Which Spark Plugs work better?
03-19-2003, 08:20 AM
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Which Spark Plugs work better?
I'm getting ready to replace the spark plugs this spring as I normally do and I thought I would get some opinions. The motor is a modified Gen 6, 502EFI right at 500hp. The stock plugs are the AC-MR43T. I know that the only difference between the MR and the R is that the housing is made of stainless steel. I don't get into salt and I change plugs every year so I don't think that is a huge factor (although I buy the MR's anyway). I was curious if any of you went to a extended tip plug like a Champion RV15YC4 and if you noticed any improvement? I'm guessing with the Champion RV15YC4 that the gap will be .045!? I was just wondering if there is a clearance issue with using an extended tip plug?
Thanks!!!!
Dave
Thanks!!!!
Dave
03-19-2003, 12:13 PM
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Although mine is a whimpy stock 454 the book gives me the choice of the AC plugs or Champion RV15YC4 and that's what I use and am very satisfied with them. I just installed a new set last weekend and the stock gap is .045!
03-19-2003, 12:46 PM
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Hello, Guys,
I have tried almost every plug known to man. There are no magic plugs, just like Teague said. I have had the best results with JAutolite and NGK, although AC has been very good also. If you buy the AC from a discount parts house, they are "untested" plugs and can have any number of problems. If you buy them from the GM dealer or NAPA, they are supposed to be tested. You can tell by checkin the gap. If the gaps are correct, you have tested plugs. If they are varied, I won't use them!!
I always use antiseize and the gap and heat range recommended. In the stock Mercruiser engines, long reach plugs are not a problem.
I have tried almost every plug known to man. There are no magic plugs, just like Teague said. I have had the best results with JAutolite and NGK, although AC has been very good also. If you buy the AC from a discount parts house, they are "untested" plugs and can have any number of problems. If you buy them from the GM dealer or NAPA, they are supposed to be tested. You can tell by checkin the gap. If the gaps are correct, you have tested plugs. If they are varied, I won't use them!!
I always use antiseize and the gap and heat range recommended. In the stock Mercruiser engines, long reach plugs are not a problem.
03-19-2003, 03:27 PM
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Like most everybody else I have always run the sparkplug that came with the engine. I now find myself looking for alternatives too.
This is because the stock plug for a '99 502 Mag is a NGK-BR6FVX. Merc wants $10.50 apiece for them. Thats $91.56 with sales tax here. Im sure I can find them slightly cheaper on the net but with shipping it will be about the same.
Its not that I cant afford the plugs. And its certainly not that expensive compared to some maintainace items on a boat. Its just the principle of the matter. There has to be something else out there that works equaly as well. This is probably why there is always a couple of active topics about sparkplugs on this board.
Ron
This is because the stock plug for a '99 502 Mag is a NGK-BR6FVX. Merc wants $10.50 apiece for them. Thats $91.56 with sales tax here. Im sure I can find them slightly cheaper on the net but with shipping it will be about the same.
Its not that I cant afford the plugs. And its certainly not that expensive compared to some maintainace items on a boat. Its just the principle of the matter. There has to be something else out there that works equaly as well. This is probably why there is always a couple of active topics about sparkplugs on this board.
Ron
03-19-2003, 03:39 PM
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for what its worth I've always had excellent luck with NGK I They were the hardest plug to foul in my 2 stroke motors and seemed to hold up better than the rest. As long as you use the right heat range everyone has thier favorite plug and NGK is mine.
03-19-2003, 09:18 PM
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I run the champion RV15YC4. blown1500 I do like antiseize but after seeing what it did to my brothers very high cost medical grinder I will never use it on a set of plugs again.
03-20-2003, 06:47 AM
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Gee, nobody is preaching the benefits of any of those "french tickler" plugs? Nobody is a true believer in thirty different electrodes all splayed out in obscene directions? C'mon, surely we got us a fish or two that bit on the infomercial? Fess up!
03-20-2003, 06:59 AM
#9
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My 454 mag had NGK BR6FS, I wonder what the dif is between that and the BR6FVX? I replaced mine for 2.10 per plug. That was at my local auto parts store. West Marine wanted 2.80.
03-20-2003, 07:59 AM
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AARRRGGG What are you doing with that Anti Seize on them spark plug!!!!!
AARRRGGG
What are you doing with that Anti Seize on them spark plug!!!!! A big no no there!!! Plug have two very important function. 1 ignite the compressed Air/Fuel mixture in the combustion chamber. 2 and as important as number 1 is to displace heat from the combustion chamber back to the head and on to the coolant in the motor. Anti Seize insulate the plug so it can not perform that very important function.
Now I have a confection I do use a very and I mean very small amount on my aluminum heads. The key word is small amount. If you don't think Anti Seize can cause a problem I will send you so many plugs that have been melted and detonated to death due to not being able to displace the heat and are dripping with Anti Seize that can fill the inside of your boat.
My plug choice? Bosch Supers (copper) They are free to me....
What are you doing with that Anti Seize on them spark plug!!!!! A big no no there!!! Plug have two very important function. 1 ignite the compressed Air/Fuel mixture in the combustion chamber. 2 and as important as number 1 is to displace heat from the combustion chamber back to the head and on to the coolant in the motor. Anti Seize insulate the plug so it can not perform that very important function.
Now I have a confection I do use a very and I mean very small amount on my aluminum heads. The key word is small amount. If you don't think Anti Seize can cause a problem I will send you so many plugs that have been melted and detonated to death due to not being able to displace the heat and are dripping with Anti Seize that can fill the inside of your boat.
My plug choice? Bosch Supers (copper) They are free to me....
Last edited by MikeW; 03-20-2003 at 08:06 AM.
