Need help swapping out cylinder and piston on old MS 460

[Lakeside53]

Your stihl dealer will sell you an OEM gasket kit for not much more than Baileys. I doubt the stihl or the baileys kit will be correct for the big bore cylinder gasket though. And... why the entire kit including seals when all you need is cylinder gasket?

 

[Sunrise Guy]

Your stihl dealer will sell you an OEM gasket kit for not much more than Baileys. I doubt the stihl or the baileys kit will be correct for the big bore cylinder gasket though. And... why the entire kit including seals when all you need is cylinder gasket?

So if I'm rebuilding the carb I won't need any other gaskets or seals? Then again, those will come in the carb kit, right? Does Stihl sell just the cylinder gasket? Thanks.

 

[ZeroJunk]

Does Stihl sell just the cylinder gasket? Thanks.
__________________

Yes.


Also, I broke a ring on one of those big bore pistons the other day. Probably my clumsiness. But, it wouldn't hurt to put your piston in the freezer and get the rings warm for a while before you try to slip them on. The coefficient of thermal expansion for aluminum is fairly high compared to some metals, and it can't hurt.

 

[timberwolf]

But, it wouldn't hurt to put your piston in the freezer and get the rings warm for a while before you try to slip them on.

Hmmmm? cold piston will shrink the width of the ring groove, warm ring will make it a micron thicker. If anything that will just make it harder to get the ring in the groove and getting them stuck half in the groove when they break. I think there may be some bad after market rings floating about the last while, so maybe broken one was one of those.

I'v put hundreds of rings on, never snapped one, I just pull the ring ends apart with thumb nails with middle fingers against the other side of the ring.

 

[ZeroJunk]

Hmmmm? cold piston will shrink the width of the ring groove, warm ring will make it a micron thicker. If anything that will just make it harder to get the ring in the groove and getting them stuck half in the groove when they break. I think there may be some bad after market rings floating about the last while, so maybe broken one was one of those.

I'v put hundreds of rings on, never snapped one, I just pull the ring ends apart with thumb nails with middle fingers against the other side of the ring.

Maybe so. The freezer is an old trick for putting rings on back in my grandfather's day. I don't care whether it snaps in the groove the instant I get it slipped over the piston, it will drop in there eventually.

On these overbore rings I actually broke two of them. The second ring I was as careful as I could be and it still snapped. I sent them back and told the dealer they were too brittle, always a trade-off when trying to make something hard.

I haven't put hundreds on, but I have put a few dozen on in the last couple of months. Haven't had any problem with the Stihl.

 

[timberwolf]

If a ring is so brittle it snapps going on the piston like that it seams unlikely it would stand up long anyway under the constant flexing it's going to get in the engine.

Guess it's better in a way to have broken in your hands than in the cylinder.

 

[Lakeside53]

Many techniques, but care is required.

I engage one end and use a razor knife to slide around and pop the other end in.

The only OEM ring I ever broke was when I slipped with the friggin' screwdriver putting a circlip in a 660 I have broken a few of the "less then $1" generic 2 stroke rings...

 

[Lakeside53]

Yes.

.

But... will it fit the BB? Baileys should supply the correct gasket with the P&C.

 

[ZeroJunk]

But... will it fit the BB? Baileys should supply the correct gasket with the P&C.

I put the piston and jug on less the rings and turned it over with the flywheel. A few thousanths had to be dremeled off on the intake side for the piston to clear the crankcase, but the gasket did not appear to rub. No gasket came with the kit.

 

[Lakeside53]

lolol another "some assembly adjustment required" kit:greenchainsaw:


The OEM gasket is steel coated with rubber. If it doesn't clear the piston skirt, don't "adjust" the gasket... Use 0.5mm paper, and check the cylinder bolt torque often.

 

[ZeroJunk]

lolol another "some assembly adjustment required" kit

Yeah, the broken ring wasn't the only reason I sent it back. Just the straw. I didn't care for the depth the clip sat in the groove either. I put an OEM piston in and it runs like a scalded dog.

 

[GASoline71]

Maybe so. The freezer is an old trick for putting rings on back in my grandfather's day. I don't care whether it snaps in the groove the instant I get it slipped over the piston, it will drop in there eventually.

I've never heard of putting a piston in the freezer to intall rings either.

You sure you're not confusing that with the old trick of installing press fit wrist pins? Pistons in the oven and the pins in the freezer trick?

Gary

 

[Lakeside53]

is it done:greenchainsaw: yet?

 

[ZeroJunk]

I've never heard of putting a piston in the freezer to intall rings either.

You sure you're not confusing that with the old trick of installing press fit wrist pins? Pistons in the oven and the pins in the freezer trick?

My neighbor who is 75 years old and a jackleg mechanic of sorts like myself said there was one brand of rings they used back whenever that were bad about breaking unless you froze the piston. Of course we were talking about 4 inch pistons and the effect on a 54 MM saw piston might be insignificant, but it can't hurt anything. A couple of thousandths could mak e a difference. Or not, I don't know.