spark plugs

[tx-19]

i am running the dart pro 1 heads.it calls for the autolite 3933.i was just curious if this is to hot of a plug.if so what should i use.i am running 548 13:1 on 110 octane.thanks for any advice.

[Fiat48]

That is the same heat range as an NGK 9. Plenty cold. You should be fine.

[jmherbert]

i am running the dart pro 1 heads.it calls for the autolite 3933.i was just curious if this is to hot of a plug.if so what should i use.i am running 548 13:1 on 110 octane.thanks for any advice.
Cross it to NGK, much better plugs.

[DMOORE]

Cross it to NGK, much better plugs.
AMEN.
Darrell.

[Fiat48]

Hey now. Autolite plugs work real good.......in lawnmowers and weed eaters and such.

[78Eliminator]

Bob, can you bounce your old thread about reading the NGKs to the top? I have a couple people asking me to have you do that for the sake of national security.

[Fiat48]

NGK 9 heat range. Below are alcohol but gas is similar when soot is wiped off:
Watch the cad and the ground strap mostly.
Dead fat:
http://www.***boat.com/image_center/data/520/medium/3745.JPG
Closer:
http://www.***boat.com/image_center/data/520/medium/3743.JPG
Enough:
http://www.***boat.com/image_center/data/520/medium/3741.JPG
This is for NGK only. Your mileage may vary. No warranty expressed or implied.
Also note.....never attempt to do this with an Accell brand spark plug even tho the cad plating looks similar.

[tx-19]

i am currently running the acdelco plugs rlts42.i think they are the coldest plug they make.i think it is to cold.

[Morg]

Just to be perfectly clear. What Bob is showing you is the cad being burnt off the NGK plugs. The plating will tell you how much heat the plug is seeing.

[Fiat48]

Don't have a cross for that plug. But I suspect it is rather hot.
AR3933 crosses to ac delco = S41XL or 436XLS...to NGK R5671A-9 (stock #5238)
Peanut plug.
No clue about that plug you have in there. But I would get it outa there.

[Blown 472]

Thank you sir.:D

[fc-pilot]

The AR3933 is what we run in a number of our motors (granted that is on alcohol). When we tested different plugs we found that the NGK's were about two hundredths faster, but fell off performance wise faster. The Autolites would keep their consistency better which we really liked. Then again, this is just one persons opinion.
As far as heat range goes, that should be cold enough unless you are planning on running huge amounts of nitrous with an inadequate fuel system. :sqeyes:
Paul

[tx-19]

the spark plug we have now is the acdelco r42lts.didnt have the box last night.the boat is just river use.

[Fiat48]

That is equivalent to a #6 heat range. Id say an 8 heat range would be about what you need for lake use. 6 is too hot.
Ar3934
R5671-8