Suspenseful Porsche 911 Carrera Engine Tear Down Findings - Part 2
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- เผยแพร่เมื่อ 9 ก.ค. 2024
- Watch the tear down of my Porsche 911 Carrera engine as I investigate what's wrong with cylinder #5. I knew the engine was bad when I bought it, but I wasn't sure if it was a broken head stud, bent valve, bad valve guide, cracked head, or broken piston? Now I know after my longest video to date! Whew, thanks for watching!
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Here's part 1 in this series - • How To Remove And Diag...
Part 3 Engine Bay Clean Up - • You Might As Well Clea...
Part 4 Porsche Valve Job - • Unlocking Peak Perform...
Part 5 Exhaust Stud Removal - • Difficult Exhaust Stud...
Part 6 Engine assembly - • Satisfying Porsche 911...
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00:00 Introduction 911 Engine Tear Down
00:17 Bad engine symptoms
02:21 Remove intake system
03:48 Remove exhaust system
05:40 Leakdown Test Results
09:28 Removing fan shroud
12:23 Compressing chain tensioner
17:05 Cam timing check
18:58 New cutoff tool used to modify wrench
20:15 Removing rocker shafts
26:56 Removing camshaft
27:43 Removing cam tower
31:39 Removing cylinder head nuts
34:49 Cylinder and piston inspection
35:42 Cylinder head leak found
36:40 Exhaust valve removal from head
38:12 Worn vavle guide inspection
40:29 Valve guide clearance measurement
44:21 Problem with Porsche Valve guides - ยานยนต์และพาหนะ
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This one ended up being a MEGA video at 46 min. I tried cutting it down more, but I decided to leave some of the detail that goes into these engines. As of today's release date, all six heads are in the hands of a competent rebuilder. Happy holidays everyone!
I like your plan! The factory makes decisions based on cost vs profit. They also have a repair department to keep busy. Using the best parts is the best solution!
This is true!
I had multiple 914 6's and installed 911s engines, all styles of the bathtub models but never a targa as they flex without a roll bar. Nice job.
hi Tom. I like your valve spring removal tool... would love one myself! Couple of things I've garnered after building a few of these... the rocker shafts do sit very slightly proud of the cam tower.. when you re-assemble, and line up the grooves to be centered, you'll see there is a slight bevel on the edge of the shaft, the base of which just sits flush with the camtower.. and so the outer edge sits slightly proud. Then when you add the conical bush, it sit's completely proud. With removing the head studs nuts, they all "scream"... it's the heat cycle that sticks them. We use assembly lube when new, to get the correct assembly torque but after years of use, they take lots more to remove. If a stud is going to break, it's going to break. I don't bother with pb blaster or heat.. just a breaker bar!
Thank you. The rockers seemed very proud to me, but I've looked at how those grooves fit within the tower. As long as the grooves are centered that's what's important.
Seems like these non-californian cars are hard to take things apart. I've never had a 356 based engine with head nuts so difficult to remove.
Thanks again for sharing your experience.
Great video Tom. Valve guides were still an issue on some 993s as well. Love the DIY nature of your videos, you're an inspiration. Merry Christmas!
Yep, I wish I knew first hand what they were thinking. Not saying Porsche wasn't trying to push the envelope, but sometimes we learn the hard way. They might have optimized heat transfer, but missed out on longevity. There's a lot that goes into these choices. some good some bad. Toyotas and Chevys don't have this problem, ha ha.
Another great detailed video! Always fun to watch. I agree, the best plan it to replace parts with the best available that ones budget can handle. Well done.
Thanks Jeff. Parts for old cars is always a gamble.
On my '77, 2.7 liter engine, which the "7R" case was notorious for pulling the head studs, I did the time-cert modification and installed (if I remember right, this was a couple decades ago) the turbo studs. I took my heads to Engine Builders Supply (they were close by) and they sent them to CMW for overhaul (guides, springs and set the spring tension, etc). I would also recommend replacing the exhaust studs in the heads. They are subjected to a LOT of heat, and differential metals can either snap the studs and/or pull the threads in the heads. READ UP on timing the cams again after you put it back together. It's easy to do, but it's complicated.... Oh... how I miss it!
