spark plug question

[steve@kps]

Infomaniac, or anyone.
W/ a 454, and a B&M 250 megablower, what spark plug would you recommend?
thanks.
steve

[Fiat48]

Type of boat? V drive or jet? Peanut plug (5/8 hex) or 3/4" reach 13/16 hex head?

[steve@kps]

The plugs that were in it: Champion rv12c. The champion book i have says that plug is for the EFI engines, but is superceded to the rv12yc.
This book also shows a 525hp supercharged motor using the plug V63C gapped at .035.
I'm just looking for opinions for the 250megablower plug and whether to go w/ champion or NGK???
I use a champion racing plug in the dragster, but it's on alcohol.. I have NO experience w/ a blower on gas. Help is appreciated :D
steve g.

[Fiat48]

I quit using Champion plugs years ago because it seemed that when we got a plug finally mated to an engine, Champion would change the number or discontinuue the plug we were using. The NGK's had the same type of Cad plating and a better selection of heat range.
I don't have a cross reference from NGK to that Champion number. I would say that if it's the peanut style (14mm taper seat, .460 reach 5/8 hex as I suspect) I would put a BP8FS NGK plug in it. BP5FS is the hottest and BP10FS is the coldest available.
If it uses 14mm 3/4 reach, 13/16 hex, I would say to use a BP8ES. Same deal of the heat range with a 5 being the hottest and a 10 being the coldest.
Both plugs are a projected tip which I recommend. There's also a V series race plug NGK has that you can cross these NGK #'s to. If you are used to reading the cad burn on a Champion, then you should be right at home with theses NGK's. My alcohol stuff runs a BP9ES. Hope this helps.

[steve@kps]

good information.
These heads (world products/merlin) do indeed take the 14mm,5/8hex,.460 reach plug
The champion book calls for a V63c plug, I'm going to find out if your ngk plug crosses to this plug.
The part i'm not sure about is the heat range. 55 being the coldest? on the champion, so w/ a 250 megablower, and 91octane fuel, what heat range would you suggest we start with?
I appreciate your helping me.
http://www.keystonepropeller.com/images/wpe3.jpg

[Fiat48]

The Rv12yc you mentioned that was in the motor is equivalent to a "5" heat range for NGK. That's plenty hot. The cross for that plug is a UR5. Resistor type plug..typical stocker.
The V63C Champion crosses to an NGK R5673 -7 or a NGK 5673-6. The reason for NGK giving 2 different heat ranges to cross (6 or 7) is due to Champions rating system where they say their plugs cover a wider heat range.
All this stuff is resistor, which I was giving you numbers of non resistor. That's what the R is all about. So looks like to me a "7" heat range is the closer cross for the Champion.
I'd still put an 8 in it. Would rather have a colder plug as long as it didn't foul.
Here's where I got the info..good site for cross reference. http://www.clubplug.net/champ_ngk.html
[ January 30, 2003, 03:37 PM: Message edited by: Fiat48 ]

[steve@kps]

Fiat48, thanks for that information and link.
I'm going to try both plugs for comparisons reasons. I'll let you know how they perform!
thanks
steve g.

[JLaughreySS24]

Hey Steve, Not to change the subject but is that a fiberglass hatch I see on your SR24? If so can you post a couple of pics cause I would like to see it. Ive always wondered if HTM would get around to making a hatch out of glass. Someday I would like to switch if it looks good. Thanks Steve

[steve@kps]

That's the same hatch that was on it before. When the motor was stolen, the thieves broke the hatch. So, we cut a new piece of 1/4" fir, and reglassed the entire hatch. The only difference is, HTM carpeted the inside. I just thought it would look better if we gelcoated and splattered it. When we find a mirror to put in the middle, i think it'll really set off the engine compartment. What do you think? the topside upholestery should be back next week. When it gets back i'll post some pics. I usually put them on my website first. You might check there once in awhile.

[gnarley]

Steve you can get plexi mirrors for pretty cheap. Out here we have an outfit called Tap Plactics & I got a replacement for a missing one there for mine.

[steve@kps]

"plexi-mirrors" ...........cool, thanks Charlie, i appreciate that info. I'll check around for a local dealer that might have them. If i can't find one, can i p.m. you for a phone number of the place that sold you yours?
thanks

[gnarley]

Steve better yet.
http://tapplastic.com/

[steve@kps]

damn, charlie.........tried to pull up that website, and got killed on popups.
too bad companies do that shit......now i won't even consider buying anything from them.

[JLaughreySS24]

Thanks for the info Steve, Im sure it will turn out nice when its done!!!

[gnarley]

steve@kps:
damn, charlie.........tried to pull up that website, and got killed on popups.
too bad companies do that shit......now i won't even consider buying anything from them. Woa.... I missed a letter try
http://tapplastics.com/ with an s at the end, sorry :rolleyes: or http://tapplastics.com/plastics/plasticsinfo/acrylic.html#GP the other was a name for sale, opps