Hyway MS460 big bore on a 044 opinions please

[Chainsaw Jim]

I believe it's an illusion created by a tiny groove around each ring. It seems to me it would let oil get trapped so it can cook.

 

[Canadian farm boy]

I believe it's an illusion created by a tiny groove around each ring. It seems to me it would let oil get trapped so it can cook.

You're right. It's just a grove.

 

[jacob j.]

A couple of guys over at AS tried this conversion in the early days and were never able to really make them run well. Like Mike said- it came down to the case volume issue. The big bore 046/460 top end was pretty lazy on the 044/440 case. It might actually be better with a larger bore carb and crank stuffers- going for the velocity rather than the large mixing volume. I doubt that would net much better results though.

 

[RIDE-RED 350r]

Those rings remind me of small nitro RC engines.. Many don't have a compression ring at all, just a fine groove or two machined around the crown of the piston that traps fuel to act as a ring. Maybe the intent here was to trap a little mix oil for better lubrication and possibly a slight boost in compression?? Might not actually be a bad idea.

 

[NCFarmboy]

IIRC they are called a split ductile ring. Baileys was touting them several years ago. From what I remember they didn't last as long as reg. ring or seal as good resulting in lower comp.
Shep

 

[MattG]

I'm wondering if there's a 54mm with a longer skirt, but the same pin to crown distance as a 046. Perhaps 064/066?

Then I can't see anything stopping me getting decent ports on the hyway jug.

It might actually be better with a larger bore carb and crank stuffers- going for the velocity rather than the large mixing volume.

The bigger carb could be an idea. What do you mean by the significance of the mixing volume? Do you mean more space in the crank cases to swirl and further atomise the fuel dropouts in the charge?

 

[MattG]

I just happen to have a used 046bb kit here. The width of the cylinder at the transfer bulges is the same as an oem 046 cylinder.
As stated the BB piston has much shorter skirts.

Thanks for checking out the transfer bulges, Mike.

It's shame about the skirt length. I have just looked at my 066 book, it reckons on being 54mm bore. Need to find the pin-crown distance.

 

[BuckthornBonnie]

I just found this guy, demoing one, it's on a ms460 base unit

That guy is MasterMech... a poster here and on FHC. He did a couple stock 460 builds about 4 years ago and put some AM products to the test. He’s one of several that noted that some AM case gaskets are junk (yellow/white ones).

 

[J_M____]

Matt , I ordered a $3 farmertec/huztl piston. It was listed for a 54mm B.B. ms460 but it did have full length skirts. I used the hyway rings/clips with it since they are much better quality.

 

[MattG]

Anyone on here know how comparable the piston crown to wrist pin distance is on 044/046 and 066/660 etc?

It would be great if anyone on here, with a couple in their w/shop, could come with the "yeah, it's the same!"

 

[Canadian farm boy]

Anyone on here know how comparable the piston crown to wrist pin distance is on 044/046 and 066/660 etc?

It would be great if anyone on here, with a couple in their w/shop, could come with the "yeah, it's the same!"

The 066 piston has a higher pin to crown height and longer piston skirts. I'm headed to the shop in a few minutes. I'll snap a picture and take a couple measurements

 

[MattG]

The 066 piston has a higher pin to crown height and longer piston skirts. I'm headed to the shop in a few minutes. I'll snap a picture and take a couple measurements

Thanks Mike!

 

[MattG]

Matt , I ordered a $3 farmertec/huztl piston. It was listed for a 54mm B.B. ms460 but it did have full length skirts. I used the hyway rings/clips with it since they are much better quality.

Do you have a link of where you purchased that, JM?

I just googled and found this

https://www.ebay.com/itm/BIG-BORE-54MM-PISTON-KIT-FOR-STIHL-046-MS460-CHAINSAW-NEW/291648831626

it says huztl. The skirt does still seem quite short, but then again it's really hard to see on this online pics

 

[Canadian farm boy]

066 piston is on the left
046 pin to crown
066 pin to crown
046 overall height
066 overall height These pictures should explain things with the 046 piston vs the 066 piston. Both pistons are oem mahle.

 

[MattG]

066 piston is on the leftView attachment 100520
046 pin to crownView attachment 100521
066 pin to crownView attachment 100522
046 overall heightView attachment 100523
066 overall heightView attachment 100524 These pictures should explain things with the 046 piston vs the 066 piston. Both pistons are oem mahle.

Thanks Mike, that's really good of you. Much appreciated.

I'm now curious how much I can remove safely from the top of an OEM 066, and the roof of the BB jug, hmm 60ish thou (1.55mm). Hmm.. that's a fair bit....

 

[MattG]

Actually my above post is on drugs..... 1.55mm is a ridiculous amount.... a 066 piston probably isn't happening for this project. Have to hedge my bets on the Huztl BB kit one, I reckon.

 

[jacob j.]

That may be the way to go. I know my 046 that's running an 064 piston with .050" machined out of the squish band is sure a good runner. You can run some taller numbers that way too.

 

[MattG]

That may be the way to go. I know my 046 that's running an 064 piston with .050" machined out of the squish band is sure a good runner. You can run some taller numbers that way too.

Sorry Jacob, do you mean machining off the jug top or going for the Huztl longer piston? You mean machining right?

 

[jacob j.]

Sorry Jacob, do you mean machining off the jug top or going for the Huztl longer piston? You mean machining right?

Machining the squish band inside the cylinder, the area around the combustion chamber. It makes a smaller combustion chamber and allows for a taller piston if you don't cut the base.

On my 046, the previous owner had ported it but not very well. His numbers were sloppy. I was able to correct that by having the squish band machined and running a taller piston.
It's now one of my favorite saws of all time. I loaned it to an Arborist buddy and he pieced down a
60" Spruce with it using a 36" bar.

 

[J_M____]

I ordered the piston direct from their website
http://m.huztl.net/Big-Bore-54mm-St...n-Circlip-Chainsaw-1128-030-2009-p372700.html