oil tight copper head gaskets

After having both composite and copper head gaskets spring oil leaks on both street & track I found a way to seal them. I use the copper head gasket and glue (contact cement) a thin .006" diameter copper wire to the head around the pushrod tunnels and oil return hole. Then I glue the copperhead gasket to the head to keep from disturbing the copper wire on installation. The wire and the glue flatten out.

I especially like the .006" copper wire with the .003 thin copper head gasket rings (see photo).



This is what I'm currently using and I've been cruising down the freeway at 70-80mph in searing Fresno Calif heat (as in 108 deg F).

I leaned this technique when I was racing and conventional gaskets were leaking. I used a thin copper wire in a shallow groove and thats all. It's the only HG that never failed.

I don't like composites because they can crush unevenly and warp your head.

Interesting. Where do you get the .003 copper headgasket rings without the fiber?

Dave
69S

DogT said:

Interesting. Where do you get the .003 copper headgasket rings without the fiber?

Dave
69S

Click to expand...

They are at
JSmotorsport.com
and they come with the .006" copper wire.

This way you can raise compression about one point without milling the head and losing resale value.

Less is better.

Less compression or less gasket?

How will those thin rings and copper wires work raising the compression on my early standard 750 with stock parts? No problems? I might try it just for a lark. I wasn't thrilled with the composite gasket I put in there, but it seems to be holding. No racing. I use 110LL avgas so that shouldn't be a problem?

Dave
69S

Just keep in mind changing stack height change valve rocker push rod geometry though Combats get away with .040" too long push rods a long time but not as long as others I hear till corrected. One point of CR increase say from 8 to 9 is worth ~3.5% and 9-10 maybe 2 %. No mo gasket blow by is very good news. I'll be getting some for ordinary Combat and my special needs child.

I'll be interested in thrashing this one around a bit.

DogT said:

Less compression or less gasket?

How will those thin rings and copper wires work raising the compression on my early standard 750 with stock parts? No problems? I might try it just for a lark. I wasn't thrilled with the composite gasket I put in there, but it seems to be holding. No racing. I use 110LL avgas so that shouldn't be a problem?

Dave
69S

Click to expand...

It should bring from 9to1 to 10to1. Yes, with the gas you use, no problem.
The standard copper gasket is .042". It's just like shaving the head .040"
I would like to try it but only if I really need to pull the head for some reason. I'm already around 10to1.

Will higher compression mean playing with the carb jets?

Dave
69S

DogT said:

Will higher compression mean playing with the carb jets?

Dave
69S

Click to expand...

Not necessarily but possibly. Maybe one step up on the main. If anything, probably re-fiddling with mixture screws for idle and initial blip. If you are with Amals you probably do this periodically anyhow.

For a hop-up, it seems like an economical way to go. I have a feeling Jim may have a run on these.

A bit of CR change should not require a tune change, just if ya change the carb, the exhaust system &/0r cam profile. The rebores that are over standard raise the CR as much or more that a bit of gasket thickness and no need to retune after that I found. If any thing the bit faster higher CR burn rate might like a bit less spark adv.

Hobot,
Does a rebore raise the CR?
Jaydee

It's a special pixiland boring machine!
JohnT

DogT said:

Less compression or less gasket?

How will those thin rings and copper wires work raising the compression on my early standard 750 with stock parts? No problems? I might try it just for a lark. I wasn't thrilled with the composite gasket I put in there, but it seems to be holding. No racing. I use 110LL avgas so that shouldn't be a problem?

Dave
69S

Click to expand...

Yes everything fits.

hobot said:

Just keep in mind changing stack height change valve rocker push rod geometry though Combats get away with .040" too long push rods a long time but not as long as others I hear till corrected. One point of CR increase say from 8 to 9 is worth ~3.5% and 9-10 maybe 2 %. No mo gasket blow by is very good news. I'll be getting some for ordinary Combat and my special needs child.

Click to expand...

You don't really have to shorten the pushrods .040" - as long as there is room for adjustment. As you said - Combats run that way. If you want it perfect you can shorten them.