I have a spare 77 engine and I'm hoping all the issues you mention like pulled head studs are a thing of the past.
My ‘87 Carrera smoked very badly when I bought it in 1997. It had 68k street miles, stock motor, stock exhaust, never been opened. Waiting in line at the hand car wash on Sundays, it spewed plumes of blue smoke, it was relentless. I thought for sure my valve guides were shot. Then I began tracking the car and I removed the stock exhaust and catalytic converter. No more blue smoke! I have a theory that the stock U.S. exhaust with cat retains excessive heat and damages the exhaust valve guides. Mine, mysteriously, appeared to “heal.” 50k redline track miles and two decades later, still going strong with good leak down #s. I suspect the exhaust valve guide materials is fine until you added U.S. emissions and a catalytic converter.
I wish mine was a self healing Carrera! My previous Carrera came to me with a punched out cat and I had to source another to pass smog. I noticed the cylinder head and oil temps were noticeably higher when running with the cat. I think you are right that the higher temps are hard on the valve guides. I've also read that cylinders 2 and 5 are the hottest and mine failed on number 5.
My cat is allegedly sitting on a shelf awaiting the next smog date.
Great video. Thanks for taking the time and putting in the effort to share this information.
I love these videos of old Porsche stuff. I do the newer and you do the antiques. Keep up the great work.
Nothing more important than keeping the valve timing correct. I've had 16 911 and 356 and never had a valve guide issue. Lucky me. Great techniques.
Lucky you. Do you use marvel mystery oil in your gas?
Nope, just good oil and white gas. Remember that?
White gas is for camp stoves. No?
AMACO, The ariginal no lead gas
Another great video!
Great video! The info you provided really helped me understand the inner works of the motor.
Excellent video! Subscribed
Great video and thanks for sharing, merry Christmas to you and your family
-Spanky
Definitely one of the most comprehensive and detailed video about a flat6 overhaul !! Congratulations and I wish you all the best for 2024 👍👍
Thank you, Happy New year🎇
Great video, Tom.
I'm very impressed by,and jealous of your knowledge and skill base. Excellent
Thanks for your videos. I just bought an 87 carrera. I'm a DIYer myself. I worked on my 2 Ferraris for 20 years which I recently sold and moved to the Porsche world and restored a car many years ago.
I agree with you on replacing with the best part available. No mgf has a perfect record. My 84 Ferrari BB 512i had a diff carrier from the factory which were welded and that weld could fail. I replaced mine with a billet piece.
I hope I don't have to do anything as involved as this, but if it is ever necessary, then I also would be tearing the engine down.
You will have a fantastic car when it's all back together.
Again thank you for sharing all this information.
Welcome to the Porsche world and I hope you enjoy that Carrera! Please reach out if you'd like a particular video about this car.
A great video. Thank you for sharing it. I'll be watching for the rebuild vid.
So Merry Christmas to you and your family.
✌️ Peace from Melbourne Australia.
Thanks! Merry x mas!!!!
Great video
Thanks!
Good catch Tom. I know you'll make it purr. Best of the season to you and yours.
Let's hope so! Happy holidays 🎄🎄
I enjoyed you're video
Good work and I completely agree with your plan going forward. My first thought was that the last guy found a cylinder or 3 that needed new valves or guides and did only the ones that weren't in spec. So #5 used to be in spec but had wear and continued to wear. Perhaps the owner at the time told the mechanic to do it as cheaply as possible as he was going to get rid of the car. Well, that's as cheap as possible even if it doesn't make sense with all the work it takes to do the worn guides. It's not that much more to do them all.
You are absolutely right. When the heads were bead blasted at the shop they noticed some of the guides were original Porsche guides. They are a darker color and harder to remove according to the owner.
The only reason for not doing them all is budget. I'm pretty frugal, but not that cheap, ha ha.
And a Merry christmas to You and Your family.
A comment on the rocker shaft seals. They were not used in the design. They came out during RSR racing. A new gasket kit does not come with them. It’s a good idea to use them.
Thanks, I mistakenly thought these rocker seals were standard for 3.2L like the Turbo valve covers.
Seems like they should be there. I will install them in this week's video.
