COOKED C4 Corvette LT1 TOP END TEARDOWN! Gnarly Damage! How Does This Even Happen?
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- เผยแพร่เมื่อ 29 ก.ย. 2024
- Welcome to another installment on 95 Corvette! I bought this car from the auction with minor front end damage. If you haven't seen the other videos, they can be found here: • Rebuilding a wrecked 9...
I first assumed it was just the accident damage but a little investigation in the first video discovered much more work needed, it had low compression and pushed coolant out! So, as always, a quick fix project becomes a big one. Story of my life!
In this video I tear the top of the engine off to inspect the heads and gaskets as I assumed they were blown. WELL! I was in for a surprise! I did not expect to find what I did, and its the first time I've ever seen anything like it!
I hope you enjoyed the update! As always I love all of the comments, feedback and even the criticism. Catch you on the next one!
-Eric
For someone that supposed to know cars knows the corvettes whole drive train to back wheels to front wheels needs to drop as one unit including exhaust removing 8-12 body bolts
They are a tunnel transmission
This makes corvette so interchangeable
How did you not know that
Are you suggesting I pull the body off of the chassis to pull the heads which took me 3 hours on camera?
This is why mechanics don’t agree with engineers. There is the “get it done” way. And then there is the stupid book that the engineers wrote. Guess which way is the best. Answer whatever way the guy holding the wrench decides.
@@wrecksandtech I think that engineers don't put as much value on stuff like ease of repair and servicing compared to having a more efficient/better system, which leads to certain stuff just being harder to work on.
Judging by your ridiculous comment, you never held a wrench in your hand…
Who pulls the entire body to remove heads? Well, I guess you do/would... Smh
My brother and I would watch your videos and message each other when a new one comes out so the other could watch it. He passed away unexpectedly last week and I miss him a lot. Now I get sad when a new video comes out but it is bitter sweet because it reminds me of him. Thank you for helping me remember him! I enjoy all your videos.
😥
I’m really sorry to read this. 😥
So sorry for your loss.
Condolences my fellow human.
My Family will Pray for You and Your Family.
Sorry for Your loss, we wish You our most sincere condolences.
You got the dipstick out without no damage .
2 torched heads was the price of that miracle .
The GM Gods work in mysterious ways .
Weekly project updates! Wonderful news! Thank you!
The exhaust valve in the head chamber that torched through the head is different than all the others (28:21 min). I think that someone had this engine apart before and screwed something up.
Good catch! I hope Eric comments on this.
The under the car part of the ground me thinks🤣
90s GM engineering at its finest
Possible to weld this head, whwn its alu
Get an old school LT motor they said, it’ll be fun they said… An in-line 6 BMW is easier work on!!
If you were ever wondering why some things cost sooo much to repair…here’s your answer.
I can see where a Chevy flat rate mechanic would be unhappy with working on a Corvette. Everything is a very tight fit, and there's no access panels to help out.
I'm supposed to be doing homework, emails, and looking for work post-graduation. Video gets posted, all that stuff can happen later 😎
Unusual space to burn a head through. Never seen that before. Pistons should have been torched first. Aluminum heads can be welded, but these aren't that hard to find and the aftermarket has better if you went that route.
After 55 years in the auto and truck fields I have never seen a burn like THAT!!!!
@mikebaldwin4229 ,Yeah! That was intense... But aluminum does melt at fairly low temperatures... It first becomes annealed and looses it's tempering at around 475*F. Then it becomes very soft, bends and distorts very easily.... Threads start pulling out of annealed aluminum castings... But these holes coming from the combustion chamber, were caused by detonation... An un-controlled burn of fuel that could be caused by numerous events that quickly develop... But one thing is certain with detonation: Excessive heat either inside of the combustion chamber, outside of the engine & it's cooling system or runaway temperature increases, is almost always a major factor of what caused it... In this case on both heads, close to the same areas of the deficiency that lack proper heat transfer abilities, for the materials being used to harness this much energy release.. Major damage, that probably could have been avoided, by using a more proven method to keep the detonation and the eventual thermal runaway conditions, under control...
@@michaelmartinez1345 but those holes weren't coming from the combustion chamber, they were from the water jacket in the head direct through the gasket to the block.
