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Spark plug choices


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I have a 06 VLX with monsoon 340. The manual calls for MR 43LTS (gap .045) or 41-932 platinum ( gap to 60).

I did a search and see most are using the standard plugs, it seems to me the platinum would have more spark. Is it just the cost savings or is there no noticable difference. Willing to spend the money on platinums if they increase performance or economy.

Also Skidim sells iridium plugs and show PCM gap .060 and indmar gap .045. I would think you would gap them at .060 like the platinum. Any guesses on this?

Thanks

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Here is my personal take on spark plugs....

Platinum/ Iridium mean longer life. Not necessarily better performance or better spark.

As a rule of thumb for automotive applications I ask one question.....are the plugs easy to change? If yes go standard. If they are a PITA go ahead and spend the extra dough. I am certain someone else will have different input the internet mechanics always do. :)

Gap settings do not change when installing platinum plugs, not sure why your source would suggest that.

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Here is my personal take on spark plugs....

Platinum/ Iridium mean longer life. Not necessarily better performance or better spark.

As a rule of thumb for automotive applications I ask one question.....are the plugs easy to change? If yes go standard. If they are a PITA go ahead and spend the extra dough. I am certain someone else will have different input the internet mechanics always do. :)

Gap settings do not change when installing platinum plugs, not sure why your source would suggest that.

I agree completely with you. I have had the best "performance" out of NGK V-Power copper plugs, been using those in EVERY gas motor I have owned. Platinum plugs won't give you better power/performance, but will give you a lot better lifespan. So, kind of up to you with what you want to use, but I really like good 'ole copper plugs.

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  • 1 month later...

To follow up on that post ...

The 330 LCR in my 2010 Response CB just finished this season with 335 hours on it's meter.

I already winterized the boat but as the manual suggested to change the spark plugs every 300 hours I am looking for replacement sparks.

The Bu is still running on it's factory spark plugs.

As per Indmar manual there should be AC Delco 41-932 mounted.

I removed the plugs and instead of the 41-932's I found a set of 41-101's with an unreal gap of about 1.8 Millimeters. :shocked:

Spark-Plugs-01.jpg

Unfortunately I can't get the 41-932 nore the 41-101 for a reasonable price over here.

The 41-932's are about 16 Euros each which will be a total of 176 USD for a set of sparks !!! :shocked:

For the 41-101 I was not even able to locate a source over here. :(

So my question is ...

What would be the correct NGK replacement plug for the AC Delco 41-932 or the 41-101?

I searched the forums first, but came up with various answers. Some say use NGK BPR6EFS at a 0.45 gap, others say NGK TR5 and leave the gap.

I am pretty confused ... :unsure:

Your help would be highly appreciated!

Thanks in advance!

David

Edited by Chaabo
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David, it's a small block Chevy 350. Get a set of plugs that will work for it with EFI. I'm runnin the NGK TR5 and am very happy with them. No reason to order the expensive platinum ones as long as you are willing to change them every couple of seasons. I put on 50-75 hrs a season (average) and will most likely change every 2 seasons.

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Okay thanks for the answers!

To be on the safe side I decided to go with the exact plugs that have been fitted.

I was able to locate a set of AC Delco 41-101 spark plugs for 43 $ on eBay US.

http://www.ebay.com/...ssories&vxp=mtr

A friend of mine will be in the states the next weeks and is willing to receive the package for me and take it back to Germany.

:)

Cheers,

David

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NGK plugs are the way to go. I've been running them for many years and they have always been great. Every vehicle we own has them in them.

Heck, my wife's Audi called for Bosch, then even Audi did a factory bulletin now stating the motor should run NGK's instead of the Bosch plugs.

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NGK plugs are the way to go. I've been running them for many years and they have always been great. Every vehicle we own has them in them.

Heck, my wife's Audi called for Bosch, then even Audi did a factory bulletin now stating the motor should run NGK's instead of the Bosch plugs.

