Jeff,
My motor does this as well, but only at low rpm's. This is typically due to
overlap of the intake/exhaust valves. I've got a comptune cam that does
this as well but to a much bigger extent.the duration of it is 318 and lift
is over .5" The A-8 cam has a little less lift and little less overlap, but
reliability is better and with the comptune cam you need to run at least
14:1. Have you checked at about 2k rpm when cold?
aaron
----- Original Message -----
From: "Jeff McNeal" <jmcneal@ohms.com>
To: <spitfires@autox.team.net>
Sent: 31 March, 2003 13:53
Subject: Tuning
> Another lister mentioned something that I've noticed with my carbs -- the
> slight pushing out of air with some fuel misting from the carb throat. My
> engine seems to be running just fine, steady idle, good, strong
acceleration,
> no pinging and when I turn off the engine, no running on. I've not
formally
> set the timing, in part because I'm not sure exactly what it should be. I
> started with a MkIV engine, but it's been highly modified from the head on
> down, including a fast road cam from Ted Schumacher (.425 lift).
>
> All outward appearances tell me that the timing is just fine -- but the
> reverse airflow from one or more of my carbs (at least when the engine is
cold
> -- I haven't checked it after warm-up yet) has me curious.
>
> Is this just a very fine tuning timing issue? Or should I be concerned
about
> something else?
>
> TIA
>
> Jeff
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