Hey Guys: The 65 satellite 440/512 race car was doing great all season- then it wasn't.
End of a 6.32 pass, it didnt want to idle down. Kill car and restart- no idle issue.
Checked "everything " for vacuum leaks- none found.
Checked carb- noticed some black material starting to form on carb blades, but it seemed "hard" would not easily clean off with carb cleaner- then they called our index.
Car repeated the run with a 6.33, idled up again coming down return lane.
we won the night with that pass, took pics, loaded up.

Next race was to be in bad air,i wasnt going with the car, threw a tune in it- car didn't run for crap, thought: how the heck did i miss a tune that bad?
Guys just backed up an index , did well.
Pulled data when car got back- tune wasnt that bad, but drivers bank and little lean and should not have been- what the heck?
Pulled carb, black material on edges of blades might not let carb blades close correctly and, perhaps its a intake gasket- sure enough, pulling oil through intake bolt holes going through to rocker area- but carb has this oil all up in it- sigh,
Tear Carb down, give it a good bath, get it ready, new intake gaskets, use thread sealer on bolt holes- we should be ready to go, cars sounds "right again".

we go to races, have a t&t friday night - jetting not good, get jetting squared away- car will not run the number, in fact, it keeps getting slower, even when Da's are getting better.
Check everything, check everything- rinse and repeat several times- plugs look great, carb clean, afr's are dead nut for both banks.
Qualifying saturday- car makes a decent run on Q1, slows down again on Q2- but we cant find a dang thing causing it- now im pulling out whats left of my hair- I dont miss tunes very often and unusual i cant see in my mind whats not right or, a good theory anyway. Plugs staying nice.
Back up an index, slow car down, make rounds, car starts belching smoke out the valve cover breather on passenger side bank after the run, when we kill the car- tiny bit on passenger side- but i notice both filters are now oil soaked- i think we have lost ring tension , cracked a ring- but the plugs look fine! We decide to try and make a round, maybe two to protect our points lead, lose out but, its ok, we were in first place, now 10 points behind- not a problem.

Get car home, do a compression check- passenger bank is 200, 200, 208, 198, drivers bank is 197, 187, 187, 200- so, ok, maybe, maybe we have lifted the head between 2 and 4 a little but, nothing for sure.
Pull the rockers, do a pressure test at tdc and btc .

Number 1 -5% loss
NUMBER 2- 10% LOSS
NUMBER 3- 10% LOSSS
But, on cylinder 1. with no valvetrain on the car, i can hear air leaking
Number 2- more air leaking
Number 3- same as 2

air not in intake, not in header- - its coming out the lifter galley - you can actually feel the air moving if you put your hand between the pushroad galleys.

We pull the heads- cannot find even the slightest indication of a bad head gasket, and i mean- nothing.

These are cometic mls gaskets- can this leak be between the layers and just gets worse with heat cycling?
Needless to say the heads are going to machine shop for a cleanup for straight/flat but i sure would like to know- for sure- whats happening here and, im wondering if crankcase pressure "pushed" oil up the intake bolt holes, wetting the inatke gasket, softening it and thats how we pulled in the vacuum leak that pulled oil up into the intake/carb?

Im just puzzled how the head/ gasket/block can look that good, but be leaking and, plugs stayed looking great. The oil is what was screwing up the tune- i get that. I figure the smoking was because the carb was no longer pulling the crankcase pressure out , it had to go somewhere, yet i still don't "know" why it was smoking after we kill engine unless its draining back oil into a cylinder one we kill it and lose crankcase pressure.

Can these MLS gaskets breath between the two layers , let oil flow back and yet still hold almost 190 lbs of cranking compression?

Puzzled guy that just really wants to know.

Thanks guys- hope you are all well.

strickly just thinking out loud/giving you a BTT. Are the rivets out of the MLS gaskets?

It sounds like ring sealing issues to me, sorry

Thats the only way air is going to get in the crankcase.

If it were my motor I would try some good composition head gaskets. Like a Fel-pro. Cheaper and easier than tearing motor down to check rings. Myself I don't care for for mls gaskets head and block surfaces have to be perfect or they will leak. Good luck and let us know how it works out.

