[alfa] Sealants in Alfa engines (and differentials)

["Jay Mackro" <jmackro@xxxxxxxxxxxx>]

Michael Findlay had asked:

I have heard that some 105 engine builders are using sealant to ensure
there is no coolant leakage from the bottom of the liner. Is this good
practice? Should the sealing rings be used as well as sealant or should
these be left out? Should the sealant cover the surface below chamfer
for the O ring or simply the area where the O ring should be? Does
anyone have a recommended sealant?

I concurr with another poster - to paraphrase, yea, you could probably
subsitute some sort of goo for the O rings, but why would you want to?
This is a low-probabability area for leakage  on Alfa engines (and Lord
knows, there are a lot of high-probabality areas!).  If the O rings were
no longer supplied, I guess we would have to come up with some
alternative.  But to my knowledge, they still come with gasket sets.

Perhaps goo would be better than the O rings on a block that was
severely corroded, with pits on the O ring sealing surface.  Still, I
don't think I would eliminate the O rings - I think I would use the goo
to supplement them.  My sense is that the design of these engines
requires some "spring tension" between the liners and block.
Remember, the liners are supposed to protrude higher than the deck
surface before the head is installed.  And, torquing down the head
is supposed to smoosh the liners down level with the deck.  Plus,
these engines need to deal with the differential thermal expansion
between the aluminum block and iron liners.  Frankly, it always
surprised me that fatter O rings weren't required to accommodate
this movement.

Hey, speaking of sealant, what would you use between the axle
tubes and aluminum center section on an Alfa differential?  There
is no gasket used here, but the steel-aluminum interface is
supposed to contain the gear oil.

Thanks

Jay Mackro
San Juan Capistrano, Ca.
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