Hey guys-

I am getting ready to put the head back on my laskey motor, and was wondering what those running lowered compression use for spark plugs. I just realized that I was still using the same plugs that I was on OEM compression (2-steps colder than OEM for the boost). They are NGK3330's. Pre-gapped .030.

Wondering what plugs people are using, and what gap, for a 9:1 motor...

Thanks

John

 

sorry I dont have any info, but what is your HP goal?

 

use the same plugs man, i wouldnt see a need to change the plug. I guess you could use a heatrange hotter if you want since you have lower CR now. I would just stick with the plugs you were using, but get the resistor type instead of the non resistor plug you have.

 

Got a part number on the resistor plug?

I am just going to toss these back in there if I cannot find a set first thing tomorrow when the head goes back on. They are white from the burnt coolant in the cylinders, but they were not mis-firing when I removed them (occasional "pop" when unloading it from a high load-low RPM pull, which I would expect from the rich AFR nature of that particular situation).

My mechanic came by and verified the block is still straight with a precision straight edge and a feeler gauge. The head was confirmed as still straight yesterday, so everything looks good for re-install...

Oh, and this was yet another studded block that failed. It had ARP studs vs. OEM bolts.

Thanks again!

John

 

you are incorrect. ngk 3330 is a resistor type plug.

 

ahh my apoligies.

 

Was the motor built before you blew the HG? What plug were you using before??

 

ChefJ - From my original post...

It was built before. It was the second gasket that blew (first one went a few months back with the original owner... The head was not re-torqued when the gasket was replaced). It lasted with the original owner about 20,000 miles before the HG let go. Not sure of the cause, but everything looked good when it came apart... I had my mechanic come over and check out the piston heads and the cylinder walls as well as verify the block as straight. He said that it looked like I was getting a good clean burn, so I guess that is good...

We got everything major back together and ready to go. The stupid powdercoater got some powder in the valve cover though, so it looks like I am spending a few hours at a car wash blasting the hell out of it, then rinsing it in kerosene to get all the water out.

It was an OEM head gasket. It was not coated in copper. The new one is sprayed with Permatex Copper Spray-a-Gasket, which Mike Laskey recommended to me via email. He said it causes a better seal to the head and to the block compared to the OEM material. 3-coats. 30-seconds between each coat. 2 hour dry time to get tacky/setup.

The plugs were/are NGK3330 Copper plugs.

John

 

Wow. Difficult to blow the stock headgasket with lowered compression. What kind aof boost were you running 30+psi??
I run an R5671A-8 ngk plug.

 

14psi. Glad I did not get around to upping the boost at the dyno yet... It failed 2 days before the dyno.

Its easy when the HG is not installed correctly!

john