First observations of the New Mahle Piston

[Jay Smith]

I started a post a couple of weeks ago trying to get some feed back as to the durability of this new top pinned piston and was also looking for an alternate slug for the "market cornered" Weisco-Mercury Hi Performance piston for the 2.5 coated motors !

All the feed back both on the board and privately has NOT been encourging. I now have a set in my hands and the general look of the piston is no more that just "OK"( I was hoping for something that all the wait was worth being patient for and it simply ain't there).... The set I have have no "UP" indication stamps on these piston any where and the "P" and "S" are drawn on with it looks like red fingernail polish ????????????

The piston IS very light coming in at 464 grams they lost alot of weight by cutting the ports in the pistons VERY large , larger that the sleeve opening this is ok for weight reduction BUT it leaves a very thin and what looks like it would be prone to break "stabilizer legs". Also in the exhaust meat are of the piston there is a parculiar "lump" of metal that partrudes from skirt and sticks out about 1/8" and does this for about 1/2"- 3/4" and I haven't a clue of a reason why unless it is a heat sink and the thickness is to absorb heat and disapate it away from the exhaust port side of the skirt.......


Over all with no GOOD reports I will have to suggest to my customers to give MAHLE a wide birth and a while to do some more prefecting and as of this moment I don't trust them ( the pistons ) in thier motors no matter what the cost benifits after all when and if they come apart it wasn't a good deal to take the cheaper route !

Just my observations and from what I have been told !

[merc326]

Thanks for the info Jay.

[supercat]

Jay,
I just had my run in with the mysterious moving pin in the side pinned pistons. Mercury tells me there isn't a problem even though they changed to the top pinned piston. Have you heard of Mercury admitting to the problem?

[Jay Smith]

Mercury indeed doesn't have a problem YOU and every unfortunate soul that has destroyed engines do ! I am to the point that I will not do a rebuild UNLESS the pistons have be retrofitted with top pinned locater pins and welded.......I have yet to have had a failure after this process is completed !

I use John Marles @ 1 661 250 7157 in Ca.

[us1]

Originally posted by Jay Smith
Mercury indeed doesn't have a problem YOU and every unfortunate soul that has destroyed engines do !

I like that, thats pretty funny. How true it is.:D

[Markus]

Mercury gets to sell more pistons, heads and blocks this way.

I had a pin come out really fast on a cut Wiseco piston on a Yamaha that never saw more than 7000 rpm, so it is no just Mercury, though.

[Dave S]

It seems that if THIS don't break THAT will.:( The pistons seem to be the weak link at this point. I wonder if it's because this motor design goes back to 1977 175 hp. Back then the pistons were forged and the bore was smaller. The ratio between the bore and length of the piston skirt was better, the 2.5 piston seems over top heavy above the wrist pin as far as area. Also the old 175s had less ports and area ,that was kinder to the rings. And we be trying to get more power than the orignal was ever meant to make.:p Whats the price difference between the wiscos and mahles????

[Jay Smith]

Dave S ,
I just sent a set of Mahles back for credit and gonna bite the bullet on the Mercury Hi Performance (Weiscos) I think the difference is around $350.00 ish ! ( NOT WORTH TAKING A CHANCE ON A CUSTOMER'S ENGINE BEING DESTROYED !!! )

[supercat]

I like the idea of welding the pin in place, but aren't the new top pin piston pins staked in? On the 280's I just got, the bottom of the pin is accesible through a window cut in the piston and the pin is staked in place. Can these still fall out?

[Jay Smith]

Yes thay can and I have heard reports of the top pin rising and causing the motor to detonate , I myself have NOT seen this condition but I have heard from reliable people it can and does happen on occation !

[supercat]

My 280's had low hours on them, (20ish) not run abusively, and all 6 cylinders on both motors needed re plating due to the pin pushing the rings out. Mercury says "you ran them too hard" BULL!!!
Has anyone condidered a class action suit against Mercury? This is crap!!!!

[us1]

I always found it amusing that Mercury and most other mechanics tell you that a piston is junk if it has any metal fragments imbedded in the crown that cant be removed. They say it causes detonation. Yet its OK to push a locator in from the top and have it exposed in the combustion chamber. :confused:

[mendo]

I say vote with your money.

Buy pistons from the person that makes the best ones.

Or buy pistons and have them fixed like John Marles does.

If Merc wants your business they will provide quality parts.

This is the US. Someone will see an oportunity and make some quality parts and get most of the business.

If we sue Merc everything they sell us will have to cost more.

If they pay attention to what is selling they will make good stuff so that they can sell it.

[Propelled Marine]

If you buy from Mercury you'll make them rich.

Buy from John Marles you'll make him rich...lol

[us1]

Originally posted by Nick Korneff
If you buy from Mercury you'll make them rich.

Buy from John Marles you'll make him rich...lol


I'd go with choice #2. Hahahaha:D

[supercat]

Either way I end up broke!! lol

As far as Merc raising prices if they are sued, look what they are charging now for inferior parts!! How many years has this problem exhisted???

[mendo]

You won't be broken.

And in the long run, it will probably cost less if you break less.

Value baby, Value!!

buy the good stuff the first time or buy the good stuff after you already paid for the bad stuff that you broke.

The money you SAVED by buying the good stuff could buy a lot of BEER!!

YOU ARE SAVING MONEY!!!!

:D :D :D