372XP Rebuild and mod.

[AUSSIE1]

Couldn't handle the compression, or what?

Meteor piston, OEM pin and bearing.

Yeah that's my take on it. Healthy apart from ending up loose in the small end/piston. A sudden loss of power. New piston, brg and pin and all's good. Sure they run nicer, but there is a limit to where it compromises reliability, especially for a work/firewood saw. Everyone is different, but 180-190 is my upper limit these days.

 

[blsnelling]

Meteor piston, OEM pin and bearing.

Yeah that's my take on it. Healthy apart from ending up loose in the small end/piston. A sudden loss of power. New piston, brg and pin and all's good. Sure they run nicer, but there is a limit to where it compromises reliability, especially for a work/firewood saw. Everyone is different, but 180-190 is my upper limit these days.

Big end rod bearing was fine I take it? I know others are doing their own testing.

 

[parrisw]

I'm watching and learning. It'll be interesting to see where this ultra high compression in a work saw trend ends up. I'm tempted to go back in several of my saws, but am still a little reluctant.

Me too Brad. I don't know what it will do in the long run. I really don't care much anyway, the amount of time I actually put on my saws, it will probably last a long time, if it blows, then I'll know the limit then wont I. This is actually an aftermarket crank too, so I'm somewhat concerned.

I've sold a few ported saws to my friend for his Tree service, I won't sell him a high compression saw though, for full time use, I'm not ready to put my name on that.

 

[parrisw]

Meteor piston, OEM pin and bearing.

Yeah that's my take on it. Healthy apart from ending up loose in the small end/piston. A sudden loss of power. New piston, brg and pin and all's good. Sure they run nicer, but there is a limit to where it compromises reliability, especially for a work/firewood saw. Everyone is different, but 180-190 is my upper limit these days.

I've always thought that too Al. I've always liked around 180. I'm just trying stuff on my own saws and having some fun.

 

[parrisw]

All ready for tomorrow. I wish my 385 was ready, need a couple small parts for it, so it can't come, wanted to get more time on it too.

I never did show the muffler mod, go big or go home right? This thing BARKS!! The vid doesn't do it justice.

The two coming tomorrow, my other 372 nearest.

 

[komatsuvarna]

Must be 372 weekend . I just got mine back together this weekend too.

Looks good Will!! I bet she makes some torque with that compression.

 

[parrisw]

Must be 372 weekend . I just got mine back together this weekend too.

Looks good Will!! I bet she makes some torque with that compression.

Sweet!! Do tell, what did ya do to it? I love these saws, in-case y'all didn't know that.

 

[komatsuvarna]

Sweet!! Do tell, what did ya do to it? I love these saws, in-case y'all didn't know that.

Had a good friend do some machine work on the cylinder for me. Cut some from the chamber and .040 off the base. Set timing at 100, 122, and 78. Didn't do much to the lowers on this one at all....gonna see how that goes. Seems to be a good runner, but I need some wood to put it in!!

Pictures if it's ok....

Exhaust

Here's how I mark the uppers. First I should say I measure port timing from TDC. Put a ring in the bore, start at BDC and rotate the crank until you get to the number ya want. Then pull the jug back off and mark it. Then check it from TDC just to be sure.

 

[komatsuvarna]

Just a few tools...

 

[parrisw]

Nice work Durand. I like those numbers, close to my other 372, I think my other one is 99 or 100 can't remember, 120 trans, 80 intake, runs real good, but could use some more comp. For marking your timing, why not just draw through the spark plug hole and use the piston as a guide? That's what I do, save's time.

 

[srcarr52]

Mine will be going together this week. All the work is done, just waiting on a new bearings and a few misc. bits. I forgot I had robbed the bearings to rebuild a kwik-way stone holder for grinding valve seats.

 

[Mastermind]

I'm watching and learning. It'll be interesting to see where this ultra high compression in a work saw trend ends up. I'm tempted to go back in several of my saws, but am still a little reluctant.

I ain't keen on over 185 in a 372........

I worry about the cranks.

 

[parrisw]

Mine will be going together this week. All the work is done, just waiting on a new bearings and a few misc. bits. I forgot I had robbed the bearings to rebuild a kwik-way stone holder for grinding valve seats.

Cool, you guys should post up some vids too!! Don't ya hate it when you rob parts, then a while later you think Crap!! Forgot I did that, then have to wait for more.

 

[parrisw]

I ain't keen on over 185 in a 372........

I worry about the cranks.

Worry smurrry, that's for Moms! You never know the limit till you pass it.

 

[Mastermind]

Worry smurrry, that's for Moms! You never know the limit till you pass it.

On my own saw.......no worry.

I build saws for other folks though ya know.

 

[komatsuvarna]

Nice work Durand. I like those numbers, close to my other 372, I think my other one is 99 or 100 can't remember, 120 trans, 80 intake, runs real good, but could use some more comp. For marking your timing, why not just draw through the spark plug hole and use the piston as a guide? That's what I do, save's time.

Bout the same principal....just never did it that way before I've done it this way so much Im used to it I guess.

 

[Jacob J.]

I ain't keen on over 185 in a 372........

I worry about the cranks.

That's why I run 32:1, especially in the winter.

Cool, you guys should post up some vids too!! Don't ya hate it when you rob parts, then a while later you think Crap!! Forgot I did that, then have to wait for more.

I do that all the time and then forget. D'oh.

Well Will, great sounding saw so far, seems really tight on the acceleration. Now I'm gonna need you to build me a XPW.

 

[parrisw]

On my own saw.......no worry.

I build saws for other folks though ya know.

Exactly. That's what I'm talking about. If ya didn't see my earlier post about selling any High Comp saws to anyone, I won't do it, well, unless they really know the risk, definitely not for full time use, but who really knows how long they'll last.

Bout the same principal....just never did it that way before I've done it this way so much Im used to it I guess.

Ya, I figure its just one less step.

 

[blsnelling]

I ain't keen on over 185 in a 372........

I worry about the cranks.

I knew the 372 had some big end rod bearing issues in the past, but was surprised to hear that the wrist pin bearing went bad.

 

[parrisw]

I knew the 372 had some big end rod bearing issues in the past, but was surprised to hear that the wrist pin bearing went bad.

Same here. But can you really pin the whole problem on high compression?