Great vid, Tom. I'm with you in that I would have rebuilt all 6 heads, too. But, like you, I would not just go all in on a full top end/bottom end rebuild "just cuz I'm in there". Not too difficult a job to get to where you're at, though you got a treat with the exhaust removal, LOL. That's the great thing about doing this kind of stuff yourself - you're not paying exorbitant labor costs for some other guy to mess it up. Nice job!
Given the low and gentle miles these cars experience today, I totally agree.
Why build another 300k mile engine when I will probably put 30k on it in my lifetime.
Very enjoyable video Tom. I love the way you just get on with it. I do have tool envy....
Thank you, Happy holidays.
And the best to you & family
Hi Tom, great video as usual! Just something of note, there are no seals on those rocker shaft pinch bolt areas. That’s only a race car part. I believe they use them in the RSRs. But regular 911s never had them unless a later engine builder added them as a preventive measure.
You are right, I checked the parts diagram and the seals aren't on there. My other 3.2L engine had them, so I kind of figured the later cars got them too. I'll be adding them to this engine as it seems to be a good idea. They are generally referred to as RSR seals like you say. Thanks for bringing this up.
@@GarageTimeAutoResto Hi Tom! The RSR seals are definitely a good idea to stop any leaks in that area. While you have the cam towers off, I'd recommend that you slightly chamfer the edges of the rocker pin bores, otherwise the fairly sharp edges will most likely damage some of the 12 seals when you install them.
Cool, thanks Lucas. My other engine has them.
New guides,check seats, recut seat if poss or replace
relap valves 👍🏻👍🏻👍🏻
Yep, already done
th-cam.com/video/sYTEi3XTGqo/w-d-xo.html
Head stud was on the 2.7 ltr mtr, remember when Porsche went to the 3 ltr they went to a new case
Please post the shop that will do your engine work. Enjoyed this video and look forward to your other posts! Well done!
Yes, will do once I get the heads back and look them over. I don't want to mention them until I'm happy with the work.
Hi Tom, it would be prudent to pull the chain housings and replace the chain guides since you’ve gone this far. You’ll also be able to make sure the housings have a proper seal. Too bad about the usage of the RTV on the valve covers. I have picked chunks of that crap out of the oiling holes in Porsches before.
Thanks for the suggestion, I'll definitely look into it.
That was something much harder than RTV. Hopefully it's not lurking in other places. I'll flush the oil cooler and see what comes out.
Never boring over at your garage Tom. Sorry about your engine situation but selfishly I am hoping to benefit from your misfortune. This video is very timely as my 86 engine is burning oil and I do suspect it will be worn valve guides. Would appreciate any details about the replacement guides you use and the machine shop & costs . I’m thinking that shipping my heads to a Porsche specialist /experienced machinist will be the best option as there are not any competent shops in my area that I would trust. Thanks so much for taking the time and effort to share your experience with us. Looking forward to seeing your next video.
Happy to help. I don't view this as misfortune. It is more par for the course with old cars.
I'm a sucker for a good deal and I knew going in to this car that it had a problem.
I'll share the machine shop details in the next video after I get them back.
Hi, no question in my mind you shoud use Technovance Valve guides, I owned and operated a Machine chop in Phoenix AZ and that's what we always use. They are incredible.
Br Peter
Thank you for the recommendation from something new who knows. Also thanks for your repair service. Fewer and fewer shops are doing this important work
Great informations. Inches are a little bit confusing to me. Greatings from Bavaria.
Inches are confusing, but it's all about breaking old habits.
Always like watching engine tear downs and fault finding. Question:- as the engine was out and you found the bad valve guide, did you check any of the other cylinders and heads. Would have hated to assemble everything then find out another head was bad.?
All heads have been reworked
th-cam.com/video/sYTEi3XTGqo/w-d-xo.html
I should have waited for the next episode. I should have realized due to your attention to detail
Excellent breakdown... While you are in there, Lol. How about a smaller combustion chamber with 993 cams to spice it up a bit?
Now we're talking. This video was too long, but I did cc one of the non leaker heads and got 91.4cc.
I would love to change cams, but I need to get this car running and renting again without headaches. I'm afraid the motronic might freak out if too much is different. Have you done this?
