I have a friend with a B16 block/ GSR head, high compression headgasket (from Toda but not sure which headgasket he has) and he also has high compression pistons of some sort, but he is not sure what pistons they are but his pistons are hitting the spark plugs!

I did a compression test, and the engine is about 225 psi across which doesn't seem high enough to have pistons hitting the spark plugs, any ideas as to why this could be happening?

Any suggestions would be greatly appreciated! This is a problem we would like to get resolved so we can get back on track with his NA build up! The car is currently running with spacers in the spark plugs, and makes 159 horsepower at the wheels (measured on a dynojet)

 

buy ngk part # 6945 plugs are shorter

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hondaddict &raquo;</TD></TR><TR><TD CLASS="quote">and he also has high compression pistons of some sort, but he is not sure what pistons they are but his pistons are hitting the spark plugs!</TD></TR></TABLE>

If he has high compression pistons and is only making 159 whp on a B16 sounds like he has more problems than just the spark plug hitting the piston.

 

He hasn't said what other mods the car has to think that... if he only has pistons.. I think its normal whp for a b16 with that.



Modified by PanamaVTI at 10:16 PM 7/20/2004

 

i agree. 159 HP on a built motor. i wouldnt be worring about hitting the spark plugs

 

The power the engine is making is part of our concern, but it is all in the tune,...... it has a spoon reflashed ecu, and a large dip (about 25 horsepower, and 20 lb/ft of torque) when VTEC kicks in. But regardless of the power output, the pistons should not be contacting the plugs, especially if compression (as I measured it w/ a compression gauge) reads only 225 psi.

To me that puts it about 11:1-ish.

Are you all motor guys having pistons hitting plugs as a regular occurence, you seem to make it sound as if it is no big deal, when I assure you that it is an area of concern.

 

did you try those shorter plugs the guy suggested?

 

do you have your head milled??
if you say you don't know what type of pistons he has .. that could be one reason..
try shorter plugs as everybody is saying.

 

I have never had that problem before.The craziest setup ive had was 13:1 pistons,a slightly milled head(forget how much,it was 2 years ago),honda head gasket with the middle layer removed,ls/vtec w/gsr head,NGK plugs and never had that problem..the gauge would be around 270psi w/ctr cams.The engine made 210whp and 14x torque.You should definately try different plugs.

 

probably the wrong spark plugs. i had that happen about 2 years ago. i grabbed a IQ20 (supra) spark plug on accident when i grabbed my IK's and on cylinde sounded kind of bad so i checked them all and cylinder 4 had a bent plug. I looked and all were IK20's and the bent one was a IQ20....

so make sure its the right ones

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMotive &raquo;</TD></TR><TR><TD CLASS="quote">I have never had that problem before.The craziest setup ive had was 13:1 pistons,a slightly milled head(forget how much,it was 2 years ago),honda head gasket with the middle layer removed,ls/vtec w/gsr head,NGK plugs and never had that problem..the gauge would be around 270psi w/ctr cams.The engine made 210whp and 14x torque.You should definately try different plugs.</TD></TR></TABLE>Just curious...what was the minimum octane gas were you able to use with that setup?

 

I had the same problem with the same setup
Run a shorter plug
brk7gte ?

 

I was having this problem at the track last lime I went. Everyu time I went to read my plugs I noticed the gap had closed from .045 to .020. My traps were only 109 which was only 2 miles per hour higher than my old milder setup. So I took some washers off another set of old plugs and stacked them on top of the other ones . Regapped to .045 and it went 113 mph. So Im guessing it can rob alot of power. I was gonna look for some shorter plugs, maybe I will try those 6945s. Thanks.

 

if you're still hitting try some washers but be careful you can risk shooting the spark plug back out of the cylinder if you don't get the right amount