stem, it could have damaged the guide also, giving us that noise around the valve spring. My only concern here is that it hasn't pushed the seal off - or at least, not enough to let oil in and give us that classic puff of blue smoke on startup.
It's gunna be interesting to see who's guess hits closest to the truth. 👍
Either a loose seat or crack in the valve seat area, that's my guess!
Burned valve from running the lash to tight I am guessing.
Exactly
seems a logical assumption except why would the gases force their was out around the valve stem when the least path of resistance would be the exhaust port........
@@kiwiclassicsandcustoms9160 Good question. I know you will figure it out. You were right about the initial performance. Or the lack of it. Should have been a lot snappier. Still a valve issue I think. For some reason. Looking forward to the answer to this one.
@@kiwiclassicsandcustoms9160 I think it is forcing past the valve on power/ compression stroke- bent/burnt.
The coolant was not changed since build completion, safe to say, little to no "other" maintenance was completed. Behind Door #1, Burned valve from running the lash to tight.
As horrible as the valve train sounded during the entire test drive I'm surprised there is only 1 cylinder like that.
Roger this! It just didn’t sound healthy.
I agree with 488ci comment. This is one hell of a catch by Kiwi. Can't wait to see him dig into this little beauty and find the culprit.
The old 2.02" 'X' heads used to be prone to cracking between the two valves. The T/A uses a 'J' casting with 2.02' valves like the 71' 360 but it had the smaller 1.88 intake. In either case, the old dollar bill trick on the exhaust pipe will verify a burned valve. If the dollar gets sucked into the pipe its a burned valve. If not, it's a ring. Or, if you check the compression and squirt oil into the cylinder, the compression will rise if it's a ring and stay the same if it's the valve. I am sure you know this, just my 2 cents worth. Good luck with the project.
Bummer, this is a unhappy ending. Good catch.
It kind of sounds like it has a cracked head. if the valve guides have been replaced (or worse, knurled) that might be the source. I can't wait to see the repair and cause!.
Glad you found it, could be something cheap yet until you know for certain. One time a squirrel built a nest inside the air cleaner on a 360 I had in my plow truck over the winter. Vacuumed out all I could. Fired it up and blew some walnut shells out of the pipes. Thought it was fine but just like your example it was down on power and pull. Reworked the carb, little better, noticed what you were finding the same way, only with the valve cover off. Pulled the head which I didn’t want to do but after three days I finally found what you guys found in less time. In my case, a piece of walnut shell perfectly sized and shaped had jammed not allowing the valve to seal all the way on one cylinder. Hopefully it is not a burned valve, I know you will get to the bottom of it, you guys are good, way to find the problem so fast.
Major bummer such a special car is sick, but I'm sure you'll bring her back to life Dr. Kiwi. Look forward to part 2.
Odd. Nice clif hanger. Will stay tuned.
smoke test the spark plug hole - will show guide leak, valve leak, etc. hope it isnt cracked head
Great suggestion!
@@kiwiclassicsandcustoms9160 yup, i was tending a crack or hole type deal.At least we not asuming kiwi doesn't kno his job like a lot of commenters seem to think
Thanks man!
He's from down under corse he knows his job😮😅
@@garrypritchard1658 Not strictly true , Kiwi's a kiwi. They dont like being called Aussie.
I would still pressurize the cylinder before pulling the head off. A continuous flow of air will be easier to pinpoint, and it is possible that the problem is not in the head and the compression is leaking into the crankcase, and the sound just happens to be coming through the oil drain holes in the head.
Of course you drove it, felt it, heard it and then said naaaa let’s actually fix this sucker. Good for you man seriously some people would just run it and say ehhh it’s old or what ever
I've seen that before. You can hear that uneven "galloping" sound when turning it over, which is caused by the difference in compression between one or more cylinders. Could be a valve not closing all the way, bad valve stem seal, stuck rings, or a few other things, especially with an engine that has sat for a really long time. In that engine it is obviously valve related. I specifically remember one case where a guy started up an engine that had sat for a really long time. A valve completely stuck open (commonly called a "dropped valve") and cracked the piston. A lot of bad things can happen to engines (and any other mechanical device designed to move) when it sits for a long time without moving. Most people say you should not start a stored vehicle. To me that is totally wrong. It should be started and warmed up on a regular basis. It should also be maintained on a regular basis, including oil and coolant changes. I've seen engines completely destroyed because the rings were literally welded to the bores by rust, and when someone tried to turn it over, it gouged the crap out of the cylinder walls. I would recommend completely rebuilding both heads on that engine.
