Wiseco Pistons???

[Instigator]

Remeber reading that you merc guys were having problems with the Wisecos coming apart at elivated RPM levels. Think it was the ring guide pin backing out?? Anyhow, I'm rebuilding a friends '89 JohnRude XP 200 and it has two holes that are already +.030", so my choice is sleeve those holes so I can run factory pistons or go +.040 and run Wisecos. This thing will never see over 6K (unless he lets me borrow it!) and I'm wondering if anybody has had positive results at these lower (OMC) RPM levels?? Any help would be greatly appreciatted. Thanx, Instigator

[Ray Neudecker]

they have not been as much of a problem in that application.Be sure to allow an extra thousand or so for clearance. They will grow more than a cast piston. Also be sure and check them carefully for size before installing. be very careful with the pin clip tobe sure that they seat properly and that the pin can not get by them.

[rocko]

i'm running a 2.6 omc on my vector with wisecos and havent had any problems.as far as i know the only pistons affected were the ones for 2.5 mercs.the company i work for uses wisecos and we are also a distributor for them and we havent had any problems with them in a long time.good luck rocko

[T-REX]

All pistons can loose a locating pin...Wiesco jus do it more often...You can help this problem if you nead the pin before installing it, also as Ray said, use more clearance, and always let the engine cum up to temp before taking off...Operating temp is critical with a forged pistons, if you run a motor with forged pistons before the motor is up to temp the pistons will heat faster than the cyl walls and will swell faster than cyl and stick...cold sieze, $$$$$... You get what you pay for, save now, pay later...Jus my opinion...REX

[Greg Moss]

I have used Wiesco's for a long time.They work good in the OMC's. The new Wiesco's have different clearance cut into the piston to keep the cold siezer prolem in check. Check the piston before you cut the cylinder to big. I would run them they are a good piston. Greg

[Rickracer]

I was faced with the same choice, bought the Wisecos, then changed my mind, sent them back and ordered 2 sleeves and Pro Powers. I'm sure I won't regret it.

[FCnLa]

I know that a forged pistons are heavier. Would this cause a problem? Just curious.

[Rickracer]

I haven't weighed any cast pistons, but the weight is pretty close to the same. I generally balance/weight match all my pistons anyway.

[alan knight]

I think most folks use wiseco pistons for (2) reasons: broad range of sizes and the lower than OEM piston prices.. have installed many many wiseco and the only problem I run into in the cross flow app. is crushing in the wrist pin boss area. Merc V6 wisecos are a different subj. tremendous problems. I used a lot of DMI slugs years ago with no problems until they started manufacturing the rings in argentina. I believe I read some few years ago that wiseco has gone the argentina route also. Note: have also had problem with low tension cir clips. called the tech dept. and the std. reply is we have had no complaint,but will you please send the clip to us for testing.

[Greg Moss]

I have had the same problem with the clips. Talked to Wieseco and the gave me the same never heard that problem before story. I have started useing Spir-loxs in all piston I install and have no more trouble. If you ever use them you will love them. Wiseco sells them or they can be gotten at any bearing store for $.50 each.

[Sleekster]

Thanks, Greg. I'll be putting my looper together sometime this year (I hope) and I'll make sure I get the Spir-loxs. I reeeeeeeally don't want a pin working loose. Thanks for the tip.

[alan knight]

I really appreciate the info Greg I knew that the race car boys used them but I never tried them on the O/B ps ask old Paul FNC about the boat ride in my toy next time you talk I pulled the powerhead off today(sold it to another die hard) seems I never get to keep one for long. Guess I really should put wing nuts on everthing as much as I change powerheads. Got another 2.5 for it,more bang, I`ll see if Paul can drive it. later Alan