@@michaelmartinez1345 Seen the same But it was from non gm antifreeze static electricity from spark plug ground
the spark wanting to cross as close to spark plugs as it can
but milage is way higher like 100.000
optispark time
the Dex cool was engineered to disperse the Electrolises
and the aluminum is peeling in layers you can tell
This channel keeps getting more and more entertaining, man. Your content is fantastic. Keep it up. One of my favorite automotive channels these days!
Dude, I’m genuinely impressed with your ambition. To go from rebuilding a Porsche to a Corvette..... just Awesome.
with each upload this editing just gets better and better
Eric Sandler at his finest
I just wanted to say thank you. My wife and I've been watching you since you started this channel and we always enjoy it, you're funny you're clean and I get to learn a lot. Especially the vehicles and engines I don't want to buy. Go Ford!!!
I think that was a regular HG failure to start with, but someone kept driving it hard and what you are seeing is the erosion of the cylinder head by the combustion gasses.
Agree. I would expect piston damage if it was lean enough to torch the heads.
I wonder if somehow improper head bolt torque (on those cylinders) at factory may have played a part.
Um he did say it was in a collision, the cooling system was breached and it ran til it burnt up.
@@nbrowser "Um" he also thought it was caused by a fueling issue, which is very unlikely IMO.
As someone who has pulled heads from a C4 before, I felt your pain quite intimately when it came time for that exhaust to be removed. Excellent video!
I try to watch all of your videos. Not once have I read some one bad mouthing your business. If I need an engine I would not hesitate to buy from you. Carl
After tens of thousands of cars through our shop in almost 40 years, I've never seen something like that on both sides. I'd guess lean running, not bad gas. Maybe a vacuum leak.
It boggles my age-addled mind that you can remember where all the nuts and bolts go when you put these cars or engines back together somewhere down the road. Glad you got new heads for this engine, although I am somewhat disappointed that the dipstick gave up with such little fight.
My thought, as well. Usually, when I take something apart, the bolts are bagged and tagged. Or bagged and zip tied to the part they held in. It takes time, but it is SO worth it. At least for an amateur such as myself.
I thought the same. But if he gets stuck, he could check his video.
Eric's arch enemies are dipsticks. And with reason.
A mid week tear down! What will Eric give us next? I've never seen the kid of damage that this car had. Good luck.
I could be wrong, BUT I don't remember a teardown this last weekend.
@@briananderson8733 There was one Saturday,
Kid of Damage is my new punk band name.
Looks like maybe Nitrous
That block's deck still might be worth checking with a straight edge on those hot spots. Even so, that's crazy!
hmmm.. corvette.. Arkansas... crashed.... sounds like corvette met trooper byrd aka the byrd man. prob a yt video of it.
That's some wild blow out. I've seen some perplexing things under warranty, but nothing even close to that.
Watching you tearing down an engine and it's not even Saturday? What sorcery is this?
I'm really fascinated by this head damage. It looks like highly concentrated heat, like a plasma cutter focused right at those two spots. The rocker chambers look pretty clean though, not like heads from an engine subjected to long term high temperature abuse. This damage probably occurred over a short period of extreme use, some relatively abnormal event for this vehicle, a high speed police chase would be believable.
If I recall, the '95 Corvette used an early OBDII, or OBD1 Enhanced, engine control strategy. It came out during the transition so it's not impossible to think the program may have been less than optimized. Under extreme operating conditions it may have been running some way out of bounds timing and AFR parameters. It would be interesting to know what secrets the ECM holds.
The damage is low in the head's installed position, so if the engine were low on coolant, the high side of the combustion chamber, on the opposite side, would be the first subjected to untransferred heat. The effect would be mooted however if the coolant left the system all at once, like if the bottom of the radiator were ripped out and the engine continued to be run at high speed. Curiously, the damage is toward the center of the block, not furthest away from the water pump and radiator outlet, like the #7 and 8 cylinders would be. Here again, if the system had no coolant at all the center of the engine is where heat would concentrate. Also, the center of these heads is where two exhaust chambers come together, again, more concentrated heat. That all seems consistent with identical damage occurring on both heads, in the same location, at the same cylinder positions, 5 and 6. Combustion chambers #3 and 4 probably weren't far behind for the same damage.
