Copper base gasket on a twin cam

[tdrglide]

Has anyone used copper base gaskets on a twin cam? This is custom thickness not available from Cometic in anything other than copper or aluminum. I have a copper set here already. If so, what sealer was used.
Thanks

[les]

There was a recent discussion of this that might help.

https://harleytechtalk.com/htt/index.php/topic,111792.msg1336670.html#msg1336670

[tdrglide]

Thanks Les. Good info there. I think I'll try the type 3 aviation. Just wanted to make sure whatever I use plays well with copper.
 

[No Cents]

  why are copper base gaskets needed for your twin cam build?
I can't say I've ever seen a situation for the need of a copper base gasket on a twin cam.

[turboprop]

Has anyone used copper base gaskets on a twin cam? This is custom thickness not available from Cometic in anything other than copper or aluminum. I have a copper set here already. If so, what sealer was used.
Thanks

I always used Copper Coat on copper gaskets. Be sure to anneal them first.

[kd]

   Anneal first.  I'm with No Cents wondering what dimension you can't put together for base gaskets? You may have more conventional options.

[tdrglide]

Because custom thickness will give me approx ~zero deck height with short cylinders. Actually I measured the rear and it is a little less than 0.002 down mocked up. Close enough for me. Thickness not available in coated steel. And I already have them in copper. I believe copper base gaskets were sometimes use on evo's but I never have. My other option is to have some made with aluminum.
0.062 thick

[No Cents]

  are you saying you need a .062" thick base gasket? 
What crank and cylinders/pistons combo are you using on this build?

[tdrglide]

Kind of a spare parts lock down build. Some have been sitting around for years. Yes, need 0.062 thickness base gasket or spacer. Don't want to buy new cylinders.

[Ohio HD]

I've used copper head gaskets on older Iron Head Sportster motors without any real issues. I have no idea how a copper head or base gasket might work on a cylinder with studs holding it all together. Maybe fine?

I'd be more likely to use two 0.020" base gaskets, and get a sheet metal job shop to make 0.025" thick (24ga.) 304 stainless plates on their laser. They can use a base gasket as a template for the spacer plate. That gives you 0.065". I'd glass bead blast the plates to create texture on them, so any sealer you use will adhere well.

And maybe also use these S&S lower cylinder dowels with the o-ring on the top side of the dowel. You might use them with the copper gasket if you go that route too.


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[tdrglide]

I thought about using a 0.040 aluminum spacer I can get cometic to make along with a 0.010 viton coated steel on top and bottom. Might be the best way to go. No sealer required.

[tdrglide]

The copper ones I got from Cometic. Talked to their custom gasket guy, had them on the shelf. 

[Ohio HD]

I use sealer even with Cometic base gaskets. Nothing to loose, everything to gain.

[tdrglide]

I'll keep that in mind.

I also have some of those S&S dowels. Just need to get some new orings.

[838]

When putting together a build like this would  piston clearance (at the bottom of the stroke) need to be accounted for?

[No Cents]

most definitely...all clearances "must" be checked.

[tdrglide]

Yes,  most definitely

[les]

A search of 510-0381 on the S&S site isn't bringing up those dowels.  I'd like to buy a set.  Can someone stick my nose in the right direction?

[Ohio HD]

I got mine from Calif Phil.


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[Ohio HD]

I'll keep that in mind.

I also have some of those S&S dowels. Just need to get some new orings.

O-rings:

o-ring is a #11
use Viton
0.441" O.D. x 0.301 I.D. x 0.070" thick, about a durometer of 70

[Deye76]

I've stacked Cometic base gaskets dry, on a TC, when the so called custom pistons, were still proud. Sealed fine.

[les]

Thank you, Ohio.

[TorQuePimp]

Flatout gaskets makes rubber coated copper gaskets

Might not hurt too see if they offer something

[jmorton10]

This discussion reminds me of the first stroker I built.

In 1970 I built a panhead with a 5 inch stroke (92 cubic inches). I had to use custom "stroker plates" under the cylinders. The bike was a beast until it snapped the sprocket in half while I was racing one of my buddies lol.

~John