Headgaskets

http://www.cometic.com/

+1 on Cometic MLS

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+1 on Cometic MLS

My machine shop ( https://www.facebook.com/pages...ning/160369280651807 ) recommended Cometic C5871 Multilayer Steel Coated Gaskets. Not cheap, but supposed to be superior for sealing aluminum heads to a cast iron block.
http://www.jegs.com/p/Cometic-...ets/2849496/10002/-1

first step is to measure the both the block & cylinder head deck surfaces for warp / variation

the 1013 gasket is a steel shim type gasket, it has a wire sealing ring around the chamber where the 8347 is composition construction and does not have the wire sealing ring

composite gaskets are able to tolerate more warp / variation than steel shim gaskets, not sure what the MLS will do if the surfaces are less than perfect but they do require a specific machining finish quality

http://www.crankshaftcoalition.com/wiki/Head_gasket

getting back to my first comment, if the engine won't hold a composite gasket look for the reason why because the composite gasket is the most forgiving, the hardest to knock out unless the problem is detonation or just plain too much darn compression

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Not cheap,

Look to be about $100.

Standard run about $40.

$60 more.

If your engine build somehow was to come in at only $6,000 (please tell us all your secret), buying the Cometic gaskets bumped your cost an entire one percent (1%).

Our cars are worth $40K-$80K.

I think we could all afford an extra $60.

Heine, have you found the reason for the blow out? So not to experience it again, even with better gaskets? Is timing too advanced, detonation? I know you wrote timing was set "by ear"? I suggest a little less advance at least to start with when you get it assembled...

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Originally posted by No Quarter:
Heine, have you found the reason for the blow out? So not to experience it again, even with better gaskets? Is timing too advanced, detonation? I know you wrote timing was set "by ear"? I suggest a little less advance at least to start with when you get it assembled...

Mikael,
I did find the problem today. One of the brandnew TFS heads are warped !!! 0.25 mm (0.01") - I just don't get it. The engine has NEVER been hot, and the ARP bolts are tightend per description. So I have to get the heads maschined, and assemble it all Again with new and better gaskets. Just got an email from Dan Jones, and he recommend Victor-Reinz 3502SG head gaskets. Maybe I should try them ?

Just wondering if you re-torqued the head bolts after the new engine was heat cycled a couple of times?

Steve

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Originally posted by T.Solo:
Just wondering if you re-torqued the head bolts after the new engine was heat cycled a couple of times?

Steve

No, I did not, as the spec. sheet from TFS said that I shouldn't
But I think I will do that when I assemble it all Again !!!!

Quote from the TFS Spec. Sheet:
It is not necessary to re-torque the head bolts after
initial break-in. For head stud installation, follow the head
stud manufacturer’s instructions.

I used the Edelbrock heads and their installation instructions stated:

"ALL ENGINES - A re-torque is recommended after initial start-up and
cool-down (allow 2-3 hours for adequate cooling)."

I checked mine and only got 2 or 3 bolts to move ever so slightly.

Steve

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Originally posted by danishcarnut:

quote:

Originally posted by No Quarter:
Heine, have you found the reason for the blow out? So not to experience it again, even with better gaskets? Is timing too advanced, detonation? I know you wrote timing was set "by ear"? I suggest a little less advance at least to start with when you get it assembled...

Mikael,
I did find the problem today. One of the brandnew TFS heads are warped !!! 0.25 mm (0.01") - I just don't get it. The engine has NEVER been hot, and the ARP bolts are tightend per description. So I have to get the heads maschined, and assemble it all Again with new and better gaskets. Just got an email from Dan Jones, and he recommend Victor-Reinz 3502SG head gaskets. Maybe I should try them ?

Change gaskets. The point of Fel-Pros is that they don't need re-torking. Even with the head a .001" out, the head gasket should be able to handle that.

Send a nasty note to TFS about their lack of quality control on their finished products but you'd have to prove they delivered the head that way.

Your engine builder could have decided to shave the heads and it could be his machine that is out of whack.

The Reintz gasket materials was always recommended by the racers on the Clevelands and will give you the ability to torque the bolts tighter.

What happened to your engine would make me question everyone who was responsible for putting it together.

This engine is not notorious for blowing head gaskets at all.

If we were talking a Ford 427 with aluminum heads, then that's a different story.

There is a science to building a head gasket for the match of aluminum head on iron block.

The head actually floats on the gasket and the gasket has a controllable amount of crush to it.

Normally I would have recommended the Fel-Pro blue head gasket to anyone. Now I have to keep this in the back of my mind?

I have to admit that I didn't check the heads before assembling. We just took them right out of the box and mounted them. So I can't prove anything. All I can do is to get both heads shaved, and reassamble it with the new gaskets. But this time I will re-torque them, for sure !!! But it will ofcause raise my compression rate, witch is allready high (10.8 : 1), shaving 0.01" of the heads will give me 11.11 : 1 compression rate. That's high, but hopefully I can still run on pumpgas (Shell V-Power)

Can you just mill a warped head? I'd imagine the cc per chamber will vary. or is it so little it doesn't matter?

You do not need to mill .010". A good mill will take the.001 off. Even if you wound up cutting off .002", so what?

