Using different brand pistons

[Reggie08]

I'm finally going to try to get started on re-fixing my motor this upcoming weekend. For those who don't remember, I rebuilt an 85 'Rude 90hp that had a burned #2 piston. It was initially believed the high-speed jet was clogged. Cleaned the carbs thoroughly following the rebuild only to have the #2 piston burn up again after only 4 hours of break-in.

My question is, can using different brand pistons be bad for the motor or does it not matter? I'm not sure what brand are in the motor now but I believe they're Wiseco's.

 

[Dhadley]

Re: Using different brand pistons

The Wiseco and OE pistons are within the same weight tolerance.

Is the dome or the sides of the piston damaged?

 

[Reggie08]

Re: Using different brand pistons

The dome is melted and burned up. I was finally able to get a hold of the guy I ordered my rebuild kit from and ordered the same brand piston but thanks for the information!

Dhadley,
i'm glad you replied though. I had/have some question regarding this. If you remember, I did some preliminary "static" testing on the motor after this piston burned up and thought/believed the timer base might be bad because the #2 and #4 pistons were showing up at the same time in my timing light when I checked the WOT timing on the #2. (old thread: Burned up the #2 piston...again ) Is there a way to test the timer base separately? What might be some other problems to look into? The guy I ordered my piston from suggested I re-clean my carbs again because it sounds like to him the cylinder was running to lean and a jet may have still been clogged. I have two full days off this coming weekend and hope to get this motor back up and running soon.

My initial plan was to just start throwing money into this motor by replacing the timer base, stator, power packs and possibly coils but obviously, I don't want to do that if the parts aren't needed but because of my time constraints with 2 jobs, I haven't had the time to keep working on it :redface: if that makes sense

 

[Dhadley]

Re: Using different brand pistons

If you're burning off the edges of the piston dome, like in the pics in the other thread, it's probably ignition related. If it still runs I'd start checking the systems now rather than risk burning another new piston.

We really need to go back and remark the flywheel for all 4 cylinders like we talked about before. Find TDC on each, write the number above each mark, measure for 24 and 28* and check the timing on #2. If you're still getting a double fire there's not much use of putting a new piston in until that problem is fixed. Double firing can come from the timer base or the pack. We also need to verify the center hub magnet on the flywheel is OK and correctly aligned.

 

[Reggie08]

Re: Using different brand pistons

Will do. I agree with your statement of getting this fixed right the first time because I really don't want to have to put a 3rd new piston in this motor. The motor still runs so I can at least fire it up and check the WOT timing with the motor in the water once I get it back. Right now my boat trailer (with said boat and motor) is in the shop getting a spring bracket repaired/fixed but as soon as it comes back I intend on tackling this motor again.