Hi Eric,
Pardon the intrusion. I think 45 degrees at 4000 rpm is a bit much.
Especially with a high compression engine. I think 35 degrees would be
more like it. You can get "silent" detonation at higher rpm which will
greatly damage engine parts, no audible warning. There would be very
little power gain from the extra 10 degrees & maybe even a power loss. I
think 45 degrees would be pretty risky.
Dave Russell
Frenken, Eric wrote:
> Olin, to me it seems your sparks are firing much too late. 8deg @
> 1,000rpm is way too late, I'd say this would mean around 0deg @
> 600rpm (or 0deg static). As far as I know your engine should have a
> static timing of 12-15deg BTDC.
>
> An increase of 10-12 deg per 1,000rpms is ok in this rpm range,
> increasing slower from about 2,300 rpms on, when the tension of the
> second spring cuts in. No increase above 4,000 rpms.
>
> I figured the following timing:
>
> 24deg @ 1,000 rpm 37deg @ 2,000 rpm 41deg @ 2,300 rpm (second spring
> cuts in) 43deg @ 3,000 rpm 45deg @ 4,000 rpm
>
> As fuel has not gotten better (lead wise) from the early days on, I
> would set static timing a bit later than 15deg, though I've set mine
> to 15 deg and haven't experienced any pinging since then, but I use a
> distributor without vac advance.
>
> All deg and rpm in this mail are crankshaft related.
>
> Eric BT7 Heinsberg/Germany
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