From memory, on a 289 head with an existing 53cc chamber, mill off .010" reduces the chamber volume by 1cc.

Check the specs on the compressed Reintz gasket. It may be thicker than the Fel-Pro compressed?

You will not know if the engine will ping on pump gas until you try it.

Actual measured 10.3:1 will run no problem here with 93 octane and iron heads.

Aluminum heads do not allow you to run higher c/r than iron though. It is the compressed pressure of the fuel that you are attempting to manage.

Aluminum and iron with the same compression ratio will create the same pressure compression to the fuel.

I wouldn't be surprised if you need to limit total advance to 32 and slow the curve down so that it is not in full until about 5,000 to 5,500 rpm?

Best of luck. Sometimes it's better to be lucky than good.

Heine, there's one thing you can check: is the block you screwed the heads on perfectly square? Alloy heads are soft enough to permanently bend if torqued onto a warped block.
Second, it's often possible to 'correct' alloy OR iron heads that are up to 0.060" warped (sometimes, even more).

In a nutshell, you lay a straightedge across the full length of the head and by using shim-stock, you determine how bad things are warped. Then add 1/2 the thickness of the warpage to each end of the head, torque it down with all the bolts on a deck-plate. Set the whole thing in a 450F oven (no more!) for at least 4 hrs, followed by VERY slow cooling back to ambient.

This is common practice at big engine shops, who may be able to tease a warped head back to flat without any machining, using multiple treatments as above. There's an article on this featured in the Dec 2014 POCA Newsletter in more detail. Might save you having to ship parts back & forth across the Atlantic.

Note- warn your lady first: using your home oven this way will 'flavor" your dinners for a few days, and women often get grumpy when their pot-roast tastes like engine oil....

Steve, if so then, you torqued them improperly. It is necessary to back off each bolt and torque them making certain that you hit the torque spec while the wrench is moving. You will not get proper torque by simply turning a torque wrench on them while already tight. You may still have under torqued bolts on those bolts that did not give.

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Originally posted by danishcarnut:
I have to admit that I didn't check the heads before assembling. We just took them right out of the box and mounted them. So I can't prove anything. All I can do is to get both heads shaved, and reassamble it with the new gaskets. But this time I will re-torque them, for sure !!! But it will ofcause raise my compression rate, witch is allready high (10.8 : 1), shaving 0.01" of the heads will give me 11.11 : 1 compression rate. That's high, but hopefully I can still run on pumpgas (Shell V-Power)

You could always open up the combustion chamber with a little grinding then "CC" each combustion chamber for equality.
Would rather with today's gasoline have less compression ratio than too much...Mark

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Originally posted by 1Rocketship:

quote:

Originally posted by danishcarnut:
I have to admit that I didn't check the heads before assembling. We just took them right out of the box and mounted them. So I can't prove anything. All I can do is to get both heads shaved, and reassamble it with the new gaskets. But this time I will re-torque them, for sure !!! But it will ofcause raise my compression rate, witch is allready high (10.8 : 1), shaving 0.01" of the heads will give me 11.11 : 1 compression rate. That's high, but hopefully I can still run on pumpgas (Shell V-Power)

You could always open up/increase volume of the combustion chamber with a little grinding then "CC" each combustion chamber for equality.
Would rather with today's gasoline have less compression ratio than too much...Mark

good idea, if CR is an issue then Furnace Straightening is worth looking into

Many good advises here. Thanks alot !! This community is great. I think I will dig in to the Straigthening process. But that deckplate have to be quite thick to withstand the warped head, I think ? Is the article from POCA visible somewhere online ? I'm not a member

We have a special owen on my job, that I can use. I have used it for wrinkle paint before. It can easily be turned up to 450 degrees F. So all I have to do is make me a deckplate and torque my head down to it.

quote:

Originally posted by danishcarnut:
Many good advises here. Thanks alot !! This community is great. I think I will dig in to the Straigthening process. But that deckplate have to be quite thick to withstand the warped head, I think ? Is the article from POCA visible somewhere online ? I'm not a member

We have a special owen on my job, that I can use. I have used it for wrinkle paint before. It can easily be turned up to 450 degrees F. So all I have to do is make me a deckplate and torque my head down to it.

If the oven was large enough to fit a block. Could not the head just be bolted onto an engine?!
Can't imagine a torque plate being stronger than torquing the warped head to a Cleveland block...Mark

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I used the Edelbrock heads and their installation instructions stated:

"ALL ENGINES - A re-torque is recommended after initial start-up and
cool-down (allow 2-3 hours for adequate cooling)."

I checked mine and only got 2 or 3 bolts to move ever so slightly.

FWIW, I re-torqued my Edelbrock heads (ARP bolts) after the first week of running the new engine and got NO movement. All bolts were still at perfect torque.

Rocketship, sure you could use a block, but unless its first verified to be flat, it could create more warpage problems than what you have now. Used blocks are routinely out-of-plane both lengthwise and crosswise, and overheating them causes even more movement, so most shops true up blocks before using them in performance builds. A steel or aluminum deck-plate on the other hand is a shop tool and normally doesn't see engine heat or vibration.

If you do have to machine the heads Cometic gaskets are available in custom thicknesses to help restore the lost dimension.