How come

[cat-face timber]

I am sure this has been beaten to death, but...

How come the change from horizontal to vertical cylinder?
More expensive to make?
Harder to make?

Just my curiosity getting to me again.

Thanks

CFT

 

[blsnelling]

I'm guessing it had to do with ergonomics and size, but don't really know.

 

[sawjo]

My guess is piston porting and no more reed cage technology, perhaps better air cooling potential and (with a few of my oldies) less shock potential, with the SP being right under your trigger hand

 

[lesorubcheek]

http://www.arboristsite.com/showthread.php?t=26692&highlight=horizontal+vertical

Here's a link to one thread from over 4 years ago. Probably find more hunting around a bit. Remember that lots of saws used to be vertical. Take a look at most from 50's and early 60s. Then it seemed a trend to horizontal after saws like the XL-12, and then back to vertical again with lots of European saws by the early-mid 70s. Only thing I remember that stuck was muffler location made less fire hazard for a vertical cylinder where the muffler could be up and in front. This is a great question that'd be nice to fill in the full story.

Dan

 

[Kenskip1]

How about the exhaust being directly beneath the operator, and as we know, warm air rises and this could affect the operators safety, Ken

 

[RandyMac]

I am sure this has been beaten to death, but...

How come the change from horizontal to vertical cylinder?
More expensive to make?
Harder to make?

Just my curiosity getting to me again.

Thanks

CFT

Vertical cylinders came from way back, late 1940s, it's funny to see "new" stuff being a repeat of the really old. I'm waiting for the return of other rediscovered "new" innovations, how about rotary valves?

 

[JasonBmac]

The following is largely speculation with no actual facts to back it up.... LOL, this is the internet after all....

The original chainsaws used industrial engines that were built with vertical cylinder orientations. Saw parts were simply bolted to existing engine designs.

Once chainsaw manufacturers began to make their own engines, they could tailor them to the application. Engines began to be integrated within the saw body. Some manufacturers went with horizontal cylinders to achieve whatever goal they had for the saw.... Homelite's reed induction motors, for instance were quite long with the carb at the crankcase end opposite the cylinder.... Horizontal placement made sense.... And since they were an industry leader at the time, they were emulated. Top handle saws have an obvious advantage with a horizontal cylinder, as others noted.

So, now we have large saws with vertical cylinders (makes the saw more compact), small saws with top handles and horizontal cylinders (more compact).... Saws with engine configurations that SUIT the purpose.

Orientation of the cylinder has virtually no impact on ring or bearing wear. Gravity accelerates at about 9.8m/s/s. Acceleration on a piston at full rpm's is several hundred times this... It's a non-issue.

J

 

[Cantdog]

OK, I'll Take a Shot as Well!!

My guess would be that the "straight through" design brought the vertical cyl to be the norm. No corners to turn, higher rpm and more available horsepower per cc. Carb on the rear of the cyl and 180 degrees away the exhaust. In the regular horizontal motor the carb was on top and the exhaust was on the right at 90 degrees to the intake. Any time you turn a corner with flow or horsepower you cause an inefficiency and lose some of what you are trying to generate and use. The muffler exhausting gas and sound away from the operator was a added benefit as well.

 

[indiansprings]

I often wonder if it had more to do with the exhaust location. We burned up a Homelite Super EZ when I was a teenager cleaning out fence rows. The exhaust being against the ground for extended periods of time sawing out multifloral roses and brush finally overheated the saw, wound up trashing the jug and slug. I remember switching from the homelites xl 12/925/super ez to the stihls front muffler design was a big deal for us.

 

[JasonBmac]

I bed your right on exhaust location... It gets real hot stumpin' with a horizontal cylinder arrangement...

I don't buy the "straight thru" arguement, though. That would be true if the cylinder was but a pipe elbow, but there is no relationship between the carb and the exhaust in a piston ported 2 cycle engine: The carb exhales into the crankcase, then via transfers to the cylinder, then squish'n'boom, then exhaust.

If you look at the port arrangement in the cylinder, you'll find no difference.

Also, many horizontal saws do put the carb opposite the exhaust.... Minimacs, mac 310 series, many others....

J

 

[cat-face timber]

I can say that I have ran both and....

I like the horizontal beceause I can blow sawdust off the log and see where I marked it.

 

[GlenM]

I always reasoned the horizontal was better for top handle saws, vertical for rear handle saws.
(what do I know)

 

[Cantdog]

I bed your right on exhaust location... It gets real hot stumpin' with a horizontal cylinder arrangement...

I don't buy the "straight thru" arguement, though. That would be true if the cylinder was but a pipe elbow, but there is no relationship between the carb and the exhaust in a piston ported 2 cycle engine: The carb exhales into the crankcase, then via transfers to the cylinder, then squish'n'boom, then exhaust.

If you look at the port arrangement in the cylinder, you'll find no difference.

Also, many horizontal saws do put the carb opposite the exhaust.... Minimacs, mac 310 series, many others....

J

Just for the sake of argument; how is there not atleast a 90 degree turn to flow in the conventional horiz. cyl? Macs homlites inhale through the top into the crankcase through the reed valves forward and down. These are not piston ported motors. The flow in these motors has to reverse direction in the crankcase to get from the carb to the
combustion chamber. The transfers are on top and bottom center rather than left and right on the side. Maybe I'm missing something but the modern vert cyl is a much more efficient pump seems to me.

 

[Jacob J.]

Only thing I remember that stuck was muffler location made less fire hazard for a vertical cylinder where the muffler could be up and in front. This is a great question that'd be nice to fill in the full story.

