Bryan, Yes, with the ignitor, dwell is not a problem as it should remain
constant, which means the timing should also. David Alton at APT claims that
for a street engine the vacuum advance distributor should always be used (see
their web site). I think you should be able to pull the vacuum off the intake
manifold, but check with someone who knows the dellorto carb set-up. In any
case "Speed Timing" is still the way to go the settings the books give at idle
assume that you have an advance curve that will give the proper advance at
speed. Unless you use a dyno to set the total advance I find that the 36-38
deg total advance @ 4000 rpms works well, with an absolute max of 40 deg.
> You are absolutely right. The crank timing should not change. I didn't really
> 'think' when I sent my first message.
> When I had the head off, that's when I checked for TDC, and noticed that the
> 'pointer' on the front of the timing cover was off by 2.5 degrees, so I just
> assumed it had moved. It goes to show how 'accurate' the actual factory
> Since I am using an ignitor electronic ignition, I don't think I have any way
> adjust dwell, so I don't think think there's anything to worry about there??
> I don't have the vacuum advance for my 'stock' 1275 dizzy hooked up at this
> point, since I'm using a dellorto side-draft, which doesn't accommodate for it
> If I don't hook this up, will that cause a problem down the road ??(so to
> Does anyone out there have any info on modifying a side-draft, for vacuum
> advance?? It seems like a a properly placed hole drilled through the carb body
> would do the trick, but I don't want to do that unless I'm really sure about
> what to do.
> At this point I'm not really in the mood to spend a lot of $$ to buy a new
> mechanical advance distributor. I've poured a lot of time and $$ into this
> project so far, and it's getting harder for me to justify spending even more
> at this point.
> Regards - Bryan
> >X-Unix-From: email@example.com Fri Jul 30 21:31:02 1999
> >X-MSMail-Priority: Normal
> >X-Priority: 3
> >To: "Bryan Vandiver" <Bryan.Vandiver@eng.sun.com>
> >Cc: firstname.lastname@example.org
> >MIME-Version: 1.0
> >Subject: Re: Timing the 1275 ?
> >X-MIME-Autoconverted: from quoted-printable to 8bit by triumph.cs.utah.edu id
> >Bryan, If you used an "offset cam key" the timing mark on the "crank"
> change. TDC is TDC for the piston not the cam and the piston is connected to
> the crank not the cam. The key is to install the timing cover and crank
> while your dial indicator is still on #1 piston so you can mark TDC. Then if
> you don't have and advance timing light you can also make marks at 10 and 37
> deg, I use different colors for each mark. Total advance should occur at 4K
> and should be between 36 and 38 deg according to Vizard (as I recall the book
> calls for 34 deg stock). Then you can "speed time" it at 4k and then check
> timing with a static light so you can R&R the distributor fast if you need to
> later. If you don't have either a advance or regular dynamic light have
> else speed time it and then go home and static time it and make your two marks
> on top where you can see them, you can then repeat the setting whenever you
> disturb the distributor. Did I mention that t!
> >he points dwell affects the timing but the timing doesn't affect the dwell.
> Thats another story, always check the dwell before the timing.
> > Crash