MMWS (Cross Performance) 066/660 Cylinders

[wcorey]

Since Niko (and company) effed the other thread up I figured I’d start a fresh one…

Finally picked up my very first 066 a few months back, I’m pretty cheap and pretty patient with acquiring saws and this is one model where a good deal has successfully eluded me for years.

It was a red light saw-in-a-box deal that was too good to pass up, missing a lot of parts but the big essentials were mostly there and in good shape. Needed a piston, top handle, brake handle, air cleaner cover and a bunch of small stuff, a lot of which I can live with aftermarket parts on.
Unfortunately turned out the cylinder’s an 064, didn’t notice at the time ‘cause they look sorta similar to the old 066 ones. Not that it would have changed anything… So good timing on these cylinders.
Slowly accumulating parts for it and patiently waited for the mmws/hl cylinders to get done.

Air cleaner cover is the last major piece I haven’t found but a least not essential to running it.

Was going to hold off buying the mmws/hl cyl until I heard some feedback on how they came out but the deal o’ the day thing was too good to pass up so I grabbed a couple.

Still waiting on a few small parts before I can run it.



Overall the cylinders look pretty good and so far I’m happy enough with what I got.

Numbers look good, more or less ‘as advertised’, 102 ex, 20 bd, 81 int without base gasket.

Squish about .019” without gasket (one issue here though, see below). Casting quality mostly looks good, particularly inside the transfers where it often lacks. Good thick base, piston looks decent with no obvious issues. Caber rings, a nice addition.

The Bad… well there is some… I wouldn’t drop in/run either of them without a careful once over, I’d consider it absolutely essential.
Nothing that can’t be addressed with some light grinding/cleanup though.
Really better than/nothing more than what I’ve come to expect with the chicom stuff in general.

Lots of casting flash and plating ‘crusties’. Beveling is inconsistent and sketchy, one was generally better than the other. Ex port roof is kinda flat.

One cylinder had a sort of pocket in the bottom corner of a lower transfer with some nasty looking flash and ragged edges of plated aluminum waiting to fall off. And in behind there was a substantial amount of what appeared to be gritty blasting media all stuck up in there. Didn’t wash/blow out, needed to be scrapped out.

Both had a lot of crusty plating along the edge of the exhaust port openings, one on the roof, the other the floor. I mean relatively big chunks that could be broken off without much effort, had a small pile just from poking around with a screw driver. Miscellaneous smaller spots randomly scattered on other ports.

And that pic is after I chipped the big stuff off already...

The plating chips easily on the corners.

A big piece of sparkplug thread was barely hanging on, waiting to break off on the end of one hole.


Guess I need to start another page for more pics...

 

[wcorey]

The combustion chamber on one had a bunch of little ‘plating balls’ stuck to the squish band and since the piston is shipped in the bore it made a ‘ring of dings’ all over the top of the piston. Small and inconsequential mind you but I wouldn’t want that stuff kicking around in a running motor…

One cylinder has a raised ring/hump that’s about .009” high x .15” wide all the way around the squish band along the edge of the combustion chamber. Hard to see looking down at it but very obvious when you pull the solder wire out. That will be the one to get a squish adjustment.

Upper transfer roofs vary from each other sort of randomly in both height and angle by 1-2 degrees.
Probably not consequential but I'll fix them just cause...

 

[Mastermind]

That doesn't look good. @Gentleman

 

[trboxman]

I'll have one on hand by next weekend, hope it looks better than that.

 

[wcorey]

They'll be fine with a small amount of work.
They come sealed up in shrink plastic, if I were selling them that would be gone and all would get a once over before leaving.
Depends on who it's going out to I guess, didn't really bother me...

 

[trboxman]

Yes, I'm sure they will. The ones from Huztl at a much lower price are fine in the same manner. I was hoping against hope that an AM "performance" cylinder wouldn't just be "fine" after I do all of the clean up, I wanted it to be "fine" with no clean up required. I get that this is a new run and that everything usually has a few kinks to get worked out, however...

