Stihl ms 460/660 Hybrid. 469e

[NateSaw]

Not in this case. The skirt never passes the roof of the intake. It needed epoxy at docs recommendation to allow flow around it. I had the thought of epoxy in the transfers.

Edit. I'm an idiot. I see what you mean now.

 

[huskihl]

I'm calling S.
Once the bugs are worked out and things are right for this specific build... this thing 'should' Eat! A stocker. Especially if he maximizes the cylinder/case volume/charges.
Me personally, I'd like/love to see this with a 2mm larger piston.

I'd play around with case volume as well...
Needless to say, I'm digging this project.

Call it whatever you like. I’ve been to lots of chainsaw gatherings and seen my share of “perspective”. A stroked 395 is the only one that left an impression.

I dig the idea of oem big bores and hybrids but in the end, there’s a reason the manufacturer decided against it.

 

[Ketchup]

Lowering the jug you gain duration without potentially sacrificing the inlet charge.
Cutting the case you gain duration while losing a little volume... is it enough to notice a difference? I guess that would be something to play with for R&D purpose.

Maybe Look into transfer stuffers to change the velocity, volume and direction of the charge.

I used to think both of those things. Here is my current thinking. Open to debate, but it makes a lot of sense.

Charge pressure is made from the point the intake closes to the point the transfer uppers open. Dropping the cylinder doesn’t change that duration. If you then raise the uppers, you reduce case compression timing.

Dropping the jug does not affect case volume. The piston still goes to the same height. Removing material from the case, lowers or piston are the only things that increase case volume.

Edit: I guess that’s not entirely true. You do lose a tiny amount of transfer tunnel length on bottom fed cylinders. Usually you gain it back when you raise the uppers, but it is a change.

In this case, the 460 case already has less volume than the 660 jug was designed for. Adding stuffers would be interesting but this combination should already have a high powerband.

@NateSaw, I’m really excited to see this thing cut. Where does the bottom of the piston end up relative to the transfer lower at BDC? Is it in the middle of the lower or below it?

 

[NateSaw]

Call it whatever you like. I’ve been to lots of chainsaw gatherings and seen my share of “perspective”. A stroked 395 is the only one that left an impression.

I dig the idea of oem big bores and hybrids but in the end, there’s a reason the manufacturer decided against it.

I tend to give the oem guys the same credit. There is no substitute for a proper ported oem model. I think carb swaps are cool, when they work. But I'd never do what I'm doing here for a customer. No friggin way.

 

[NateSaw]

I used to think both of those things. Here is my current thinking. Open to debate, but it makes a lot of sense.

Charge pressure is made from the point the intake closes to the point the transfer uppers open. Dropping the cylinder doesn’t change that duration. If you then raise the uppers, you reduce case compression timing.

Dropping the jug does not affect case volume. The piston still goes to the same height. Removing material from the case, lowers or piston are the only things that increase case volume.

Edit: I guess that’s not entirely true. You do lose a tiny amount of transfer tunnel length on bottom fed cylinders. Usually you gain it back when you raise the uppers, but it is a change.

In this case, the 460 case already has less volume than the 660 jug was designed for. Adding stuffers would be interesting but this combination should already have a high powerband.

@NateSaw, I’m really excited to see this thing cut. Where does the bottom of the piston end up relative to the transfer lower at BDC? Is it in the middle of the lower or below it?

Great points and excellent question. Lemme get back to you in that next time I go in it.

 

[huskihl]

I tend to give the oem guys the same credit. There is no substitute for a proper ported oem model. I think carb swaps are cool, when they work. But I'd never do what I'm doing here for a customer. No friggin way.

It’s not an oem thing. I’ve put together a few saws with standard bore AM cylinders that are still running fine.

Just saying that it’s a rabbit hole.

 

[NateSaw]

It’s not an oem thing. I’ve put together a few saws with standard bore AM cylinders that are still running fine.

Just saying that it’s a rabbit hole.

I mean oem configuration. Those guys used formulas to build the original. Am parts that are for that model are copies, however loosely. I'm sure the engineers at stihl and the like have formulas and use cad etc. Things match. Volumes and displaxements. That's what I'm agreeing with,if that's what you mean.

 

[NateSaw]

It’s not an oem thing. I’ve put together a few saws with standard bore AM cylinders that are still running fine.

Just saying that it’s a rabbit hole.

And proper sized cranks and bearings. That's huge. Builds like this are guaranteed to wear parts sooner.

 

[Rich Fife]

I dig the idea of oem big bores and hybrids but in the end, there’s a reason the manufacturer decided against it.

The Main reason I'd imagine would be the standards and field parameters/limitations set by various agencies and the companies bean counters governed by the almighty dollar/profit margins. I mean, nowadays... why would any company build a powerful long lasting saw when they can build them to last 3 to 5 years of daily use and then set the market to where its more feasible/cheaper to purchase a new product at the end of that saws slated lifespan...

I mean, on the engineering aspect of it all, we see everyday... guys in their garages building more powerful saws that last just as long as OEM/stockers. If joe-schmoe out in the sticks can figure it out, surely the engineers can... and strictly from that stance, I'm 100% positive their hands are tied on multiple facets and that's why the manufacturers don't build more powerful/long lasting quality products.

Soon stihl and other manufacturers will be offloading a bunch of their models... and we will be forced to use battery powered tools. The new-ish Solid-State batteries might yield something ok-ish.... .

 

[NateSaw]

 

[NateSaw]

Y'all have to be patient. There's 2 more in wood. Takes an hour a minute to upload.

 

[NateSaw]

Yes, this is softish old oak. Hero wood. I wanted to load it up slow. Pig rich and mostly cold first cut.

 

[NateSaw]

Here we go fellas. I'd say it's beginning to look up. Sorry @huskihl... No fireworks, yet.

 

[huskihl]

Here we go fellas. I'd say it's beginning to look up. Sorry @huskihl... No fireworks, yet.

Tick tock tick tock…

 

[NateSaw]

I have a few observations already.
1) I don't think the French ticklers in the am boot are good enough. The low tunes OK, but it's clearly puddling a bit, as the first snap after idle stumbles.
2) This is with fresh lrb rings, so compression will build, although the cylinder needs to be honed.
3) The intake benefited leaps and bounds from opening earlier and being widened... I think opening at 82* might gain more.
4) a well ported 460 will smoke this thing, so far. But, it pulls.

 

[NateSaw]

Tick tock tick tock…

If y'all got a pull going, I want in. I need to recoup some money from this build

 

[ManiacalMark]

That last cut I could feel the dust getting in my eyes. So how’s it feel compared to a well ported 460?

 

[NateSaw]

That last cut I could feel the dust getting in my eyes. So how’s it feel compared to a well ported 460?

I don't know, I haven't run one yet. @Canadian farm boy 's 446 hybrid smokes it I think. Everything I've run that Kevin has done smokes it, I mean 70cc and bigger.

 

[Canadian farm boy]

Saw sounds and looks pretty healthy. You’re on the right track. Keep at it Nate.

 

[Maintenance Chief]

I don't know, I haven't run one yet. @Canadian farm boy 's 446 hybrid smokes it I think. Everything I've run that Kevin has done smokes it, I mean 70cc and bigger.

Honestly it runs pretty good for what it is. When I did my 2700 poulan/346xp hybrid I had a junk cylinder and a cheap piston, guess what? It cut a hell of alot more wood than a 3$ smoked thrift store poulan! It's not gonna beat the pants off a professional ported saw but it runs good.
You should be proud and acknowledge that you learned some things along the way , predictions are for psychics not sawyers.