I could hear it during the test drive video, I thought it was an exhaust leak.
at first I thought the valve issue was a cracked valve, where the valve head meets the stem. Explains why when the stem is in the closed position the valve face doesnt meet the valve seat and loss of compression but on second thought it's around the valve guide/seal. So probably too tight lash may have caused Bent valve that wrecked the guide and seal.
Won't find out till you pull the head.
Yeah first thing I thought was exhaust leak. Bad guide and valve id say.
Sometimes the mic will pick up things the ear can’t and vice versa. At first I wondered why he didn’t comment on that. Sounded pretty horrid on this end.
Yeah my guess is a crack between the head surface/ chamber and the guide boss? Otherwise it would take the path of least resistance out the port.
That seems the most plausible theory !
3 guesses, 1) the valve is slightly bent, causing it not to seat well, 2) the valve is burnt, 3) the valve contacted the piston from the tight adjustment, and the force cracked the valve guide. It could also be a combination of any of these. As much as I regret to say on such a beautiful car, you will no doubt have to remove that head at least, to pinpoint it.
Do you have a rear-looking Borescope? Also (probably doesn't matter since the head has to come off anyway) but you could fire it up in dim light; you should see the blue combustion flame from wherever the breech is. The only thing I can think of that doesn't spell cracked head is if the exhaust from that one port is completely blocked, burning the valve and leaving nowhere else but the guide to chuff through
It's still an absolute gorgeous car. Actually reading the title of the last video I was afraid you are going to find some -major- rust issues. But it seems to be absolutely perfect from what I could see. So I am very glad (for your customer) that it's "just" an engine issue. Sure that's a bummer but its's not like finding a metric ton of bondo and rust in and on the chassis (like usual). Thanks for the upload!😊
Thanks for the update. It's the shame what it is. Pray the head is okay. Pity to see that kind of issue.😢
She's still beauty for sure. There are times that an internal engine problem isn't caught until...
I can't see that that restoration is done that bad but I've had engines fail when least expected due to a very minor issue. Truly a shame that it happened here.
Possibly a sodium filled exhaust valve (hollow valve head and stem) which has failed. Once the sodium has disappeared the valve will overheat and fail very quickly and in some cases gasses exit the combustion chamber via the hollow valve centre. The sound which you detected could be this very leak.
Quite the mystery, and brain teaser! But, at least he's got a professional on it. Must be weird problem month! My neighbor came to me in desperation after dealing with a problem on his Lexus is. A local parts store (big box, I won't mention who because they made good in the end) scanned it for him. Of course they told him it was a bad upstream 02 sensor, (typical) and sold him one, with the socket to fit it. After playing hell replacing it, it helped for a day, then it started running crappy again, falling flat on it's face anything over half throttle. They scanned it again and said it was his MAF sensor and sold him one. That helped for about an hour, then back to where it was. I told him scanning simply reads failure codes and he'd probably have to take it to a shop and have it diagnosed through the process of elimination with some resistance testing. But, I gave it a quick look, and went for a ride with him. It was idling weird and inconsistent with the check engine light going on and off. He mentioned he'd had the battery replaced at said part store and the problem started shortly after that. So, I went back under the hood for a look. I noticed it right away when I looked at the battery! The battery is located on the passenger side, back by the firewall, like my Lexus. Probwhy I didn't spot it the first time. I asked, did you replace the positive battery terminal? He said, they noticed it was corroded when they replaced the battery and sold him another and replaced it when they replaced the battery. They replaced the factory steel terminal with a pos Chinese lead one! I drove him to a different parts store, got a steel one, replaced it, problem solved. He threw the old 02 sensor and MAF sensor away. We went back to the first parts store where I spoke to the manager and explained that they had created the problem. He gave them back the lead terminal and they refunded him on the parts the sold(conned him into buying) him. I bet that computer didn't know whether to shit or go blind! 😂 Anyway, good luck with that head, I hope it isn't cracked!
Listening to the audio from your road test I wasn't sure if it was just how the mic was picking up the side exit exhaust but it sounded like an exhaust manifold leak or possibly your bad/burnt valve?
