Almost sounds like you don't have a good fuel flow at low RPMs. Have you
checked to see if the fuel return line is clogged? Is the pump putting out
enough volume? Could it be that the lever on the pump or the cam that
activates it are worn so the pump is not making a full stroke? Or is the
spacer between the pump and block too thick so the lever isn't ridding fully
against the cam? I know these 'guesses' are out there, but it sounds like
you've covered everything else.
Lots of questions I know, but this long distance diagnosing can be tough
and there is an order of hot cakes riding on the out come, right Teddy?
Please keep me posted on what you find.
Paul
OROC
----- Original Message -----
From: Dan Neff <neffster189@adelphia.net>
To: Roadster Listgroup <datsun-roadsters@autox.team.net>
Sent: Sunday, April 07, 2002 1:29 AM
Subject: Vaporlocking
> Greetings y'all,
>
> Well, I've been driving and tweaking my car all winter, and figured
> FOR SURE I've got this thing tuned so sweet it couldn't possibly have
> vaporlock problems come summer time. NOT!
>
> Pretty much a normal (non-race) setup: non-smogged, 1.5 yr old
> Ztherapy SU's, header, Boone's EI dizzy, fuel line goes around front of
> engine, bracketed away from it (another WyCROCer ran his fuel line around
> the front of the rad, made no difference). Heat shield's there and in
> good shape. Fuel pump's only a year or 2 old. Valve job a year ago. Runs
> like a top. Gets about: 30mpg highway, 27mpg town, 3,000 mpq oil. NEVER
> overheats - we thought the temp gauge might've read low, but the head was
> STRAIGHT and stock thickness last year. I've put about 60,000 miles on it
> in 4.5 years :) - and it's ALWAYS had vaporlocking problems in the
> summer (80-95 degsF) (until now, there's usually been several possible
> influences/mech'l problems).
>
> Even today where we hit around 70, I get in stop'n go traffic/lights,
> and it puts up with it for a little while, then starts sputtin' and
> farting (so do I, but that's another story...). Maybe it's altitude?
> I'm at 7,000 ft.. Everything boils at a cooler temp up here. 'Course
> once I get on open road, it clears up after a minute or 2. I WOULD say
> it recovers quicker than ever before...
>
> I could've sworn one of you Arizonian roadster folks mentioned never
> having had a vaporlock problem, even in 100+ weather! If so, HOW SO???
>
> Wish I could test the altitude theory by bringing it down to Solvang.
> sigh. Maybe next year.
>
> thanks,
> dan neff '69 2000
> colorado springs, co
> http://www.wycroc.org
>
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