What saws used 42mm Pistons?

[jammin_with_j]

Hey guys, trying to help out another member on the site who looking for a NOS NLA piston for a 44 Husqvarna. Been reading up on the saw and see it shares its looks with the 444. I started looking through the parts I have and came across two new 42mm pistons. One looks like the right piston for the 44 and the other, well I'm not sure.

Can anyone identify this unknown piston? Its a 42mm diameter piston, 1.5mm ring, the wrist pin looks to be about 10mm in diameter, height of piston is 37mm.

View attachment 244752View attachment 244753View attachment 244754View attachment 244755

 

[ChainFinn]

you sure that its not 38mm high/tall ?

how much the space between wrist pins holes, about 13.3mm ?

compression height, how much, around 24.5mm maybe ? and between top and ring, about 3,6mm ?

 

[jammin_with_j]

you sure that its not 38mm high/tall ?

how much the space between wrist pins holes, about 13.3mm ?

compression height, how much, around 24.5mm maybe ? and between top and ring, about 3,6mm ?

You're right its 38mm tall, it looks like between wrist pin holes its 15mm, i measured the needle bearing and its 15mm.

Question; how do i measure my compression height?

The distance from the top of the ring to the top of the piston is roughly 4mm, so most likely close to 3.6mm since I'm just using a steel ruler here at work so its a bit rough.

 

[ChainFinn]

I have one 42mm piston without wrist pin and ring, and it has 13.3 space for conrod, and its 38mm high etc...


i used term compression height for measurement between piston top and center of wrist pin.

 

[ChainFinn]

and if i remember right, its for 242 huskie.

 

[jammin_with_j]

Is this a 44 Piston?

This is what I believe to be a 44 Piston. I checked the number on the box with the IPL of some 44's and it seems to be the right number, but is it the right piston in the box?

View attachment 244763View attachment 244764View attachment 244765View attachment 244766View attachment 244767

 

[huskydude]

It looks like it


USED HUSQVARNA 44 CRANKCASE WITH FLYWHEEL, OIL PUMP AND OIL CAP | eBay

 

[jammin_with_j]

It looks like it


USED HUSQVARNA 44 CRANKCASE WITH FLYWHEEL, OIL PUMP AND OIL CAP | eBay

It does indeed look like the right piston, thanks.

 

[jammin_with_j]

I have one 42mm piston without wrist pin and ring, and it has 13.3 space for conrod, and its 38mm high etc...


i used term compression height for measurement between piston top and center of wrist pin.

I don't think the "compression height" is the same as what you have measured on your piston. This one appears to be approx. 20mm.

 

[ChainFinn]

I don't think the "compression height" is the same as what you have measured on your piston. This one appears to be approx. 20mm.

View attachment 244773

This is what i meant.

but offcourse, they vary from model to another opcorn:

 

[SawTroll]

A 42mm bore has been quite common on saws from 42 to 45cc (depending on stroke). :msp_wink:

 

[jammin_with_j]

View attachment 244773

This is what i meant.

but offcourse, they vary from model to another opcorn:

Thanks for the help ChainFinn, I'm gonna keep that photo for later reference, I'm sure I will need it again.

 

[jammin_with_j]

A 42mm bore has been quite common on saws from 42 to 45cc (depending on stroke). :msp_wink:

Thanks for the guidance Niko, would you care to abreviate on Husqvarna models that may have used a 42mm bore?

This piston came from an old Husqvarna and Stihl dealer that closed down (not a normal combination dealer), I bought up a lot of their unused inventory. Most of the Stihl parts are still in packages and clearly labeled so I can seperate them quite easy. But with the markings on the top of the piston I believe it is a piston for a Husqvarna, although I could be very wrong.

I do have a 444 Husqvarna that runs, but haven't checked it for compression or the shape of the piston. Was hoping it might possibly be a piston for the 444, or atleast be able to identify this one so I can put it to use.

 

[ChainFinn]

A 42mm bore has been quite common on saws from 42 to 45cc (depending on stroke). :msp_wink:

But can You tell me, what 42mm pistons with pssibly 12mm wrist pin, might be ok to fit inside the 444 . With a little machining....except for the 346 piston ?

Sorry about off-topic.

 

[jammin_with_j]

But can You tell me, what 42mm pistons with pssibly 12mm wrist pin, might be ok to fit inside the 444 . With a little machining....except for the 346 piston ?

Sorry about off-topic.

That I cannot answer fully with my limited knowledge. I do know that the OE 346 and 345 shared the same piston. The 42 and 242 shared the same piston and the 45 had a similar piston just longer stroke. I've got no ideas about wrist pins, or other information on other characteristics of the piston, ex. side skirts and ring height.

I'm just stabbing in the dark on that one.

 

[nmurph]

OE's are the cheapest and most plentiful. They do require the crown be turned down some to fit.

 

[ChainFinn]

OE ?

as an OEM ?

I do have skills and machines to do simple machining, and i am tryin to learn all this PO-UP stuff.

Well, no more thread hijacking , i promise.

 

[SawTroll]

Thanks for the guidance Niko, would you care to abreviate on Husqvarna models that may have used a 42mm bore?

This piston came from an old Husqvarna and Stihl dealer that closed down (not a normal combination dealer), I bought up a lot of their unused inventory. Most of the Stihl parts are still in packages and clearly labeled so I can seperate them quite easy. But with the markings on the top of the piston I believe it is a piston for a Husqvarna, although I could be very wrong.

I do have a 444 Husqvarna that runs, but haven't checked it for compression or the shape of the piston. Was hoping it might possibly be a piston for the 444, or atleast be able to identify this one so I can put it to use.

Husky; 44, 444, 242, 42, 242xp, 45, 346xp (45cc), 345 are those I remember.

Stihl; 024, 024S, MS240, 028AV (early 43cc version), 025, MS250, 030AV are those I remember.

Then there are the brushcutters etc.....

 

[SawTroll]

OE ?

as an OEM ?

I do have skills and machines to do simple machining, and i am tryin to learn all this PO-UP stuff.

Well, no more thread hijacking , i promise.

He was referring to the original 45cc 346xp, that often is called OE for "old edition".

 

[komatsuvarna]

He was referring to the original 45cc 346xp, that often is called OE for "old edition".

Yep, Take a 346xp OE 42mm piston. Chuck it in the lathe and spin about .050 off the crown to get to .080 on the ring land. It ''should'' fit in a 44 husky and be able to run the base gasket and have ~.020 squish. I spun a popup on the one I built and it was a strong torquey little saw. Just watch for the ring end pins as they get close to getting in the intake port.:msp_biggrin: