Would you run this piston in a MS361 rebuild?

[PogoInTheWoods]

Someone evidently thinks it'd be ok.

This is from a Hyway p/c kit. Piston is nice (aside from the obvious) and the cylinder is very nice. But......

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.....this slop is excessive and seems like a needle cage failure just waiting to happen once it gets a chance to start sliding back and forth a bit. My inclination is to send it back, but the cylinder is real nice. I'd have gone with Meteor but they only sell the piston from everything I could gather..., including from their own web site.

Comments?

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[s sidewall]

I would say side shims but the casting at the wrist pin doesn't look that good so that killed that idea.

Steve Sidwell, Samsung On5 using Tapatalk

 

[s sidewall]

On a second thought, seen Chevy small blocks with that much , how much side to side movement on the rod at the crank and how much crank movement in the case? If very little, it should stay pretty close to the center of the piston.

Steve Sidwell, Samsung On5 using Tapatalk

 

[motor head]

Someone evidently thinks it'd be ok.

This is from a Hyway p/c kit. Piston is nice (aside from the obvious) and the cylinder is very nice. But......

View attachment 588025
​

.....this slop is excessive and seems like a needle cage failure just waiting to happen once it gets a chance to start sliding back and forth a bit. My inclination is to send it back, but the cylinder is real nice. I'd have gone with Meteor but they only sell the piston from everything I could gather..., including from their own web site.

Comments?

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Scarey, probably not

 

[brandonstc6]

I bought a tecomec piston for mine and it was only $20 shipped. I haven't installed it but it looks good.


Sent from my iPhone using Tapatalk

 

[Chashowlett]

Don't like, what's your old oem stuff look like?

 

[Tree94]

Hey guys, would someone explain to me what exactly stands out as wrong with this piston?
Thanks.

Still learning here, knowledge is power

 

[Justsaws]

There is a space between the top end of the connecting rod and the insides of the piston casting that is larger than needed. Certainly larger than desired. The issue being the bearing could slide out of the rod enough to bind if the space is too large.

It does not look as though the space is too large in the photo, it is larger than needed. Sometimes the issue can be corrected with a wider bearing.

 

[Tree94]

There is a space between the top end of the connecting rod and the insides of the piston casting that is larger than needed. Certainly larger than desired. The issue being the bearing could slide out of the rod enough to bind if the space is too large.

It does not look as though the space is too large in the photo, it is larger than needed. Sometimes the issue can be corrected with a wider bearing.

Ah, thank you

 

[rmh3481]

I would not run that Htzl bearing, but with that said, the piston is centered by the cylinder. The purpose of shims or thrust washers on the outside of the wristpin is to keep the bearing centered in the connecting rod. An unsupported bearing will fail. Use mild steel washers if you need to.

 

[PogoInTheWoods]

Bearing is OEM.

Got credit for the piston and kept the cylinder. Was offered a Meteor replacement piston but opted for OEM for $7 more that I can get locally a lot faster. No way was I gonna run that Hyway piston. Almost 4.5mm excess clearance between the pin bosses is way, way, too much..., even for an AM kit. Got it from HLS and they agreed. There's more of these defects than folks realize and why it persists. The piston is going back to the factory for inspection as defective and hopefully correction of any manufacturing issues that caused the problem.

Here is a better pic of the bearing slop and also one of how it should fit. 'Preciate everyone's comments. Was curious about what folks would think.

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[blsnelling]

I personally doubt it would have ever been an issue. I'd be interested in knowing the difference in width.

 

[Justsaws]

If it allowed the lower end of the crank to wander over enough to rub then it is a problem.

Unsupported or single side roller exposed percentage is bantered about, not the exposed width including cage just the rollers, I was "informed" 30% single side roller exposed is the cutoff, seems huuuuuge. Never had an unsupported wee end bearing problem on a chainsaw, so I do not know.

 

[PogoInTheWoods]

Difference is around 4mm and change..., enough for uneven wear and eventual failure of the needle cage (and probably the piston too) IMO.

 

[blsnelling]

Difference is around 4mm and change....

That's quite a bit!

 

[Rockjock]

Bearing is OEM.

Got credit for the piston and kept the cylinder. Was offered a Meteor replacement piston but opted for OEM for $7 more that I can get locally a lot faster. No way was I gonna run that Hyway piston. Almost 4.5mm excess clearance between the pin bosses is way, way, too much..., even for an AM kit. Got it from HLS and they agreed. There's more of these defects than folks realize and why it persists. The piston is going back to the factory for inspection as defective and hopefully correction of any manufacturing issues that caused the problem.

Here is a better pic of the bearing slop and also one of how it should fit. 'Preciate everyone's comments. Was curious about what folks would think.

View attachment 588547

View attachment 588548​

Wait a tic.. the OEM piston was JUST 7.00 more? 7.00!! WOW!!! I wish we had those prices!!! I doubt it will go back to the factory, just tossed in the bin and forgotten.. it is not as if they will do a recall or anything.

 

[PogoInTheWoods]

1135-030-2000 47mm OEM Stihl MS361 piston is $37.00 from an honest dealer.

HLS sends certain types of defective units back to the mfr. depending on the mfr. Hyway is evidently one of em who pays a certain amount of attention to problem products. No name unlabeled box stuff gets tossed.

 

[Rockjock]

1135-030-2000 47mm OEM Stihl MS361 piston is $37.00 from an honest dealer.

HLS sends certain types of defective units back to the mfr. depending on the mfr. Hyway is evidently one of em who pays a certain amount of attention to problem products. No name unlabeled box stuff gets tossed.

1135 030 2005 sells for $ 182.41 CAD$