- Joined
- Nov 26, 2009
- Messages
- 3,191
Lots of people are interested in solving the oil leak problem with copper head gaskets. As most already know - I recommend .005" copper wire around the pushrod tunnels and oil return hole and I think its best to put it on both sides of the H.G. (it flattens out and embeds into the H.G.).
The variable is the sealer. I recommend contact cement as Ron Wood used in his high HP dirt trackers. The stuff is called "pliobond 20" (or 25 etc - they are the same with different solvents). I've tried "the right" stuff and "yamabond" and silicon but didn't have the same success. And it turns out that you need to coat each surface so it bonds to the metal and prevents the oil from worming its way through (the glue will also bond to itself no problem). When you do everything and do it right - bingo - no leaks.
So I tested various contact cements. There are others and something might be even better but so far the pliobond has the highest temp resistance of the contact cements and holds up the best. I applied the sealers side by side on an aluminum plate, applied even heat with a flame and used a lazer temp gauge indicator (you have to point it at a dark area).
Here are the results so far:
Pliobond darkens & hardens at 450 to 500F and loses integrity at 500 but still stays in place and when its cooled and remains adhered to the metal.
Silicone sealer resists heat up to 500F, starts to fail by 550 and loses its adhesion. Did not harden but has mediocre oil resistance.
Permatex “Ultra” oil resistant gasket maker lost adhesion at approx 500F and failed. Minimal hardening.
Gasgacinch and Weldwood contact cements burned black & hardened before pliobond and lost their adhesion at lower temps around 400F.
Permatex motoseal #29132 grey (same as popular Yamabond 4) bubbled at 400F and hardened but did not lose its adhesion. Became very hard but was still adhered when cool.
Yamabond 5 (clear contact cement) bubbled at 400F burned black, became brittle and lost adhesion.
Permatex high tac turns to liquid, smokes and loses adhesion at about 350 F.
Permatex formagasket started smoking & bubbling at 250 – 300F and failed.
Always use compressed air to check that the oil return hole is not plugged (clear with 1/32" tie wire).
If someone knows of a higher temp contact cement - let me know or send me some and I'll test it. "The right stuff" deserves another chance but I'm out and I gave up on it after it failed. It may be that the sealer has to be on the harder/stiffer side.
Note that Maney cylinder sleeves protrude a couple thou above the aluminum and they may need something to fill the gap if the sleeve doesn't embed into the copper H.G. (Maney suggests "the right stuff").
I used to race with nothing but .018" copper wire in a shallow groove (no sealer) and it never failed but needed several re-torques.
The variable is the sealer. I recommend contact cement as Ron Wood used in his high HP dirt trackers. The stuff is called "pliobond 20" (or 25 etc - they are the same with different solvents). I've tried "the right" stuff and "yamabond" and silicon but didn't have the same success. And it turns out that you need to coat each surface so it bonds to the metal and prevents the oil from worming its way through (the glue will also bond to itself no problem). When you do everything and do it right - bingo - no leaks.
So I tested various contact cements. There are others and something might be even better but so far the pliobond has the highest temp resistance of the contact cements and holds up the best. I applied the sealers side by side on an aluminum plate, applied even heat with a flame and used a lazer temp gauge indicator (you have to point it at a dark area).
Here are the results so far:
Pliobond darkens & hardens at 450 to 500F and loses integrity at 500 but still stays in place and when its cooled and remains adhered to the metal.
Silicone sealer resists heat up to 500F, starts to fail by 550 and loses its adhesion. Did not harden but has mediocre oil resistance.
Permatex “Ultra” oil resistant gasket maker lost adhesion at approx 500F and failed. Minimal hardening.
Gasgacinch and Weldwood contact cements burned black & hardened before pliobond and lost their adhesion at lower temps around 400F.
Permatex motoseal #29132 grey (same as popular Yamabond 4) bubbled at 400F and hardened but did not lose its adhesion. Became very hard but was still adhered when cool.
Yamabond 5 (clear contact cement) bubbled at 400F burned black, became brittle and lost adhesion.
Permatex high tac turns to liquid, smokes and loses adhesion at about 350 F.
Permatex formagasket started smoking & bubbling at 250 – 300F and failed.
Always use compressed air to check that the oil return hole is not plugged (clear with 1/32" tie wire).
If someone knows of a higher temp contact cement - let me know or send me some and I'll test it. "The right stuff" deserves another chance but I'm out and I gave up on it after it failed. It may be that the sealer has to be on the harder/stiffer side.
Note that Maney cylinder sleeves protrude a couple thou above the aluminum and they may need something to fill the gap if the sleeve doesn't embed into the copper H.G. (Maney suggests "the right stuff").
I used to race with nothing but .018" copper wire in a shallow groove (no sealer) and it never failed but needed several re-torques.