cylinder base shim sealant - question that my gut already knows the answer to

[Optimusglen]

I'm in the process of getting my '71 2.2T engine back together to go into my 914.

When I installed my pistons and cylinders and checked/adjusted deck height etc. I applied Threebond 1215 to the mating surfaces, i.e the case, the shims, and the cylinder bases.

a week or two later I'm getting ready to progress and I believe I need to pull them all again and reapply only just before I'm ready to install and torque down the heads. That's at least the route I'm planning on unless one of you with experience on the issue says otherwise.

[trond]

I never used any sealant on the cylinder base gaskets, and never had any leak. not even sweating. I suggest sealant may not be required if seal surface looks good

[gled49]

+1 for Trond. Never glued base gask. A lot of folks do, no confidence in their work.

[HaroldMHedge]

Curil T is what I would use as recommended by Wayne and Henry Schmidt.

Here is some good reading on this from sealant for cyl. gaskets.

Originally Posted by Henry Schmidt

The reasoning behind using Curil T is that it is non-hardening. This allows the cylinder to move without disturbing the seal. With heat expansion, the cylinder to case to head joints are constantly moving.
The copper gasket (in a perfect world) should work without additional sealant but with these old engines "perfect" is illusive.
We generally put a thin bead of Curil T in the corner of the cylinder where the spigot meets the base. This seals the cylinder to the case rather than coating the gasket.
A fine distinction but it seems to work well. It also seems to make more sense when dealing with the 3.6 base o-ring.

[Alan L]

Never used anything.
Alan

[RogueEngineer]

Used Curil-T with success so far.

[Optimusglen]

Threebond 1215 was also suggested for this location in the sealants thread.

[Henry Schmidt]

Any non-hardening, oil resistant sealant will work. I use CurilT because I read somewhere that it was certified for nuclear reactors.....that's god enough for me.
For those who resist using sealants as a safe-guard: what's the harm?
If the cylinders leak, you have 25 hours worth of work ahead of you.

[trond]

agree. stupid not to really. No downside at all to use some. It is a big job to go back

[stownsen914]

Not sure if anyone answered the OP's question about whether the sealant needs to be reapplied. I'd say that since the sealant cures (semi-hardens) and the heads are not installed and torqued, yes it needs to be cleaned and sealant reapplied.

[Optimusglen]

Originally Posted by stownsen914

Not sure if anyone answered the OP's question about whether the sealant needs to be reapplied. I'd say that since the sealant cures (semi-hardens) and the heads are not installed and torqued, yes it needs to be cleaned and sealant reapplied.

Yeah, thank you for responding. I am planning to do that but I chose to order new base shims because these things bend so easily. Worth it to not have to try and clean the old-new ones up.