lpg timing

[malcolmjeffries]

What is the best timing for 1990 3.9 classic running lpg

[scruffy]

Hi, I believe that 9 degrees advance will suit . Check with BeeUtey on this forum and he will tell you what settings and plugs work best. Bob

[bee utey]

10 to 12 degrees BTDC at idle works well but make sure your advances are working properly, lack of vacuum advance will reduce economy, lack of mechanical advance will make the engine sluggish at revs.

[UncleHo]

G'day Bee Utey :)

I have an 85 3.5 HC (9.35:1) RRC carbied model, on LPG (Impco) and am running at 8 deg.BTDC is that OK ? or should I go higher,Vacc advance is good,as is mech adv.getting about 5klms per Ltr gas.


cheers

[bee utey]

G'day Bee Utey :)

I have an 85 3.5 HC (9.35:1) RRC carbied model, on LPG (Impco) and am running at 8 deg.BTDC is that OK ? or should I go higher,Vacc advance is good,as is mech adv.getting about 5klms per Ltr gas.


cheers
I don't have a lot of experience with the older RRC carby models, although all the 9:1 P76's I did all ran well at 10 degrees. It depends on cam timing and advance curves as well, too much advance, especially under light load (=vacuum advance) the engine may run jerkily. I used to run without vacuum on the P76's and rely on mechanical only.