Need Racing Spark Plug Info

[jefffoxsr]

I haven't changed my plugs in several years since I don't drive the car much. 5 years ago I put in Autolite 103 racing plugs. I think the 103 is 2 heat ranges cooler than stock, but I can't remember for sure.

Info on my car. 86 gn, mild ported gn1 aluminum heads, 63 turbo, 55# injectors, alcohol injection, pump gas, JE race pistons, never run race gas, 125 mph at 22# boost (1/4 mile).

I have a few questions:

1. Is there an equivalent racing plug that is platinum or iridium for my use?

2. What Autolite plug would be one heat range cooler than the 103?

3. What plugs are you guys using that work well for 2 heat ranges cooler than stock, or for similar set ups as my car?

Thanks.

 

[WHEEZER]

Stick a set of Autolite 23's gapped .30 in there and forget the "trick" plugs. They'll be fine.

 

[jefffoxsr]

I can't remember, but I thought the 23 was only 1 level colder than stock. I have used them before, when the car was a bit more stock. They worked well.
I was told to use the 103's when I got the aluminum heads and I rebuilt the engine.

 

[WHEEZER]

Are you experiencing a problem you expect to be plug related? Have you taken out the plugs and read them?

 

[bison]

Stick a set of Autolite 23's gapped .30 in there and forget the "trick" plugs. They'll be fine.

He needs the long thread version. The 23's are for the iron heads(short threads).

 

[WHEEZER]

Thanks for that Bison. I wasn't thinking aluminum when I posted even though he specified.

 

[pwr.slave6]

Try NGK 108 or 109
Would use either in the gn-1.

 

[jefffoxsr]

No running problems, but I thought since iridium was out now that there might be one that people are using for gn1 heads.

The only problem I can't figure out is why the top of my manifold gets covered with oil. I clean it and it gets full in 30 minutes of driving.

I replaced the pcv, the grommet, etc.

That's the only place I can imagine the oil is coming from.

 

[SVORay]

I get oil from my trick valve cover breather. It doesn't have a good fit and oil gets splashed out the bottom of it.


Anyways, I'm not sure what the right plug is to use since I'm still new but just don't use Platinums. I've heard they stay hot and will cause pre-ignition problems on motors like ours. I'm not sure on that new trick plug they got out. I've found in most cases like forced induction motors, that typical plugs like Autolites or Ford motorcrafts work just great. Now there is huge NGK following out there amung the Gen 2 Lightnings and supercharged Harleys. I've even heard of LS1 guys having really good luck with them as well.

 

[Russ Merritt]

Autolite 3932s work well. I've also tried 3910s with success. Both are race plugs.

 

[jefffoxsr]

Thanks Russ.
How do the Autolite 103's compare to the 3932 and 3910?

I guess what I'm asking is What is the difference between the 3 of them.

Thanks.

 

[Russ Merritt]

Thanks Russ.
How do the Autolite 103's compare to the 3932 and 3910?

I guess what I'm asking is What is the difference between the 3 of them.

Thanks.

The 103s are hotter and have a regular ground electrode where the other 2 have cut back electrodes.

 

[bison]

The only problem I can't figure out is why the top of my manifold gets covered with oil. I clean it and it gets full in 30 minutes of driving.

I replaced the pcv, the grommet, etc.

That's the only place I can imagine the oil is coming from.

Check your valve cover gaskets. I recently found a huge leak on a friends car because of an improperly installed valve cover gasket. Same symptom you have. It was blowing oil all over the intake. Some was leaking down the back of the engine also.

 

[Nick Micale]

Autolite 3932s work well. I've also tried 3910s with success. Both are race plugs.

The 3932 plug is a very cold plug and would probably foul quickly with street use. It is also a washer-type plug so you need to determine where it ends up in the combustion chamber - could be too long or too short for a Champion head?

The Autolite AR-3935 or AR-3934 would be better heat ranges for the street.

 

[jefffoxsr]

Thanks for the responses guys.

Nick, how does the Autolite 103 compare to the AR-3935 or AR-3934 in terms of heat ranges and other specs for my use on the gn1 heads?
These heads were bought in 1999.

 

[mybuick]

i would like to know what would be a good plug for my combo for street and change them at the track.

 

[jefffoxsr]

Nick, I called autolite and the tech said that the AR 3934 and AR 3935 are gasket seat plugs and that the gn1 heads take a tapered seat plug.

Is this information correct?

 

[Nick Micale]

Nick, I called autolite and the tech said that the AR 3934 and AR 3935 are gasket seat plugs and that the gn1 heads take a tapered seat plug.

Is this information correct?

That is what I said above:

"The 3932 plug is a very cold plug and would probably foul quickly with street use. It is also a washer-type plug....."

You need to ask the rep what is the equalivant type plug for a tapered seat to work with your GN-1's. He can also give you the various heat ranges of them.

 

[jefffoxsr]

Thanks for the comments Nick.

The rep said the AR103 would be the one, and the AR94 would be one step colder than the AR103. Both are tapered seat.

 

[V8killR4U]

I kind of have a similar question. I just changed my plugs and got some 103's for my Aluminum GN-1's. The plugs i pulled out had a washer of some type on them. The 103's had no washers when i bought them. My question is do I use the washers or not?