044 conversions-10mm to 12mm,12mm to 046?

[Deets066]

the "+" signs denote later casting runs in the same mold series so just looking for fewer "+" signs doesn't get you an early cylinder
the different makers used different letter and number combinations to designate mold series in case of the need for later recall, but as far as I know there is no definitive listing for cylinder mold series to serial number range
If you want a great 044/MS440 without an actual port job, use an OEM piston appropriate for your crankcase (meteor is ok for the 12mm or even for the 100mm in my book, but opinions vary) and get a nice clean slant fin jug.
If you are having it ported go modern and ask your builder if they have any preferences.
Dave

Did you ever get that 12 mm slant fin jug on a saw?

 

[dall]

i have a slant fin 044 that has the 5 plus signs in my building

 

[Adirondackstihl]

Don't buy a Meteor 10mm piston

 

[drf256]

Don't buy a Meteor 10mm piston

But it may be a way to run a 12mm jug on a 10mm case.

 

[VinceGU05]

Don't buy a Meteor 10mm piston

why?

 

[drf256]

why?

The pin bosses aren't tight to the rod end.

 

[VinceGU05]

The pin bosses aren't tight to the rod end.

watcha talkin about Willus.? so the piston can float on the wrist pin sideways too much?

 

[Chainsaw Jim]

I measured two 10mm pistons along with a new 12mm piston and noticed the two 10mm didn't have the same ring locating measurement.
The first pic is the ms440 12mm piston, the other two are both 044 10mm.

 

[drf256]

watcha talkin about Willus.? so the piston can float on the wrist pin sideways too much?

Yes. There was a great post w pics from @Definitive Dave on the AS about this.

There's room between the rod end and where the piston bosses cover the rod. The 12mm rod has a wider small end than the 10mm one. It seems that meteor made a 10mm pin bore in a 12mm piston and left it at that. It may have the same pin spacing as the 12mm. That I'm not sure of.

I'm running a 10mm meteor and I've had no issues with it.

 

[Definitive Dave]

Did you ever get that 12 mm slant fin jug on a saw?

I plan to have it installed on a very early 12mm restoration project

 

[VinceGU05]

Yes. There was a great post w pics from @Definitive Dave on the AS about this.

There's room between the rod end and where the piston bosses cover the rod. The 12mm rod has a wider small end than the 10mm one. It seems that meteor made a 10mm pin bore in a 12mm piston and left it at that. It may have the same pin spacing as the 12mm. That I'm not sure of.

I'm running a 10mm meteor and I've had no issues with it.

I guess it doesn't matter too much how much float it has. The piston runs in a bore and can't float anywhere more than .05mm.
I can't see .5mm difference on pins being an issue either. If we were talking mm's I would agree.

 

[Adirondackstihl]

watcha talkin about Willus.? so the piston can float on the wrist pin sideways too much?

Zactly!!

 

[Adirondackstihl]

I guess it doesn't matter too much how much float it has. The piston runs in a bore and can't float anywhere more than .05mm.
I can't see .5mm difference on pins being an issue either. If we were talking mm's I would agree.

But the bearing can walk quite a distance left or right, leaving quite a bit a real estate unsupported by a bearing.

The piston won't walk, but the rod can......a lot

I did a thread on this over on AS a while ago.
Even spoke with Meteor about the issue.
They were gonna look into changing some tooling.

 

[VinceGU05]

The bottom end on a 10mm I have here has 1.5mm float and only .25mm up at the piston end. The piston was 35mm across the pins. Serial no. Is 12751....
Unfortunately the jug looks like this.

 

[Deets066]

But the bearing can walk quite a distance left or right, leaving quite a bit a real estate unsupported by a bearing.

The piston won't walk, but the rod can......a lot

I did a thread on this over on AS a while ago.
Even spoke with Meteor about the issue.
They were gonna look into changing some tooling.

Same thing happens when you put a 288 piston in a 66. That's why you run the 288 bearing, it's tight to the pin bosses

 

[Adirondackstihl]

Same thing happens when you put a 288 piston in a 66. That's why you run the 288 bearing, it's tight to the pin bosses

Understood
But you can't run a 12mm bearing in a 10mm piston........well.....not without reaming the pin bore

 

[junkman]

Understood
But you can't run a 12mm bearing in a 10mm piston........well.....not without reaming the pin bore

Do you still have the pics showing how much the pin bearing walks out of the rod ?

 

[Deets066]

Understood
But you can't run a 12mm bearing in a 10mm piston........well.....not without reaming the pin bore

Yup, not many other options besides spacers to keep the bearing center. Or just buy the right piston

 

[Adirondackstihl]

Do you still have the pics showing how much the pin bearing walks out of the rod ?

Somewhere B

 

[Adirondackstihl]