RE: RTV on Cylinder Liner O-Rings, or Not...?

["Jeff Greenfield" <alfaguy@xxxxxxxxxx>]

Dennis -

I've built a lot of Alfa engines in the last 20+ years, some race, many
street.

I've never heard of using RTV on the liner 'o' rings, and have never done so
and have never had a problem (knocking on wood). I agree, that they look
awfully frightening, but they seem to work.

My procedure is this: I will thoroughly clean the block, paying attention to
the area that the liner o' ring contacts and make sure that this is
absolutely clean. There is usually a build up of accumulated crud here. I
also clean the bores in the block that the liner fits into so that they
slide right in.

When everything is as clean as can be I begin the assembly. I put a small
amount of synthetic grease (not petroleum based, as that will damage the
seals) on both the lower portion of the liner (where it fits into the block)
and the o' ring.

The liner should slide right in very easily. When all four liners are
installed, I use two lengths of copper pipe with some large washers on
either end and head nuts on the top to hold the liners in place. You can
also use some large sockets, or the factory tool (which is nothing more than
a length of pipe with a flange on one end).

Remove these just prior to installing the head and you should not have any
problems.

HTH, YMMV ...

Jeff

-----Original Message-----
From: owner-alfa@domain.elided [mailto:owner-alfa@domain.elided] On Behalf Of Dio
Genio
Sent: Tuesday, August 05, 2003 1:02 AM
To: Alfa Digest
Subject: RTV on Cylinder Liner O-Rings, or Not...?

I am about to rebuild a 2L engine from the bottom up.
Will install new Motronic 10:1 pistons and liners.
Those paper thin liner O-rings that keep water and oil
separate are not very confidence-inspiring.

Some expert sources have advised me to add a small
fillet of Permatex special high-temp RTV over the ring
and then seat the liner.  Other people say to not add
anything at all to the o-ring. I'm unsure as to which
method is better.

I like the idea of RTV assisting where the o-ring
might not seat entirely, but once the RTV cures, any
slight movement of the liner would certainly cause
this additional seal to be corrupted. Since the only
thing holding the liners in place is the head, I can
imagine that inserting pistons in the liners and
connecting them to the crank would cause the RTV seal
to lift out of its "seat."  Is there some method to
ensure that the liners stay put once seated with RTV
(even while installing the pistons and rods)?

Any further thoughts out there on this o-ring issue?
The last thing I want in my newly rebuilt engine is
water in the sump...

Dennis
San Diego


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