OK then gents (& ladies):
There is always a certain amount of debate over what is the correct timing
to use to prevent pinging and get best performance. Everyone seems to have
their own ideas, which can usually be summed up as "advance till it pings
under load, then back it off a bit"
I've noticed a lot of people saying they use 15-20 deg BTDC.
The factor which never seems to be mentioned is compression ratios/pressure.
Of course, the higher the comp ratio, the less advance you can get away with
for a given octane rating.
The reason I raise this is :
66B. 18GBUH engine. Compression pressure = 170. K&N filters, #6 needles.
Mild cam. Stock distributor. Free flow, single muffler exhaust. NGK BP6ES
plugs.
Local fuel here is about 94 - 96 Octane leaded.
Dynamic timed at 700rpm, vaccuum advance disconnected and blocked at carb =
5-7 deg BTDC.
And it still pings very slightly under heavy load (like full throttle, 3000
rpm up a steep hill) when warm.
Now, either I have something very strange with my engine, or I am doing
something very wrong, or everyone else on this list is imagining things (and
I'm not quite egotistical enough to believe that!). I've tried disconnecting
the vaccuum advance; this helped the pinging problem, but introduced
hesitation on sudden throttle opening (not entirely unexpected).
Comments, anyone??
Tim
66B rdstr YGHN3-3238
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