spark plugs (confused)

[saintlee]

I read these forumes about an hour a day and the more i read about plugs the more confused i get.
Most talk is about the AC Delco MR43T and MR43LTS Marine Spark Plugs.
The original plugs in my engine were AC-41-932. After research I found that they were replaced by the AC-41-993.
then again replaced by AC-41-101 (Iridium)
My engine is a 5.0 gl-e 4012160010
I guess my question is which plug is correct and why.
I want to use the Iridium only if correct and good for marine use.
Thanks in advance for all your help . Past and Present

 

[halfmoa]

Re: spark plugs (confused)

Well I'm confused too because the AC Delco 41-932 is still in production. Are you saying that the manufacturer has changed the plug to the AC 41-101?

 

[saintlee]

Re: spark plugs (confused)

reason for post (CONFUSED)
I read that the 41-932 is now replaced by 41-993.
I believe both are platinum
The 41-101 is the Iridium version.
Are these marine plugs? My original plugs still had the red overspray on them from factory (41-932)

 

[Don S]

Re: spark plugs (confused)

The AC MR43LTS plugs work fine for the carbed engines like you have. The Iridium plugs are used in the MPI engines.

If you were to order the spark plugs directly from Volvo, you would get Champion plugs (Not iridium), which is the worst thing you could do to a marine engine.

I read that the 41-932 is now replaced by 41-993.

True, and they are Iridium plugs.

 

[halfmoa]

Re: spark plugs (confused)

The 41-932 is still in production. The only difference I can find between the two is that the 41-101 plugs have approximately 1/8 inch longer threads and they're iridium. They're both permanently sealed tips with zinc bodies. Does that make them marine grade? IDK for sure but sometimes there's no difference between standard production parts and marine grade.

My opinion is that unless the manufacturer has issued a service bulletin stating to change the plug to a different part number then I'd use the original equipment. The iridium plugs are longer. I've rebuild an engine and had to have the pistons notched to clear the plugs. In a fight of piston VS plug everyone is a loser...especially the owner of the engine!

EDIT: Don posted as I was typing. My unwritten rule of iBoats is that if Don's opinion differs from mine, I'm wrong...

 

[Don S]

Re: spark plugs (confused)

No, you may be right. It looks like the 41-932 & 993 are now platinum. They used to be iridium, and said so right on the plug and they cost $21 each.

 

[saintlee]

Re: spark plugs (confused)

So Don
Can i use the 41-101 (amazon $5.65) on a carbed engine
or should i stick to the original 41-932 now 41-993 platinum
or switch to AC MR43LTS ???

What did you mean by this?
"which is the worst thing you could do to a marine engine."

 

[Don S]

Re: spark plugs (confused)

You got 6 years with the original, and they came from GM, not Volvo.
Volvo only uses their PN, for plugs and in boxes of 4. Since they changed the PN, who knows what's in them now.
Mercruiser uses the MR43LTS in their equivalent year & model carbed engine, and the 41 series in the MPI.
I know nothing about the 101 number or where it came from so will not comment on it ability to do the job.

I really dislike Volvos spark plug specs, or should I say lack of specs. Just a Volvo part number that keeps changing and is not cross referenced to anything.

 

[saintlee]

Re: spark plugs (confused)

Well after all that I guess I will stick to the original ac 41-932 aka 993
Thank you for clearing that up
My last question on the matter is what plug GAP ???
Thanks Again

 

[halfmoa]

Re: spark plugs (confused)

GM 5.0s gap from .35 to .45 depending on application.

 

[Don S]

Re: spark plugs (confused)

According to the parts chart and the owners manual .060. The service manual doesn't even say.

Here is the parts chart.
http://vppneuapps.volvo.com/ww/PIE/...46079&p=T424&d=Parts Chart&s=32150&lang=en-GB

Here is the owners manual (17mb)
http://vppneuapps.volvo.com/ww/PIE/...03&d=Owners Publication&s=17409798&lang=en-GB

 

[saintlee]

Re: spark plugs (confused)

The parts chart uploaded fine
but the owners manual failed to upload

end result AC 41-993 Gap .060 for my 5.0 gl-e carbed engine

Thanks to all

 

[Don S]

Re: spark plugs (confused)

It takes a while from Volvo, took me about 3 minutes.
You can also go to this link and download it directly from Volvo.
http://www.volvopenta.com/volvopent...lication_search/pages/publication_search.aspx

 

[saintlee]

Re: spark plugs (confused)

waited a little longer and it works
thanks