Engine Gunk? Is this a problem?, pics.
Thread Starter
Instructor
Joined: Aug 2001
Posts: 167
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From: Dover NH
Engine Gunk? Is this a problem?, pics.
I started with replacing a bad water pump; next thing you know, the heads are off. Has that ever happened to you?
The car has 35,000 miles and has sat a lot. I have owned it about 8 years and only put about 3,000 miles on it.
When I pulled off the valve covers, intake manifold and timing cover, I noticed this sort of baked on oil sludge.
The crankshaft though, looks good with an clean, oily glow.
The end goal here is to replace the camshaft, clean and paint up the heads. I don't have much engine building experience. Should I worry about the grime on the block, or just let it be? Also, what about the pistons, should i clean those up? If so, any best way to do it without getting contaminates in the engine? Should i rotate the engine to TDC on each piston that I am cleaning?
I've been around this forum for a lot of years now, and its always turned out to be an amazing resource.
Thanks,
Jamie
The car has 35,000 miles and has sat a lot. I have owned it about 8 years and only put about 3,000 miles on it.
When I pulled off the valve covers, intake manifold and timing cover, I noticed this sort of baked on oil sludge.
The crankshaft though, looks good with an clean, oily glow.
The end goal here is to replace the camshaft, clean and paint up the heads. I don't have much engine building experience. Should I worry about the grime on the block, or just let it be? Also, what about the pistons, should i clean those up? If so, any best way to do it without getting contaminates in the engine? Should i rotate the engine to TDC on each piston that I am cleaning?
I've been around this forum for a lot of years now, and its always turned out to be an amazing resource.
Thanks,
Jamie
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The lower end looks pretty clean. The heads look like they have been 'cooked'...a few times. Is that a problem? Well, if it runs OK, not at the moment; but wait a while and things will begin to happen.
Since the heads are off, it would be best to have them reworked: cleaned, valve seats ground, new valves, valve seals, springs. Or, you can just put them back on and hope for the best...
Since the heads are off, it would be best to have them reworked: cleaned, valve seats ground, new valves, valve seals, springs. Or, you can just put them back on and hope for the best...
Safety Car
Joined: Mar 2009
Posts: 3,558
Likes: 4
From: Oakland California
The lower end looks pretty clean. The heads look like they have been 'cooked'...a few times. Is that a problem? Well, if it runs OK, not at the moment; but wait a while and things will begin to happen.
Since the heads are off, it would be best to have them reworked: cleaned, valve seats ground, new valves, valve seals, springs. Or, you can just put them back on and hope for the best...
Since the heads are off, it would be best to have them reworked: cleaned, valve seats ground, new valves, valve seals, springs. Or, you can just put them back on and hope for the best...
Better save some time and money, in the long run, and get those heads reworked.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Looks like a motor that has had a lot of short trips and has had very few long runs. It gunks up like that because it never gets all the moisture and combustables cooked out of the oil that acumulate when it sits
Le Mans Master
Joined: Jan 2007
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From: Omaha NE
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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Or a motor that never had it's oil changed during those 35,000 miles...
Race Director
Joined: May 2007
Posts: 11,334
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From: Out of Site...Out of Mind. Corvette: anything else is just transportation.
St. Jude Donor '09 thru '20
The lower end looks pretty clean. The heads look like they have been 'cooked'...a few times. Is that a problem? Well, if it runs OK, not at the moment; but wait a while and things will begin to happen.
Since the heads are off, it would be best to have them reworked: cleaned, valve seats ground, new valves, valve seals, springs. Or, you can just put them back on and hope for the best...
Since the heads are off, it would be best to have them reworked: cleaned, valve seats ground, new valves, valve seals, springs. Or, you can just put them back on and hope for the best...
You've got a second vote on that.
Sense you've got it apart, do it right.
Thread Starter
Instructor
Joined: Aug 2001
Posts: 167
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From: Dover NH
It wouldn't be the first time that "one thing has lead to another". I'm pulling the heads apart today to take a closer look and start to clean them up.
