.040 deck height vs .040 copper head gasket

[calvinater]

Which is better? 0 deck w/ copper head gasket
Or .040 deck with no gasket ? Does keeping the combustion out of the cylinders help to keep the engine cooler? Thanks
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[nsracing]

The 0.040 copper is more work and more cost. First, you have to machine the gasket so it will not overhang and get hit by the piston. You also have to machine the head so the gasket is just right in there.

The other option is simpler. You just machine the cylinder or case to achieve the 0.040 deck =DONE! And you saved the cost of the copper.

So..pass it around.

[Pruneman99]

With a nice tight deck, you burn won't happen in the cylinder, Quench is a good thing. With a big deck, all is lost. Personally I don't use the the gaskets. I've never had a need. Maybe an all out race engine might be different, but I don't like adding stuff that I don't need. There are a few that swear by the gaskets, some who think they are the devil. It's all personal preference.

[[email protected]]

the deck height and the gasket have nothing to do with one another, other than the actual deck height is increased by the thickness of the gasket.

There is so much misinformation about "zero deck" engines it's sickening. There's no such thing, at least one that will live more than 30minutes that is.

Deck height is NOT the distance from the top of the piston to the top of the cylinder, at TDC.

Deck height IS the distance from the top of the piston to the deck of the head, at TDC.

Sometimes they are the same, but often they are not. Like when you use a stepped head (Ugh), or use a head gasket.
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[mark tucker]

most gaskets are sized bigger than the bore so no trimming required unless your trying to put a small gasket in a big bore, yes use the gaskets, no more work than not using them when building the motor. but the soft empi gaskets should be re torqued after a few heat cycle's( atleast the bottom row on head studs, Ive never had the top ones loosen/lessen) the cb head gaskets are not soft(aka hard) they normally do not require retorquing.but it wont hurt nutten if you do as long as you dont over torque than thats on you. I will not build a motor with out head gaskets unless it;s a rotary engine or...the head don't come off the cylinder.

[DeathBySnuSnu]

I also like the soft copper gaskets.
My engine is nekkid and you can physically see the leaks when at cold start. The soft copper seals it up.
It could possibly be the sub standard (by my standards) of the machine work at that time.

But as far as your question.
It don't matter much if any as long as the assembled deck is right and you trust the machine shop work.

[ach60]

[nsracing]

I am about to build an 'above-deck' engine. I am .0505" above the cylinder.

I already have a set of ledged heads. My plan is to machine some of the ledge to give me around 0.035" clearance.

My question is - would the cylinders be cooler since I have moved the heat area higher in the bore??

Anybody's thoughts on this?

[[email protected]]

yeah but this isn't a V8 forum.

One advantage of the head gaskets is in long stroke engines (84/86mm) you can run a .060" head gasket, and run the piston up into the gasket .020", which gives the piston more cylinder at BDC to support the piston. Effectively making the cylinder longer, without buying custom (expensive) cylinders which require special machine work.
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[fivelugshortaxle]

That's how my 2276 worked out. Piston was .015 out of the cylinder....I used .060 copper for a deck of .045. Worked out nicely. And no, I didn't have to machinee the copper gasket. And personally I like the idea of a little so.ething soft between cyli der ad head for a nice, leak proof seal.
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[Alstrup]

Erhm, a zero deck solution - can - be a good solution in some combo´s. But not necessarily with copper shims. Copper shims work well now and here, and is an easy fix if extra tolerance is needed for stroke or rod change. BUT, EVERY SINGLE engine that I have torn down which had done some miles and had copper gaskets were leaking BAAD! Never never use them on engines that sees a lot of miles. Race engines, fine, since they rarely see many miles before inspection. If you want to take advantage of the small benefit with zero deck and have the deck height tolerance in the cylinderheads, you should machine the step in the head. THEN you have a chance of making a proper seal between cylinder and head. This is the only way the engine will keep stay sealed for a long time.

T

[raygreenwood]

Dang....seems like he type 4 people figured this out a while back.

For engines going long miles...lap cylinders into the heads with XXX valve grinding compound for perfect interface. Make sure your cylinder bores have the slight inside chamfer. Then right before installing heads apply a very thin layer of something like Indian head sealant, gas-ga-cinch or copper coat...basically a cylinder head "shellac"...not an RTV
Very thin transparent smear of sealant.

The sealant does no sealing between the mating surfaces. It forms a ring of carbon shortly after first start up that seals in the chamfer/bevel as it burns. The excess just burns away.

This runs 100k miles easy. The factory had a bulletin out ages ago about deleting the factory head gaskets on type 4. This is not saying head gaskets are bad...just that the stock type 4 head gaskets were a bad design.

https://www.ratwell.com/mirror/www.dolphinsci.com/techbull.html

Ray

[yamaducci]

[FreeBug]

When the factory rebuilds put in head "shims" on the type 1, they were steel.

[vwracerdave]

[nsracing]

I define the deck heigth as the top of piston to the closest part of the head.

The closest part of the head in relation to the top of piston happens to be the flat portion of the head which happens to sit on top of the cylinders. I am only talking about flat piston tops.

So... we measure deck heights from top of piston to top of cylinder. The head is going to sit on top of they cylinders. I will submit that the top of piston to top of cylinder is the DECK HEIGHT.

[fivelugshortaxle]

[dsrtfox]

I think you mean cast iron against aluminum unless you have Nickie's...

[fivelugshortaxle]

[raygreenwood]