372 with 385 top end

[EJ mcnamara]

I just got a call from Paul Ebels hardware to a lot of there wood port saws that’s a big deal for me because he is one of biggest dealers in the USA

 

[EJ mcnamara]

Randy is right these mismatch builds are a lot of work but man are they fun lol

 

[Intoxsawcated]

I'm surprised how little vibration was added with having a crazy heavy piston, wrist pin and rod added without adding weight to the crank.

Sent from my SM-S767VL using Tapatalk

 

[mdavlee]

@Mastermind

@drf256

@mdavlee

Sent from my iPhone using Tapatalk Pro

That’s impressive work for sure

 

[Mattyo]

Wait...you put a 066 rod on a 372 crank?
????

 

[Mastermind]

I just got a call from Paul Ebels hardware to a lot of there wood port saws that’s a big deal for me because he is one of biggest dealers in the USA

I've done a bunch for Paul. He's a good man to deal with. I just got too far behind to be able to handle anymore.

 

[Intoxsawcated]

Yup, old style aftermarket 064/066 - ms660 rod easy peasy. If I remember right it's 1 or 1.5mm longer center to center than the 372 rod. Big end pin is 16mm same as 372.

I'd like it if it had a wider small end though. I guess I could have the cylinder bored to 56mm or use a 54mm 385 topend and a stihl piston. Can't find any other 55mm piston. Lighter piston and pin would be nice.

Sent from my SM-S767VL using Tapatalk

 

[EJ mcnamara]

Yup, old style aftermarket 064/066 - ms660 rod easy peasy. If I remember right it's 1 or 1.5mm longer center to center than the 372 rod. Big end pin is 16mm same as 372.

I'd like it if it had a wider small end though. I guess I could have the cylinder bored to 56mm or use a 54mm 385 topend and a stihl piston. Can't find any other 55mm piston. Lighter piston and pin would be nice.

Sent from my SM-S767VL using Tapatalk

I put a 55mm 272 wiseco piston I make it’s a lot easier build to do with the 390 cylinder and I had a 272 54mm made too the piston is ultra light and string

 

[EJ mcnamara]

I've done a bunch for Paul. He's a good man to deal with. I just got too far behind to be able to handle anymore.

yes he is randy plus I no your super busy man but that is a good thing

 

[MG2186]

yes he is randy plus I no your super busy man but that is a good thing

How’d it run compared to well done 372 or 385/390?

 

[Mattyo]

Link to a 272 55mm piston? Was this a one off that wiseco did?

 

[Mattyo]

Its an interesting idea to use a 660 rod on a 372 crank. Im pretty sure I can get the crank apart. Getting it back together and lined up proper is a different story lol. Obviously the length is helpful for a taller head. Still uses a 12mm pin... any other advantages?

On a 372 the concern of going to higher power is that the bearings are 6202s....smaller than 6203s. Seems to be that even 54mm piston is pushing it...

Thoughts ?

 

[mdavlee]

Wait...you put a 066 rod on a 372 crank?
????

372 rod fits on a 460/461 and gives 1-1.5mm longer rod best I remember.

 

[EJ mcnamara]

The 385:390 made the 372 quit abit more torgue and it turned 13.500 out of the wood and kept more rpm in the wood a lot better setup I’m doing a big bore 681 solo saw right now 55mm set up and a 044 stihl 55mm setup and me and joe are going to dyno the results

 

[EJ mcnamara]

And you can cut the windows in this piston to match the transfers and this piston is anadized so it’s stronger

 

[EJ mcnamara]

This is my 54mm piston for hybrid setups for the Sachs 7900 solo 681 stihl 044/046 and the 272/281 cylinder setup and the 372:385/390 these have super wide skirts to open intake and exhaust

 

[drf256]

Randy is right these mismatch builds are a lot of work but man are they fun lol

Are you having any issue with lack of case volume? Have you attempted to increase it in any way with gains?

 

[Mastermind]

Are you having any issue with lack of case volume? Have you attempted to increase it in any way with gains?

I'm pretty sure the whole lack of case volume worry is unwarranted. If more case volume was really something that mattered, then why do stuffers make an engine more responsive?

 

[Intoxsawcated]

Given these engines are small and are designed to run under load between 9 and 10k and operate probably no less than 7k under heavy load they don't really need large case volumes. The newer saws being designed for efficiency seem to be using lower volumes with small ports and long scavenge loops for to keep velocities up and power where it needs to be for chain speed.

Sent from my SM-S767VL using Tapatalk

 

[Bigmac]

@EJ mcnamara do you have and videos of them cutting? Super cool work!