372 with 385 top end

[Chainsaw Jim]

I really like how much power that thing has before the science of a scored cylinder at temperature comes into play.

 

[Mattyo]

I only got far enough to get parts. I really think it'll be a trick to put a 385 cylinder head on a 372. If you try to match up the gaskets it doesn't look good.

The other issue is the wrist pin being 13mm on the 385. Homelite410 suggest swapping the whole bottom end in. But the dimensions of the crank along the length of the crank won't fit.

The biggest cylinder head I could find with a 12mm wrist pin is an 046 big bore Chinese kit. Then the trick would be to just adapt it to the chassis. So I put a 372 case on the bridgeport and milled off half an inch just to see what happened.

1 ...the impulse nipple dissappeared. 2 I realized the bolt holes basically dissappear. Youd need to make an aluminum riser plate that bolts PERMANENTLY to the chassis. ...then drill and tap for the 046 bolt holes.

The whole project gets kinda nuts. If you come up with other ideas....I'm all ears.

 

[Tractorsaw1]

I've got plenty of projects ahead of me right now. I hope to get 6 top ends done in the next week

If you get ahead later down the road & are interested- say the word. I have a 390 jug & slug

 

[mdavlee]

I have a few of the cylinders. Just not a functioning 372 bottom end. Myself I'd just bore and plate a big bore 372 jug or stroke a 372 and use a xpw to get almost 80cc.

 

[Mattyo]

Assuming us chrome can rebore a 372 jug to 54mm....what piston would you use?

 

[Mattyo]

You still have the 12mm wrist pin issue

 

[mdavlee]

Assuming us chrome can rebore a 372 jug to 54mm....what piston would you use?

I was thinking 52mm wiseco. The only 54mm would be a 460 big bore.

 

[cowroy]

It would be a cool hybrid. I've got a video somewhere of a 372XPW at the 660 buildoff at the WKGTG that pulled a 36" bar as fast and even faster than some of the buildoff saws. It was a woods port to boot.

 

[Tractorsaw1]

I'm probably muddying up Jims thread. The 2083 is 83cc with a 54mm piston - a Stihl 066 piston is a drop in fit. The 83cc is is a dual transfer cylinder. Would be interesting to see what the quad port 390 could do - would be a mm bore increase with the quads & maybe a better carb option as well on a lighter saw. 2083/390

 

[Iron.and.bark]

Doesn't the dolmar 9010 have a 12mm wrist pin? It's 54mm.. Left field suggestion...

 

[mdavlee]

Doesn't the dolmar 9010 have a 12mm wrist pin? It's 54mm.. Left field suggestion...

52

 

[mdavlee]

It would be a cool hybrid. I've got a video somewhere of a 372XPW at the 395xp buildoff at the WKGTG that pulled a 36" bar as fast and even faster than some of the buildoff saws. It was a woods port to boot.

Yep. That was Durands. It beat over half the 660s.

 

[LBracing]

No problem adapting a 390 crank in a 372 . The only thing to make it fit is the crank is wider . Press it apart, remove material from the inside , put it back together and its done . Been there done that , nothing fancy .

 

[Iron.and.bark]

52

You are right, I should still be asleep

56mm is available with a solo 603 cylinder, but good luck finding one.

Can't remember if a solo 690 cylinder is 54 or 55..

 

[jacob j.]

You are right, I should still be asleep

56mm is available with a solo 603 cylinder, but good luck finding one.

Can't remember if a solo 690 cylinder is 54 or 55..

The 690 is 55mm. Solo USA still has NOS 690 top ends for $350 a pop plus shipping. The 603 top ends and pistons have been long gone.

 

[jacob j.]

I was thinking 52mm wiseco. The only 54mm would be a 460 big bore.

A 660 piston would be 54mm with a 12mm wrist pin. A big bore 066/660 would be 56mm with a 12mm wrist pin, as is the Partner K-1200 piston. The Echo CS-900 uses a taller 54mm piston with a 12mm wrist pin.

 

[mdavlee]

A 660 piston would be 54mm with a 12mm wrist pin. A big bore 066/660 would be 56mm with a 12mm wrist pin, as is the Partner K-1200 piston.

That's right. I forget the 66 is 12mm

 

[Red97]

All these hybrid/super saw builds.

Think I may start gathering parts for one myself..

One piece at a time, anything can be accomplished with enough determination.

Jim, with the stihl/husky, and super 357 hybrid under your belt this shouldn't be too difficult.

 

[Chainsaw Jim]

A backwards 066 piston will work. A 505/2083 piston would be the perfect choice. The case can be clearanced to match the collar. It looks like a better match than the other hybrids I've done. Here's a few pics of a clapped out 372 case and a 385 cylinder on it.

 

[P.M.P.]

Way to be Man where theres a Chainsaw Jim Theres a way. I was told when I was young to think that there always a better way no matter if you think you found it there is still a better way no matter what others think. They can keep that negative.Staying positive is key.It really gets the brain wokin and its helped me threw the years and will continue too.

clapped out 372 case

HeHeHe he said clapped out