Aluminum liquifies from its solid state pretty fast, just a few degrees is all takes to go from soft to molten. It also conducts heat very rapidly, and in response to heat, it expands a lot. All of this would come into play during a brief period of extreme high temperature operation. Also, abnormally high temperatures would have excessively expanded the heads exerting high tensile pressures on the bolts and spot faced bolt perches. Once cooled and contracted that would have left less yield pressure allowing the bolts to break free more easily during disassembly then if they had been at their specified torque/pressure. We saw evidence of that.
The failure does not seem to be at the thinnest part of the casting, but does seem to be along the most direct route from the combustion chamber to the exterior of the engine. The escaping heat did not deflect and dissipate into the water jacket, it continued on through the next layer of casting ejecting out the exterior of the head. That means the hot gas jet first blew out the bottom of the combustion chamber into the steam port, then focused on the exterior wall until it blew that out, and finally had an escape path to the outside. Wow, crazy sequence of events! Would love to have had an inside view of that happening...
In all it seems like specific mechanical design features, extreme engine operation, a highly compromised cooling system, and possibly unoptimized engine control, all conspired to produce this really weird material failure. For sure I've never seen anything like it, but way cool to see and consider. Thanks Eric, this one's a real hoot.
I am guessing that the head bolts stretched it were not torqued properly. I had a car that kept leaking coolant no matter what I did, chased it for almost 80k miles, when suddenly a bad "exhaust leak" started. I pulled the valve cover off, and there was a busted head bolt, no valve cover gasket (tons of rtv instead) and no exhaust manifold gasket at all. The manifold was sealing from carbon build up, pretty obvious it had been run that way for quite a while before I got it.
Pulled the head off, and it was leaking coolant between cylinders, right where the head bolt was broken. It passed a cold compression test, and on short drives, no problems at all, but it would eat coolant and need topped off every 10k miles or so. My guess is as it heated up, the head gasket would start leaking, probably only under load.
You can see in the video some of the head bolts are really tight, others look almost hand tight.
I don't know why someone would be messing with head bolts on a 45k mile motor, but this screams tinkeritus to me. I think someone pulled the valve covers, started retorquing the heads and forgot two.
Excellent deductions! I tend to agree with your theory. 🤔
If you got that car after it was totaled by the insurance company they probably blue them holes in the heads the outer hole is to round like a torch tip having been a mechanic for over 40 years I have seen this done several times
Yep, at 28:24 you can see the burn pattern coming from the outside to the inside of the head.
Not doubting your theory, it actually makes a lot of sense. But any idea why they would purposely wreck the heads?
I believe you are 100% correct , just like @ the clubhouse said , the burn pattern is totally wrong.Thank you Thomas for your astute observation.
@@jaredbawden6707 they do that so that you can't resell them
@Thomas McNulty I assume this is because it was in an accident? Doesn't make a lot of sense to me if the car was sold as a repairable write-off
14:11 If I could move my hand that fast, I'd never leave the house.
Underrated comment! 🤣
Lmfao
Looks like a nitrous experiment gone wrong.
why just one pair of cylinders then? why not the pistons affected?
@@ghostrider-be9ek Really good question. No material transfer to the pistons. Pistons are mint for the claimed mileage. But what else torches a head like that? I have visions of someone cracking a nitrous bottle into an open intake at wot.....
A very good machine shop can save them aluminum heads. I have seen this a lot on boosted engines. Once you get it back together. Have the tune on the ecu checked (Or Prom) that is a really bad lean spot in the map.
Absolutely amazing that the block wasn't damaged.
It had sacrificial aluminium heads to look after it
Nice work, I have a c4 as well and it is tight for space under the hood, strange damage to the heads thought! Strip down the trashed heads and save some of those valve train parts.
I’d say it’s the easiest car I have ever worked on. Being able to sit on the tire and work is a dream compared to any other car where I am in a standing hunched position. I have a ‘92 6sp 🤙
@@DR.P3RKY you have a point about sitting on the tire! Mine is a 1989 Z51 coupe and they come with the ZF and 3.33 in the rear end.
