The problem is that my timing needs to be
set at
32 deg BTDC at idle to run smooth (yes, I said 32). Setting it
at 12
deg
BTDC at idle makes it stumble, miss and hesitate between 1500
RPM and
John - I'm facing the same problem you have with my 71 TVR. My
engine was running fine until I decided to do a major tuneup (I
still have points). Dick Taylor is right - spend some time with
the valve timing. The Haynes repair book specifies when the
inlet and exhaust valves are to open and close. Measure the
circumference of your crank pulley (I think mine was 20 & 11/16
inches) and make a computer-generated scale to mark it all the
way around so you'll have timing marks for all 360 degrees of
rotation (so you'll know where 65 degrees ABDC is). When
checking your valves, don't eyeball it - use a feeler gauge to
help you judge precisely when a valve is opening and closing.
I thought my ignition was firing 30 degrees before it was
supposed to - it ran best at about 28 degrees BTDC (spec for
dynamic is 4 degrees ATDC), and I thought I was having timing
chain or sprocket trouble. But checking the valve timing taught
me they were opening within a degree or two of spec, so I
started to look elsewhere. I now have my carbs apart, trying to
rule out carb blockage and gumminess as the cause of a
higher-rpm hesitation.
We need to compare notes in a few weeks.
Bob Rothstein
Northern Virginia
1968 TR-250
1971 TVR 2500
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