Couple of questions about cylinder base gaskets

[Ho Hum 74]

1. What sealant does one use on these?. I know Wayne says Locktite but I have heard Curil T is better. Plus, I do know I struggled to get my cylinders off the case due to Locktite on previous rebuild.

2. How many gaskets is too much? Wayne says no more than two but I have heard (second hand) that other engine builders are using more - sometimes up to 4 - to get the deck height correct.

Thanks
Tristan

[Tyson Schmidt]

There shouldn't be a need for more than 2 base gaskets, given the available thicknesses. The Factory spec book states flatly that stacking base gaskets is not recommended, but when building custom engines, it is often unavoidable.

I personally don't like to use Loctite 574 on anything that moves around as much as the cylinders do in the case bores. Loctite will eventually crack, and cause a leak. 've torn down a number of engines that used Loctite on the base gaskets, and they all were seeping due to crumbling, cooked Loctite. I use Hylomar HPF, which never hardens, and is therefore self healing. I use it on case through-bolt o-rings as well, for the same reason.

[MotoSook]

With the right torque on the heads, the soft base gaskets should seal w/o anything on them.

You think that's not a good idea? I've used valves (1" up to 36" diameter) with stainless to stainless seat contact that can hold over 1400 PSIG! The base gasket only has to deal with case pressure.

[ischmitz]

Originally posted by Ho Hum 74
2. How many gaskets is too much? Wayne says no more than two but I have heard (second hand) that other engine builders are using more - sometimes up to 4 - to get the deck height correct.

Doesn't EBS racing amongst others sell chims for exactly that purpose - setting the deck height?

Ingo

[Porsche_monkey]

Is your engine a 2.7? If so I believe you are limited to .25 and 0.5 mm shims.

[Ho Hum 74]

PBH,

Yes, I think you are correct. I have ordered two sets of .25mm and two of the .50mm. This should get me there.

Tristan

[Porsche_monkey]

I had to use three total.

[jgparker]

I seem to remember finding 1mm shims for my 2.7 at EBS and competion engineering. I think one 1mm shim is better than two .5mm shims.

Good luck.

JP

[MotoSook]

Originally posted by jgparker
I think one 1mm shim is better than two .5mm shims.

Yep! One less contact surface leak..

[Halm]

I may be faced with tearing down my 2.7 to fix a leak at the base of #1. So back to one of Tristan's questions, why would you stack multiple gaskets? Deck height, compression?

[MotoSook]

mostly for proper deck height, but you could massage the compression a bit...

[john walker's workshop]

to compensate for material removed when the heads are flycut, and/or the cylinder bases on the case are machined. you need to keep the cam thrust plate centered in it's hole in the chain housing so the o ring will seal.

[ischmitz]

Originally posted by Halm
I may be faced with tearing down my 2.7 to fix a leak at the base of #1. So back to one of Tristan's questions, why would you stack multiple gaskets? Deck height, compression?

Hal, That being the motor you had custom-build not to long ago in California. I hope you are kidding. Otherwise that thing should go back to whoever build it.

Cheers,
Ingo

[Halm]

Ingo, indeed it is. My story on that charlaton is with my attorney now to make sure it is pure, "best evidence". It will be told on every BB I belong to.