@@DR.P3RKY Wait until you have to get under it. You do have a point about the fenders being out of the way, tho.
C4 probably has the most aggressive layout of any Corvette. It's like looking at an Indy car.
It also has one of the lowest seating positions of any Corvette while maintaining ground clearance, meaning, it's has a lot of room to be lowered, if someone wants to.
You should rename the channel "Tales of the Dipstick".
You know, I work on my own cars, a '14 Cayman S and an '01 Subaru Outback LL Bean, and for 19 years I drove and worked on an '85 Porsche 928S2 5 speed. I'm an amatuer driveway mechanic, but it sure seems to me that it would just be easier to drop this engine and work on it on a stand.
Pinhole leak in intake manifold gasket? Those two cylinders were on the same plenum, I think. This happened to me on a Chrysler 3.3 V-6.
Interesting failure, one cylinder burned through in each bank, and the piston tops look OK. Did you happen to do an ECU code dump?
LOL - The sound of a socket or wrench clanging as is disappears into the harness/bracket void. Waiting to hear that 'hit the ground' sound is the longest 1.5 seconds of your life.
Didn't need the "Safety Tote" even once!
I am surprised the pistons tops didn't take more damage, they look great!
I have an entire LTI engine short block and heads in my garage that I tore down completely to make a 383 for my 1995 Z28. Then 2008 housing crash, and job market went to crap, and I sold the car to make bills. Still have the block and heads, tore down sitting in a corner of my garage.
hope you r doing well now. i am from far away country, bad times pushed me sold 6 rare cars (for my country), they gone very cheap, now got 20-30 cars for repair-sell. still my heart beat for old ones. but they are now very rare very expensive. job and family first.
yes, as a man never cry for bad things happen, just that cars tear me down.
Im sure I've seen that car before
Or, at least, some parts from it 🤣
Also waiting for the dipstick battle to commence
Odd that there's one dished exhaust valve.
iron has a melting temp twice that of aluminum while also only conducting heat at 1/4 the rate of aluminum while only having half the specific heat capacity as aluminum. So aluminum melts faster, conducts heat faster, and holds twice as much heat as iron. There is a good reason it took decades before engine blocks became aluminum with iron sleeves, iron is damn tough!
That is the dirtiest 49k engine bay I may have ever seen. It seems like it had an owner who was indifferent at best concerning maintenance, which tells me the 49,000 miles were hard ones. Q
Check for evidence of NO2 use I haven't seen many head gasket issues that melt to the outside unless it's a 1 in a 1000000000 and running it with no coolant did that. I didn't see any heat discoloration so that means it happend fast like a blow torch.
I'm 55 seconds in on this video and already thinking the heads are toast, let's see if I'm right....@30:03 Not what I expected, overheating was the initial expectation, but running lean presents entirely different circumstances. Most of the time the exhaust valves heat up and warp or burn.... Going back to watch some more...ok at the end had to go back and watch the first thirty seconds, crash damage, MAS out of whack? Once the system is not OEM spec all bets are off. The computer puts the lotion on the skin or it gets the hose again 🤐
I've never seen anything like that either. Are there any signs of a cheater nitrous system?
My 94 Trans Am I bought new has 337.000 miles on it now. LT1 engine, never been touched, even the timing chain is original. Still runs like new.
Original Optispark as well, right?
@@michaelkrenzer3296 my 95 corvette z07 has just over 40k and it is completely original. I have never had problems with the Optispark, but my water pump started to fail and leaked water onto the Optispark. Fortunately, I caught that within the day of it starting to fail, and replaced the water pump before running the engine again. I know that a lot of Optisparks have been killed by failed water pumps, as the weep hole is just above the Optispark, and the coolant gets past the Optispark seal and destroys the internals. That’s one of several things you have to be vigilant about the lt1 engine.
@@jvaubry Mine was more a tongue cheek comment about the high mileage engine I responded to with no issues. The LT1 has a special sound to it that will always make it...special. both crossfire and optispark got a reputation that is only partially deserved. For GM, both systems were cutting edge with some less than perfect design touches but the systems themselves were not inherently bad. The Doug Nash transmission I have a harder time with.
