Spark Plug Difference?

05-02-2002, 03:46 PM

OK, I know the Rapid Fire #1 and AC Delco MR43T thing was just done, but I have a question. Yesterday I went to Pep Boys to buy the Rapid Fire #1s. They were out of stock, but they said the price was $3.99 each. Today I went to Autozone and they don't carry the Rapid Fires. I got the AC Delco R43T for $1.60 each. I guess my question is what is the difference between between a $4.00 plug and a $1.60 plug? Also is there a difference between the R43T and the MR43T. Obviously the M stands for marine, but is there really a difference?

Should I just be happy that I saved some cash or should I get the better performing plugs?

1998 500HP carb. Thanks.

1Boatnut · 05-02-2002, 04:21 PM

I know the biggest difference is the rapid fire has a longer nose reaching further into the cylinder,causing for a hotter spark advantage. I put the #1 in my boat last year and they were difinately worth the money

Dean Ferry · 05-02-2002, 04:24 PM

Tim,
I don't know, I went in looking for a MR43T also, and walked out with the RF#1. The "M" is for Marine, and I think that makes the the Sp. Plug corrision resistant, (I have never had a corrision problem myself, I always install them with Elec. grease on them), I can't really say how they will run, give them a try, if you don't like them, at least you didn't spend alot of money!

I bet them will run fine.
MD

baja27 · 05-02-2002, 04:39 PM

Longer tip, won't rust, plantinum tip last a lot longer. Will burn cleaner than standard plug. Worth the money.

jdnca1 · 05-02-2002, 05:09 PM

Tim;
$2.40 is the difference. When Pro stock starts running platinum tipped plugs I'll change my mind. Now if you want to put in a set for 1000 hrs then go with the platinums..

I run NGK 5672A-10 or Champion Pn#791 in my Natural 632. Where do you keep your boat? I put in at Rivertown.

kaamacat · 05-02-2002, 05:56 PM

29Fever.....The MR43T is the marine version (ss base) versus the R43T. I think the MR43TS is more similar to a RapidFire as an extended tip plug. (the RF may have a platinum tip area, not sure). I've also read in a few places the the RapidFire is great for idle speed (helps with the transom soot), and runs cooler at higher rpms. I've not personally used the RF's because I have a std ignition setup, requiring a .035 gap. (the RF come at .045 and I though you were definately not supposed to close the gap on it).

05-02-2002, 06:23 PM

jdnca1,

I usually keep it at Captain's Cove West, but I'm expecting my first baby in a month or so. Needless to say there will be little boating this year. When we were planning I was looking for a way not to kill a boating season, but it just didn't work out. I'm hoping to sneak out here and there. It might be easier to just bum rides from my OSO brothers this Summer.

I think I'll just keep the AC plugs. Hell, it's what's in there now anyway.

1Boatnut · 05-03-2002, 10:23 AM

Tim, sorry I didn't state this in my 1st post. The A.C plugs you got would definately be the plug of choice after the #1 RF

05-03-2002, 11:06 AM

I always wondered, if Rapid Fire plugs are desirable, why aren't the manufacturers using them? Both marine and auto.
To the best of my knowledge, it has a split electrode, big deal, the plug can only fire off the one electrode.
I'd like to be enlightened.

05-03-2002, 02:42 PM

MKAST, I work in the auto industry. I'll bet you the reason is cost. If they can use a plug that costs them 50 cents vs. 1.50 and they get acceptable performance, in their eyes. They'll go the cheaper route. Think about this. 1 dollar savings per plug, 8 plugs per vehicle. 8 bucks a vehicle times 3 million vehicles. That doesn't add up to chump change. And thats only in plugs.

The record profits automakers were making a couple years ago were partly due to reducing content and parts within vehicles. In some cases extra things are added in so someone can look like a hero when they are removed a year later and they save a couple million.