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Vapor lock feedback [message #318487] Sun, 04 June 2017 21:46 Go to previous message
lw8000 is currently offline  lw8000   United States
Messages: 201
Registered: July 2012
Location: S.E. Michigan
Karma:
Senior Member
Hello all:
I was looking for some additional feedback on vapor lock, mainly what kind of conditions that you have seen it in. We seem to be troubled by it when temps get up over 83-85 degrees outside, it first started last summer going down the Florida where temps got up to 93+. Since then, we've had an inline fuel pump and rebuilt carb installed by JimB, that seems to have done the trick for getting around the issue (which only seems to happen when slowing down or stopping and trying to get going again).
Also since the inline fuel pump, we've had an aluminum ported Offenhauser intake manifold installed, with the Paterson blockoff kit. We had this done due to cracking of the original manifold. Some thought maybe this would help with vapor lock, however today we again had it happen to us, temps outside were around 83-84 degrees with full sun, we were on the highway for about 45 minutes after taking off cold. After exiting the highway, stopping at a sign, and accelerating again on a backroad, after 10 seconds while accelerating the engine starting surging a little bit. After flipping on the electric aux pump, the surging went away after about 15-20 seconds. We were running the dash AC at the time as well and engine temp seemed normal.

Does this seem to be a little bit extreme with it happening when it's 83-84 degrees out, or is this pretty much what everybody else is experiencing? And is the main fix still just using an aux electric pump back near the tanks? I can't imagine this could be anything else besides vapor lock. Over the years we've had everything in the fuel system either replaced or fixed all the way from the tanks up: fuel tanks cleaned & coated, new rubber hoses, new solenoid, new inline fuel pump and fuel system check (by JimB), new Carter mechanical fuel pump, new fuel filter @ carb, rebuilt carb (from JimB), new aluminum intake with blockoff plates, new Robertshaw 195 thermostat, and even a new fan clutch (Delco 15-4947). Everything seems to be in order.

Feedback, thoughts and anything else is more than welcome. Thanks all!

Chris

Chris S. - 77 Kingsley, 3.70 FD, mostly OEM - S.E. Michigan

[Updated on: Sun, 04 June 2017 21:55]

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