The 2 comments are good possibilities but to come up the spring means the guide is gone and if someone did bronze wall bushings it could have trashed on. Lucky she didnt drop a valve on test ride. Tare down time. Good call kiwi. ❤
Could be a bent valve and, get ready coolant could have rotted a hole into an over ported intake runner. I want to say porting near push rods you have to be careful, bronze guides can shift also. I like to glue them with red lock tight, graphite grease works good on intake valve stems as it stays and counters unleaded fuel not lubing the valve stem. Or "get ready for this one"back in the early '70's Chrysler was going thru dark times. It was not uncommon for them to leave lots of casting clay in the blocks, this mixed with coolant would make an abrasive slurry that may have worn a hole under the spring from the coolant flowing. I have cleaned gobs of casting clay out from behind rotted freeze plugs in early '70's blocks?
@TheGforcead very true but engines have had the coolant left in them for over 20yrs without issues so let's lean on the dark times or guide failure but nevertheless I can't wait to see how this shakes out. 50yrs of engine building this is very odd.
its puzzling it would seem to be coming up around the valve stem but why would it push out with such pressure when its got the exhaust port to escape though easily..... path of least resistance and all that........
@@kiwiclassicsandcustoms9160 Maybe something in the exhaust manifold itself restricting it?
@@kiwiclassicsandcustoms9160 leaking around the valve on compression stroke.
Possibly blown headgsket on the valley side i had a Windsor blow a headgasket externally towards the exhaust manifold side sounded like a chopper yet had no oil leaks or water leaks blew the steel ring of the gasket love ur videos Kiwi from Australia
I think the exhaust valve has been clobbered by the piston and worn out the valve guide. I had the same issue with my 351w.
Good find Kiwi! Hell of a mechanic
What an absolute beautiful car - one of my all-time favorite Mopars. Too bad on the issue, but I am sure she will get fixed up and be back 100%
I did have a spark plug on my gtx that you could blow through, weirdest thing so I kept it to show others. Sounded like an exhaust leak kinda. Anyway I await the diag it's a nice car almost too nice to drive on the street
Yeah the first thing I checked was the plugs but they were good. The noise is definitely coming from under the valve cover.....🤔
Yikes, you can hear the issue when your just cranking the thing. Hope its just an issue with the valve. Thank you for putting out this content KIWI.
Looking forward to what you find in tear down. Such a beautiful car. Too bad something has happened to the engine.
I've had a similar sound when an exhaust valve was split on a 948cc A-series engine, but it could also be a burnt seat, something caught between the valve and the seat or a slightly bent valve even. The A35's engine with the split valve - not certain why the valve cracked / split, but I have heard it can happen when a valve gets too hot or has been burnt for a few thousand miles. Maybe running lean on one cylinder? Mismatched spark plug that's too hot? On the A35, the valve had split all the way from the lip to the stem and there was a 2mm gap at the lip, so she'd been burnt for a while. I don't always hear the hiss around the seat of a burnt valve, but there was a definite hiss like that Challenger's #1 exhaust valve from the one that was split.
A bit of a tell-tale sign that something was amiss with the sound the starter made on cranking the engine over - the stumble on one cylinder. Good catch, my friend! ...and in Typical Kiwi Fashion, near enough isn't good enough and it needs to be RIGHT before the customer gets it back. I admire that ethic as it's one of my own and seldom found nowadays. Taking a bit of pride in your work and ensuring your good reputation by going the extra mile to ensure the long-term enjoyment your customer has with their vehicle by spotting an issue and correcting it before it gets worse and potentially costs more to repair. Good on ya, mate! All the best
Kiwi, given the noise up through the guide, I'd be tempted to pull that exhaust manifold loose, then try your test again. If it's a plugged port/manifold making the guide the path of least resistance, that should change it enough to hear.
Sounds like a burned valve. Had a Metro that liked to do that.
My thoughts too but why would the gases push up the guide instead of just heading out the exhaust port??
@@kiwiclassicsandcustoms9160 Because both valves are closed on the compression stroke, right?
