<VV> 1967 Corvair Monza - fuel pump "puffs" --> "blow up" damaging the pump ?

[Charles Lee]

Hmmm...

Re:
Now the fact that the fuel pump vent can "leak down" into the crankcase, it 
makes me wonder if worn rings can "blow up" into the pump, damaging the pump 
diagram ?


----- Original Message ----- 
From: "Tony Underwood" <tony.underwood at cox.net>
To: <virtualvairs at corvair.org>
Sent: Sunday, July 25, 2010 12:26 PM
Subject: Re: <VV> 1967 Corvair Monza fuel pump now "puffs" like a tea kettle 
from the "safety valve" ?


> 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...?
>
>
>
> tony..
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