You are right, I prefer the NGKs as well, had them in my BMW's for Years without any problem.

If I only knew which exact NGK plug would be the right choice for my 330 LCR EFI MPI ...

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Just want to throw this out there for everyone.

Any engine without CAT's on it will run better and longer using standard electrode plugs. (That's the AC MR43LTS, or NGK comparable)

Indmar had used the platinum or iridium plugs in pre-CAT engines because that is what comes in them and they are what is needed for their engines with catalytic converter exhaust. Platinum and Iridium plugs like to run hot and lean, perfect for CAT exhaust engines with O2 sensors. But Non-CAT engines run relatively cold and rich using a pre-determined calibration so you won't see a benefit from the more expensive plugs, they will last longer, and cost less.

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Peter is absolutely correct ... sounds like something I would have said ... wait a minute I did say that!!! I guess Peter was listening in Service School!!! Good job Peter!!!

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NGK TR-5!! Read back through the thread and look at all of the NGK supporters. I've been running them in my Sporty for 10 years, no problems.

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Platinum and Iridium plugs like to run hot and lean, perfect for CAT exhaust engines with O2 sensors.

Peter, don't want to come off sounding like I'm being an a** here, but show me where it says platinum and iridium plugs "like to run hot and lean." Heat range is heat range when it comes to spark plugs. I'm running the NGK TR5's and they are the same heat range as the AC 41-932. My boat has never run so smooth or started better than it does now with the NGK's. I just am looking for a reason that I shouldn't be running the good 'ole coppers in my boat. Thanks.

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As Peter also said, the non-cat exhaust on older boats run richer so you will notice when you pull the plugs out that they will be generally darker than if you pull the plugs from an engine with a cat system. If you go back to the older carb based engines this is particularly noticeable and so you generally find that the platinum or iridium plug will not last as long as they do in the cat equipped engines so need to be changed more often.

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Peter, don't want to come off sounding like I'm being an a** here, but show me where it says platinum and iridium plugs "like to run hot and lean." Heat range is heat range when it comes to spark plugs. I'm running the NGK TR5's and they are the same heat range as the AC 41-932. My boat has never run so smooth or started better than it does now with the NGK's. I just am looking for a reason that I shouldn't be running the good 'ole coppers in my boat. Thanks.

The heat has noting to do with the heat range of the plug. In this case it is more related to exhaust gas temperatures and the richness or leanness of the air fuel ratio. The platinum plugs operate better with higer EGT's and a leaner air fuel mixture which is what we see on catalyst engines. The standard plugs are more tolerant to lower EGT's and richer air fuel ratios. I would save my money if I didn't have a catalyst engine and use the standard MR43LTS plugs. I haven't seen an appreciable difference between AC and NGK plugs ,,, use whatever makes you happy

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I totally understand that platinum is more tolerant of higher in-cylinder temps, but that doesn't mean they are the better choice. Will the coppers wear out faster in those condition, oh yeah!!!! But, I am willing to change plugs more often because I have seen better performance out of the coppers. My boat LOVES the NGK TR5's that I put in. Smoother idle and the last 2 tanks of fuel, it used less fuel per hour than it did with the stock platinum. I wonder if this because my Monsoon is the 1st year of EXT-CAT. Who knows....???? Anyway, to each his own.

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The heat has noting to do with the heat range of the plug. In this case it is more related to exhaust gas temperatures and the richness or leanness of the air fuel ratio. The platinum plugs operate better with higer EGT's and a leaner air fuel mixture which is what we see on catalyst engines. The standard plugs are more tolerant to lower EGT's and richer air fuel ratios. I would save my money if I didn't have a catalyst engine and use the standard MR43LTS plugs. I haven't seen an appreciable difference between AC and NGK plugs ,,, use whatever makes you happy

What gap should I use with the MR43LTS? The 41-932's were gapped @.60". 03 Monsoon.
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