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Tom_Overfield

Head gaskets differences

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Hi Folks,

As a couple of forum members know I have been fighting a set of aluminum heads that weep a couple of drops of water at the top of the head gasket between the head and intake. It never does it hot, only after the engine cools down overnight, then on inspection I find the drops of water.

Both heads were resurfaced flat before installation I might add.

I replaced the gaskets and carefully torqued the heads and even smeared a slight amount to Permetex #2 around the water jacket holes on both side of the head gaskets. Started up, warmed up, cooled down and re-torqued and next morning same thing, just a couple of drops of water same area on each head.

So this morning I am sitting there scratching my head wondering what else may be causing this. I had several sets of head gaskets and they were all the same with the exception of a copper set I had, and those had smaller holes for the top area water jacket holes that have the weird shap to them.

So I opened up one more set of head gaskets and lo and behold I found that even though they were the same brand and had the exact same part number, the holes along the top edge were smaller. Here are some photos of the two different gaskets and you can see on the gasket with the larger holes how the water found its way out. The larger holes are 3/4 inch in diamater and the other ones are 1/2 inch. It would be natural to assume that the gaskets were made with larger holes for cooling issues but if they don't seal, then they aren't much good in my opinion, does anyone know for sure?

The photos are all of the head side of the gasket with the exception of the one with the number of 0008, that was the block side of the gasket.

Tom

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Tom, what's the brand name on the gasket(s) with the large 3/4" holes across the top?

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Tom, what's the brand name on the gasket(s) with the large 3/4" holes across the top?

Afternoon Dee,

Both gaskets are Felpro, same part numbers.

Tom

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I think I would increase torque setting by at least 10..different style gaskets, studs with resistance.studs no bottomed out....deck surface warpage....I blew gaskets between 10-12 several times with aluminum heads..so till kids out of college, we run iron smoothed and buffed , numbers gound off painted aluminum ..(poor mans chrome)

-----.Felpro in the 1990s re cast our beloved v-12 gaskets with larger holes.. look in your twotz indexes has been discussion / debate

but, no question that the reissue is better. I was able to gather my stock pile and return them to my federal mogul rep and get the "new" new ones...I am not certain how to tell diff on packing..poss date..your small ones are the old style

The holes need to be large enough, but small enough to direct coolant to rear of engine...

I think all the old heads to be marginal ..the old aluminum alloy is weak..get new repros if your gonna drive it..or do irons like me..and forget about it

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A very good friend of mine is a cylinder head gasket engineer at Federal Mogul (who own FelPro). I've sent him a link to the thread and hopefully I can get his feedback on both the weepage issue and maybe a little background on the gasket changes they've introduced on the V12 set over recent years. Most company's will keep a record of engineering changes - but typically not for long on how/why those changes were implemented. The details tend to get lost over time!

He's currently travelling out of country on business, so a reply might be a few days or a week or two in coming.

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Thanks Jim,

It will be interesting to see what his take on it is. I just spoke with Earle Brown and he informed me that sometime in the past, several members thought the cure to overheating in the V-12 was to increase the size of these two passages in the headgasket. This information was given to the manufacturer and the holes have been 3/4 inch ever since. Matter of fact, the factory even agreed to exchange the older style for the new at that time.

Tom

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Jeff,,I agree with you on the old aluminium heads being a royal pain, but then again I am a stubborn old guy who loves a challange. Plus at $1850 a pop, well,,I can do a lot of work for that much.

Tom

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I tried gasket shellac...silicone, modern mopar- gold aerosol headgasket sealer (for neon troublesome headgaskets) I tried headbolts instead of studs..

finnally, i installed iron heads..torqued to spec..then run and retightened with my 3/8 ratchet as tight as i could...I have been almost 10,000 miles with screwing with it...

I would love to know how folks keep aluminum heads tight with 45-50 ft lbs cold...I know specs are important .........but??

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Well Captain Tom, I should have kept quiet...yes yes been told before...

low coolant, high oil level. coolant blowing out right bank dual pipe...right gasket blown between center cylinders..

(my pic too big for now) Seems the center stud 1st one to torque is in to a waterjacket, and has been pressurized by

compresion and seeping coolant into cylinder for a while..plug looks ok, cylinder was firing..piston top clean as a whistle..."steam cleaned"

ok...Hey Peech!! talk to me..Head is off. chkd for flatness..gonna shave a .010 to clean and then??