Cylinder head is toast... coolant leak from poor maintanence led to overheating/ hot spots in the heads.Hissing that loud is caused by cracks in the valve seat....spring can be good valve can be good guide can be good..but that loud of a hiss/ compression leak sounds like its going right past the seat through cracks in the head casting chamber itself...probably has cracks in both heads..time to remove and magnaflux
Hopefully not toast as they're extremely rare. I do tend to agree on your cracked head theory 👍
From the back of bleachers: I'm going to with cracked head. It makes no sense if you're losing half your compression past the valve or valve seat - it'll go out the exhaust port, not by the stem/guide, path of least resistance and all that. I'd be looking around the spark plug hole between the valves for a possible crack into the valve guide. Weirder things have happened. How was oil consumption with the crankcase pressurized? Noticeable?
Good job in diagnosing the problem
Quite a head scratcher eh Kiwi. I think you might have to bite the bullet on this one. Disassembly required mate. Can't wait for the update. Cheers buddy.
So a crazy thought, the valve broke and plugged the exhaust port. The only place left for the compression to escape is through the guide.
Sure it's thinking outside the box and no one has ever encountered such a thing but hey ya never know. This is think tank level consulting work! ;)
Considering the quality of the rest of the car, it would be hard to believe that the machine work would have been skimped on. But maybe a knurled guide with the valve wiggle specs just barely within spec (or perhaps unchecked and overlooked) along with the tight lash keeping the valve from seating very tightly thus causing a burnt valve/seat.
I encountered this once on a 305 Chevy. It was a cracked head and the crack went from next to the valve seat up around the exhaust port then continuing along the valve guide.
Won't know until you take it apart I'm curious also
Yep. I heard that on your test drive. Burnt seat and valve. My 68 had 2.02s can't remember ehat 70 had
Burnt valve from too tighter clearance. Good to see you have plenty of work on now you have started working on cars other than Fords lol. And the update will now be part 3... bourbon after work no during.
😁🇬🇸🤘
Cracked valve seat, between the exhaust and intake valve seats is my guess.
My thoughts too but why would the gases push up the guide instead of just heading out the exhaust port??
@@kiwiclassicsandcustoms9160 the crack may run up through the guide?
Great review Kiwi do those mufflers with that 180degree direction change restrict the exhaust flow and limit the hp ? Burnt valve is my guess on #1 cylinder. Looking forward to seeing what you find out
Normal youtube show: BUT OVER HERE WE HAVE A BRAND NEW CRATE ENGINE FROM OUR FRIENDS AT SUMMIT!
Burnt valve and compression slipping by a loose valve guide? That's my guess. Surprised it wasn't pushing oil out of like the breather or PCV system somewhere if that is the issue. Could also maybe be a head gasket blown on the inside of the lifter valley, maybe, but that's probably a bit of a stretch. She is a pretty sweet ride, hope y'all get to the bottom of the mystery soon! Take care Kiwi, and hey Uncle Tony!
I agree its either a burnt valve or a bent one. It could be a cracked head but there would be other signs if thats it.
Cheers 🇨🇦
At first when I heard it had been leaking coolant I thought the performance maybe be caused it to overheat and blow a head gasket causing it to stutter down low. Then maybe a burnt or otherwise damaged valve. Beautiful car, a spell with "doctor kiwi" should make it feel a lot better. Looking forward to seeing the antidote to her feeling unwell.
Kiwi... Looks like a great opportunity to totally 'refurbish' the Cylinder Heads!
.
What a cliff hanger! That would have to be a big hole for air to come out around the valve guide as well as go out the exhaust with the valve open. It would be super weird for the valve to be sealed and the air to come around it in some way. I'm doubting *all* of the air is coming out there but a good bit is for sure so maybe a very roached guide and burnt valve/seat? Once you pull that head I'd guess the problem is obvious.
The only way that could happen is if the compressed air has nowhere to go. It is either escaping through a crack or hole in the head while the piston is coming up to make compression or you heave a plugged header tube and a bad valve seal. If the piston is on a compression stroke, it's a crack or hole by where the sound is. if the piston is coming up to push the exhaust out, then there is a rag or something in the header tube/exhaust manifold port, for that cylinder. Maybe a bent/crushed header tube. So it cooked the valve seal. When running and the exhaust valve opens to let out the very hot burnt exhaust, and the tube is blocked, it makes compression and the least path of resistance is the valve seal. Or if it was ported to much and blew through a thin wall.
It has cast iron exhaust manifolds.
Burnt valve or cracked seat.or depending on how tight they were originally adjusted, a slightly bent valve.
