Aftermarket Pistons / OEM Circlips

[PogoInTheWoods]

Can I get away with using Stihl circlips (9463-650-1000's) with aftermarket pistons in an 026 and 028? The ones that came in the aftermarket kit for the 026 would simply not fit into place without actually needing to be squeezed smaller with some degree of deformity to pop into the slot. I'm not exactly comfortable with that and can get new OEM clips, but noticed the old OEM clips seem to be just slightly thinner stock than the aftermarket ones which will probably be much easier to install -- if they'll stay in place under operational conditions given the difference in thickness of the clips in general.

Don't even want to wrestle with the 028 in the same manner if I can use the Stihl circlips there, too -- which are also listed as the 9463-650-1000's.

As usual, TIA for any input or advice.

Poge

 

[ncfarmboy]

I use the OEM all the time in AM pistons have had no neg. results even though the OEM's are slightly smaller. Have used OEM Husky in Dolmar's which are like Stihl no tab to grab.
Shep

 

[ZeroJunk]

I had the same issue with an 026. I was afraid to use the OEM clip because the slot was deeper and it looked to me like it could allow the pin to slip over it and I bent the fat clips that came with the piston.. I actually bought another brand piston because I didn't want to blow the saw up over a clip. The last Meteor I got for an 028 had the clips with the half circle tabs on the ends where you can squeeze it together. I wish they were all that way.

 

[PogoInTheWoods]

The last Meteor I got for an 028 had the clips with the half circle tabs on the ends where you can squeeze it together. I wish they were all that way.

I hear ya. There is one listed in my 028 IPL for older 44mm piston versions -- 9462-650-1000 ->6-111-990-(43.79)

Poge

 

[PogoInTheWoods]

Bumping this nearly 9 year old thread for any historical input that may have accumulated over the years..., and because I don't have the time to read 20 other threads about circlips!

I've had exactly two circlip failures over the years. One was OEM on an 036 that evidently wasn't completely set in the boss groove. The other was from a recent Hyway piston kit on an 039 that appeared to simply be metal fatigue.

I've usually just used the circlips that came with the aftermarket piston kits and haven't looked back. Always trust the Meteor clips, but always sorta crossed my fingers with the cheaper kits if thruth be told. The main reason for using the supplied clips has been the size of the clips relative to the slot in the wrist pin boss has typically been quite noticably larger than OEM and I was concerned about sloppy fitmment with OEM clips.

Coincidentally, I again find myself with an 039 getting a Hyway top end kit. The circlips in this kit were absolute junk and both collapsed under very little stress trying to install them. I ended up using the slightly smaller thickness Stihl OEM clips which went into place easily (maybe a little too easily?) and are just thick enough to retain the wrist pin. Concern here is whether there's enough rigidity in the clip to remain in place in the larger slot.

The obvious question is whether or not folks have had failures using the thinner diameter OEM Stihl circlips in place of the AM clips.

TIA for any/all experiences anyone cares to share.

 

[HarleyT]

I always stopped by a Napa and chose the right size of one of these...

 

[HarleyT]

Well two.....

 

[ZeroJunk]

I had a MS660 puke and the only thing was the tab on one of the clips broke. So, I have changed my feeling about that. I have noticed that Meteor quit supplying the clips with the tabs, so I guess there is a problem. I would have thought that they did not have enough mass to break off, but apparently they do.

 

[L34]

I cut tabs off once installed.
Harley,I have seen you mention these clips on various occasions.
How well does the square edge of the clip fit in the clip groove (rounded)?
Obviously no failures with these clips.
Cheers Chris.

 

[Ronie]

I reused the OEM clips in this one with a Golf piston. Lost the clips on both sides.

 

[TheTone]

I always stopped by a Napa and chose the right size of one of these...

View attachment 793876

Why don't they use these? they would be so much easier to put in and take out.

As regards "tabs" or "ears" on circlips and why Stihl and Husky don't have them, I've inserted a quote from one of my previous posts:

Just to make sure the piston pin circlip physics is understood . . . I wish I had CAD software to illustrate, but I'll have to do it verbally. At chainsaw rpm the piston is going up and down hundreds of times per second. This creates tremendous acceleration forces. Remember that force = mass x acceleration. Now if we have a circlip with the gap at 3 or 9 o'clock and the piston is going up, the top half of the circlip is being pushed down. The fulcrum point will be at the midpoint of the circlip and the outer half of the clip will be bent away from the fulcrum point and also away from the groove that it rests in. At this point it will be the least confined by the groove and more subject to any sideways forces that would move it out of the groove and in a worst case scenario pop it free from the groove. Now imagine that there is an "ear" on each half of the circlip. You now have much more mass at the outer edge of the circlip, which by F=ma means the circlip will bend even more and be more susceptible to popping out. This is the rationale for (1) not using circlips with ears, and (2) lining up the gap at 12 or 6 o'clock, where the forces will cancel each other out. Hope this is clear.

 

[Huskybill]

I always stopped by a Napa and chose the right size of one of these...

View attachment 793876

One edge is square the other edge is rounded which way do you install them?

 

[Jacob J.]

I reused the OEM clips in this one with a Golf piston. Lost the clips on both sides.

View attachment 793917 View attachment 793918

I've not found OEM clips to be a good fit in a Golf piston, but I've also seen variances in the machining tolerances of Golf pistons, which I
won't buy them. I used one early on in a Husky 2100 and part of the skirt came off after about two hours.

 

[Huskybill]

Did you mic the bore size on the 2100? There is “A”, “B” & “C “ size bores. Too much piston slap/ clearance will crack a piston. I forget which piston I put in my 2100.

 

[pioneerguy600]

I've not found OEM clips to be a good fit in a Golf piston, but I've also seen variances in the machining tolerances of Golf pistons, which I
won't buy them. I used one early on in a Husky 2100 and part of the skirt came off after about two hours.

They are the piston of very last resort I would ever use again, I have a few used paperweights I removed from others rebuilds. One case was a Sachs Dolmar 116 where the owner installed a Golf piston, it didn`t last the first tank of fuel, the skirt on the intake side snapped off just below the pin. I miked the piston and it was not far off, the metal in the piston was very open grain pot metal. Not one Golf piston has ever restored proper compression so I removed them and reinstalled OEM piston and rings, voila, compression came back to near normal.

 

[HarleyT]

I have had trouble with Golf pistons before, and won't try any more.

I had one that hit the counterweights at BDC, and had to make a chamfer on the bottom inside lip {per the customer's request}, as he supplied all of the parts beforehand.
I tried the circlip thing when once I tried those cheapo wire clips from the aftermarket kits, and they would lose their "spring" grip after installation. So I just took the piston to NAPA and tried their clips right there until I found the clips that fit right.

 

[Huskybill]

I’m not sure which piston I just put in my 2100. I ordered a new one.