Which spark plug??

[Jeff Alton]

What plug should I use in this motor.

3.4
Twin plug
10.5CR
mod S cams
ITB's
headers (1 5/8)


Thanks

[kenikh]

I assume the 2nd plug was machined standard, not undersized?

[Jeff Alton]

Standard 14mm plug, top and bottom.

Cheers

[cstreit]

I'm really happy with my NGK's...

I can't remember the number, but I use the 14mm as well with nearly the same motor... R-587 something I think... I had to switch away from the projected tip style when I upgraded from 3.0 to 3.3L

I have some back at the garage and can check the numbers when I get back if you want.

[Porschekid962]

Chris what about going 3.3 meant no preojected tip? I assume its because of the high comp pistons and clearance?

Bosch, NGK, cant really go wrong with either because you can order pretty much whatever you want from both. What setup are you using for your ignition?

[Jeff Alton]

I guess I should have asked about heat range! oops. I have always had good luck with NGK's but just not sure on which one for this new motor.

Cheers

[cstreit]

Pkid, it was a suprise to me too, because I had 95mm 10.5:1's prior and a visual inspection of the new piston made it look like they were the same height and dome shape. However the projected tip style were JUST hitting the plug at TDC right at the edge of the exhaust valve pocket.

The non-projected tp gave me a few mm clearance.

Jeff, I originally used the 9 heat range (which in NGK parlance is cold) but got some fouling at idle and had hard starts. I moved to 8 and haven't had an issue since.

[Jeff Alton]

Chris, thanks, I would be interesred in the numbers.

Cheers

[TimT]

Have had success with these


NGK R5671A- 8

[Jeff Alton]

Thanks Tim, so you think that would be okay with my motor configuration?

Thanks

[Porschekid962]

This thread has come about at a wonderful time. Now I am second guessing the plugs I went with. Chris are you running the 100mm JE's with 10.5:1? I currently have Bosch plugs in there top and bottom and when I checked deck height I forgot to put in the lower plugs. Silly mistake I know.

Any reason why you went with NGK over Bosch?

Jeff saw youve got the longblock together, recieved any electronics yet?

[len911]

As a point of reference...

3.2l with 11:1 Cosworth pistons, twin plugged using Electromotive modules, cam is similar to a GE80 (but from Elgin), 1 5/8 headers, ported and 46IDAs.

Car came with NGKs BPP9Es but was fouling plugs. Ended up going to BP7ES (hotter) and it seems to run great! It is equivalent to a Bosch W5DC. Lou

[Jeff Alton]

I run/ran NGK 7's in it when it was a 3.2 with 964 cams with no problems.

Thanks, keep the tips comming!

Cheers

[Jeff Alton]

Chris, I put the old standard NGK's in tonight (with a very huge gap for this test) and turned the engine over a bunch of times. The piston never hit the plug, am I okay with the standard style plugs or should I get the ones like you have?

Cheers

[cstreit]

Jeff,

I'm using the same ones that TimT has above. Had great luck with them so far. (Tim, did you find them at your local place?). FWIW I get them at the local NAPA for about $1.29 apeice!

I chose NGK over Bosch because that's what Richard Clewett recommended when I originally go the Electromotive setup from him. Since they work well enough, I never saw any reason to change to Bosch, even if they are from the fatherland...

Jeff, as long as you have clearance, you're fine. In fact I'd prefer the projected tip for 2 reasons. First you lose a little more compression with the recessed version and second, the recess doesn't stick out into the combustion chamber as well so I assume ignition is a little harder. Since I switched from 95mm to 100mm I'm mixing in race gas on 90+ degree days to be on the safe side...

[Jeff Alton]

Thanks guys!

Cheers

[edbaus]

Here is another vote for the BP 7 Es's.

Have them in both cars. Both twin pluged.

Thanks

Ed

[beepbeep]

Use NGK 7:s or even 6:es. 9:es are way too cold and fit for turbocharged cars running on track. They foul on street. BP7ES is OK.

[gumba]

I'm using a W4CS with a similar set up. 46mm Webers instead of ITB's.

On a different note, I see your looking for for an open trailer. Have you checked out this trailer place. It's in Parksville, BC. I'm looking for an aluminum trailer and their prices seem pretty reasonable.
http://www.expresstrailer.com/a-car.htm

[Jeff Alton]

Hmmm, no I had not. I will check them out.

Cheers