What about the block? Is that cleanable and should I try or leave it alone?
What about the block? Is that cleanable and should I try or leave it alone?
Drifting
Joined: May 2006
Posts: 1,480
Likes: 2
From: Circleville Ohio
Vader Vett
If you start cleaning that intake area,bad dirt & stuff will get all over I wolud clean lightly dont look for shiny.
Replace your lifters .Cam And timing chain. seals are A gimmie.
Feel the inside edge and all the way down to the piston any bad edges at the top and any scratching in the bores ????(run the pistons up and down to do this on each bore).
Any edge or scratching and well,,, sit down That whole engine will need going through .I cant tell you the guys that do it half azzed and two weeks after the motor s back in the car he s got A bad Vibration.Do not let this happen to your re-build Get someone who knows A little more that you an see what they think.
Hows the rest of the car ?
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Verdad Gallardo
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
Well, with the heads off, you can't make the check you really need...a compression leak-down test to check the piston ring integrity. You could make up a flat plate (about 1/2" thick steel) to seal off the top of the pistons (one at a time) to do that test. There's no other way to check the rings {that I know of, anyway}, and that is an important test if you want to leave the bottom end alone.
A [very] rough 'gauge' of lower end wear is the amount of ridge/lip at the top of the cylinders. In 30K miles, you shouldn't measure much more than .003-.005"...if the oil has been changed frequently. If you see more than .010" ridge/lip, you might want to consider a full rebuild, as the cylinders coudl stand to be rounded up again.
A [very] rough 'gauge' of lower end wear is the amount of ridge/lip at the top of the cylinders. In 30K miles, you shouldn't measure much more than .003-.005"...if the oil has been changed frequently. If you see more than .010" ridge/lip, you might want to consider a full rebuild, as the cylinders coudl stand to be rounded up again.
Melting Slicks
Joined: May 2009
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2024 C3 of the Year Finalist - Unmodified
I was in the same situation as you 6 years ago. Leaking water pump led to timing chain and gears, new pan gasket and motor mounts. The car never performed well, developed a progressively louder ticking and the rear main seal started leaking. Ended up pulling the motor and finding a broken top ring on one cylinder, two stuck lifters and a wiped cam. Wish I had rebuilt it back then, because a 35 year old motor with very low mileage isn't necessarily a good thing.
If you plan on keeping the car, rebuild it and you get to enjoy a fresh motor now and possibly for the next 35 years. Try to enjoy the climb up that slippery slope of "while I'm at its." If you are going to sell the car, slap it back together and let the next guy worry about it.
If you plan on keeping the car, rebuild it and you get to enjoy a fresh motor now and possibly for the next 35 years. Try to enjoy the climb up that slippery slope of "while I'm at its." If you are going to sell the car, slap it back together and let the next guy worry about it.
Team Owner
Joined: May 2001
Posts: 87,375
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From: Western NY
I know this will raise a few eyebrows, but if you're on a budget, and a total rebuild isn't a viable option at this point, you could buy a can of "engine flush", and a stiff parts cleaning brush, and attack the lifter valley, to get the heavy junk out....assuming the oil pan is off, and you have a drip pan to catch the crud that washes down.
Thread Starter
Instructor
Joined: Aug 2001
Posts: 167
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From: Dover NH
The car's mileage is pretty well tracked through the service records (I'm the third owner). Plus, as I've gone through it, you can still see the original parts, like riveted ball joints and rotors.
The cross hatch pattern looks pretty good and I'll measure the ridge once I get my hands on a dial indicator to see if there are any issues with the cylinder wear. I feel pretty good that the rings are ok; the car ran well before I pulled it apart. It did burn some oil, but that was likely because of the leaking valve seals and valve cover gasket.
My plan is to clean up the heads, valves and block the best I can and reassemble. I don't have an engine lift to pull the block out, so I'll have be careful as I prep the block in the car for new gaskets. Long term goal is to continue to enjoy the car, but hopefully drive about 2k to 3k more miles a year instead of the 500 that i've been averaging.