Have the heads been ported? I hope this is not the problem - but I have seen incorrectly or excessively ported cylinder heads crack in weird places.
We'll find out soon enough 😔
Maybe the compression is going out the exhaust, but the manifold has to be off to hear it? Kinda like the valve cover does. Cracked valve seat or cracked valve guide? Cracked head? Small block Mopar heads are notorious for cracking between the valves, but it rarely causes an issue.
Odd problem. I guess the exhaust manifold being on mutes the leakoff much like the valve cover? Valve guide must have gone elliptical... lets blame unleaded gas?
I have a AAR with something like that and it was a cracked head in between the valves
I can't figure out why the gases are forcing their way out the guide instead of just heading out the exhaust port ....??
@@kiwiclassicsandcustoms9160 - I think it's a crack that is next to the guide. The valve is closed on compression stroke so it's sealed from the exhaust port, and the crack is in the chamber and up through the casting to the valve cover area.
@@pete540Z that makes more sense 🤔
If that head needs replacing, it will be hard finding a TA head OR should I say finding the $$$ for that special head!
@@chrisluquette1615 that is a concern!!
Seems like the valve guide would need to be pretty loose to do that. What's weird is pressure follows the path of least resistance, so that guid has to be real loose, or there's resistance where it shouldn't be. Be interesting to see how it turns out.
Did it have the gallop in the cranking the first time you started it or did it develop while you had it?
Yes it did
@kiwi I could hear it was a pot down when you started it. Bent valve
Mr. B. Here ! 🍩🍩☕️👀😎👍. Very informative & interesting ! Great video ! 👀👍👍
Nice trick Kiwi, getting 2 videos by leaving us hanging on these last few mins. :) (of course I am joking, sometimes making innocent little jokes don't always come across when typed)
I am looking forward to the diagnosing & resolving the issue(s).
So THAT's where the loose screw fell to! Or, a bent valve. Happy hunting!
What seems strange is that we can hear the cranking rpm drop and an additional load on the starter when that cylinder is in compression cycle.
Cam lobe worn off? Take rough measurements on valve/rocker travel.
Bent exhaust valve on the #1 cylinder. That's my opinion based on racing 340's since the 1970s. Time for a teardown.
That seems like a good theory but the leaking compression is coming out around the valve stem area not out the exhaust port where a bent would leak it to ...
I wonder if a flat cam lobe on exhaust would force cyl pressure past guide? was lifter noise on 1 exhaust or intake? just spit ballin here
Watch this space !!
Kiwi, please teach Tony about mics and how they are used for sound so we can hear you guys on Wednesdays.
Whatever it is. Hopefully it doesn't require replacing the head. That's an all original car. That would suck. Especially if it was caused by the engine builder. If the valve lash was that much too tight. I'm afraid of what else they could've done wrong. I don't build engines. But when I work on things I'm not 100% familiar with, I look up the specs. Doesn't seem as if that was done here. Good luck Kiwi. And good luck to the owner too. Sounds like you might need it
And those T/A heads are incredibly rare !!!!
On AAR/TA, it's mechanical rockers with HYDRAULIC lifters. If the valve "lash" adjustment is 0.100" too tight", whatever that means to him, he could have bent a pushrod, or possibly hurt the cam. I'm not sure if you can see #1 exhaust cam lobe, because it's at the extreme front, but I'd certainly try to look down the oil drain back hole in the left head and look at the cam lobes. If the valve "lash" adjustment is that far off, I'd also be making absolutely sure the rocker shafts were not installed upside down or something silly like that. I've seen that done, and that can do a LOT of damage.
I would guess a broken valve guide. Or a bent valve that got bumped a valve at float. Did the seat back out or something weird like that?
All the noise is at the valve but how do we know its not pushing into the manifold too? Just wondering.
I can imagine a blocked ex port somehow (not really) but I agree with the burnt seat and or valve...
Did we not see a glimpse of a thermostat valve on the exhaust manifold? If so, that could cause the pressure issue at the valve when cold.
On the passenger side there's one
Nothing found underneath when on the rack so I really expected that some jackass hit you during the test drive ! Phew ! lol. Whatever is revealed that the issue is at least it’s just a mechanical issue from my standpoint. Such a beautiful T/A ! Take care
Seems like it has a gallop to it when cranking. I wonder if that’s the cylinder that’s down
I think so!
