timing

[bonvo]

is it possible to do any damage with to much timing? im not sure where mine is set right now but it doesnt ping and it starts up right away but i know its higher then 12 degrees what do you guys think is a good point to set the initial timing

[Cuts metal like mad]

depends on the induction setup and the ignition setup. With a weber downdraft and electronic ignition, I'd say 12-15...

[bonvo]

depends on the induction setup and the ignition setup. With a weber downdraft and electronic ignition, I'd say 12-15...

 

thats exactly what im running but we have it set at the moment i think at about 18 not sure would need to double check it

[ggzilla]

YES -- too much timing can damage your engine, melt the pistons, crack the ring lands, etc.

 

Total should be less than 32-35 degrees at full throttle and high revs. Datsun distributor may have 24 degrees total mechanical, so you could have up to 11 degrees static advance. Another distributor may have 22 degrees, so 14 degrees static might be OK.

 

That being said, you can usually tell if it's too far advanced by listening for "pinging". But it's hard to hear if you have loud exhaust.

[bonvo]

have any of you guys ever heard of pinging getting worse when you retard the timing? my dad says he thinks its worse now that we bumped the timing back a little i think it needs to be retarded more but thats me

[datzenmike]

The rotor turns counter clockwise so to retard the timing you have to turn it clockwise. Sound right? ...and no, retarding should not increase pinging.

 

Forgot to ask ... this a stock carb with vacuum advance?

[Jester]

Great topic Bonvo.

I was talking to Steve @ Z-Therapy on this issue. He told me that a lot of the "match box" dizzys have a TOTAL advance close to the 70 degree mark. That is seventy!!! It is in the way they are made. He recurves his to keep them under 38 degrees total advance. My spare is going in soon!

[datzenmike]

Under certain conditions of light throttle or deceleration, an advance of around 50 degrees is possible. 70 seems a bit high. The dizzy has a mechanical advance of 20-24 degrees built in but has to be revved to 3K? The static timing is 12 degrees set by timing light at idle. So there is the maximum 33-35 degrees total advance at full throttle. At full throttle there isn't enough vacuum to cause any dizzy vacuum advance but if the throttle is lifted suddenly at high RPM, full vacuum advance of 12 or more degrees would be added to the static and mechanical advance pushing it up well into the high 40s, maybe higher... but only at high RPMs and light throttle. No L engine will run with much more than 35 degrees total advance at full throttle.

[freaky510]

I have been told that you need to unhook the vacuum advance when you time your motor to get a true tdc. any truth to this??

 

I have aways since unhooked my vac adv when timing a motor and they seam to work out great just my .02

[datzenmike]

Not after about '70. The vacuum is ported at the carb and the opening is above the throttle plate. As the throttle is opened the plate moves above the opening and applies vacuum to it advancing the dizzy. There is no vacuum advance at the dizzy at idle on any L20B and L18s. Maybe some of the earlier '60s L16s maybe not.

[freaky510]

do you time yours at an idle or 2500 rpm?? I was told to time your motor anywhere from 2500-3000 RPM with the vac off it give you a more accurate load timming.

 

just they way my grandpa showed my and we never used a light lol

 

now i just have my mech do it