I have not and you are correct about the software being necessary to correct the tune.@@GarageTimeAutoResto
@@GarageTimeAutoResto I think 964 cams are as big as you can run when staying with the Motronic. Might be worth giving Steve Wong a call as he is probably one of the most knowledgeable guy on the planet for these, and not far away from you!
Agree, I haven't met Steve yet, but I've heard great things about him for sure. Apparently he is the same autocross circle of friends, so hopefully we cross paths soon.
no seals go in the rocker shaft grooves as far as I know. You actually locate the rocker shaft by feeling for the grove with a feeler gage to locate it correctly. When you tighten the shaft it swells up slightly and this makes the seal. Setting the valve timing with the dial indicator all had to be done at a terrific rate of speed as a dealer mechanic. Factory assembly quality in the seventies was not good. Often they came from the factory with loose head studs.
That's correct, a common upgrade is called the RSR seals which do help with oil leaks in this area.
I mistakenly thought that Porsche put these on later engines.
Like this mystery tear down videos. If you keep all head studs, when you reinstall heads after rebuilding is the torque of head bolts same as if new studs were in place? Porsche torque procedure is two steps, initial torque, then with dial gauge, a certain amount of turn? Is that still the process for you as the stud threads would not stretch like they did new?
I prefer a standard torque of 24 ft-lbs.
The reason is that I want to retorque them again anyway after 500 miles. The angle method isn't very practical.
The studs do not permanently stretch, so either method would work with reused studs, but I prefer the older way.
HEY MERRY CHRISTMAS
Observing your meticulous disassembly and finding the root cause was bitchin. Mahalo
Thank you!
They’re not stuck or over torqued. It’s the break loose moment! Normal.
Nicely done! Enjoyed the length of the video. No issue to my mind in using a superior material where available. Are worn valve guides a big issue on 3.2's in general? Heat is the enemy? Merry Christmas and thank you for all the great videos this year.
Yes, the heads run pretty hot. Some materials are better than others. Valve guides became a problem in the late 80's and 90's. This coincides with Porsches financial troubles.
After I wrote you, I did some research on the topic. I was aware that 2.7s suffered from the problem (among other things) but not the later 3.2 and even 3.6s! My own 3.0 had a top end rebuild not that long ago (previous owner), but I'd have to check the invoices to see what that exactly entailed.
Reassembly technique on the last top end rebuild seems to have been a bit sloppy. The rocker shafts, overtorqued or loctitie head bolts, etc. may have caused some top end oiling problems that contributed to the valve guide wear. Good luck avoiding all the while you are in theres on your project.
I'll do my best. Not sure I follow your logic about oiling problems associated with locktite or rocker shaft torque
.
BTW ARE YU GOING TO DO THE OTHER SIDE I MEAN THE ENGINE IS OUT
Yes sir, all 6 heads have already been delivered to a good machinist.
owned a German cylinder head shop for 30 years, porsche valve guides are junk.. Canyon engine components has best guide made.
Thank you for this! Very helpful to me and hopefully others. As much as I love Porsche some stuff is junk.
$8k price drop? To pull motor and “replace” 1 head? Dayummm.
Does that seem like a high number? I was happy with it. Some people pay $15k for a top end rebuild.
I can’t imagine paying for a valve job that needs to be redone after so few miles. Glad it only needs a valve job. Could have been much worse. Is that car one of the special anniversary models?
I know, these engines are great when well taken care of, but this one is a disappointment. So many mistakes that could have been avoided.
The anniversary model was one year only, had special paint and seats. Not too many made.
I don't think this is an anniversary model, but I don't have a Porsche certificate of authenticity either. It does have a lot of options.
millimeters work easier
I dont think you found the leak.
You will find all 6 exhaust valve stems will have that amount of play.
Its normal for air cooled engines to have sloppy ex valve stems.
I measured the clearance in this video and it's way out of spec. Not sure what you are talking about.
@@GarageTimeAutoResto Yeah but all 6 valves will be the same out of spec. Why does that valve leak but the others dont.
It doesn't leak combustion pressure from the valve guide it leaks from the valve seat. This happens when the valve guide can't hold the valve concentric and the seat wears rapidly.
