pic/ factory top pinned pistons, fixem now

[stvhelm]

1 season on this. approx 75 hrs. the pins are way too soft. the ring worked right thru the locating pin.


http://forums.screamandfly.com/forums/attachment.php?postid=498988

These got new pins and are all fixed up by John Marles. nice work

http://forums.screamandfly.com/forums/attachment.php?postid=510866

fixem now. it costs 3x when youre too late

[Dave S]

What brand are the new ones?? Thanks.:cool:

[Tom Foley]

Helmut , That was a nasty looking piston ! I have a 96 - 260 with 100 hours on it . What is the best route to go for prevention of that situation . Honestly the hours probably are not even near as severe as your motors , but I love my motor ! Usually if I take a motor down that far I replace every bearing top to bottom , I have never done a 260 but I am assuming it will be simalar in process . I look forward to your reply . Thanks again , Tom

[us1]

Nobody ever believes me when I tell them that the factory top pin piston will fail too. The pin are too soft as you can see.

[us1]

Originally posted by Tom Foley
Helmut , That was a nasty looking piston ! I have a 96 - 260 with 100 hours on it . What is the best route to go for prevention of that situation . Honestly the hours probably are not even near as severe as your motors , but I love my motor ! Usually if I take a motor down that far I replace every bearing top to bottom , I have never done a 260 but I am assuming it will be simalar in process . I look forward to your reply . Thanks again , Tom

Tom I repin the pistons to avoid this problem. Check out my website. www.us1.cc

[Jay Smith]

John's "fix" is the only way you can sleep at night knowing that the locater pin is not going to be the "Bad Actor" that causes your costly engine failures and or repairs ! $300.00 VS the alternitive just ain't smart.........

[Scream And Fly]

With the Marles-modified pistons and JSRE rods and wrist pins, you will have one of the strongest, lightest, and most reliable rotating assemblies available for high performance use. We'll put it to the test too!

Greg

[Markus]

Steve Heintz sells light wright wrist pins as well. They are not modified standard Mercury pins, but made from a different alloy.

[David_L6]

Originally posted by Markus
Steve Heintz sells light wright wrist pins as well. They are not modified standard Mercury pins, but made from a different alloy.


Does he have a web site? or do you have his e-mail address?

[us1]

Steve Heintz
MERCURYRACING@insightbb.com

[baja200merk]

so you did smoke your motor?

kevin:)

[Tom Foley]

Thanks John , Jay , Helmut , Greg , I now know what has to be done ! I do have a few questions about skirt deposits from blowby caused by the alignment of end gaps , does this happen inbetween ring changes of 100 hours or so ? Also John you mention angle cutting the pistons , is this what I see on the new pistons for Helmut ? Thanks again guys I will absolutely get this done when I rebuild. I Would like to have all my parts aquired and send out the pistons and get them back in a week or so if that is possible so I can dedicate a weekend to reassembly without thrashing ! Thanks for the lesson ! , Tom .

[us1]

I can turn around the parts in one day if I am not too busy. The ring alignment really has no affect on compression, leak down or deposits. If you are having trouble with deposits you should run a good quality race oil and make sure the ring gap is around .020. Yes those are used pistons I have rebuilt with new welded locator pins and angle cuts. They have also been lightened.

[stvhelm]

yes, that piston came out of my motor. It would burp every few seconds while idleing. figured it may have been a bad plug or something. It did that all day and when i got it home and ran it on the flusher it was doing the same thing. I did a compression check for the hell of it and that number 6 came out at 60lbs while all the other cyls were still around 170 give or take 1-2lbs. I dont know how long it was like that cause I was out trying a new cleaver and still hittin 120 on the gps. it seem to be running the same as when i first put it in when i took it out. I thought it was just a ****ty prop. guess not.
I wouldnt "Smoke" my motor. smoking is bad for you.:p ;) :D

[1BadAction]

Originally posted by stvhelm
I wouldnt "Smoke" my motor. smoking is bad for you.:p ;) :D

ha ha. be prepared to eat those words if you ever do smoke a motor, cause I am sure somebody will bring this up. :D

[stvhelm]

Tom, I thought my best route was new pistons. in four years I bought 3 new sets. every time it was because of pin failure. get yours redone and save yourself the aggrevation. if I recall someone just recently has a new set of gold top pinned rings for sale on here for 200 bucks. if your bearings arent showing any blue heat marks then they should be fine. just inspect the cages they are what wears out.

I just found that thread but i think they may be sold http://forums.screamandfly.com/forums/showthread.php?threadid=65813&highlight=east+coast+rings

[us1]

Is it running yet????????????

[mendo]

Shouldn't you be working?????

:D

[us1]

I am. Lap top with cellular hook up.

[eli]

Stv if you say the pins are to soft and the ring mowed it down? what kind of pistons were they? merc or mahles for merc i just put in 12 new mahles in my 2 motors and was not wanting to hear what your saying ,i just spent $ 6000.00 on machine work and parts and installed the pistons last night after i lightened the pistons and rods 40 to 62 gm less per hole there wasnt 1 piece in them motors that was close i,m down to the hundredth ,i hope it lives, this thing breaks next year my wife wont let me fix it i put rings gaskets and machine work $1800.00 not cryin just worried. Jay Hinz

[us1]

His pistons are 260 HP 2.5 factory Mercury top pin pistons. Not Mahles.

[stvhelm]

the motor is done. I just rewired all the gauges tonight. the weathers been awful. hopefully soon

[mendo]

Originally posted by us1
I am. Lap top with cellular hook up.



What!!!!!

You didn't get that wire ran accross to the shop yet?

I could help you with that!!!!

Maybe trade?

:D

[us1]

I am on line when I leave the country.

[mendo]

Another High-Tech tool.

Don't you have enought tools?

Sent you PM.

David

[Richard K.C. Mo.]

Since we have the pistone guru online, diff. in 2/4 cycle air liquide cooled. Take your time going to put this on dics.

[us1]

Could you rephrase the question?

[David_L6]

US1,

I think I know what Richard is asking... There has been some discussion about this on another board. I sent a piston from an outboard (one of the pistons that you have now) to a "custom piston" manufacturer and was told that they couldn't duplicate the piston because it was for a 2 cycle motor.


What are the differences in 2 stroke and 4 stroke pistons. (i.e. different alloys?)

Same question for pistons used in air cooled and liquid cooled motors???

[us1]

The problem 4 stroke pistons manufactures have with making 2 stroke pistons is the 2-stroke piston is not round. A forged 2-stroke piston is cut on machine using a cam. It’s an entirely different method of manufacturing and the manufactures I have talked too are not interested in completely retooling their process.

[Richard K.C. Mo.]

David, that is it what i wanted to ask, but just started making my own wine. I got it to about 14%, i didn't drink enough to spell -check or for thought process to be fully functional. I may have that backways too.

At any rate, thanks guys am putting asmuch info as i can in hard copy. :)