Timing Problems

[TOYrantula]

Alrighty Guys....
I have timed my engine up and all runs fine for about 10mins. Then things go wierd on me. When she is cold, she'll backfire through the carby and not ping at all, yet when she is warm, it wont backfire through carby, but ping its tits of under hard acceleration.
What could this be from?? Maybe something lose in the distributor??
Engine is V6 Chev on unleaded.

Regards,
Damien

[80diesel4play]

If it's a dizzy type non comp' - then check advance - probably not advancing so as cam comes in the ignition is still at 6 degrees.
Open up teh dizzy and flick teh points plate to see if stuck etc...

Check vacuum hose to advance unit on side of dizzy.
If it's a computer or ecu run system - then I have NFI.

[Roktruk]

Seen something similar on a Holden blue motor. As engine temp increased the module on the distributor was packing in, eventually stopping the engine.

Pinging at temp can also be caused by wrong heat range plugs, cruddy plugs or crap buildup (carbon) in motor. Makes little hot spots that can pre detonate the fuel

[RUFF]

Do you have the vacume advance hooked up or plumbed the the right spot on the holley?

80diesel4play
This engine runs a factory HEI Dizzy.

If you have the vacume advance hooked up to the corect port in the carb the try unplugging the line and then suck on it and see if it holds vacume.
Im sure i checked it while i had it and it was fine.

[OVERKILL ENG]

I would tyend to agree with rocktruck on this one.
if the advance wasn't working then it wouldn,t ping at all as it would be retarded.It may cause it to backfire though if the vacum advance didn,t work.
I would check the module first.

[Punchy]

them chev v6's were a nasty engine for that

Start with them basics as well..

Hammer in the left hand and timing light in the right

Make sure the harmonic balancer timing mark is actually true..like TDC is actually TDC

It may say x degree..but could be actually 3 mile down the road saying y degrees..

start with the basics..

After you have acertained that... Set the initial ignition timing..

Get it so it starts and runs right at idle...without the vac advance connected
Then measure out how much advance it is getting mechanically as you rev it..

IF the beast is going past 34-36 degree's total ignition timing..you may have a buggered dizzy and need the advance plate stops repaired...

Dont worry about the vaccum advance for a bit...it should do jack squat while your on the gas anyways..
vaccums only really used to increase mileage on the highways by increasing the advance at part constant throttle..

I never use them anyways...one less thing to go wrong..
PS:
NO VACCUUM ADVANCE AT IDLE

RIght timing and still pings ?
The chev v6 had hi compression to start with...nature of the beast..

Check he carb settings arnt all stuffed up as well...to much fuel will make it ping as well as too little will as well..

try a colder plug range

hmm
mayby a b6s...chev racing plug

cheers

[TOYrantula]

Alrighty then I'll try all that.
I know a mate has one and he said he timing mark was no way near TDC. So will check all this. Keep you all posted.

Regards,
Damien