Copper Head gasket which way up?

[DaveT]

Is there a correct way to fit the copper head gasket? does the gasket seam face to the block or the head?

I've tried searching the forum but I'm unable to find any reference to correct fitting.

Am I correct in believing that 25lbf is the correct torque with a smear of grease on both sides.

[Chris KC]

I'm not sure that it matters much Dave.

20lbft, using the correct tightening sequence which you will find in various publications.
Go round a few times, tightening in increments rather than all in one go.
Finally after first good warm-up, wait till the engine is stone cold again and re-torque.

Yes, I grease mine lightly on both sides.

[DaveT]

Thanks Chris, 

I'll toss a coin as to which way to place the gasket, and I've just checked 20lbsf is 27 Nm/s for my small metric torque wrench.

One think I've discovered is that I cannot fit a low compression head and gasket to my block as it's got oversize inlet valves and the LC gasket just touches the inlet valve and that's before it's compressed. So I'm refitting the HC head with new core plugs.

[Rick F]

The usual advice is to lightly grease both surfaces of the gasket, then install crimped face down, smooth face towards the cylinder head. I tighten mine to 18 lbs ft

[Chris KC]

In fact I put mine the same way up, though I have no shred of evidence to say it is 'correct'!

Dave, unless you are very fussed about originality the HC head will go a lot better than the LC, sounds good to me.

[DaveT]

I had the HC head fitted before I started the decoke, but I always thought the engine sounded "more coarse" so I thought I'd try the LC head to see if there was any sound difference. but the large inlet valve is too close for comfort with the gasket.

[Tony Betts]

same as chris.

i dont think there is evidence to fit one way above another.

in my early days of sevening, the older members always suggested turned over edge facing up.

so thats what i do.

austin books suggest 18lb. myself i pull the head up to 20lb.

decent results will only be true on correctly flattend surfaces. so if you are just replacing without rebuild work, you may find different results.

ive tested on the bench, studs blocks, and nuts.

in good threads, with good quality studs. problems normally start at 30lb plus.

quality of the thread in the block, and your supply of studs. may get different results.

standard supply nuts, start to strip at 22lb. these are useually 1x depth nuts. a thread is aat its maximum effectiveness at 1 1/2x depth.

so if you are tightening at 25lbs, you may want to look at a higher quality nut.

tony

[Chris KC]

It might be worth checking your compression ratio; the trouble with 80-odd year old cylinder heads is they may have been skimmed a few times. For a daily runner about 6:1 is a sensible limit, much more than that and it will not only get noisier but the bottom end may start to feel the strain. The downside of a lower ratio is merely lack of performance!

[Colin Reed]

Hi,
I have always fitted with crimp side to Head
The reasoning that older Engines had the the head removed for decoking  Quite often 
and if there had been any fretting it would be on the head and so much more easily remedied

Colin 
NZ

[Bruce Nicholls]

For what it's worth, on all the engines I have had the head off, from A7 to Lotus, the gasket has always gone back with crimped side up, with no problems to date.