how are these plugs?
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I would use what the head manufacturer recommends or cross reference of the same plug, heat range would be your choice, what heads do you have ? 
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Team Owner
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From: Sorrento Italy
Originally Posted by MotorHead
I would use what the head manufacturer recommends or cross reference of the same plug, heat range would be your choice, what heads do you have ?
Drifting
Joined: May 2006
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From: Youngstown Ohio
Check recommendation from your maufacturer, NKG's have a good rep, used by alot of ricers, not that there is any thing wrong with that. I use Champions and like them, but I get them free as I run thier vintage graphics on my car. A nice educational site I recommend:
www.edelbrock.com/automotive/sparkplugs.html
I'm running C57HCX as cold all out race plugs, and RC12YC (NASCAR) plugs for every day non race. The C57's load up at low RPM's. I can run a set of RC12's forever, (they have been in 9 months). The RC12 are available at most parts stores, they also come in 9's if you want to go colder. The primary issue to check is plug tip/piston clearance, a bunch of metal and ceramics rattling around in a cylinder just can't be good. I think 5's will be a problem for you, to cold for regular use.
David
www.edelbrock.com/automotive/sparkplugs.html
I'm running C57HCX as cold all out race plugs, and RC12YC (NASCAR) plugs for every day non race. The C57's load up at low RPM's. I can run a set of RC12's forever, (they have been in 9 months). The RC12 are available at most parts stores, they also come in 9's if you want to go colder. The primary issue to check is plug tip/piston clearance, a bunch of metal and ceramics rattling around in a cylinder just can't be good. I think 5's will be a problem for you, to cold for regular use.
David
Last edited by 73-84 IMSA Widebody; Sep 8, 2006 at 07:08 PM.
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
14mm x 3/4" gasket, do not use taper fit-Champion C59YC Autolite 3910 or 51, A/C R41 CXLS & NGK R5672A-9 is a good starting point. For street applications use AC FR3LS or Champion RC9YC spark plugs or equivalent.
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I am using NGK R5672A-8 in my Vic Jr. heads, they are a racing plug but they seem to work fine, they are a medium heat range - $3.69 at Jegs
Drifting
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From: Youngstown Ohio
Motorhead, 8-9 are about as cold as I would run for regular use. For 3 months I would run my car, some idleing etc., after 3 starts it would not start again, fouled out plugs. The original builder/driver of my car, in his late 60's now would just bitch me out if I talked about putting in hotter plugs, he could never seem to understand I'm not running 4-6, 000 rpm's constantly, he's an original go fast guy. I had to **** him off when I switched to hot plugs for "regular" driving but have had no problems what so ever since going to a two set strategy, cold for racing, hot the rest of the time. live and learn..................
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From: Sorrento Italy
my engine builder gave me 3 options which, on his opinion, are best choice for my application:
ngk BCPR5ES or BCP5EV or BCPR5EY
i know 5 grade is really pretty cold, maybe he thinks i drive over 4.000 rpm all the time
as a matter of fact, usually, i've always preferred to drive a colder plugs then a warmer ones, in my (little) experience with other high compression cars warm plugs has always been a headhache and cause of malfunctions.
ngk BCPR5ES or BCP5EV or BCPR5EY
i know 5 grade is really pretty cold, maybe he thinks i drive over 4.000 rpm all the time
as a matter of fact, usually, i've always preferred to drive a colder plugs then a warmer ones, in my (little) experience with other high compression cars warm plugs has always been a headhache and cause of malfunctions.
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
The numbering for spark plug heat ranges is not universal, some companies even go in the reverse direction eg. - the hotter plug is a higher number.
For NGK plugs the range ( that I know about ) is 11 (coldest) to 5 (hottest) so 8 is exactly in the middle, medium heat range.
Panic, AFR recommends the NGK R5672A for your heads, the info I posted above I got off there site
For NGK plugs the range ( that I know about ) is 11 (coldest) to 5 (hottest) so 8 is exactly in the middle, medium heat range.
Panic, AFR recommends the NGK R5672A for your heads, the info I posted above I got off there site
Thread Starter
Team Owner
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From: Sorrento Italy
Originally Posted by MotorHead
The numbering for spark plug heat ranges is not universal, some companies even go in the reverse direction eg. - the hotter plug is a higher number.
For NGK plugs the range ( that I know about ) is 11 (coldest) to 5 (hottest) so 8 is exactly in the middle, medium heat range.
Panic, AFR recommends the NGK R5672A for your heads, the info I posted above I got off there site
For NGK plugs the range ( that I know about ) is 11 (coldest) to 5 (hottest) so 8 is exactly in the middle, medium heat range.
Panic, AFR recommends the NGK R5672A for your heads, the info I posted above I got off there site
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From: Sorrento Italy
Originally Posted by Twin_Turbo
Some NGK plugs are made in France, I have the BCPR6ES now, the last set was French made, the ones I have now were made in Japan
Drifting
Joined: May 2006
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From: Youngstown Ohio
Panic, every engine is different, just FYI if I run 5's/cold, 3 minutes of idleing means it won't start and throw the plugs away, install new ones, they load up and don't seem to recover if cleaned. Just my experiences, file it under hmmmmm.
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
NGK-BCPR5ES cross references to Champion-RC12YC and RC14YC which are street plugs and recommended by AFR ( they actually recommended the RC9YC for street applications ) So your engine builder was on track
