sealer for copper head gaskets

jseng1 · Dec 18, 2016

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.

Torontonian · Dec 18, 2016

Interesting comparisons. I'm holding an 80ml. tube of Permatex's new product. Ultra Copper Advanced Formula Maximum temperature Gasket Maker. High temp range is -54 Celsius to 316 Celsius (-65 F. to 600 F.). OOOPS.. :shock: just read... not recommended for headgaskets or parts in contact with gasoline. O.K. , so just checked my original tube with a bit left in it and the specs. are the same. Wonder what Advanced Formula means ? Anyways , I always use a light smear of this on both sides of a new or annealed copper head gasket. Never had a leak. Enjoy.

pommie john · Dec 18, 2016

I use silver metallic rattle can paint. A couple of coats on each side of a copper head gasket, let it dry before assembly. I can't remember who recommended this method, but it seems to work.

I'd be interested to see a scientific test for it.

jseng1 · Dec 18, 2016

Torontonian said:
Interesting comparisons. I'm holding an 80ml. tube of Permatex's new product. Ultra Copper Advanced Formula Maximum temperature Gasket Maker. High temp range is -54 Celsius to 316 Celsius (-65 F. to 600 F.). OOOPS.. :shock: just read... not recommended for headgaskets or parts in contact with gasoline. O.K. , so just checked my original tube with a bit left in it and the specs. are the same. Wonder what Advanced Formula means ? Anyways , I always use a light smear of this on both sides of a new or annealed copper head gasket. Never had a leak. Enjoy.

Is this a silicone based product?

Torontonian · Dec 18, 2016

Yes I believe so. Item # 59703. Ultra Copper silicone. Permatex.ca

texasSlick · Dec 19, 2016

Good info Jim. Thanks.

Are you now recommending applying contact cement to entire gasket, or only where necessary to hold .005 wire around pushrod tunnels and oil drain Hole?

Also, any other recommendations for spigotted Barrels?

Slick

Danno · Dec 19, 2016

pommie john said:
I use silver metallic rattle can paint. A couple of coats on each side of a copper head gasket, let it dry before assembly. I can't remember who recommended this method, but it seems to work.

I'd be interested to see a scientific test for it.

I used aluminized spray paint for years with good results. Norton, Triumph, BSA, Harley and some 2-stroke engine copper head gaskets.

Danno · Dec 19, 2016

pommie john said:
I use silver metallic rattle can paint. A couple of coats on each side of a copper head gasket, let it dry before assembly. I can't remember who recommended this method, but it seems to work.

I'd be interested to see a scientific test for it.

I used aluminized spray paint for years with good results. Norton, Triumph, BSA, Harley and some 2-stroke engine copper head gaskets.

tricatcent · Dec 19, 2016

I think maybe this is the answer

oil-leak-the-head-gasket-t25033.html

worntorn · Dec 19, 2016

For a standard Commando I gave up on the copper, got rid of the oil leaks and gained some compression.
The answer for me was a. .020" flame ring gasket ( RGM) with some Permatex Aviation Gasket goo around the pushrod tunnels. Plus a retorque at 50 miles and another at about 500.

The leaky copper headgaskets I tried were all around .040", so the CR is about half a point to the good with the thinner gasket.
16,000 miles so far on that. The cylinder and head dry like Melba toast. The engine was noticeably stronger with the half point CR gain, or was there more than that due to leakage with the copper gasket?

Glen

eskasteve · Dec 19, 2016

pommie john said:
I use silver metallic rattle can paint. A couple of coats on each side of a copper head gasket, let it dry before assembly. I can't remember who recommended this method, but it seems to work.

I'd be interested to see a scientific test for it.

I've used hi-temp aluminum spray paint as a sealer for darn near fifty years. When I was 16 I was racing an alcohol fueled outboard hydroplane and had trouble with head gaskets. I good friend of my dad's told me to try the paint. He had been an engine builder for a very successful sprint car team and that's what they used. I even used it on my ill fated experiment with a Drouin supercharged Norton. The copper head gasket stayed
oil tight right up the point when the crankshaft decided to blow itself up. I'm sure that there have been a lot of really dandy sealers to come on the market in the years since but spray paint has worked for me and so far (about 22,000 miles) my current 850 is oil tight.

jseng1 · Dec 19, 2016

Flame ring gaskets do seal well but they can compress and that could lead to head warpage. I've had them shrink and start to leak after a few years.

Form a gasket doesn't work well on a head gasket. It has the lowest temp tolerance of them all and was the 1st to fail in the above test comparisons. Be aware that Norton head temps average around 300 when cruising and can get as high as 500F in brutal conditions.

Aluminum spray paint may work but its probably the liquid paint - a form of liquid glue (flattens out when assembled) that's doing the sealing rather than the metal powder.

Waisted head bolts are great but you can still have a leaky HG with them. I've been using waisted (triangulated) head bolts on Nortons longer than anyone I know of (from around 2010) and even though they are an improvement they alone will not prevent leaks.

Silicon has the highest temp resistance but it has poor adherence to the metal. It will actually creep out of a cylinder base and migrate away. It doesn't seem to keep its tension when used on a HG.

