I experienced vapor lock with my 66 in heavy traffic during the summer. The
cure was an electric fan which flowed a lot more air than the crappy stock 4
blade steel fans. When you need it the most, idle, the fan just didn't kick
out enough air. Maybe the 7 blade fans are better but I found it easier to
get an electric fan.
Back in the very early 80s I was isolated from other Roadster owners. Now
it's much better : )
Mike
----- Original Message -----
From: "Todd Osborn" <trosborn@california.com>
To: "Roadster Listgroup" <datsun-roadsters@autox.team.net>
Sent: Sunday, April 07, 2002 4:03 PM
Subject: Re: Vaporlocking
> Dan,
> Are you sure it's vapor lock? You may be fouling the plugs, are you
running
> N-17 needles in your SU, these run very rich at low rpm, worse at high
> altitude. I too have never experienced vapor lock on my roadster, had a
> friends roadster lock up at Tahoe (6200 ft) one time, but it flat wouldn't
> run, no sputtering and such. Didn't find the cause, just waited and
refired
> fine. Mine runs very rough if I have to idle in traffic for more than 10
> min., I' running N-17's and probably have the float level too high.
Haven't
> tuned the SU in in a while since I want to put the Solexes on. You might
try
> some low speed runs to recreate the problem, then stop immediately and
pull
> the plugs. If the plugs are black then it's too rich and fouling, if the
> plugs are gray or gray white, then it's too lean and it may be vapor lock.
> If it's vapor lock I would check the return valve as already pointed out,
I
> find this valve very funky and I think Tom Walter said you can replace it
> with a simple restrictor (~1/4" rod with small hole drilled through it).
The
> very small but continuous fuel flow should prevent vapor lock. Good luck.
> Todd Osborn
> San Jose, CA
> '68 2L DATSFUN
>
> ----- Original Message -----
> From: "Dan Neff" <neffster189@adelphia.net>
> To: "Roadster Listgroup" <datsun-roadsters@autox.team.net>
> Sent: Saturday, April 06, 2002 10:29 PM
> 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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