Spark plugs, Volvo numbers don't match

[Wave34]

Volvo Penta 5.7 Gi-D 2004

I would like to change my spark plugs.
In the Volvo manual, for a 5.7Gi-D, it is listed as 3861632
On the engine block name plate, it is listed as 3851632
And what is installed right now from the previous owner is AC 41-993

I would like to go with the same AC plugs since the boat was running fine. But I just want to make sure it's the good one since I don't have a cross reference chart vs Volvo numbers.

I'm curious to know why the manual says something different as my engine name plate.

 

[Scott Danforth]

volvo doesnt make spark plugs, they buy them. they assigned a part number to the AC plug that came in the motor from GM to begin with.

should be AC delco MR43-LTS The M stands for Marine (stainless body)

the 41-993 is an iridium spark plug with a nickel alloy body. it will be fine for the application and should last about 20 years of normal usage.

 

[Wave34]

Thanks Scott for the reference number.
B.O.A.T.
Regular plug at $22 CND each because of the S.S., or Covid, may be because in Canada, who knows.

I will check my local autopart store for the AC 41-993

 

[Scott Danforth]

amazon

 

[Alumarine]

Also try rockauto.
Even with shipping to canada they are reasonable.
Have always had trouble finding AC plugs in canada for a good price so have usually used NGK.

 

[Wave34]

Scott, the attachment picture of the plug was on Amazon.ca
Sometimes some merchants are way out of price.

Marc c, I will take a look at Rockauto.
I never bought from them, but heard that they have good prices.

 

[Alumarine]

Scott, the attachment picture of the plug was on Amazon.ca
Sometimes some merchants are way out of price.

Marc c, I will take a look at Rockauto.
I never bought from them, but heard that they have good prices.

I think if you select Fedex Ground for shipping that also includes any brokerage fees.

 

[Texasmark]

volvo doesnt make spark plugs, they buy them. they assigned a part number to the AC plug that came in the motor from GM to begin with.

should be AC delco MR43-LTS The M stands for Marine (stainless body)

the 41-993 is an iridium spark plug with a nickel alloy body. it will be fine for the application and should last about 20 years of normal usage.

I have become an "Iridium" fan. I almost have ALL my internal combustion engines converted down to and including lawn mowers and such. I do the cross via NGK online manual (Page 241 as I recall is for my Merc. outboards): https://www.ngksparkplugs.co.za/wp-content/uploads/2019/01/NGK-Catalogue-2019.pdf

 

[QBhoy]

Delco 993’s are actually platinum plugs. Often thought to be iridium...but they aren’t.
you don’t need fancy plugs in that tbi engine. Only in the MPi/gxi.

 

[Wave34]

Delco 993’s are actually platinum plugs. Often thought to be iridium...but they aren’t.
you don’t need fancy plugs in that tbi engine. Only in the MPi/gxi.

Yes, 993s are platimum.
My engine is a MPI Gi-D.

I just found in a box given with the boat a set of iridium plugs Delco 983.
After inspection, they look like new. I suspect a mechanic at some point suggested a spark plug change, without knowing they were iridium with a long life.

Anyway, I installed those new/used iridium plugs and will test them next spring.

 

[QBhoy]

Yes, 993s are platimum.
My engine is a MPI Gi-D.

I just found in a box given with the boat a set of iridium plugs Delco 983.
After inspection, they look like new. I suspect a mechanic at some point suggested a spark plug change, without knowing they were iridium with a long life.

Anyway, I installed those new/used iridium plugs and will test them next spring.

Must admit. I’ve had the NGK iridium in mine for a few years now. Been running so much better than the delco platinum it dud have in it previously. Big difference