Which spark plugs?

[Gene Fiore]

It has been suggested to me to run a slightly colder plug when out at the drags to see if it helps performance. I am currently running the OEM Autolite plug, part# 46. I've been looking on Autolite.com but can't seem to find out much. Anyone have ideas what would be a colder plug, whether it's an Autolite or some other brand?

 

[rbohm]

8) generally a colder plug wont help with a stock engine. one thing you can do is index the plugs. also push the timing as far as you can without detonation.

 

[AZstang66]

I know that you can go to Autozone/Checker and get them to find it for you.
As little as I trust them, they do have the computer which can find it. I think one time I bought slighty hotter plugs, Motorcraft I believe (if it isn't the same as Autolite) and they just brought them out.

 

[wsa111]

Gene, i like the NGK iridium plug.
I found the NGK iridium ix WR51X 7510 spark plug. This plug is very new on the market & has a pin sized iridium center electrode. Since I installed these plugs my idle is smoother & the throttle has better response. The cost is about $6.00 a plug depending where you buy it.

I believe if you go the autolite a lower # that would be colder.

What is the color of the insulator on the a46's??

Check this link out http://www.dragstuff.com/techarticles/r ... plugs.html

V/R Bill

 

[Does10s]

Gene,
We were using Autolite 44s and 43s. But that was for a heavily boosted motor.
I agree with rbohm that a more or less stock motor shouldn't need a colder plug.

Will

 

[mustangsilly]

I suggest "reading" your plugs. Look for a picture guide which indicates plug conditions based on appearance. I'm sure there are some on the internet. Generally, a sooty, black plug is too cold, a rusty colored plug is good. Electrodes shoud have flat, sharp edges. Use extended tip plugs for better reach in the head, which puts the spark further into the combustion chamber. If you advance the timing, the plug will run hotter, so check the plug color after making any changes to the ignition.

 

[Gene Fiore]

I just took my plugs out to look at them. OK, all you experts...what do you think? Remember, this is a stock motor with about 150,000 miles on it and it does burn oil pretty good. The only modifications are the exhaust and DUI distributor. Plug #2 looks to be in some distress while others look pretty normal. As you can see some of the plugs show a dark brown deposit on one side of the porcelain...others have the same markings but are on the oppposite side so you can't see it. It's hard to see the plug gap from these pics, but they are all still at around .055

http://i120.photobucket.com/albums/o180/gene_fiore/spark_plugs001.jpg
http://i120.photobucket.com/albums/o180/gene_fiore/spark_plugs002.jpg

 

[rbohm]

8) i wish my plugs would come out looking that good

number does seem to have a bit of a problem with valve guide sealing, but overall they look great. clean, them, regap them, and run them again.

 

[wsa111]

Gene, for 150,000 K miles on the engine those plugs look darn good.

I would stick with that heat range.

My choice are the iridium plugs by NGK, that might help you a little, but the cost is at least $6.00 apiece. Bill

 

[mustangsilly]

They look pretty good. How many miles on these plugs? #2 may have a valve seal leak or a little blow by on the rings. Have you checked the compression on #2 cylinder?