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Hot running Rockford PTO

Started by Joe Lallande, February 21, 2010, 06:18:46 AM

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Joe Lallande

My Belsaw M-14 mill is powered by an Oliver Super 88 diesel engine stationary power plant. I use a Rockford rear mounted PTO to drive my belts. While running the rear of the PTO housing is very hot to the touch.  I have replaced all of the bearings and this made no difference. I pump grease into the rear bearing zerk until it comes out of the shaft opening. Is this high temperature normal? Please advise, thank you.

bandmiller2

Joe your not getting any clutch slippage are you.Does the clutch engauge with a crisp snap?? After you mill a wile feel the back of the engine and then the clutch housing very possible its just heat transfer from the engine.You did the bearings,and if your quite sure the clutch is not slipping I wouldn't be worried.Frank C.
A man armed with common sense is packing a big piece

Joe Lallande

I replaced the clutches also and have a good engagement.  I have the drive belts off. My 18" output shaft which has my 6 grove 9" pulley is supported by 1 11/16 pillow block bearing. I am able to adjust the preload on the shaft with this bearing.  I am trying to adjust the shaft with a little preload.  The only heat I feel is from the rear of the PTO housing where the two large tapered bearings are. The PTO housing is very hot and this is with no belt load.

ladylake

I'd loosen up that preload.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

bandmiller2

From what you say Joe it sounds like the two tapered roller bearings are adjusted too tight with respect to eachouther.When they run they get warm and tighter.I think if the mill was run awile and the belts removed you'd find that output shaft would not turn free.However those two bearings are adjusted give them a little less preload.Frank C.
A man armed with common sense is packing a big piece

Joe Lallande

The PTO was running hot in this area before I replaced the bearings and also had bearing noise due to some pitting on the outboard race. I adjusted the preload like I do axle bearings. The shaft turns freely now and I have no bearing noise only heat. I will try and adjust the pillow block bearing again before I pull the unit off. With the pulley on the shaft this thing is very heavy to handle. Thanks for your help.

bandmiller2

Joe from what you say I don't think the problem is in the clutch assy.Probibly the external pillow blocks as you suspect.If you can remove the pillow blocks and belts,just run the bear unit and check for heating,that would eliminate one or the outher as the problem.Could be alignment of those big outboard pillows, or the belt load you can't help.Next time I run my mill I'll feel the clutch housing and see how hot it gets.Joe how long is the shaft that comes out of the clutch unit most I've seen don't have room for a pulley and pillow block.?? Frank C.
A man armed with common sense is packing a big piece

Joe Lallande

The shaft from the PTO housing is 18" long. I have one pillow block bearing on the end of the shaft. I took the pillow block bearing off and I have slight free play of the shaft in both directions. I adjusted the pillow block bearing again . I will run the engine this weekend.

bandmiller2

Joe we're running out of things to try.The alignment of that pillow block and the shaft has to be questioned.If your drive pulley is close to the clutch unit you could run it without the pillow.The engine and pillow block bearing should be on the same base,as one unit outherwise any shift will cause missalignment.such as engine settling.Mayby its just the nature of the unit to run hot.Frank C.
A man armed with common sense is packing a big piece

rpg52

Joe,
I have exactly the same problem and have been puzzling over it for a while.  In my case, I have a 1946 Detroit Diesel 3-71.  It has a long output shaft with a 7 belt pulley on it.  I have a generator head running off one pulley but the end of the shaft (past the pillow block bearing) is what I drive the mill from.  (It has a coupling and short drive shaft to a differential - no belts.)

The bearing past the clutch was getting hot, so I removed the whole assembly.  The double roller thrust bearings in it needed a press to remove, which I don't possess, so I bought the bearings and had a friend press them on the shaft.  He cut the old bearings off, but said they didn't look too bad, just some staining.  He pressed on the new bearings, but it still runs hot.  I grease it before using, and the grease just oozes out while it is hot.  It gets so hot I  can't leave my hand on it.  I can't see how the shaft is mis-aligned, and am still puzzling over it.  If you find a cause I'd love to know because I'm at a loss.
Ray
   ???
Belsaw circle mill, in progress.

Joe Lallande

Thank you Ray! I have been thinking about this for two weeks now. I would like to start cutting again this spring. I plan to contact Twin Disc, where I found the clutch discs and Floey engines for advice. I will let you know.

rpg52

Joe,
Am I right in assuming that you have a Detroit Diesel engine too?  I saw that Oliver used them in some of their tractors and I assume in their stationary engines too.  I've been looking through my old manuals and think I may have an answer - or not.  First a fyi, Rockford made the clutches for the early engines (pre 1950), after that (late '40's) they (GM) started manufacturing their own. 

The Rockford clutch assembly includes a clutch adjusting ring, which when turned clockwise or counterclockwise either increase or decreases the distance between the pressure plate and the flywheel.  I think (bear with me here) if the adjusting ring is too tight, and the clutch was engaged, it would force the clutch against the end of the splined shaft, and push the shaft against the thrust bearings, causing them to heat.  Does that make sense?  The solution is to readjust the clutch to increase the distance between the pressure plate and the flywheel.  This would relieve the pressure against the thrust bearing and stop the heat generation. 

