Copper head gasket question

Not a dumb question. The seam, actually the entire gasket, does move against the head and block, so most people prefer them seam up, as they believe the 0.0005" imprint left is easier to remove from the head by re-machining it than to deal with the imprint in the block.

I belong to the other camp of rebels and prefer my copper seams down against the block. The thin siamese area between 1-2 and 3-4 actually flexes during hard throttle and I find superior sealing and longevity with the gasket seam down. Others experiences may vary. I do not worry about the 0.0005" imprint. The purpose of the gasket is to conform into and seal against planar variances and irregularities up to a few thousandths.

Gasket retention is also a function of deck and head surface roughness or texture. If the head and deck are both planar (unwarped) any remaining gasket seam imprint may actually serve as additional mechanical lock to a new compressed gasket.

Pick your camp- go with the majority and put it seam up or be a rebel and go seam down. Sealers and gasket dressings are a whole 'nother debate!
 
Hey Mike,
'rebel', eh..hm :) !
Well, those two areas that you mention are even more problematic...the BIGGER your bore ! If you , say, have a 4" bore or thereabouts, you may become even more of a rebel than seam down to get a good seal. Wire...think wire in these areas, it works !
 
anybody have a picture of copper wire reenforced gasket as I would like to do it on my 6.1 head. you can email me thanks
 
Interesting and to add to what Mike said, my Studebaker head gasket is marked "This Side Up", which places the seam against the block.

I think the most important thing is to lay the gasket on the block, and then lay it on the head. Make sure all gasket surfaces are pinched on both sides by the head and block.
 
Thanks to all the responses - Mike's answer nailed it for me, the reason the vendors make the suggestion is due to the wear pattern and it is easier to deck the head than the block.

The second reason I asked is that my un-restored 29 had it in there seam down and while it may have been done by the last mechanic to dress the valves - it had been there a long time.

So, last fall the plan was new rings, valves, and gaskets only to find the rear main in the block was cracked and delaminating - had to go full rebuild (expletives removed). Which after an expensive winter, I now have both surfaces newly cleaned and could now go either way.

I do have to say - I still can't figure out how this car was running. It had a good 1/8-3/16" of carbon built up by every valve head, and it needed to go .060 over on the bore. No wonder there was a little piston slap at times.

Thanks for the advice and opinions,
Mark
 
Carbon under the valve heads means too much oil is getting past the valve guides, so make sure they don't have excess play.
 
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