Millimetres? God no 10s and thous please
With respect..
If the guide is worn..
The valve will seal better...
Strange...
It will have a larger seating angle..
But will allow more oil to pass..
Further investigation needed..
Ok, I think I showed that the valve seat is leaking. Water is pouring out. You can't expect the valve seat to live very long when the valve is not centered.
Sounds like the owner didn't use premium fuel and did not use the proper valve guides
.... remember, there's no lead in the fuels......keep fixing....use proved modern materials.....
Great point. I typically add marvel mystery oil in every tank. Not sure if it helps the guides or not
This is not a job an amateur could try to do. Only for experienced mechanics , I would say
Using cylinder leakage you should have been able to find the problem
The cylinder leak down test did identify the problem. Once you determine the valve seat is leaking the only way forward is to remove the head.
Here's the thing I learned about the leak down tester. When the engine was in the car with full exhaust and catalytic converter the air sound coming out the exhaust was barely detectable. There is a long distance from cylinder #5 to the single exhaust outlet.
The air rushing around the exhaust seat vibrates the head fins and kind of sounds like a leak at the head to cylinder interface. So the air sound can be a bit tricky to diagnose where it's coming from. The closer you can put your ear to the problem area the better.
I'm putting my money on poor craftsmanship on the previous shop's "rebuild" Doesn't look like they replaced the valves and those valve guides don't look like they have only 20k miles on 'em. The locktite on the head studs and not enough sealant on the cam boxes indicates someone with little to no knowledge/experience with these motors. Also barrel nuts on the cam boxes look like they're in the wrong spot. I'd hope for a look at the rebuild sheet to see what they replaced and charged the PO for. if they charged them for rings you're going to need to look again. Those alusil cylinders don't just a take a new set of rings and seal.
Should I publicly shame the so called prestigious LA area shop?
@@GarageTimeAutoResto your call to make. If I were in your shoes, I'd definitely contact them and ask WTF happened and see what they say first. Then make my decision. I've been doing this for 30 years or so and take my reputation very seriously. What you showed was pretty poor work. No professional Porsche shop should be putting out that level of work and charging for it. Maybe make sure the PO didn't do it himself and tell you they did it or some such thing.
Oh, I have receipts. This shop often posts about DIY jobs gone wrong.
@@GarageTimeAutoResto That's pretty damning then. What about the rings like I mentioned about? Did they claim to re-ring it as well or just a valve job?
No new rings. Only a few valve guides were changed. This was confirmed by the machine shop as the original valve guides are much darker in color.
they are not loose they do not have to be so tight it is not American
I hope the end result is in better repair than your shop is.
I obviously have the wrong idea of Porsche guys like me having an organized work area.
If I were your friend I'd yell at you like your dad to "CLEAN YOUR ROOM UP!!"
I don't know if anyone has said this before... but your video is very over-exposed and washed out, your audio is way hot and you're clipping audio on the high end. I think there is interesting stuff here, but this content is difficult to watch for mostly technical reasons (technical filmmaking). However, as an enthusiast of engine mechanics... the details matter. Technique matters. The bulk of your viewers and potential viewers are here to witness the art of working on particular engines. IMHO, your experience will be better received with more professionalism in mechanical process as well as appearance-- working on a super dirty engine in a cluttered garage, with low grade equipment and tools, diminishes the experience greatly. Watching you grind the Allen-key with goggles that scratched-up made me want to leave the room. You will have a large following with some improvements. Seriously... you are so close to greatness but its tough to take you seriously when you and everything else looks like a mess.
I'm working on improvements, thank you.
It's very difficult to work and be the film crew/Editor all at once and actually get projects done.
Dirty engines and dirty tools kind of come with the territory of these old cars.
Keep watching and you will soon see a clean engine and garage.
So an amateur worked on this engine
All work was performed by "professional" shops. The car was purchased from one of them and I have receipts.
@GarageTimeAutoResto If the mechanic is not factory trained they are not professionals
Some independent shops can be good if they only work on Mark of Porsche
Sounds like whoever put in the guides either used sub par parts or did not know how to do the work
A VW Beetle wearing Running Shoes. Who cares !