copper head gasket

[exeric]

I got the thick copper head gaskets for my '41 Scout from Greer. I've never used gaskets like this so I would like to hear from those who've used them. Opinions, tips, tricks, love or hate would be most appreciated.

[RichO]

I anneal them then coat them with the dregs of silver paint after I drain off the clear that it's suspended in. But you can use copper coat too. It ( the paint method) always worked on my 101 but I'm sure you'll get other methods offered..

[Rubone]

Silver paint has always been the best, but modern paint does not have the aluminum content (the part that made the seal) like early ones did. Old high heat silver H-D paint had a high aluminum content and was available in cans, not just aerosol spray.

[T. Cotten]

Just curious Folks,...

Were OEM gaskets for aluminum heads copper, or composite?

Thanks in advance,

...Cotten

[RichO]

Rubone, I use the"Big" bottles of silver I get at the hobby shop for models.It's like the old ones you remember. Cotton, I have good success with copper ones on my WL with #5 aluminum heads but I don't know if they were used as OEM.

[PanheadFred1]

I've been using copper gaskets for a while now and I'm very pleased with them. Anneal them and I spray them with copper coat. They can be re used also if you anneal them before re use.

[T. Cotten]

If you gotta seal them with paint, Folks,...

Then what's the point of the gasket?

Thanks in advance.

....Cotten
PS:

... Anneal them and I spray them with copper coat. They can be re used also if you anneal them before re use.

That makes me wonder, PanheadFred,...

What hardens them when used?

[PRG]

Howdy Eric,

Have had these in service for 30 years on a 440, 441, 346 and 348 and would not return to composite for any reason. As an aside, the huge torques spec’s for composites back in the day was to crush those gaskets into submission where they were most prone to failing, the high heat area around the exhaust valves. After 70-80 years of this stress, Four cylinder heads especially become distorted at the head bolt washer lands as to be unusable. With copper, I torque to only 30ft lbs, no glues, treatments or leaks. The key thing is surface prep, ie, all adjoining surfaces must be flat. You will note your gaskets have stamped out on sheet with a small lip around the underside from shear, the underside surface is not as smooth as the top side. This and the other surfaces can be addressed merely by dressing them on 600-800 grit paper on a sheet of glass.

Though not as prone to distortion, v twin heads can become deformed on the face at the washer lands especially around the exhaust pocket. In some cases, because of non OEM or stretched original head bolts, overzealous tightening results in bolts bottoming out and the cylinder threads stretching up profound of the deck. A pass or two with sand paper on glass will reveal those areas if present. Finally, the heat transfer rate between deck and heads is hugely aided by copper, especially if dressed as the more surface area in contact the more efficient that transfer is. Very important for this of us living down south and summertime urban riding.

[T. Cotten]

... Finally, the heat transfer rate between deck and heads is hugely aided by copper, especially if dressed as the more surface area in contact the more efficient that transfer is....

Aren't the heads hotter than the cylinders, Peter?


HEATCHRT.jpg

So many questions, yet I get no answers, Folks...

.....Cotten

[kitabel]

Why a gasket?
Because it controls the piston to head clearance @ TDC.
Too thin (or none) may make contact when hot.
Too thick will invite knocking. I suspect my 642 was too loose, but never corrected it.

What's the factory clearance spec?

[T. Cotten]

Why a gasket?
Because it controls the piston to head clearance @ TDC.
Too thin (or none) may make contact when hot.
Too thick will invite knocking. I suspect my 642 was too loose, but never corrected it.

What's the factory clearance spec?

What about them K Models, Kitabel!

Eric did say the Greer's were fat.

Somebody's gotta know what OEM was.

(My ordinance-packed WLA kits ain't copper.)

....Cotten

[exeric]

I measured the Greer head gaskets @ .063". I'll try the gaskets, sans paint as I can see the benefit of direct metal heat transfer. The heads are not that hard to get off an engine in the frame, so there is always plan B. I did use dye, and sandpaper on a granite surface plate to attempt to get everything flat. Fortunately, my cylinders were at stock bore and not abused. I have to thank Indianut for all his help, and advice (hard to pay back guys like him). Also, thanks to everyone that replied with their insight, experience, and advice. . . Most appreciated.

[T. Cotten]

...I'll try the gaskets, sans paint as I can see the benefit of direct metal heat transfer....

So Eric,...

You want heat from the heads to conduct to the cylinders?

....Cotten

[PaulCDF]

CU Gasket Spray.JPG
Eric;
I went with copper on the advice of my engine builder. Preparation as aways is important FLAT mounting surfaces on cylinder tops and heads. Even torque and re-torque when cold during break-in periods.

Geers, and Kiwi both sell copper and composite head gaskets. I am a novice so went on the advice of my builder (he did the complete lower end and machining on my cylinders and heads) and
I did the 'top' assembly (I was trying to work with-in a budget). All that said if copper wasn't in the budget I would go with a quality composite.

Tom; you have forgotten more about engine building than I will ever know; from what I have found in my copy of Dyke's soft copper, asbestos or layers of the two were used

Eric you have the copper gaskets in hand seems a shame not to use them though you could always sell or swap for composite. Kiwi has an interesting tech video on head gaskets might
be worth a look:

Tech Videos – Kiwi Indian

Best Wishes.

[Rubone]

H-D generally used copper on engines with same material heads and cylinders (cast iron / cast iron) and composite on dissimilar materials (cast iron./ aluminum). But not always. The Wldr/WR racers never used a gasket at all, only silver paint, and this practice carried over to the K series. However race bikes were torn down very often and head gasket life was perhaps not a great consideration.. Ks seemed to do just fine but also had the very wide gasket area of the WR type cylinders. H-Ds copper gaskets were also formed with ribs that crushed under compression of torque to hopefully deform into any small voids in the gasket area, another reason paint was used, many modern copper gaskets are flat. H-D wasn't too concerned about squish, it was built into the design through cylinder height, piston crown height, and head shape/machining. It only became an issue for tuners after the fact looking for the best overall performance and heat control. .