<VV> Block top Cover Leaks

[Tony Underwood]

At 07:47 hours 09/12/2006, Smitty Smith wrote:

Before I go on about top cover gaskets, I shall mention that Smitty 
has his opinions of RTV and I have mine.   I use several types of RTV 
at work, both O2 cured and catalytic cure, use it for sealing and 
weatherproofing laser assemblies.   GREAT stuff for keeping out 
gasses, water, etc but most RTV simply don't care much for hot 
petroleum products.    Some RTV sealants are quite tough, cure to the 
consistency of tire rubber and the stuff is hard to cut with a 
razor.   Others stay rather flimsy and almost gummy.   And, like the 
stuff you see in the tubes at K-Mart, others are the silicone rubber 
goop we're used to seeing.

You have to go looking in strange places to find the tough RTV that 
resists hot oils.    The stuff in a tube you get at Wal-Mart won't 
much like it.   Still, even this homeowner's RTV is useful for 
smearing a little of it onto a cardboard gasket to enhance its 
sealing ability.   But using regular RTV in lieu of a regular gasket 
in a regular car engine isn't likely to work out as well as most 
people think.


Either seek out the serious commercial stuff, or stick to gaskets (no 
pun).   Now, that said:



>Smitty Says:  I am curious about this.  I have torn down dozens and 
>dozens of Corvair engines.  I have also rebuilt another couple of 
>dozen.  I know that isn't many by the standards of professional 
>Corvair mechanics but enough for me to see a trend.  I have never 
>seen an engine yet with a leak from the top cover gasket area.


Neither have I.   Not once have I ever had to arbitrarily repair a 
leaky top cover gasket in anything I owned or worked on for anyone 
else or pulled apart or saw in a junkyard or whatever where 
ever.   Nor have I ever done anything odd with the stock type gaskets 
when putting something together, no sealer or anything else (although 
I generally do give the gaskets a coating of heavy "old fashioned" 
wheel bearing grease), assemble it as-is, and no leaks ever 
resulted.   With the grease, if you ever do have to take it apart 
again the cover/gasket comes off without a chisel.

I'm somewhat perplexed as to the "common leak area" of the top cover 
gaskets being mentioned often.


Now:   For that matter...

I've given thought to simply eliminating that baffle altogether and 
using an oil separator at the top cover vent, or maybe eliminating 
the vent as well and installing a vent(s) on the valve cover(s) ala 
most every other car engine of the period.   Oil slung off the crank 
would experience some additional cooling by splashing on the top 
cover which is exposed to a lot of turbulent air under the shroud, 
couldn't hurt.

Anybody ever tried that?   I'm tempted...



>That means to me that it is not a chronic leak area, or does not 
>deserve all the attention some folks give it.


I'm inclined to agree... at risk of possibly offending someone who 
feels differently, and everybody knows how politically correct and 
unoffensive I am...  ;)


>Am I wrong.


No.                  Maybe it's an eastern/seaboard kinda 
thing...   no top cover leaks.

tony..