Michael---It's good that your engine is now running well since getting
it back from your mechanic. It is very possible that the "sluggishness"
you now feel is because of the timing (retard) changes. As Hugh
reported, a lot depends on whether this mechanic set the timing with the
retard connected or not. To set it at 4 deg. ATDC with a perfect retard
cancelation taking place (as you accelerate) would be OK., as this could
add around 14 deg. to the timing advance.
If you want to check this, it's best to use a timing light. Do these
'before and after' test, with and without the vacuum connected.
If you find the timng to be less than 10 deg. BTDC with no vacuum
connected, then increase it to the 14 deg. that you had before.
Reconnect the retard if you wish, or leave the line plugged. If you opt
to have no vacuum connected to the dist. it may then idle fast. Back off
equally on both idle set screws as Oliver mentioned, till you are
satisfied with the engine speed. This should not affect the other
carburetor settings.
Dick
From: SamuelsMA@aol.com Date: Sat, Subject: ignition timing
Listers:
After all the rough-running problems related to carburetion that I was
experiencing a couple of weeks ago, I finally gave up and took the '76
into a good mechanic. I got it back today, running and accelerating
smoothly. I didn't get a really good explanation as to what was wrong
with the carburetor settings, except that he adjusted and balanced both
carbs and the bucking/backfiring went away.
Anyway, the point of this post is that he noticed that the timing was
set on the car, presumably by the P.O., at 14 degrees BTDC. This is a
heavily modified motor with high compression, aggressive cam, headers,
lightened flywheel, etc. The mechanic set the timing to spec, which is 4
degress ATDC according to a sticker on the underside of the hood.
Although the car is smooth, it feels noticeably weaker to me than it did
before the timing change (and before the carbs got screwed up). It just
has a "sluggish" feel. The car did not "ping" or detonate before on
premium fuel with the advanced timing.
Should I advance the timing in steps to see what happens? As long as I
don't hear detonation, is there any problem with doing so? What timing
settings would be expected for optimal performance on 93 octane fuel
with a motor like mine?
Thanks.
Michael
'76 Tahiti blue
CF 57044U
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