What happened to this saw?

[Alvareri]

Recently picked up a bunch of saws and parts in a package deal which included an 020t, 066, 440 and a couple 440 cases. Well I tore down the complete 440 because it had low compression and found this. Upon closer inspection, it turned out the coating (nikasil I'm assuming) had completly disintegrated on the exhaust/ intake sides of the cylinder and was easily scratched off the bore. I did a quick google search and saw the Lil red barn big bore kit matches the cylinder I have but the rings/ piston did not appear to match. Anybody know which kit/ P&C this is so I don't cheap out and make the same mistake as the previous guy? It is a 52mm big bore cylinder. I'm just glad the crank is OEM... looks way to clean, just have to verify the crank arm bore is good and no plating is stuck in the bearings.

 

[Chevboy0167]

Um..... 4 piston rings????

 

[Alvareri]

Um..... 4 piston rings????

That was my reaction as well but it turns out they just have a groove ground into them. They seem super thick however in comparison to OEM

 

[Chevboy0167]

I'm not a Sthil guru but all the pics I find on new rings and piston kits show solid non-grooved rings. Me thinks somebody put a set of el cheepo or junk aftermarket ones on there. I have never seen rings with groves like that.

 

[Lee192233]

I'm happy with the 2 Meteor piston cylinder kits I've used. Just make sure you set the squish to .020" or so. I don't have a lathe to cut the cylinder base so I made cylinder shims/gaskets with aluminum cans and coated them with a thin layer of motoseal. With the plating flaking off like that I'd recommend splitting the case and replacing the bearings and seals. I wouldn't trust the bearings after being bombarded with plating.

 

[Huskybill]

Piss poor planning on someone’s easy fix, I always preach to do things right or down the road it can hit you in the butt when you need it the most.

We rode dirtbikes for many miles over mountains and through the valleys one break down deep in the forest sucks, never had it happen fix it right. We rode the pipeline in mass.

 

[Woodslasher]

I think @Mastermind Worksaws or @huskihl said those are Hyway rings, but hopefully one of them will confirm that.

 

[farmguywithasaw]

Ahh just put it back together and run 16:1 lol

 

[Chevboy0167]

Even if them rings came in a piston kit, I sure as heck wouldn't use em. Makes no sense..... NFGAA

 

[huskihl]

I think @Mastermind Worksaws or @huskihl said those are Hyway rings, but hopefully one of them will confirm that.

Not sure what brand they are. Randy says they’re junk. No opinion, myself

 

[huskihl]

But that’s definitely a typical $40 Chinese cylinder in the pic. And that’s why no one with sense or experience will recommend using one

 

[ballisticdoughnut]

This is what can happen when you buy ****** chicom parts. Put a OE Stihl P&C on it and be done. Can't imagine your into the saw too much if you got all that stuff as a lot. Maybe find a nice used cylinder and get a new OE piston if you wanna save some coin.

 

[Woodslasher]

I say put a 460 top end on it!

 

[Yukon Stihl]

Plus find out what caused the original issue
put it back together and pressure vacuum test.
Unless you plan on a complete teardown and split the case.

 

[Alvareri]

I think @Mastermind Worksaws or @huskihl said those are Hyway rings, but hopefully one of them will confirm that.

Yes these rings are definitely weird, I've never seen anything like them in dirtbikes, jetski's, other power equipment

 

[Alvareri]

But that’s definitely a typical $40 Chinese cylinder in the pic. And that’s why no one with sense or experience will recommend using one

Yup that's what I was thinking, find of funny someone would spend the coin for a new crank but not the P&C. Thinking I will definitely steer towards a hybrid 440/460 build with this saw with an OEM cylinder and Meteor piston

 

[Alvareri]

I say put a 460 top end on it!

I think I might do that! Might go all out on this saw and cerakote the case, deck and cut the squish- I bought a lathe, ultrasonic cleaner and got a blast cabinet since my last saw build.

 

[northmanlogging]

Recently picked up a bunch of saws and parts in a package deal which included an 020t, 066, 440 and a couple 440 cases. Well I tore down the complete 440 because it had low compression and found this. Upon closer inspection, it turned out the coating (nikasil I'm assuming) had completly disintegrated on the exhaust/ intake sides of the cylinder and was easily scratched off the bore.View attachment 949563View attachment 949562 View attachment 949559View attachment 949560View attachment 949561 I did a quick google search and saw the Lil red barn big bore kit matches the cylinder I have but the rings/ piston did not appear to match. Anybody know which kit/ P&C this is so I don't cheap out and make the same mistake as the previous guy? It is a 52mm big bore cylinder. I'm just glad the crank is OEM... looks way to clean, just have to verify the crank arm bore is good and no plating is stuck in the bearings.

to answer the original question, looks like it was either straight gassed (no mix oil) or ran way to lean for way to long, possibly sucking air somewhere, make sure to check the crank seals or just replace them now.

As for the parts....? there is a reason I will only use OEM pistons and cylinders. they cost more, but are worth every penny.

 

[Alvareri]

to answer the original question, looks like it was either straight gassed (no mix oil) or ran way to lean for way to long, possibly sucking air somewhere, make sure to check the crank seals or just replace them now.

As for the parts....? there is a reason I will only use OEM pistons and cylinders. they cost more, but are worth every penny.

I was thinking it was more the cylinder construction/ manufacturer- the last photo shows where I scratched the nikasil with a screw driver and it scratched off like cheap chrome plating on plastic toys. I will still be replacing the seals and doing a leakdown test for sure because I split the case.
I definitely am with you on OEM parts, you either pay 1 time up front or double later with your time AND money

 

[huskihl]

A 440 is worth using good parts on. It’s OK to save some money on non mechanical parts like pleated air filters, plastic covers, mufflers… things that don’t have moving parts in or around them,