Wiseco piston dilemma

[camoweasel]

This post is an update of my 350x engine build but since this is a odd problem, I figured I would start a new post.

I have an 85 350X, that I had apart to install a new Wiseco 10.25 piston @ a standard bore of 81 mm. This engine had very low hours so an overbore was not necessary. I recieved the piston in the mail; verified by looking up the parts numbers twice, and took it down to my engine builder. Upon firing up the engine once it was installed in the frame, I detected a problem. After the motor had been running for 30 seconds, I began to bogdown or load up as if, it started to become tight. Thinking maybe that it's a new piston, I restarted it, and kept the throttle open a bit to help it stay running. It did the same thing over and over. Within about 20-30 seconds, the engine would come to quick seize.
BUT here's the kicker. If I was to rotate the motor right after, it would be very tight and hard to turn. BUT only after about 5 cycles of kicking, it would return to normal kicking pressure. OR of if i waited about 30 seconds to let if cool down, it also too would return to normal kicking pressure. SO I knew that somewhere inside the engine, the tolerences were to tight.
I returned it to the engine builder, with the engine still back in the trike. He called back a day later and explained to me what he seen after tearing apart the motor once again. He believes it was either one of two things.

1) Wiseco sent the wrong size piston rings or
2) the grooves that rings sit in, weren't deep enough.

He claimed that when the piston rings became hot, they expanded to the point where the tolerences were to tight rendering the engine form rotating freely. But after they cooled a bit and shrank, everything went back to normal. The cylinder walls were still good, so no damage was done but recommended to me that we reinstall the stock piston with a new set of honda rings.
I have ran Wiseco pistons before and always thought they're quality was just as superior has Honda components. I am completely flabergasted as well as the my engine builder?? He has never seen anything or heard of anything happening like this. According to plastic wrapper that the rings came in , it says 81.00mm ring set?? I have no idea what to do?? I wanted to use the piston, but now I'm unsure of what to do??

[tom oneil]

Did anyone check ring end gap & piston clearance before install? Sounds like the rings may need a file fit.

[camoweasel]

I really am not sure since I'm not the one that did the engine work. I can only assume that since it was the standard bore and the new piston was the same, it shouldn't have been the problem. HE did mention thought that it did seem sight when installing the piston kit. What is a "file fit"?

[SWIGIN]

You need a new builder or learn to do it yourself.I trustno one with my motors since this stuff can happen. Wiseco did niot send the wrong rings, the next size over stock would not fit in the bore. He just messed up and didnt check the ring gap.

[camoweasel]

so how should this be fixed??

[MTS]

the instructions are in the box the piston came with....003 for every inch of bore if i remember right,, the piston/cyl clearence is probably also a little tight if it was a stock bore. the piston/wall clearence is on the outside of the box...pretty hard to miss. But see it lots.

[motorhead]

Always check the ring gap on any piston/ring replacement. This is basic.

He should have never just installed the parts without checking.

Maybe you caught it in time, before it ruined the cylinder.

[Dirtcrasher]

If it locked up, I'm sure there was some cylinder damage. He'll probably hone it a bit.........

Thats "IF" that was truly the issue, he may have found something else and blamed Wiseco. Wiseco made the grooves deep enough I'm sure.

I'd make certain not to give him a dime for this or any future work.

[tom oneil]

My first comment was going to be "grab your parts & run". But I'm sure you figured that out by now.

[Slingblade]

I would go to your builder and ask to see the parts. If you don't really know what your looking at, try to find someone who knows and take them along. I'm not an accomplished engine builder by any means, but I have bought and installed a few wiseco's. Most that I have seen need very little or no file work on the rings, especially on a stock bore. But ALWAYS check it. I've yet to see any that were so far off as to actually seize in a 4 stroke. Something sounds very fishy......

[cr480r]

were the rings provided by wiseco? cuz sometimes aftermarket pistons are designed to use a specific ringset... either way its the builders responsibility to check clearances during assembly..

[camoweasel]

Yes, they are wiseco rings. So if it is the stock size piston, and my bore is still original, shouldn't the clearences be the same?? I know now that they should always be checked but it just baffles me why it's not working. So, if the clearences are tight, what would have to be done to the cylinder, piston, rings, in order to make everything work?? More boring, filing, honing?? I want to make this piston work.

[cr480r]

the rings could filed to increase end gaps.. the bore could be honed for more piston clearance.. if the ring lands are truly too shallow(unlikely but possible), then wiseco should be contacted..

[camoweasel]

Ok so here's a slight update:

Not mentioned in the instructions, the bottom ring groove is slightly deeper then the top one. Even though the two oil rings have the same part number (N100), one is slightly fatter then the other, so maybe there was a chance they had the two oil rings reversed? I reversed them, and will take it back tomorrow and see what happens.

[SWIGIN]

Wait, you really have no idea what your doing, please stop before you make it worse.

There is a compression ring (top ring) and a scraper ring (2nd one down) and not only do you have to get them in the right grooves but you need to have them right side up. Your paper work will tell you how they go and how to tell them apart.

The oil ring is the bottom one and it is has 3 pieces to it. 2 thin rings and a separator. Here again, the papers will tell you how to install them.

You NEVER just start swaping rings around and trying it. Where are you in PA? If you bring it to me I'll put them on right.

[camoweasel]

Hey give me some credit here. http://http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf Here is Wiseco's ring installation guide that DID NOT come with the kit. As far as the instructions go, I know I have the oil expander and both oil rails right. The two oil rails sandwich the expander. The expander isn't overlapping and the two rails will be placed 90 degrees from each other. It's the 1st and 2nd ring that are not clarified. It doesn't distinguish which ring is which. The only markings on both rings are N100. The one ring is abit thicker then the other. Now I'm going to assume since I have the piston here in my hand that the thicker one belongs on the bottom due to the groove being deeper then the bottom? Can you clarify this? Again, it doesn't mention anywhere which is which.

[tom oneil]

Yes, the thicker is the scraper ring. Look for some sort of orientation mark as which side goes up. A dot, a line, anything.

[camoweasel]

Thank you!! Like I said, the only ID on each ring was a (n100) located near the gap on each ring. That must be the marking then. I bet, they had the rings on backwards

[tom oneil]

Before you put them back on the piston, measure the ring end gap and piston/wall clearance.

[Vealmonkey]

SWIGIN is really knowledgeable when it comes to 350x engines. He will help you however he can. Please be careful what you are doing. I would hate to hear a bad story. I think any engine, even on an original bore would need honed at the very least before reassembly as it helps the rings during break in. Piston ring end gaps and clearances are very critical. I'm hoping for you that this thread ends with a positive outcome. And please don't forget to check for proper oil level.

[Dirtcrasher]

Shiney ring on top, carbon colored next groove, then the oil expander and the scrapers go OVER the expander; ALL marks up.

I've seen guys overlap the oil expander or try to put it in AFTER the scraper rings which is possible but it isn't right........

Don't spread them any more than needed or the snap, especially the top 2.

You have 5 grooves. Starting at the top I go 10PM, 2AM, 4AM, 6AM (oil expander/holder) and last 8AM. Always worked for me.

[oscarmayer]

ok you cannot just drop in a weisco pisotn and expect it to work. the piston clearances are different than the old stocker, you needed to hose the cyclinder out to the correct clearances then gap the rings. if your going aftermarket piston, your best bet would have gone the next size up and had it bored and hones to the manufacturer's specs. I would imagien you had the piston grab the side walls once it heated up and that means a ruined pisotn. The builder should have known this and had he gap checked for the piston and made the corrections or told you he needed a different piston.