Spark Plug Information Needed

[Vegascorbin]

I searched for this and did not find what I am looking for.

I am looking for information (or a GOOD web site) that discusses the pros and cons of the different types AND the different brands. I have been to http://www.sparkplugs.com/ and it is not what I am looking for.

Our 240 is used as a Dir track Race Car and we have to keep it stock. Our races are typicly 10 laps (3/8 mile track) for the heat and 15 or 20 for our main events. We also have to sit in stageing (usualy with the motor runnung) for 10 to 20 minutes waiting our turn. We get to about 65-80 top speed before we go into the corner. (don't know for sure as haven't been back to the track after getting the injectors working right)

This type of abuse can benifit from the proper spark plug, but which one? A plug that runs great on the open road at 90+MPH won't help use much.

Sorry for the length of the post but I want to give the proper information so I can get better answers:)

Thanks in advance

[IanS]

Im not sure I can give you a good answer as to what plug you should use, but I can give you info to help make that decision for your self.

How spark plugs work

Heat ranges, the heat range of the plug determines how much head the plug itself will dissipate to the head. For example, a hot plug will not dissipate much heat to the head, which means it will stay hotter when the engine is running, this is good because the hot plug helps burn off excess fuel and keep the plugs from being fouled. Hot plugs will not foul easily, but because they run hotter, they are more likely to cause pre-detonation which can destroy your engine. A colder plug on the other hand will dissipate more heat to the head, therefore running colder, which makes them more susceptible to fouling, but the are less likely to cause pre-detonation.

Electrode types, the three most popular electrode types are as follows, copper, platinum, and iridium. Copper is by far the best at producing spark, it will create a more powerful spark than either platinum or iridium, but the down side is, copper is soft, it burns away as the plug fires, and it will have the shortest life span of the main three. Platinum is a often used because it is much harder, therefor it lasts much longer, permitting longer service intervals, its only downfall is you wont get as powerful of a spark. Iridium is relatively new in the automotive market, it is much harder than platinum and conducts much better as well.

Gap is also very important, a large gap makes the electrical jump harder, effectively increasing voltage, this makes for a more effective burn. With a large gap you get good burn, but you run the risk of blowing the spark out at high rpm. A tighter gap wont blow out as easily, but will not burn as hot either.

Its been a long time since Ive dealt with the KA, so I don't know appropriate heat ranges or gaps, but I can tell you what you should look for. You should run a heat range slightly colder than stock because you do not use the car below running temp, and you are running at high RPM for extended periods. As far as gap goes, you can rely on those on this forum to get close, but you will need to find the right gap for your car using trial and error, you want the gap as wide as possible without spark blowout, this will mean lots of test driving, and re gapping. Plug type is up to you, if you choose to run copper, bring lots of spares, I would recommend changing them very often, they will wear quickly under that abuse. I would stay away from platinum, its just not what you need. If you choose to run iridium, you wont need as many spares, but at least one set is a good idea, I don't think iridium is worth the extra cost in your case, the juice isn't worth the squeeze per say.

If you have any more questions, just ask, I hope this was at least slightly helpful.

[Vegascorbin]

Thanks for the information. It did help.

Probably just make a plug check part of ouor regular pre-race routine.

I guess we need a copper electrode plug that is a "cold" plug. And when we gap them go for a "loose" gap.

I guess now I need to search data specks on plug web sites. If anyone has further information or opinions let me know.

Thanks again. I knew I could count on NICO!

[IanS]

I did some quick checking for you.

If you are still running a SOHC engine, the OE plug is ZFR5D-11, this is a copper NGK. I would suggest running NGKs as the Nissans tend to like them better, although Denso's are a good alternative. Stay away from Autolite, Bosch, and Champion.

The ZFR5D-11 has a preset gap of .044 and a heat range of 5.

For your application I would suggest running a ZFR6D-11, this plug has the same gap, but a heat range of 6, which is one step colder.

I did a little searching and found that the heat range 5 plugs are stocked at most parts stores, the heat range 6's were slightly harder to find. It seems that Nissan spec'd the 6 as an upgrade for the S13, I found them here Courtesy Nissan I would guess you can get these plugs from any Nissan dealer.

As I said before, the gap will require some testing. I would guess you will be happy with a gap around .040.

[Vegascorbin]

Thanks for the addtional info.

Just for future referance where did you get your information from? if it is a web site, please post URL. IF it is from a book etc I would like to know that also. Sonds like you have a good source.

Thanks again.

[IanS]

Thanks for the addtional info.

Just for future referance where did you get your information from? if it is a web site, please post URL. IF it is from a book etc I would like to know that also. Sonds like you have a good source.

Thanks again.

I am a mechanic, Ive picked up my knowledge over the years, I did some researching on spark plugs when I was building a DSM for a friend a few years ago. I didn't get the info from any one source.

[Vegascorbin]

Thanks. Guess I will just have to become a full time mechanic to learn this stuff:) NICO ( and Sideways = smiles) comes through for me again!

[Slappy]

Read

http://forums.driftinginsider....t=541