BPE HEI Distributor
Just pretty linited on time but see what I can point you toward.
If the valve overlap has increased, compression is lower, or things like that which dilute the fuel mixture at idle or take heat (energy) from gasifying the fuel mix at idle, then more initial will be needed. In the 'how to' section of FABO Halifaxhops posted a chart of suggested initial timing for cam duration and engine displacment.
If the cam is now more performance oriented and say a 4 bbl carb instead of a 2 bbl and enaything else that builds efficiency and heat into the mixture with rpm, then less advance is needed in the curve. For examples look for some of the factory hi performance 440 timing curves I've posted vs say a 2 bbl 383 or 318.
Timing on engine.
If the engine wants more timing at 1000 rpm (you're using MVA to accomplish that) then 16 at 1000 is probably not enough.
You're smelling raw fuel indicates its not burning completely or misfiring. Classic.
I agree wiyth your gut instinct that more initial is needed on this engine.
I do think that to use with vac advance, the mechanical timing over 1800 rpm will need to be reduced.
Get the idle and off idle, then go look for the thread on afjust GM type advances at RFS.
Also note his warning about using unequal springs on certain types of advance mechanism. In that case just make a compromise.
Seems like it will be worth checking out the transfer slots.
The idle mix screws are needed to provide extra richness, but then the PV is somehow helping by making it a little leaner off idle.
I'd be interested in the t-slot position at idle, along with rpm and vacuum in N and in gear.
Ok Ok. Different engine then situation will change to some degree.
Just pretty linited on time but see what I can point you toward.
If the valve overlap has increased, compression is lower, or things like that which dilute the fuel mixture at idle or take heat (energy) from gasifying the fuel mix at idle, then more initial will be needed. In the 'how to' section of FABO Halifaxhops posted a chart of suggested initial timing for cam duration and engine displacment.
If the cam is now more performance oriented and say a 4 bbl carb instead of a 2 bbl and enaything else that builds efficiency and heat into the mixture with rpm, then less advance is needed in the curve. For examples look for some of the factory hi performance 440 timing curves I've posted vs say a 2 bbl 383 or 318.
Timing on engine.
If the engine wants more timing at 1000 rpm (you're using MVA to accomplish that) then 16 at 1000 is probably not enough.
You're smelling raw fuel indicates its not burning completely or misfiring. Classic.
I agree wiyth your gut instinct that more initial is needed on this engine.
I do think that to use with vac advance, the mechanical timing over 1800 rpm will need to be reduced.
Get the idle and off idle, then go look for the thread on afjust GM type advances at RFS.
Also note his warning about using unequal springs on certain types of advance mechanism. In that case just make a compromise.
well I can help with the 3310
Thats pretty extreme. Shouldn't need that much advance.
Seems like it will be worth checking out the transfer slots.
Well that's interesting.
The idle mix screws are needed to provide extra richness, but then the PV is somehow helping by making it a little leaner off idle.
I'd be interested in the t-slot position at idle, along with rpm and vacuum in N and in gear.