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If the head is "flat" and not warped at that center stud hole I would remove that center stud and check the block for flatness in that area. You may also have a hairline crack ( valve seat area)? There is no open water pass-thru between the head and block at the center so it's hard to believe the "water" is coming up around the stud and then going past the head gasket...but who knows?

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I just went out and checked another V-12 that had the head off and it does not appear this stud is in a water jacket like others are, as Dee said, so unless the head has a passage between the water jacket and the hole for the stud, it isn't getting water that way. All I can think of would be to have the head checked for being flat, surfaced if needed, clean everything and reinstall.

I did install the old style gasket on the passenger side head and after four heat and cool cycles and tightening four times when cold I think I have the problem solved, no more seepage visible on the outside of the gasket anywhere. I'll keep my fingers crossed.

Tom

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I'm gonna seal threads on suspect studs..and jimzeffer fixed me up with nos copper mccord gasket.. My gaskets always seem to fail around stud, due

to material deterioration, (paper gasket)..I have iron heads..so no issue with metal gaskets...I have never used 'em before..always "fiber" style due to alumheads and fact that coppers arnt made anymore..

question..copper or metal gaskets are they really tougher????????

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Jim;I'm assuming that You mean "Copper Clad" when You say Copper Head Gaskets .. ?? Am I correct ??

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Yes they are copper clad. fiberous material in between but, the copper seems to me to be more resistant to decay from liquids of any kind, ?

I guess they stopped making them due to the trend for aluminum parts vs the old cast iron they were designed to seal..

here is similar only not copper ..tin??

what do you think..those who have used them??

Edited by Mssr. Bwatoe (see edit history)

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Jeff,

I used them on the orignianl cast iron heads I used to start my engine after I first rebuilt it. They never leaked a drop and when I took the heads back off, they looked good enough to reuse. If I was using cast iron heads and could find a set, I would use them over the fiber gaskets in a heartbeat.

Tom

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I guess I'm lucky because my aluminum heads were one of the few things that *didn't* leak. I also used the Felpro head gaskets. One thing I noticed is that my 37 block didn't have the same number of holes as I suppose later blocks did -- perhaps they changed it somewhere along the line to improve cooling?

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heads were not flat, I'm pretty sure that was the issue...torque and clean hope for the best...I think the

metal gaskets will be better....

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look at the ngks i ran since last.. I read thatthey were hot and burning rich..any suggestions about

carb jets??? I want to build a spare carb, with right stuff, I do have true duals, which believe leans it out??

but they look dark...cylinders had what u see, except the steam cleaned #6..

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Jeff, I see the gasket accually failed near the head stud to the right of the center one. It's near the water passage so purhaps it was the cylinder head? I still would check the block surface in this area just to be sure. The head gasket may have been the culprit...manufacturing flaw? To me your plugs and cylinders look pretty normal for a good running V12 engine especially considering the fuel we have to use these days. The standard main jets used in the '40-'41 06H carbs were #54 and I don't think I'd go any leaner. The post war carbs had #57's and were richer, maybe one of the reasons (other than weight) the pre-war cars got better gas mileage? I think I'd stick with the standard econimizer valve ( rated 7.5 in/hg) also.

Edited by peecher (see edit history)

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I put 75 miles on the car, lef side new style felpro, right side 1950's copper clad asbestos..smaller

holes on copper ..45 miles chk torque no change end of day still ok, gonna chk cold his am..

Interesting observation, coolant temp rad 165, front of felpro head ft 165 rear 180

heat on copper head r ft 174 / 181 The temps are closer in range on more restrictive gasket..is that maybe why it was made that way?

This is after 1/2 hour heat soak, (i was hot and went into the ac re-hydrate)..Coolant full

in radiator , I think over filled, almost to ledge in the radiator neck..water never bubbled or

even showed movement...Big diff..pressure must have been escaping from that spot for long time..

Here is what I was doing...N-S had a company picnic of some sort, and this was the feature..i got a chase car...

http://www.youtube.com/watch?v=hENJTzQfxEQ

Edited by Mssr. Bwatoe (see edit history)

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