Your experience with Hyway pistons…

[Gord404]

If I need a new cylinder kit I have had great success with meteor or hyway and have used a lot of them over the years, compair a hyway to a china knock off and see the diffence in casting and quality, I also have a box of differnt sizes of Cabers so I don't find anything wrong with Hyway rings but I prefer Cabers, in my regon the saws usually go to aborests , loggers or firewood guys so longevity is a must.

 

[cookies]

Ive a 268 that really needs waking up and debating which way to go about this porting or like you say pop up any views welcomed thanks

in my experience pop ups add compression but take away from air/fuel swirl creating a strange flame front pattern on the piston crown. I would add one to a clamshell but not a pro saw. If your saw is feeling weak it might just be time for a new ring or a piston if its worn smooth, I suggest oem over saving a few bucks. nAftermarket pistons from meteor and hyway have smaller windows than oem with meteor weighing more and hyway weighing less than oem. It might be wisest to buy a new piston with ring and ship it with the powerhead to be ported to get it done right and move forward.

 

[corriscaveman]

I will add to check piston to combustion chamber clearance. In otherwards, make sure the pop up doesn't hit the ground strap on the spark plug.

Use an old plug that is gapped properly, install in plug hole, rotate engine over by hand via the flywheel to ensure the piston will not smack the plug ground strap.

I had this same fear for a Husky 350 rebuild with a pop up and base gasket delete. Didn't hit plug but only had .0165" squish... a bit tight for my liking so I installed a thin Husky base gasket.

I should add that the new cylinder I used was a HWY kit. Cylinder base flange was much thinner than an OEM and a Meteor cylinder flange. It looked as if the HWY jug came already machined down. So much to a point that I had to buy shorter cylinder mounting bolts as the OEM bolts would bottom out in the crankcase riser without tightening down the cylinder!

Hi, would you say that .020 is where someone should be at? Thanks

 

[Chevboy0167]

Yeah, .020" should be ok. Typically, ya want to be no less than .018". Got to have room for things to expand with the heat.

 

[huskihl]

Yeah the full circle pistons are what Husqvarna called “power flow” design. Not sure when or in what model saw they switched to the non full skirt design. I feel like the full skirt offers more support and is a more robust design. Some think the newer design is better for flow into the lower transfers but I’m not convinced based on personal observations.

The only benefit to the full skirt piston is a small amount of added durability. They are heavier, which is hard on the bearings and hurts RPM. Due to the design, 100% of the charge has to flow through the windows in the piston, as opposed to part of it flowing through the windows and the rest flowing between the slab and the wall. And the full skirt also adds quite a bit of drag, again hurting rpm, that you don’t get with the windowed slab side piston.

 

[huskihl]

Hi, would you say that .020 is where someone should be at? Thanks

.018” on 50cc saws, .025” on 120cc saws

 

[corriscaveman]

in my experience pop ups add compression but take away from air/fuel swirl creating a strange flame front pattern on the piston crown. I would add one to a clamshell but not a pro saw. If your saw is feeling weak it might just be time for a new ring or a piston if its worn smooth, I suggest oem over saving a few bucks. nAftermarket pistons from meteor and hyway have smaller windows than oem with meteor weighing more and hyway weighing less than oem. It might be wisest to buy a new piston with ring and ship it with the powerhead to be ported to get it done right and move forward.

Would love to send it to the u.s. to be ported properly but unfortunately postage costs would be too much.

 

[ballisticdoughnut]

So bit of an update. I did pick up a Hyway pop-up piston for my 266/268XP hybrid. OEM 268XP piston and cylinder are B grade and in very good condition. Clearance was right around .0027” which is acceptable considering it’s seen some use. Measured the Hyway piston it was bang on with the OEM piston. Used the wrist pin, circlips, and ring (new one I installed previously) from the original 268 piston. Gotta say I’m quite impressed and I’m a “OEM or die” type of guy in general. Quality of the casting itself and machine work are excellent. Wrist pin, circlips, and ring all fit perfectly. Didn’t see anything about it I didn’t like. I’ll definitely be using them again in the future.

 

[Hulpio]

I've been to Taiwan a couple of times. Visited several factories, not engine etc related though but overall the look how they do things gives good impression. They have realized that quality is not made by inspecting, it is made earlier. Workers are treated like human beings and facilities are nice.
Biggest problem I had as a technical manager was to make these guys understand what really is wanted. After that R&D turnover time was quite short and they made what was agreed together. So things made in Taiwan are not chinesium and Taiwanese people did not like chinese in general.
Go to a Taiwanese city downtown and try to find a cigarette butt from the street...

 

[Lightning Performance]

I've been to Taiwan a couple of times. Visited several factories, not engine etc related though but overall the look how they do things gives good impression. They have realized that quality is not made by inspecting, it is made earlier. Workers are treated like human beings and facilities are nice.
Biggest problem I had as a technical manager was to make these guys understand what really is wanted. After that R&D turnover time was quite short and they made what was agreed together. So things made in Taiwan are not chinesium and Taiwanese people did not like chinese in general.
Go to a Taiwanese city downtown and try to find a cigarette butt from the street...

You just described pride and workmanship not how many units can we put out the door. If you worked on cars in the 1980s you knew this cuz all the bolts came from Taiwan when we switched to metric here.