Ignition timing for B18D

[iain]

Any suggestions on what the baseline timing figures for a B18D engine should be when fitted with D cam and large bore 4-2-1 exhaust manifold and system? Distributor is Bosch 002 (centrifugal advance only) which will theoretically allow a total of 30 deg advance (at crank) from the base static setting (I measured this myself). Haynes manual shows a static figure of 19-21 degrees (if memory serves me correctly) in the specs, but says to time at 10 (static) in the text. I tried both methods, the engine definitely ran better with more static advance; which would seem to support the theory that modified engines usually require more static/idle advance to run well. BUT I don't have any information to say where in the rev range the distributor should reach maximum total advance and what that maximum advance should be to give best power output without running into pre-ignition with modern fuels. It would be useful to get hold of the ignition advance curve for this distributor so I at least have a start point! Any info and known methods for determing these settings would be much appreciated!

[swenglish]

Hi, I've just been throught the whole process myself. I have a B18 with a 'D' cam, and 4into1 manifold. Sadly my head is a bit high on the compression side for modern fuels so we weren't able to explore the full advantages of the advance curve.

However, I would have thought you should be aiming for about 35 - 36 degrees of full advance and slowly increasing this figure until you get pinking (The best way is to do it under real road conditions). I'm not too sure what RPM you will hit full advance between 3500 and 5000 depending on distributor.