When you say it smoked out the breather when shut off, not running? The only thing I can think of after shut down would be water vapor. How did the cylinder walls look after pulling the heads? My son had a 340 many years ago. It leaked compression pressure into the lifter valley between the head and the block. Dave Koffel taught me to loosen each head bolt after torqueing and retorque. The bolt/nut will always turn further the 2nd time. It fixed the issue on the 340. Done it ever since. I'm curious why all the tune up/jet changes?
Doug

Did you ever leak it down before the issue to compare?

Dave

Yes, we have done leak down prior, no, its not the rings, cylinder walls are fine, crosshatch looks good.
After doing some more research and making a couple calls, Apparently this IS a known issue and , yes, MLS gaskets can leak between layers if the head lifts slightly .
Top of the gasket/head leaks into the lifter galley area around/through the head gasket at the top of the block .
Never ceases to amaze me the odd things i run into.
Now, that said- if the heads don't show to have lifted between 3 and 5 ,,,, im back to square one with this troubleshooting nightmare.
Rings appear to be fine from an upper inspection, walls all look good and no- the smoke is not steam- steam doesn't fill the breather filters full of oil and there is no indication of water vapor in them, the oil or oil in the water.
Near as i can figure- engine is turned off, back pressure stops, oil rolls back down the leak path and lands on hot piston or, something HOT and viola, the smoke comes back up and out the breather.

Best i can come up with- everything looks great, tests great except for hearing air come out the lifter galley with a pressure test and its not coming out both sides per say- its coming out right above 3 and 5. You can stick your finger in there pretty good and feel it better- stick a piece of paper in it and it will blow the paper around.
Going past the rings, it would be pretty well diffused to the whole internals i would imagine.

Update for whoever it might help: Just got off the phone with cometic: Yes, the MLS will leak between the layers if you have a slight head warpage issue develop and/ or a head stud/bolt not holding torque when hot.
Not unusual for there to be leakage between the layers when these things happen- but- the gasket doesn't "blow", it just leaks.

FYI

Did you re-torque the heads after a heat cycle?

MLS gaskets are made from stainless steel, and while very strong, stainless steel is very hard, they do not conform to anything, head and block must be machined very smooth and flat. I know MLS gaskets are all the rage right now, but this old school guy likes copper head gaskets with an O-ring in the block. Top Fuel still uses copper head gaskets, and money is not an object, so why do they use them? They work. I have seen MLS gaskets leak water between the layers as well. MLS gaskets were designed to fix the OEM issues with head gasket failures in the 80's and 90's which they did.

This may be a stupid suggestion but old school test for rings was to do a compression test and then do another with oiled up cylinders to seal the rings. Is this approach of any value with a leakdown tester?

I have seen broken compression rings pass a compression & leak down test, but when running they would expand & seal & the let loose & blow oil out the breathers

Yes.Heads are headed to machine shop now. Cometic also suggested new head studs or bolts since we have everything off. Seems they have found some studs not holding torque when hot on employee race cars , may be happening with head bolts. These head bolts are several years old.
We have never checked torque at temp.

JWB : Thats pretty well in line with what Cometic said as well. We did go back and check between the layers and, sure enough- full of oil. Appears to have leaked a tiny bit of water and you can see the "air path" that was taken between cylinders.
Heads are headed to machine shop now to get them back to straight/flat.
We are going back with the felpro for the last 3 points races, then its on to building the new aluminum block.
The cometic was nice in that we could run a tighter fire ring .
I do find it interesting the gasket didn't "blow" in the conventional ways but instead just leaked a tiny bit between the layers.
Made trouble shooting a bear though.

6 pak: Im honestly not sure, never tried that with a leakdown test.
I don't think it would really, in that the escaping air pretty well tells you where the problem is.

csk: Exactly ! Thats why i thought we had lost tension on a ring. This engine has the pistons out of the hole over ten thou , had just made a 7k pass and i figured we got a little extra piston rock up top and cracked/broke a ring.
I figured a cold compression test would show a hole down 30-40 lbs - was shocked when that wasn't the case.
Of course im tickled pink we don't have to pull the engine out with only 3 points races to go.

My thoughts are it is more than a head gasket. Good for you if that's all it is.

we got other head off and that gasket was actually worse- but we didn't do a a leakdown test on the passenger bank and definitely had oil hitting the two center cylinders- not a lot, but some.
Hoping this is all there is.