I have an 87 with the 4+3 and can concur that the ratios make no sense and the shift feel is like a John Deere tractor.
@@michaelkrenzer3296 No, its on its 3rd.
sounds like a great bit of luck eric and i am tipping my cap to jeff for setting you up with a good set of heads, thanks to you both for keeping another rocket on the road
I can admit when i did head gaskets on my old 5.7L vortec suburban it took me two frustrating days to get the dipstick tube back in there.
These videos are getting so good 👍 easy to follow but gets to the point of what's going on
What makes your videos fun is that you are doing the work.
I've seen a ton of C4 videos and the person only explains the process. You're doing the work and talking us thru the process. It looks complex till an expert. Shows us it can be done.
I'm grateful for your channel and knowledge. (:
i owned a 94 6 speed 87k spun a rod bearing - omg 9 hours to pull engine - then got a 39k engine and it had a broke valve guide - have fun and enjoy
When I finally have the money and knowledge to ls swap my Jeep commander the old 4.7 is yours. I’d love to see you tear it down.
from my VERY novice perspective; would all of that been easier to do if you had pulled the engine?
Removal of the heads would have been easier but removal of the engine would require all the work shown here plus more
You took something apart mid-week, Your the man.
I haven't a clue what the original problem is, but it must have been running like shit.
And didn't happen at idle.
I think at 49K I would still put a new set of mains and big end bearings in it. Probably a set of rings as well.
made my back hurt just watching !!
20:50 - Cameo appearance by...
*drum roll*
the dipstick!!!
curious about what cause this. seems very interesting. fuel must affect others too, i think. lean maybe injector fail or ignition.
Ohhhh, I wonder if the driver chip for those cylinders FI units is the same. Why weren't the other cylinders torched? But also everything else in engine looks fine - usually too lean will scar or mark the valves and pistons but they looked fine.
I'm sorta leaning (haha) towards a head gasket issue, maybe paired with improper headbolt torque on the affected cylinders.
@@tedsaylor6016 i am europan GM mechanic, especialy OPEL omega (same with cadillac catera) up 94 models injectors have seperate chip, but i heard first years of 90s have common chips. if so, broken wire or chip maybe, just as like you, never see lean damage like this. maybe that part of head alu was so thin to hold. GM 3.0 and 3.2 v6s have sodium valves, handle much heat.
@@tedsaylor6016 and after open hole can the water clean piston?
I wonder if there is a poor tune on there, or a tune more or less requiring 94+ octane and someone ran 87 instead...
Cooked the heads but saved the engine, and someone sent you new heads! I call that a win-win! Hope there are no more big surprises with this vehicle.
I'm not sure if it was bad gas because I've seen the same thing happen on a old Honda Accord and basically the customer overheated the fuck out of it but I believe whenever it was overheated it was just so hot that it predetonated far too much in burned a hole in the side of the head
Man, in the 21 years between when my '73 was built and this '94 they sure managed to cram a whole lot more stuff into the engine bay!
Man, I was so pumped I I thought this was part two of this c four corvette project! I want to see what ends up happening to this car so bad it is one of my absolute dream cars
If only the real world had fast-forward for all the time-consuming boring stuff!
During filming how many times did you hit the top of your head on the lift above? 😮 Good tear down diagnosis. -Glen
A mid week tear down and loosening the manifold with supreme editing that takes me back to middle school… it almost feels like my birthday!! 🎉😂
It's a well know fact that the 'Italian Tune-up' doesn't work on US market cars ...lol
All factory sparkplugs from GM have a white dot on the tip where you plug in the wire. I couldnt tell in the video
When a coroner is forced to do emergency surgery in a field hospital.
"Damn it, Jim! I'm a doctor, not a..." - Deforest Kelley
If your getting surgery from a coroner, it is a strong indication that you are dead, and certainly not an emergency!
Love seeing a skilled person! I really like your tear downs, not at least that you understand how to dose timelapse so nice. Thanks a lot for hours of entertainment!
i have a set of heads for this if you need them
On the plus side, you can find some great aftermarket heads for that motor. If I had to guess, somebody used old gas and ran the AFR into the 15s. I'm surprised it didn't burn the valves.
