Case vs Bore Fed Transfers

[Marshy]

Ok guys, I have a question I'm hoping y'all can help me with. I'm looking at building a hybrid. The saw has case fed transfers and the cylinders I'm looking at using have bore fed transfers...

What are your thoughts on using a cylinder that bore fed on the case of a case fed saw? Will it work or am I wasting my time? Thanks.

 

[huskihl]

Ok guys, I have a question I'm hoping y'all can help me with. I'm looking at building a hybrid. The saw has case fed transfers and the cylinders I'm looking at using have bore fed transfers...

What are your thoughts on using a cylinder that bore fed on the case of a case fed saw? Will it work or am I wasting my time? Thanks.

You'll need a windowed piston. And it may be beneficial to fill the case above the bearings up to the cylinder

 

[jacob j.]

You'll also have to make sure the width of the cylinders at the base is similar, since cylinders from case-fed saws tend to be a lot wider.

 

[Lightning Performance]

This should be interesting. Case volume will increase imo.

Pics

 

[Marshy]

The idea is to put a 660 cylinder on this solo 667 case and use the 667 crank with a 12mm wrist pin. (Assuming the case has enough room to fit the 660 base on it.)

Case:


Solo 667 cylinder:


667 piston:

 

[Lightning Performance]

460BB is too short

What is the plan for a piston?

 

[Marshy]

460BB is too short

What is the plan for a piston?

660 piston has windows. It would be a de-stroked 660 essentially (38mm stroke vs 40mm).

 

[Marshy]

Heres a 660 piston.


Cylinder

 

[Lightning Performance]

661 might be a better fit.

 

[Marshy]

661 might be a better fit.

No, transfers are case fed but from under the exhaust port. Dont think it will work at all.

 

[Marshy]

You'll need a windowed piston. And it may be beneficial to fill the case above the bearings up to the cylinder

If that's all that's needed then easy peasy. Being that the case on the 667 is so small compared to the 660, it might be best to leave it... this my winter project. I have to figure out if the case is large enough for the 660 cylinder flange.

 

[drf256]

Not sure how big the small rod end is on the saw.

A 288 piston will fit in an 066 rod end with a 395 bearing. I figured a 281 piston might be the ticket for an 044/046 hybrid, but it was a no-go. There wasn’t enough room for the 13mm pin with any bearing in the 1128 rod. Coulda tried individual needles, but nah...

I’ve got a few am 066 jugs if you want one (for free) for mock-up.

The problem I see is the wide openings for the transfers and the bolt spacing. If you can’t cover the case reliefs, you’ll have to get it welded up and re-milled.

You’ll need that extra case volume as you are trying to jump from a 48 to a 54mm bore.

Consider a 52mm 038M cylinder. They have the smallest bolt pattern to bore size I’ve personally seen. I plan on bolting one on a 262XP if I ever find the time.

A 6mm jump in bore is a lot. Gotta also see if the case can accept that piston width at BDC.

 

[Deets066]

Not sure how big the small rod end is on the saw.

A 288 piston will fit in an 066 rod end with a 395 bearing. I figured a 281 piston might be the ticket for an 044/046 hybrid, but it was a no-go. There wasn’t enough room for the 13mm pin with any bearing in the 1128 rod. Coulda tried individual needles, but nah...

I’ve got a few am 066 jugs if you want one (for free) for mock-up.

The problem I see is the wide openings for the transfers and the bolt spacing. If you can’t cover the case reliefs, you’ll have to get it welded up and re-milled.

You’ll need that extra case volume as you are trying to jump from a 48 to a 54mm bore.

Consider a 52mm 038M cylinder. They have the smallest bolt pattern to bore size I’ve personally seen. I plan on bolting one on a 262XP if I ever find the time.

A 6mm jump in bore is a lot. Gotta also see if the case can accept that piston width at BDC.

All good points Doc

 

[Marshy]

Not sure how big the small rod end is on the saw...

The solo is 12mm wrist pin. I read the 660 so 12mm also. Thanks for the offer btw.

All good info you mention. I think what I'll do is start a new build thread. The idea of this thread was really to discuss the using a bore fed cylinder in a case fed case... sounds like a non issues. Thanks again for all the replies.

 

[Deets066]

The solo is 12mm wrist pin. I read the 660 so 12mm also. Is that not correct?

Yes, 660 is 12 mm

 

[drf256]

With a 12mm pin, you may want to try a 272 slug in a 52mm jug. It’s got a very tall crown height which may help make up you loss in stroke.

 

[nenicu]

Look at" Building the ultimate sleeper saw" on the other site. Poulan 2800 with stihl 380 magnum (52mm) cylinder.

 

[nenicu]

I did one similar with 50 mm cilinder and 044 piston. 10 mm pin.

 

[Marshy]

Look at" Building the ultimate sleeper saw" on the other site. Poulan 2800 with stihl 380 magnum (52mm) cylinder.

Thank you sir. That is an epic build. Will read it all!

 

[drf256]

@ChipsFlyin