<VV> 1967 Corvair Monza fuel pump now "puffs" like a tea kettle from the "safety valve" ?

Tony Underwood tony.underwood at cox.net
Sun Jul 25 15:26:26 EDT 2010

At 08:39 PM 7/24/2010, Charles Lee wrote:
>A replacement (used) pump eliminated the liquid leak, but now "puffs" like a
>tea kettle from the "safety valve" diametrically across from the "T"
>connector, where the other pump was leaking liquid gas previously.

That vent has a somewhat indirect connection to the crankcase.   Your 
engine has a bit of blowby.   ;)   It will puff a bit out that vent 
if the engine has a stopped up crankcase vent.  Check your hoses and 
plumbing leading from that crankcase vent tube to your air cleaner 
etc and make sure they're all clear of any obstructions or sludge or 
whatever.   Check the crankcase vent tube too... take the oil filler 
cap off and blow some air through the crankcase vent tube.   You can 
use a piece of heater hose or garden hose or whatever, and simply 
huff and puff into it with the other end jammed into that tube.  If 
it doesn't flow freely with some breeze wafting out the oil filler 
spout, break out the coat hanger wire and start fishing it through 
that tube and ream out the clog.

I once was checking out an engine stored in a barn, found a crankcase 
vent pipe plugged into the rubber grommet inside the air cleaner 
stopped up with mud dauber nest.    Absolutely no clue how it got in 
there since the aircleaner had a filter element in it and everything 
else seemed intact.   Those little suckers are ingenious, yesterday 
went looking through some coils of fuel hose and vacuum line in the 
shed and every one had the ends stopped up with dried mud.   Likewise 
a couple of bolt holes in some cylinder heads stored on the upper shelf.

Ahh, rural living...

Anyway, that vent in the pump works in conjunction with a "cofferdam" 
cast into the bottom pump housing (in later vintage pumps, anyway) 
that extends up past the gasket mating surface between the bottom 
casting and the valve body to keep fuel from leaking into the 
crankcase in the event of an internal seal fail around the central 
part of the casting surrounding the pushrod... instead, a fuel leak 
here will puddle up around the "cofferdam" and leak out through that 
vent hole.

>I'm learning a lot more about fuel pumps than I had planned !!!!

Fun stuff, ain't it...?


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