Peter writes:
>First, in the above example, advancing the timing means moving it more
>degrees *after* TDC (ie to 6 degrees after) or in the other direction
>(ie. 2 degrees after, then 0, then 2 degrees before TDC)???
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Peter,
When Im talking advance, that means basically BEFORE TDC. anything after
TDC is really retarded ( in more ways than one :-}). SO given that some
Triumphs are factory set (Vacuum line disconnected) at 4 deg's after, then
you would advance timing by setting it to two, deg after (from the factory
spec), Do the load test, advance it again if no pinging, to TDC etc. etc.
until you just hear it ping, then back off a couple deg's. Remember, this
is not to be done on any emission controlled vehicles, or you will surely
fail testing. . .If your not worried or don't have to pass any tests, than
this method will ensure that your timing is set best for your engine,
however, you shouldn't exceed a maximum of 32-34 degrees TOTAL advance at
the crank shaft on just about any engine (that's the advance at around 4000
rpm reved up in your driveway). The 2000 rpm load test would be done,
preferably climbing a hill then fully mash the throttle. The idea is to
almost lug or load the engine heavily so you can detirmine if the engine
will knock under high load conditions, something you don't want to happen.
If all is well, and it doesn't knock under high load conditions, then you
have set the timming advance for your particular engine for maximum power-
As an example, the GT6 I have is timed at 15 deg's BEFORE (vacuum ADVANCE
line disconnected) TDC. As long as there is no knocking or engine
detonation, you aren't going to damage anything, and I've been setting my
engines this way for twenty years (or more). As an added benifit, your
engine will run cooler at idle, because its running more efficently (again
for maximum power, not emissions) It's an old racing, seat of the pants
timing trick I learned.
Barry Schwartz (San Diego) bschwart@pacbell.net
72 V6 Spitfire (daily driver)
70 GT6+ (when I don't drive the Spit)
70 Spitfire (project)
73 Ford Courier (parts hauler)
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