All,
First, thanks for all of the suggestions to date!
In my obsessive desire to get the car to "purr" at idle, I have:
Set the valve lash (I even measured the cam lobes for good measure)
Set the timing
Set the idle
Set the mixture
I am getting between 20-21 vacuum at the intake manifold.
Roughly 185 compression on all four cylinders
But I was still getting a "jumpy" idle, normally varying between 800-900 RPM,
occasionally dropping into the 700s..
So, on a suggestion from Randall I went and got myself a timing light and
found the timing is jumping, to the advance side.
Hmm.. maybe the dizzy gear end float.
Checked it. Just over .007.. just exceeding the upper limit.
But I thought, maybe its the Pertronix dizzy with a loose advance.
Pulled it out and dropped in my recently rebuilt Lucus tonight.
Set it to the same timing as the other (8' BTDC), and I still have the jumpy
timing, again to the advance.
So, I've got something that is causing the spark to fire too soon at idle.
But it evens out when I give it some throttle.
At this point I am suspecting that maybe that dizzy gear is jumping around,
causing the sporadic advance.
But this space is taken up under throttle.
Or, the timing gear/chain has got some sort of slop.
I'm considering having my dizzy pedestal shaved done .003" to take up the
float space, and/or replacing the dizzy gear.
I'd like to eliminate these before diving into the gear/chain.
Anyone know where I can source a "new" dizzy gear?
Anything else I am not thinking of?
Cheers,
Guy D. Huggins
1965 Triumph TR4A
CTC 63569LO
Online project diary at http://www.genfiniti.com/triumph
** triumphs@autox.team.net **
Archive: http://www.team.net/archive
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