4 replies to this topic

[march66]

what is the spark plug gap with h.e.i. on a 604?    thanks

[brad hibbard]

I hope the link below works for you---if not please go to the Race-1 website and then the FAQ page--scroll down to find spark plug gap

 

I am always available to explain our recommendations by phone or email but I do my best to write it out on the FAQ page

thanks 

Brad 

 

 

http://race-1.com/p-...lug-gap-be.html

[march66]

I checked that out earlier but didn't know if it was diff for hei      thanks!

[sle21]

Brad, why do most engine builders recommend a much colder plug than what GM recommends?

[brad hibbard]

with the use of knock sensors we are able to determine the balance of timing and spark plug heat range

 

the hotter spark plugs require less timing or they will detonate because of high tip temperatures

with many fuels stock heat range plugs will be dangerously close to detonation possibilities with 34 degrees timing

combine that with a tight race car or hot air conditions and we have a short lived piston

 

the colder spark plug enables us to run the timing that the cylinder head likes without damaging the piston

 

to answer March66 a little more directly ----we do run the same gap with HEI that we do with MSD

 

our gap procedures are tighter than most engine builders but this helps a colder plug fire in conditions that it might otherwise foul.

 

our theory is that the 1 to 2 peak HP that is gained with a wide gap is not worth it if we have to run the first lap of every restart on 7 cylinders.

 

just my opinion---many disagree but we are sticking with it

 

hope some of that helps

Brad