N ,😊’,.
AFR into the 15s isn't bad; wait till you see it in the 18s!
@@silicon212 haha. I bet. I came of age in the turbo world where 12 is getting too lean to make good power. I remember running an SRT4 at around 9psi of boost and getting an AFR average of 10.7. I can't imagine 18...
@@americansmark the first "fast" car I had extensive experience with was a kid was an SRT-4 and the blinding display of the AFR gauge reading single digits feels very familiar
@@Onewheelordeal I remember that too. I can still smell the unburnt gas coming out of my buddy’s (insanely loud) side exhaust. We used to joke that his was an mpg gauge. I thought he ran too rich but what did I know. Fun times. I miss my SRT-4.
I'm in the middle of changing the motor in a 1st gen s10 and watching this makes me glad it's not a Corvette.
A parts tray would stop me worrying about those bolts sitting there;)
I have one of those Rubbermaid plastic carts. Two levels, no sharp edges and easy to clean with a pressure washer. Never stoop to pick up tools or parts again.
I felt the same way. If that had been me, every one on them would have been knocked off.
Any chance you still have those wheels and would be parting ways with at least one of them!?!
Yep
I found, when working on vettes or ETypes taking the front tires off makes it easier. Whe you get older working leaning that far over plays havoc with your low back.
I noticed that they were in the way as well. For the 30 seconds it would be a wise move, hindsight 45/13
I wonder what the inside of the iron headed LT1 in my 96 Buick Roadmaster sedan looks like with over 173k miles.
Probably like new!
A copious amount of wrenching
Eric, several people mentioned that the exhaust valve in the burnt cylinder is different from the others. Can you confirm that and do you think that had something to do with the failure?
these vids are my favorite way to relax after a 14 hour shift with a cold one 🤘🏾. you sir are awesome keep making great videos!
That's not lean. That's the two hottest parts of an LT1. That's reverse flow cooling for you. The block is made to run warmer than the heads.
Once they get air in them and let go that long they really cook. Run a straight edge on that deck. To melt that coolant sensor is around 350 degrees. Those heads in those spots were probably over 1300 degrees.
An older non-reverse flow small block would lift the heads in the middle and burn out the gaskets between the two center cylinders.
Check the pistons for excessive rocking. In the higher mileage LT1 when I was at a car service company, the piston slap at around 650-700k was bad. Those were the iron head LT1.
Hope the piston skirts and rings are ok.
They drove it like they stole it.
Nothing is easy to work on, on a corvette,
I’m doing all 8 body mounts, without removing the body, on my wife’s c3 this weekend.
Even the rear end pinion seal replacement, was no fun!!!
Great video, I feel your pain, and also your passion! It’s why we do cars!!!
Great video as always!!
Just swap in a LS1.
I have seen "Wire drawing" in heads before.(mostly in valves.) I have repaired heads like that before. It is Alot of work and only if the heads were "Unobtainium" would I try to fix another set.(you need a Tig welder and an oven to repair those heads.)
I didn't watch with enough detail to see if it still had a steam pipe crossover going from head to head in back of the engine? Was it present and not plugged up?
Having a torched head like that means something was severely wrong. Hot spots on the head due to lack of coolant, lack of cooling system pressure, no steam pipe, plugged steam pipe, bad fuel pump, nitrous, or any combination of those factors. Never seen an lt1 head torched like that and i've played with them for many years.
I think a different camera from usual was used.
Great video!
As soon as I saw that hole I thought "injector failure" or lean condition. But both sides? I'd also be inspecting the harnesses.
You all can keep these newer car nightmares. I'll take my daily driver 57 year old Chevelle 6 banger any day. By the time he finds a way to get the heads off I can have my total engine swapped and running again if needed.🤣🤣🤣
AT 28:21 that echaxust valve in the damaged chamber looks like it has a concave top. Am I missing something?
Good catch! Flat vs. concave.
That’s why I love pre 80’s cars none of the bs… so simple to work on
Where are you with the C4 Vette?
New heads, headers( instead of manifolds) new set of fuel injectors and you will have a great time. Better yet..... top end kit!!!
My fav channel 😊
Each video is so amazing, you’d make a great teacher