The only way compression can escape the cyl at the top is through the valve. Maybe degree the cam before removing the head? I say it is either valve timing, bent, or not sealing when it is TDC! Definitely not great. Since it is not engine wide, anticipate a valve issue.
You can hear the noise when he was pulling out of his driveway.
And during the entire test drive.
Still waiting for the follow up video to see what's happening inside the motor! When will the car be back to the shop?
Next month!
I leaning towards a bad head, maybe it can be remachined, but I would be looking for another 1970 340 head.
The trick is that head is unique to the T/A only. It's as rare as rocking horse sh*t
You can hear it in the cranking speed change/stutter.
The exhaust port / header pipe must be blocked ( with what , or how I don’t know ) . The low compression is because that cylinder is unable to pump ( get air in ) efficiently with a blocked header . The gas escaping around into the valve guide is because that has become the “ path of least resistance “ . It’s being pushed up the guide because it can’t exit through the header
Cool Mopar, 71-72 B Body sedans make great cars
Piece of carbon fell onto the exhaust valve seat? Exhaust valve guide worn or broken?? 🤔
My thoughts too but why would the gases push up the guide instead of just heading out the exhaust port??
@@kiwiclassicsandcustoms9160 yeah, bit of a mystery. Perhaps only some is getting out. A large crack from the combustion chamber to a valve is pretty rare.
@@outlawbillionairez9780 it would be yes
Probably the reason why you had a gasket pushed out on the wet side. Leaking compression into the water side of things, pushed out a head gasket maybe?
Ahhh, possible valve guide cracked from a bent valve pushing compression into the water jacket and out around the seal area? things that make you go hmmmm
All will be revealed as soon as I can get her back in.
Now if they could only find the missing minutes from the Nixon Watergate Tapes!😆
Value flotted and like the bent guides maybeen neralled not replaced 340 rev like 6500 back in the day.
I am thinking a head gasket blown near the valve escaping into the valley.. Its close enough, the symptoms match.
Time will tell
I'm sure you figured it out by now but it may be worth sticking the borescope in the spark plug hole and taking a look at that valve face.
Any Update?? that is a very weird problem and what comes along on the older cars...no matter what brand....
Not yet but soonish
You don't see many T/A's this color, which makes it extra sharp and unique.
Perhaps a bent valve or cracked seat going up thru the guide, but the hiss usually means a poor valve sealing. Either way, the head needs to be pulled.
With the clinder at TDC pressurize the cylinder then listen t see if the leak is coming back through the intake or out the exhaust pipe. Not that it's going to really matter now anyway because you know the head has to come off. The valve is probably warped.
Yeah, gotta go with the burnt valve. You'll also probably find that valve walking around in the guide a significant amount.
I’ve heard that sound a bunch of times on Harley’s with blown head gaskets but I don’t think that applies here. I’m Waiting anxiously to see what is the result. I’m suspect about the tight valve lash. Burned valve combined with bad guide? Is there carbon tracking inside the valve cover?
Yay! I thought I'd never know what the issue was...
It sounds like the too tight rocker arm adjustments held the valve open and it was damaged from not closing.
Yeah bummer on a beautiful restored car. Sounded weird in the valved train when you drove it. Maybe a cracked valve guide or something on the valve. ?
Nick's garage channel had something very similar recently! Unfortunately I can't remember the outcome. Maybe get in touch with him if you know him!
Has it had hardened valve seats installed to run unleaded gas? If not, the valve seat could be ruined, and/or the valve itself burned.
The summary of my detail analysis is that it is BROKEN 💔. BUT THEN I'VE ALREADY WATCHED THE OTHER 15 MINUTES OF THIS
Concise but accurate 😎👍😁
Smoked the exhaust valve and seat from the lash being way to tight. At least it is serviceable and not a cracked head. You do good work and appear to really care about the cars and owners.
Thanks man!!!
Exhaust manifold gasket or no gasket required, but someone put a gasket, And gasket tore or split therefore a leak?
It may have been a "mis-speak" but if the valves were truly 100/1000 (0.100") too tight, there is likely a bent valve. Surprised there's not a LOT of damage in multiple cylinders. Perhaps it was 0.010" too tight?
It was 0.100 ! The hydraulic lifters can cope with that mid adjustment at lower rpm but pump up at higher rpm