[Roadsters] Was Engine test results, suspect distributor

[Ronnie Day]

> Dan McHatton
>
> I think my problem is my distributor. I found another cap and rotor then,
went
> to grab my coil wire from my old Chevy to have a complete set of fresh
plug
> wires. While I was there, I checked the play in the Chevy distributor
rotor.
> When you twist it lightly and let it go, the springs snap it right back to
the
> home position. When you try the same trick on the Datsun distributor, the
> rotor has lots of slop in it.
>
> I'm thinking my distributor is worn and causing my backfire problem. The
> engine idles smooth as glass. Engine timing is 16 BTDC on the nose. Dwell
> angle 51 degrees. As soon as you rev it up, it misses and backfires.
>
First, I'm pretty sure even without checking that your dwell is way off.
IIRC, it should be around 30 degrees and it should be set before you set
timing. Then the timing mark should remain stable at any RPM as you rev the
engine. Yes, it should move (smoothly) as RPMs increase but any time you
hold an engine speed  the mark should not jump around, but stay in one spot,
until you change engine speed again. There are a number of reasons for
timing instability, including play in the distributor shaft or drive gears,
a breaker/advance plate that's worn out, etc.

HTH,
Ron