copper head gasket

[Tom Lovejoy]

I have used copper on my ss for 30 years, with aluminum paint. With very good results, used paint on them on advise from Mr Lee Standley. He said to do it and I did, make sure none of your bolt's bottom and mess things up, good luck Eric. Doing mine as we speak

[T. Cotten]

Maybe a vertical throttle plate favors the rear with a richer mixture.
Tom

No doubt the vertical plate has its issues, Tom!

But I witnessed heat signatures favored the front on many chubbles and sports as well.

My reasoning isn't always rational, so I would really really like to know what Indian used for aluminum heads.

....Cotten

[tfburke3]

Maybe a vertical throttle plate favors the rear with a richer mixture.
Tom

[T. Cotten]

Wouldn't the exhaust port be the hottest part of any engine?

Almost, Larry,..

If we define the hottest part by a peak temperature, the Armored School graphic suggests the exhaust valve is more than twice the combustion chamber! Obviously, the engine only survives because combustion heat is expelled, and the exhaust valve takes the brunt of it.

The valve head cools itself by momentary contact with the seat, and the rest of the gaps are somehow enough to shield the valve springs, which would certainly suffer if they came close to that temp.
As far as the ports, its obvious why the exhausts have more finnage (but not so obvious one why the fronts, which get more wind, have the most. Shouldn't they need less than the rears that are out of the wind?).

Conducting more heat from the head to the cylinder is hard to justify. An inherent problem with flattys is the distortion of a very eccentric casting, with valves on the same side that have opposite heat environments. Most designs chose to isolate the head and let it cook.

...Cotten
PS: I have always contended that the front exhaust assembly suffers the most heat, based upon the fossil record. Why wasn't it the rear?

[larry]

Wouldn't the exhaust port be the hottest part of any engine?

[exeric]

That's a good point, and makes sense, Tom.

[T. Cotten]

So which did the Wigwam produce for aluminum heads?

Sorry to get back to subject, Folks.

....Cotten

I guess I'll have to find somebody who knows at Davenport, Folks.

There's an explanation for the work-hardening of copper head gaskets in duty, but copper-lovers ain't gonna like it.

And the heat diagram I posted described a motor with an insulating composite gasket. If indeed a copper gasket would conduct more,.. then the cylinder temperatures would elevate, and it would distort accordingly.

....Cotten

[T. Cotten]

So which did the Wigwam produce for aluminum heads?

Sorry to get back to subject, Folks.

....Cotten

[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. .

[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.

[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

[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]

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

[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]

... 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