So, next question.
Do I go with another metal shim (0.018) or change composite head gasket (0.028)? The car originally had a metal shim, and with already low compression ratio (1975 L48) I am reluctant to install a thicker composite gasket, but would appreciate any feedback.
Here's some more pictures of the car and some other work I've been doing,
The cross hatch pattern looks pretty good and I'll measure the ridge once I get my hands on a dial indicator to see if there are any issues with the cylinder wear. I feel pretty good that the rings are ok; the car ran well before I pulled it apart. It did burn some oil, but that was likely because of the leaking valve seals and valve cover gasket.
My plan is to clean up the heads, valves and block the best I can and reassemble. I don't have an engine lift to pull the block out, so I'll have be careful as I prep the block in the car for new gaskets. Long term goal is to continue to enjoy the car, but hopefully drive about 2k to 3k more miles a year instead of the 500 that i've been averaging.
So, next question.
Do I go with another metal shim (0.018) or change composite head gasket (0.028)? The car originally had a metal shim, and with already low compression ratio (1975 L48) I am reluctant to install a thicker composite gasket, but would appreciate any feedback.
Here's some more pictures of the car and some other work I've been doing,
Thread Starter
Instructor
Joined: Aug 2001
Posts: 167
Likes: 0
From: Dover NH
Apparently, the pictures look worse that it really is. When i showed the pictures to the local, reputable, engine shop, the owner said it looked pretty normal and that it should clean up with just a rag.
I opted to have the shop clean the heads and do a 3 angle valve job. They did it all, new seals (umbrella type?), spring shims where appropriate, all for $300. All valve guides were ok and the magaflux was good. I painted them today.
I was able to clean the lifter valley pretty easily with a rag and some clean oil.
Looking forward to buttoning this back up again; just a few more things to go through...
I opted to have the shop clean the heads and do a 3 angle valve job. They did it all, new seals (umbrella type?), spring shims where appropriate, all for $300. All valve guides were ok and the magaflux was good. I painted them today.
I was able to clean the lifter valley pretty easily with a rag and some clean oil.
Looking forward to buttoning this back up again; just a few more things to go through...
Safety Car
Joined: Jul 2005
Posts: 3,697
Likes: 833
From: WI
Honestly, I didn't think it was that bad for an older engine. I would have done the same as you. If the engine only has 35k and let's face it, it's probably going to get driven not more than 5k milies per year anyway, why spend money on rebuilding an almost new engine. Put that money into other areas like getting cad parts replated (so they look new again, the carb professionally rebuilt .. or any other interior or exterior parts that need to be upgraded. Put some Mobil 1 in it and take it on some long weekend trips (get the oil circulating for a while) and over time, what I've seen is the synthetics will keep the engine nice and clean. Nice work and car BTW.
Mark G
Mark G
Last edited by Mark G; Aug 7, 2010 at 03:07 PM.
Racer
Joined: Jan 2009
Posts: 482
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From: Near Round Top (pop. 90) Texas
Do not use convential Pennzoil, and if you do, be sure you never go over 3000 miles.
The additives will crystallize when it breaks down.
Plugging up the oil system and collecting in the lifter valley and heads.
Ask anyone that has rebuilt a few engines.
Pennziol=junk
The additives will crystallize when it breaks down.
Plugging up the oil system and collecting in the lifter valley and heads.
Ask anyone that has rebuilt a few engines.
Pennziol=junk
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
Do not use convential Pennzoil, and if you do, be sure you never go over 3000 miles.
The additives will crystallize when it breaks down.
Plugging up the oil system and collecting in the lifter valley and heads.
Ask anyone that has rebuilt a few engines.
Pennziol=junk
The additives will crystallize when it breaks down.
Plugging up the oil system and collecting in the lifter valley and heads.
Ask anyone that has rebuilt a few engines.
Pennziol=junk
Pete
. Let us know how everything else goes.