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Author Topic:   spark plug advice needed
posted August 05, 2004 11:10 AM
plugs are showing no coloration.355 W/ small 2bl was jetted 72 went to 78 plugs showed no difference looked very lean.Ran 45t plugs during breakin,plugs were black and fouled looking,put in 44t plugs,set valves,changed oil,reset timing to 34. And went to track ran it hard 12 laps,did plug check,12 more did plug check,rejet to 78, 12 more laps.No difference still look new,no color.Any advice?

posted August 05, 2004 12:35 PM
what fuel you usin first?
a plug check is just a way of reaffirming what your **** is feeling. you can feel if its rich or lean, , also based on water temp, etc. but at speed its gonna take a while before plugs start to show color, especially on methanol. I have ran plugs for 4 nights in my 360 that still looked like new. cept for the strap of course.
just suggestions..

posted August 05, 2004 12:58 PM
im runnig avgas,motor is 355 pop up 76cc heads,all msd ignition,350cfm carb,big cam like 540,525 lift,ac44t plugs. Could my prob. be in ign. somewhere.Where should I start.What all should i look for.Cant afford anymore engine failure.

posted August 10, 2004 06:59 AM
I'd start by not running AV's meant for high altitude use in engines that run one constant rpm for long periods of time. Not at ALL meant for racecars.


posted August 10, 2004 01:44 PM
I kinda agree with you kp I had my doubts about avgas also,but 2 of my close buddys run it with no prob, yet,with almost full season on motors,also i asked my engine builder if it would be ok to run and he said it should be fine.Motor only has a fiew laps onit.
haventran a full race night on it,but plan to this wknd,and dont want any more problems.

posted August 10, 2004 08:56 PM
ok my pistons are kb, big domed,882 heads cutdown,not sure how much,been worked pretty good.Crower 00351 cam.My builder said it should be up around 12.5 to 1 comp.He also said ac44t plug shoul be fine.With 72 jets car didnt seem to miss or anything while I was running.But with the 78 jets it had a small flutter at the end of the strait around 6200rpm.But the plugs showed no difference in coloration.When I took it off the trailor this morn i checked plugs again ,black sooty color.??????

posted August 10, 2004 09:56 PM
also would valve adjustment effect what my plugs are looking like?

posted August 11, 2004 04:52 PM
I was doing some looking in the archives about spark plugs and seen a few post that said tapered seat plugs would not work in 461 camel humps. Thats all i ever used is tapered plugs in my 461's. According to Autolites website the oe plug was #303, is this a tapered or gasket plug? Is it possible to use both?

[This message has been edited by waltonjr1 (edited August 11, 2004).]

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