Here's what we need:

An adhesive with a tenacious grip that will not let oil worm past it. This means applying a glue like substance to each metal surface and letting it adhere (or stay wet) before assembly. The glue must stay soft enough to squish or flatten out to extreme thinness on assembly (a problem with dried silicone). Be heat tolerant up to 500 F. Be hard enough to prevent hot oil from moving past it.

So far a high temp contact cement fits these requirements. Perhaps if the "right stuff" was allowed to adhere to each surface before assembly - it might work (but it has disappointed me when used in compression). See perfectly formed & compressed "right stuff" sealer below after failure - hot oil just went past it somehow.

The high temp contact cement does harden with heat but it stays in place and stays adhered to the metal surfaces. And its not difficult to remove when rebuilding. So far I have no leaks at all after years of service when used with the .005" copper wire - even when cooking in Fresno 110 F traffic. If there is something better then I'm willing to try it. But I haven't found it.

Slick - Yes - coat everything with the contact cement - each surface - it will squish down to nothing and fill any imperfections. I don't know about spigotted barrels but it should work the same.

nortriubuell · Dec 19, 2016

Very interesting, thanks for posting

worntorn · Dec 19, 2016

The Permatex Aviation Form-a-gasket is rated for 400 f. Perhaps it can handle a bit more than that or temps around the pushrod tunnels don't go above 400?
In any case it has worked for 16,000 miles and had a few hot sessions. The hottest session must have been climbing the 7 mile long Salmo Creston on a hot summer day, two Vincent 1000s chasing and holding just under the ton. Right near the top one spark plug overheated and the bike went onto one cylinder for a bit, so things were getting very warm.

I've often wondered, in which situation does the head get hottest -climbing a miles long mountain grade full bore on a hot summer day or sitting idling on a hot day?
I suspect it is the latter.

If the tank is off for any reason I do a retorque.

The waisted bolts would be a good addition next time things come apart for renewal.

jseng1 · Dec 19, 2016

worntorn said:
The Permatex Aviation Form-a-gasket is rated for 400 f. Perhaps it can handle a bit more than that or temps around the pushrod tunnels don't go above 400?
In any case it has worked for 16,000 miles and had a few hot sessions. The hottest session must have been climbing the 7 mile long Salmo Creston on a hot summer day, two Vincent 1000s chasing and holding just under the ton. Right near the top one spark plug overheated and the bike went onto one cylinder for a bit, so things were getting very warm.

I've often wondered, in which situation does the head get hottest -climbing a miles long mountain grade full bore on a hot summer day or sitting idling on a hot day?
I suspect it is the latter.

If the tank is off for any reason I do a retorque.

The waisted bolts would be a good addition next time things come apart for renewal.

Yes the formagasket is rated for 400F. And so is every version of formagasket. But when I tested it in real life - it didn't survive anything near that.

worntorn · Dec 19, 2016

Was it the Form-a-gasket 1, 2 or 3 which you tested?

jseng1 · Dec 20, 2016

worntorn said:
Was it the Form-a-gasket 1, 2 or 3 which you tested?

I tested formagasket 1B it has the same 400F rating. But you shouldn't even need sealer if you're using a flame ring.

If you get waisted bolts - the bolts most likely to strip (pull out) are the studs nearest the pushrod tunnels (see below). This is where the leaks are. They see the most heat and these are the most important ones to have waisted - even more important if you have alum cylinders. Triangulated shanks are best because there is more resistance to twisting and all the machining is linear with the bolt length and that means no stress risers. But you would have to make them yourself because no one is offering them.

robs ss · Dec 20, 2016

Nice solution Jim
Please clarify though - if I zoom on your photo above it appears the flats are approx 90 degrees apart giving 4 flats per stud
Is this correct or am I not seeing it right?
Cheers
Rob

jseng1 · Dec 20, 2016

robs ss said:
Nice solution Jim
Please clarify though - if I zoom on your photo above it appears the flats are approx 90 degrees apart giving 4 flats per stud
Is this correct or am I not seeing it right?
Cheers
Rob

There are 3 flats per stud with a bit of radius between each flat - the radius may be throwing you off.

Triangulated shanks are the way to go in my opinion. I'll be setting up my mill to cut some for a race engine build in a few weeks. Here's the cross section layout for a 3/8" bolt/stud (below). Its a shame because I used to be able to just buy these ready made - can't find them anywhere now.

texasSlick · Dec 20, 2016

jseng1 said:
There are 3 flats per stud with a bit of radius between each flat - the radius may be throwing you off.

Triangulated shanks are the way to go in my opinion. I'll be setting up my mill to cut some for a race engine build in a few weeks. Here's the cross section layout for a 3/8" bolt/stud (below). Its a shame because I used to be able to just buy these ready made - can't find them anywhere now.

What would you sell a set to members of the Forum? Running a few sets off after you set up the mill should be cost effective for you and members. Put me down for a set. Perhaps some others will join in .... the more the better for all.

Slick

sealer for copper head gaskets

Similar threads