<VV> backfire on one side

[Keith Hammett]

Hello to the Corvair gurus,

 

Last night I had some time to work on the rampside again.  First some
info on what has been done.  A 110hp late model engine was selected, new
bearings on clean crank, new rod bearings, cyld. Jugs cleaned/honed, new
rings, and heads that po said were redone (looked like they were worked
over so I used them).  Everything was within specs per the 65 shop
manual.  Next was carbs, a set of late model carbs were selected and
gone through with new parts being used on reassembly.  This was then
mated to the 62 pg in the rampside.  Once in the rampy, I fired it up
and had backfire through both the carbs and exhaust on both banks.
Terry Kalp supplied a set of cut out valve covers for a hot adjustment
procedure (thanks Terry!), this helped things greatly!

 

Now, what happened last night!  I still have a slight backfire on the
left bank out the carb when the throttle is blipped.  I decided that I
would switch the carbs and see what the result would be.  Well I still
have the backfire on the left bank.  So at least I know that the carb is
not the cause of the backfire.  Seems like the left bank runs ruff,
maybe a miss fire on that side, should I short each plug to see if there
is any result?  I know that each wire fires at least to the plug
(checked with timing light).  Next up is to do a compression test.  Any
other thoughts?  Vacuum leak?, where to look on one side?  Good News the
right side runs good!

 

I do recall that it looked like the intakes had been welded up on the
heads, don't remember now if it was both heads or not.  Possible vacuum
leak?

 

Keith Hammett

Willard, Mo.