 

[Mastermind]

I've seen three, and they were all pretty damn good. The Chinese never seem to be consistent with QC.

 

[wcorey]

Like the first year on a new vehicle model...

 

[trboxman]

I've seen three, and they were all pretty damn good. The Chinese never seem to be consistent with QC.

That is the God's honest truth right there. Far too often if you want good quality out of them you have to put your own QC folks on site to keep them in line.

 

[Coltont]

That is the God's honest truth right there. Far too often if you want good quality out of them you have to put your own QC folks on site to keep them in line.

I've often wondered why it's like that? They think us Americans are that dumb? Or most likely it's quantity over quality?

 

[trboxman]

I've often wondered why it's like that? They think us Americans are that dumb? Or most likely it's quantity over quality?

They're paid by the piece. The less time you spend on each the more money you make. They need to have quality added to their pay metric.

 

[Terry Syd]

I think it may have to do with proper instruction at the factory. If you take a look at some of the 'bevels' on ports, it is apparent that the people doing the work have no idea what a proper bevel should look like. They probably are just given a tool and told to trim around the ports.

If they had a training class, with pictures of a proper bevel (and WHY) - and those employees were held accountable to getting it right or loose the job - I expect we would see much better work.

 

[jmssaws]

Wtf is a bevel?

 

[Terry Syd]

It is term that has developed in chainsaw forums. It means the beveled edge on ports.

The best 'bevel' on the top and bottom of a port is the wear that a ring will wear into the top and bottom of the port. The ring will slightly move out into the port and create a bit more wear in the middle of the port. Unfortunately, you find 'bevels' where it resembles no relationship to that kind of wear - especially on the SIDE of the ports. Like WTF? why are these morons grinding away at the side of the port? You need the sides of the port to support the ring - and they are grinding the support away.

 

[Brewz]

I kind of accept that there will be a bit of work to be done on Chinese stuff like this.
Sometimes there is a bit of rubber in the Chinese fuel and impulse lines so I always check them before fitting them.

I used a Hyway MS660 kit earlier in the year and 2 of the cylinder mounting screws would not go in. I had to remove some material so they would seat properly.

It also had horrible timing at 94/126/83 and an exhaust port half the size of an OEM Cylinder.

For what these kits cost, which is less than I can buy a set of OEM rings for in Australia, I'm OK with a bit of touchup.

I should have mine soon too.

 

[drf256]

Bill,

Thanks for doing the thread.

Is there a piece of plating hanging on that upper transfer floor?

Is the chamber plated or bare?

Looks like they casted the exhaust port shape perfectly, just upside down.

I'd cheat on that ex roof. Just bevel the plating more in the center of the port than the outer. You'll effectively show the rings a rounder roof.

 

[Brewz]

The Cross 084 top end kit I bought also had the ring around the chamber that was lower that the actual squish.
From memory it was about .022 ish on the squish with a band at .017 around the chamber.

Other than that it is nice for the price.

 

[Brewz]

Bill,
Looks like they casted the exhaust port shape perfectly, just upside down.

It does look upside down doesn't it.

Any others got a cylinder they can check?

 

[Terry Syd]

Here's a bit of a trick for exhaust port roofs that are too flat (especially if you have to grind a bit on them). You don't want the rings to catch the cylinder lining. So instead you put a bit of 'bevel' on the rings themselves. It doesn't take much, just take the sharp edge off.

If you find a cylinder where the top of the exhaust port has had the lining buffed off of it, then a bit of smoothing of the top edge of the rings can give you a longer life for the cylinder. You just want to prevent the rings from catching the liner.

 

[jmssaws]

Some of the worst bevels I've seen are on ms460 stihl branded cylinders.

I just did one that had a honest 1/8" bevel on the uppers and plating everywhere.
Horrible cylinders to port.

I've not ported many am cylinders but the ones I have have been good.
Not like a mahle but good.
Ks can be sloppy also with plating and port shape.

A lot of time a exhaust roof that looks to have a good arch is flat, always trace it on a mandrel or piston.