Dan

That's the main answer right there. In 1979 the U.S. Forest Service issued new restrictions on saws and outlawed any saws (on Federal lands) that had a muffler capable of resting on the ground after the catastrophic "Silver" fire on Angeles in 1978. That fire was started by the muffler on a horizontal cylinder saw (Stihl 075).

 

[RandyMac]

Dan is the Man!!!!

 

[JasonBmac]

Heya Cantdog,

Well, to my mind, because we're not talking about smooth continuous flow in a saw engine (macs, btw, are generally piston ported.... The homies were reedies for the most part... But that's not really relevant). It's not so much flow as it is gulps. The piston goes towards TDC, opens the piston port, or the reed valves open on low cc pressure. A gulp of air is taken in thru the carburetor. The intake tract closes as the engine continues to turn, and the charge is now trapped, in the crankcase, and is stirred in place, while being compressed (secondary compression) by the falling piston... Then finally, the exhaust ports, and then transfer ports open, the charge suddenly rushes into the cylinder.... From a standstill, effectively... Then it's trapped again, compressed, burned, exhaled.

No matter the intake arrangement, piston ported, reed, rotary, the transfer ports and exhaust ports in the cylinder are gonna be a variation on Schnurle loop-scavenging porting.... It should make no difference the orientation of the cylinder.

I'm sure there are practical considerations where it may make a small difference, but airflow thru the engine isn't the major reason for the evolution.

J

Just for the sake of argument; how is there not atleast a 90 degree turn to flow in the conventional horiz. cyl? Macs homlites inhale through the top into the crankcase through the reed valves forward and down. These are not piston ported motors. The flow in these motors has to reverse direction in the crankcase to get from the carb to the
combustion chamber. The transfers are on top and bottom center rather than left and right on the side. Maybe I'm missing something but the modern vert cyl is a much more efficient pump seems to me.

 

[Cantdog]

Heya Cantdog,

Well, to my mind, because we're not talking about smooth continuous flow in a saw engine (macs, btw, are generally piston ported.... The homies were reedies for the most part... But that's not really relevant). It's not so much flow as it is gulps. The piston goes towards TDC, opens the piston port, or the reed valves open on low cc pressure. A gulp of air is taken in thru the carburetor. The intake tract closes as the engine continues to turn, and the charge is now trapped, in the crankcase, and is stirred in place, while being compressed (secondary compression) by the falling piston... Then finally, the exhaust ports, and then transfer ports open, the charge suddenly rushes into the cylinder.... From a standstill, effectively... Then it's trapped again, compressed, burned, exhaled.

No matter the intake arrangement, piston ported, reed, rotary, the transfer ports and exhaust ports in the cylinder are gonna be a variation on Schnurle loop-scavenging porting.... It should make no difference the orientation of the cylinder.

I'm sure there are practical considerations where it may make a small difference, but airflow thru the engine isn't the major reason for the evolution.

J

Well Jason, I guess we'll have to agree to disagree. Although I agree with Jacob on the restrictions put on saws on fedral lands in 1979, I can't believe that that alone turned the entire industry from horz cyls to vertical cyls. The number of saws used on fed lands is very small indeed compared to the volume of saws sold world wide and certainly not the entire reason to retool production lines. Other than the small top handle saws that use the horz cyls I can't think of a single saw co that builds and sells a modern full sized horz cyl saw. Think of it like the old flatheads in motorcycles and cars and trucks. Do we still like to see them run? Yes!! Are they as efficient and a hemi head, twin OVHC, fuel injected modern motor? No. Simple as that. The older designed horz cyl saws were less efficient, heavier, larger, louder, slower and just less user friendly than your standard modern vertical cyl saw. I would also venture vert cyl saws are cheaper to produce as well, from an industry standpoint. Money and market usually causes changes to production. However a lighter, quieter, more efficient and more powerful saw is what sells in the market. More power, from a smaller, lighter package equals efficency. Jonsereds is a good example, they were building large vertical saw motors in the sixties and seventies when most other companies were still producing horiz cyl saws. It didn't take long for the markets to see that this was a better plan. Quieter, more powerful and you didn't have the exhaust blowing in your face. Some saw companies tried to scramble and meet the challenge and lost, others just closed up shop and went away, and a few actually made the change and survived and grew. This is the evolution of an industry and IMHO efficiency of motor design played a large part in it.

 

[heimannm]

All of the McCulloch saws from the D-30/D-44 through the SP125 were reed valve engines, horizontal cylinders, and capable of burning your jeans or your chaps with the exhaust. Oh there was one exception, the Mac 15, but that was McCulloch's first attempt at a "consumer" saw and used the same basic engine as all of the others noted above.

The 10 Series were the first piston ported McCullochs but retained the horizontal arrangement. McCulloch used to advertise that the horizontal arrangement reduced vibration by putting the movement of the piston in line with the cut...they were creative in their marketing!

The very early saw (3-25, 4-30, 47, 73, 77) were all rotary valve engines with a more or less vertical cylinder arrangement.

The only fire I ever started with a chain saw was from my Wards 90/Mono 80 with the exhaust straight out the front of a vertical cylinder, started the bark of a dead maple tree smoldering.

On all of the large frame McCulloch saws except the SP and CP models, the intake makes a 90° turn from the carburetor into the crankcase, not sure if that is really a detriment or not.

The first "modern" saw I ever bought new was a Jonsered 621, vertical arrangement, piston ported, and very advanced for it's day. That saw kept me away from all things McCulloch for over 25 years! Then I found AS...

It think at the end of the day the pure simplicity of the vertical cylinder piston ported design makes it nearly unbeatable in todays economic and environmental climate.

Mark

 

[JasonBmac]