calvin

Running an AR3933 with the cut back electrode, kinda worried the D1r may be putting out the 'candle' and am thinking of trying a standard type plug. Plugs are for a flat top pistoned, AFR 335 head combo

Thanks

calvin

ttt

calvin

no one runs a SC'd BB chevy? lol

boosted-lt1

Calvin,

Mostly 4th gen guys around here

What gap are you running?

-Scott.

calvin

Hi, no gap. The AR3933 that I run has a cutback electrode. So it's pretty much gapless

boosted-lt1

Still, a spark must jump a gap across two electrodes to ignite the mixture. This gap will typically need to be tightened up when running boost.

calvin

Correct, I understand that, but it's a bit unmeasurable. If I had to guess I would say out of the box it sits somewhere around .055 to .065

boosted-lt1

Hmm. I'm not familiar with a plug like that. The side electrode is 'cut back' real short then and can't be adjusted?

Usually about 0.035" is recommended on a plug 2-heat ranges colder than a stock plug.

-Scott.

calvin

heres a pic http://cgi.ebay.com/ebaymotors/Autol...4506.m20.l1116

It looks in that pic that the negative strap comes over the center but it doesnt. Definitely not enough to actually gap

boosted-lt1

Well in that case you may want to try a plug that can give you ~0.035" gap. I dont think anyone on a blower or turbo is going to recommend more than 40-45 gap.

-Scott.

mzgp5x

Try a Zex power racer series plug (available from Summit). I went to a Zex and have not had any fowling problems. Copper core with nickel coat. They stay quite clean. I had alot of problems with NGK. I'm running 0.035" gap. App... (97ss 383 D1 M6 - 15psi). Also, I run a MSD 6A with a MSD 8202 coil and a manual timing adjust box. No timing retard... 34* advance with MAP > 100 kpa. HTH B.

roguedriver

You can gap them calvin. I've run the AR plugs on my 383 from time to time. I can see spark blow out if that is the gap your running. There a little tricky to gap, but you can. Like the others have stated, i'd close it up to .035 and start tightening up from there. Are you having problems with it cutting out as it gets up in the rpm's and boost? If so, then that sounds like its getting blown out. I liked the AR plugs, problem is that they wear out fast, so don't run them too long or the gaps will get huge and you'll be back to square one.

Ken R.