8)

Probably premature, but when my weather moderates I'm going to try it to see if it makes a difference.  Supposed to rain over the next few days so it will probably be next week.  Let me know if this makes sense to you.
Ray

:)
Belsaw circle mill, in progress.

magicmikey

  Hello folks, I am new to the forum. May I offer a couple suggestion to the hot bearing problem?
  The clutch assy.  shouldn`t  load the bearing when engaged if the lever has some free play. However, worn splines at the clutch disc hub will as over time a ramp develops on the shaft splines. With a new disc it`s at the top of the ramp, as the load increases so does the push.
   You have a 3 bearing shaft, any misalignment will load the centre bearing. A dial indicator to measure deflection as the pillow block is tightened is about the only way to check this. Possibly the shaft is bent, another quick check.
  Good luck
  mike

Joe Lallande

I have an Oliver Super 188 diesel engine stationary power plant. I will loosen the clutch adjusting ring. I have new clutches and I have good crisp engagement, maybe too much effort?  Floey engines has a spec for a torque wrench, however you have to weld a 1/2 hex socket onto the oposite end of the clutch shaft to attach a torque wrench. Thank you all for the input. Joe

rpg52

Ahh, that makes sense MM, the splines on the shaft in my engine were quite worn - a friend suggest that the engine may have been used for rock crushing or other such high impact loading in its previous life.  After a rebuild it must have been found to be less than useful, as it must have sat around for years (being a 1946 vintage) but still in good condition when I got it several years ago. 

Not quite sure what to do now, I guess I'll try loosening the ring adjustment and see what happens.  I don't have a spec for the Rockford clutch Joe, the ones I do have are for the later clutches - these were made by GM and were different sizes and different clutch lever lengths than the Rockford version.  They also had one for torque, but like yours, they required welding a nut on the clamp on the end of the clutch lever.
Ray
Belsaw circle mill, in progress.

magicmikey

  Ray, with a die grinder the ramp can be moved a tad farther up the spline or if the hub is beefy some of it can be removed. A large cyclical load sure would cause that wear coupled with the 60 years. ;) smiley_huh

  Joe the cams have a small roller that provides the squeeze on the disc, with excessive pressure they tend to disintegrate. Usually, on a 30" lever ~10 pounds should overcentre it. When slippage begins try one notch, rarely you need 2.
mike

Joe Lallande

Here are the clutch engagement specs from Floey Engines: 8" clutch @ 55 ft#, 10" @ 85 ft# and 11 1/2" @ 91 ft#. I will try and attach my torque wrench to the clutch lever to measure this spec.

magicmikey

   Some sort of scale [bathroom?] pushing/pulling on the end of the lever will work as well.
mike

Joe Lallande

I was able to clamp my torque wrench to the clutch shaft.  I have a single 10" disc and the torque should be 85 ft# to engage. This is way too much. These numbers must be for the newer PTO, mine is a 1955. I will contact Floey and advise.

Joe Lallande

Ray, The end play on a single disc shaft PTO is 4-7/000's. Mine was at 2. I was able to remove the data plate and adjust the bearing retainer without removing the PTO. Do not drop the lock nut and plate! I ran the engine for over an hour and the housing was only slightly warm. No grease coming out. I am still hauling logs out of the woods and hope to be sawing in a couple of weeks. The clutch engagement has nothing to do with the preload. Good luck.

rpg52

Thanks Joe,
Sounds like you figured it out.  Mine seems to be different, but suspect it is a similar issue.  Part of the problem is that I haven't been able to find any info on end play.  I assume mine would be similar to yours though. 

As I mentioned before, Rockford only made the clutch assembly for GM in the early '40's - there were 14", 15 1/2" and 17" clutches made for the 3,4 and 6 cylinder version of the -71 series of Detroit Diesel.  I couldn't find any data on adjustments in the 1941 Maintenance Manual I have.  GM started making their own clutches in the late '40's, and the 1973 Operator's Manual I have shows 8", 11 1/2" and 14" clutches, with an adjustment ring accessed through the inspection hole on the top of the bell housing.  It doesn't mention anything about adjusting the end play, but suspect that is the same issue your engine had.  I have miserable weather right now, but when we get some decent weather I'll try to figure it out.  Thanks again,
:)
Ray
Belsaw circle mill, in progress.

Joe Lallande

Ray, I was able to turn my adjusting ring almost 1/2 CCW to achieve the proper clearance. I checked it with a dial indicator.  Just loosen up the preload until the heat goes away. Good luck, Joe.

rpg52

So, the adjusting ring also acts as the preload for the thrust bearing?  Interesting, I'll likely try it next week.  Thanks again.
:)
Ray
Belsaw circle mill, in progress.

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