Replacement pistons have different size wrist pin

[paw2000]

Not sure how to proceed, I have a 79 evinrude 15hp, I had to replace the lower piston due to broken ring. I was lucky no damage to cylinder and stayed with standard size pistons. So I ordered 2 pistons, lightly honed the cylinders and started to install the rods on the pistons and the pin is larger. The pistons have a part number of TS100-101k (piston kit J/E 9.9-15hp 1974-1993), is there a replacement bearing for the con rod I can get?

I shouldn't have to change my con rods out, I checked the parts catalog and noticed that the rods were changed in the 80's and they use a different bearing set up. Any suggestions?
Thanks

 

[Faztbullet]

Re: Replacement pistons have different size wrist pin

My book shows 1974-80 uses aftermarket wrist pin brg# WP14 and the 1981-92 a #WP36.
http://www.promarineusa.com/detail.aspx?ID=5268
http://www.promarineusa.com/SearchResult.aspx?KeyWords=wp14

 

[paw2000]

Re: Replacement pistons have different size wrist pin

Hi, thanks for the reply, this might be the bearing I need. I measured my old wrist pin and its .498 in diameter, the new wrist pin is .560in (9/16). I'll need to call them and ask if they can measure them. Its hard to find any info on this.

Wiseco website lists a W5215 bearing that is needed for my year motor, but I can't find any info. And I'm not sure who made these pistons. I did locate on ebay new rods for the newer motor, that uses an uncaged bearing. Not going to be cheap going that route.

 

[Faztbullet]

Re: Replacement pistons have different size wrist pin

The WP36 is a loose bearing and the WP14 is a encased bearing, it looks like a needle bearing that would go in a gearcase. Here is what it should look like in the picture below and your pistons are WSM brand. If you call Promarine ask for John..

 

[paw2000]

Re: Replacement pistons have different size wrist pin

I'm burning the midnight oil on this.. The pistons (you are right WSM) have a wrist pin Wrist Pin: 300-101 O.E. No.: 325296. I looked up the OEM number and its used in a 1981 15hp motor, so this bearing (0390635 BEARING,Wrist pin) is used with (0385964 CONNECTIN ROD ASSEMBLY) which is the same rod from 74 to 82..

Looks like in 1984 they changed the rods and bearings. So for 3 years they changed to a larger wrist pin, then changed the rod and bearing. I wish they would give dimensions on the rods and bearings. If anyone has any more info let me know.

Thanks Faztbullet, the info on the WSM brand was the key. Once I had the brand and then part numbers for wrist pin, was a simple cross reference (tho it took 3-4 hrs of searching)

 

[14ftgrumman]

Re: Replacement pistons have different size wrist pin

I wouldn't mess around changing pin bearings.

You would be better off getting 2 correct pistons for your motor, not trying to make things fit.

If the pistons that you have have the same part no., they were packaged wrong.

Insist on 2 pistons the same.

 

[Faztbullet]

Re: Replacement pistons have different size wrist pin

I wouldn't mess around changing pin bearings.

These are aftermarket pistons and fit 1974-1992 engines, you have to match the wrist pin bearing to the rods of your year. This is standard practice with some aftermarket pistons such as :Wiseco,Vertex,Mallory,WSM,Red Rhino.

You would be better off getting 2 correct pistons for your motor, not trying to make things fit.

This is only option as as pistons are NLA from BRP and only avalaible thru old stock at $135 ea!!! and the WSM are $60 ea and better piston.

 

[Dhadley]

Re: Replacement pistons have different size wrist pin

I wouldn't mess around changing pin bearings.

You would be better off getting 2 correct pistons for your motor, not trying to make things fit.

If the pistons that you have have the same part no., they were packaged wrong.

Insist on 2 pistons the same.

Using the bearing to adapt is perfectly fine. Thousands of those motors are running like that. This is nothing new, been done for many years. And this isn't the only motor that can be done using an adaptor bearing.

 

[14ftgrumman]

Re: Replacement pistons have different size wrist pin

These are aftermarket pistons and fit 1974-1992 engines, you have to match the wrist pin bearing to the rods of your year. This is standard practice with some aftermarket pistons such as :Wiseco,Vertex,Mallory,WSM,Red Rhino.


This is only option as as pistons are NLA from BRP and only avalaible thru old stock at $135 ea!!! and the WSM are $60 ea and better piston.

I'm an old car mechanic and I can't count the times that I was told "This will fit, but has to be ( drilled out, modified, they all are like that) pick one.
Allways wound up using the correct parts. I don't like "will fit, but".
That being sid, there is at least 1 eBay store that has tons of NLA Johnson and Evinrude parts. One fellow had the .030 os pistons fro my 1972 25HP. At 1/2 the cost of OMC's list price.

 

[paw2000]

Re: Replacement pistons have different size wrist pin

I might have been able to find a NLA piston, most I found were .030 over, I didn't need to have my cylinders bored and the additional cost associated. The pistons I got was part of a "rebuild" kit. I got complete gaskets and seals, all bearings (crank center and lower and all big end rod bearings) If I had a newer motor the wrist pin bearings wouldn't have been an issue. Actually the cost of the kit was less then the price of 2 pistons quoted by faztbullet.

Anyway, I actually found the dimension of the adapter bearing sold by Wiseco inside Diameter: 14.3mm
Outside Diameter: 19.1mm
Length: 15.75mm
Type: TBD
Position: Wrist Pin

I'll check with Promarine if they stock it, or can order me 2 in. This mod will be the only way to go as the these motors age. This where these message brds work, someone somewhere has done it, seen it or heard about it. The key was identifying the pistons.

 

[Dhadley]

Re: Replacement pistons have different size wrist pin

Pro Marine supplies the bearing to Wiseco. There's a cute story about how this beaing thing all came about but the bottom line is - don't worry about it. Just take advantage of all the research.