you've prob already been replied to about this but..
BTDC is before top dead centre
BBDC is before bottom dead centre
ABDC is after bottom dead centre
The prob with all these cam specs is that there is no indication of what
clearance they are measured at. Most of them are measured a 20 thou valve
clearance, or after about 1974 it became 13. The timing used by ISKY and
most engine tuners is at 50 thou clearance. The timing of the standard cams
are thus in reality much more docile than they first seem.
Greg
----- Original Message -----
From: <ellis838@concentric.net>
To: <alpines@autox.team.net>
Sent: Wednesday, 15 November 2000 02:53
Subject: Re: Camshaft details
> I hate to display my ignorance but could someone give a lesson in
interpreting this information. I assume you can figure duration from these
figures and whether it is a dual pattern. I know ATDC is "after top dead
center" what are the rest?
> Thanks for any enlightenment. Jim
>
> Ian Spencer wrote:
>
> > Someone requested camshaft details a few weeks back and I just happened
to stumble across some that someone sent to me.
> >
> > Alpine S 1-4, inlet opens = 14, inlet closes ABDC = 52, exhaust opens
BBDC = 56, exhaust closes ATDC = 10. Lift = .26 BHP = 80.5 torque lb/ft =
93.4
> >
> > Alpine S 4A inlet opens = 19, inlet closes ABDC = 57, exhaust opens BBDC
= 61 exhaust closes ATDC = 15 Lift = .26 BHP = 80.5 torque lb/ft = 93.4
> >
> > Alpine S 5 inlet opens = 29 inlet closes ABDC = 63 exhaust opens BBDC =
69 exhaust closes ATDC = 23 Lift = .298, BHP = 90.5 torque lb/ft = 103
> >
> > Works Stage 2 race, inlet opens = 25 inlet closes ABDC = 59, exhaust
opens BBDC = 63 exhaust closes ATDC = 21 Lift = .41
> >
> > I also have the specs on the Holbay E128 & H120, Burtons Fast Road &
Full Race, Piper Fast Road & Full Race, and the Howe Fast Road & Full Race
if anyone needs them. Thanks to who ever sent this to me, I don't seem to
recall at the moment.
> >
> > Ian Spencer
> > Client Services
> > University Hospital
> > Health Alliance of Greater Cincinnati
> > (513) 584-0365
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