Pro Marine pistons

[Go Time]

I recently ordered a set of the Pro Marine coated pistons for a 2.5L 200 mercury. It appears that Pro Marine has changed their vendor and their piston kits have different rings and pistons that I’ve seen in the past. I had problems with both Rod fitment to the piston where the wrist pin is and some had to be debured for the rod and washer set up to cleanly fit into the piston. The rings they use now are not RN rings and rings appear to be running .004 tighter gap than the RN rings. Anyone else purchased a set recently and like to share their experience. This has just happened and I was able to confirm that they have changed vendors.
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[thomas t]

Just put a set in a 2.5 #2515 had no problems.

[Go Time]

Did they look like this?
Did the pistons come with RN rings?

[thomas t]

Yes Only problem i had was wrist pin washers. To thick had to use OEM

[Go Time]

Yep, Mine wouldn’t work with OEM washers.

[Capt.Insane-o]

I've been using WSM kits for the past year or so due to "irregularities"

[LakeFever]

Thank you for this info! Was all set to order some

[Merc 2.5]

Been seeing a lot of " irregularities " with pro pistons lately

[Go Time]

I use WSMs in some builds as well and I think I will be using them exclusively now.

[Merc 2.5]

I use WSMs in some builds as well and I think I will be using them exclusively now.

Cant go wrong , I had sumbody reliable tell me bout a yr ago that wsm had surpassed pro pistons, didnt no then to belive or not , but I'll say yes he was dead nuts rite , I'm sure capt does as well but I beat the hell outta mine , been good , just got new set thin ring wsm promax pistons for new motor also

[nitro_rat]

another vote for the WSM's

[Chaz]

So a few month's ago .. the threads were .. I bought a new set of pistons and had too much ring gap .. they sell junk !
Never mind that it was a standard bore .. that was honed .003 - .004 too big .. I'm sendin them back , has to be their fault I gots purt near .030 ring gap !

So now , it's .. my ring gap is .004 too tight .. they sell junk !
There was some casting flash I had to sand off .. they sell junk !

In the real world , you buy rings separate , and they are all .005 over .Pretty much standard of the industry .. So now a "marine" company takes the initiative to sell kits with "file fit" rings .. and it's a problem ???

I have used WSM kits … those were the only ones I had to put in my sine fixture and make a .010 pass on each side of the pin boss to not only make the rod fit , but to have a little lateral clearance .

No big deal .. it's part of the process of "building" an engine .. minus the blindfold ..

Chaz = wunderin if Pro is buying their slugs from WSM now … who of course , buys from China …

[Merc 2.5]

So a few month's ago .. the threads were .. I bought a new set of pistons and had too much ring gap .. they sell junk !
Never mind that it was a standard bore .. that was honed .003 - .004 too big .. I'm sendin them back , has to be their fault I gots purt near .030 ring gap !

So now , it's .. my ring gap is .004 too tight .. they sell junk !
There was some casting flash I had to sand off .. they sell junk !

In the real world , you buy rings separate , and they are all .005 over .Pretty much standard of the industry .. So now a "marine" company takes the initiative to sell kits with "file fit" rings .. and it's a problem ???

I have used WSM kits … those were the only ones I had to put in my sine fixture and make a .010 pass on each side of the pin boss to not only make the rod fit , but to have a little lateral clearance .

No big deal .. it's part of the process of "building" an engine .. minus the blindfold ..

Chaz = wunderin if Pro is buying their slugs from WSM now … who of course , buys from China …

Chaz I dont believe your in same category as most people. The people like me that assembles the engine and not"build" them , we kinda need a piston kit that we can order for said cyl size and it work out of the box(almost) . But if I had to get a "kit" and start cutting on em and all that ,then I'd just have to send the new kit off to get worked on. James perry also only uses pro stuff but he does kinda like u and buys separate parts and make em fit , I'm sure you can optimize power and longevity the way you build them , it's just not a option for alot of people tho.

[Go Time]

I didn’t call them junk and they are in the mota with all clearances obtained. BUT, they are not the product that has been coming out of Pro for the last decade or so and they are not using RN rings which I think are good stuff. I just wanted to alert the community of the apparent change and see if any one else had noted the same.
The block was done by James and the RN rings normally don’t require any gap work. I call James to make sure our normal clearance were used ( they were). The situation just resulted in more work than I normally have to do and unnecessary concerns over the bore sized.
Ok, I’m off the soapbox ��

[Merc 2.5]

I didn’t call them junk and they are in the mota with all clearances obtained. BUT, they are not the product that has been coming out of Pro for the last decade or so and they are not using RN rings which I think are good stuff. I just wanted to alert the community of the apparent change and see if any one else had noted the same.
The block was done by James and the RN rings normally don’t require any gap work. I call James to make sure our normal clearance were used ( they were). The situation just resulted in more work than I normally have to do and unnecessary concerns over the bore sized.
Ok, I’m off the soapbox ��

Well that sayin sumthin since james did it and that's bout all he works with. So u know the change is with pro sumwere. Thanks for that info