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Cat/Perkins 51 HP

Started by petefrom bearswamp, May 19, 2011, 06:30:03 PM

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petefrom bearswamp

Perhaps this has been addressed before, but I was only made aware of it on tuesday last when talking with my neighbor/friend who saws full time portably with a lt50shdd51 woodmizer.
We had talked about a month ago regarding the Sawmill exchange which lists a number of 51HP mills with (for example) 2500 hrs on mill, 800 hrs on engine. This raised a red flag.
He got checking RPM on his engine and found 3100 plus or minus, then got on line and found that the factory specs are 2800 RPM tops, stating higher RPM may result in engine failure.
I checked my engine and found 3095 RPM.
Both he and i have reduced our RPM, him to 2850 and me to 2795.
Anyone out there have info regarding this?
It seems to saw just fine at this setting.
I am wondering why WM mills come with the higher RPM setting.
Pete


.
Kubota 8540 tractor, FEL bucket and forks, Farmi winch
Kubota 900 RTV
Polaris 570 Sportsman ATV
3 Huskies 1 gas Echo 1 cordless Echo vintage Homelite super xl12
57 acres of woodland

ladylake


Sure could be that they upped the RPM some to raise the HP, my little Isuzu was on a Ingersol air compressor where they had it rated at 28.6 hp at 3400 RPM when most I've found were rated at 25 hp at 3200 RPM. I'm running mine at 3200 RPM and still using the same drive pulley as the old 3600 RPM Kohler so the blade speed is slower but it saws a lot faster than the 27 HP Kohler ever did, and straighter.   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

Dave Shepard

I recall seeing the spec for that engine somewhere and was surprised to see it was so high. I'll have to check ours.
Wood-Mizer LT40HDD51-WR Wireless, Kubota L48, Honda Rincon 650, TJ208 G-S, and a 60"LogRite!

POSTON WIDEHEAD

Sounds like a good way to sell more engines. FISHY? This is a great post!
The older I get I wish my body could Re-Gen.

Peter Drouin

how do you check the rpm ?
A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

ljmathias

Use a piece of chalk or magic marker to put a line on the drive pulley, then start it up, set it on cut, and count really, really fast- gives me a migraine so I've never actually gotten an rpm number I trust...  :)

No, really, there are a number of past threads dealing with this subject, using ingenious and inexpensive systems with off-the-shelf parts- can't remember where though....

Lj
LT40, Long tractor with FEL and backhoe, lots of TF tools, beautiful wife of 50 years plus 4 kids, 5 grandsons AND TWO GRANDDAUGHTERS all healthy plus too many ideas and plans and not enough time and energy

sandhills

Definitely not the cheapest option I'm sure, but you can buy tachometers that have a rubber "shaft" (for lack of a better term) that you simply press against the end of the crankshaft.  We have one that dad got for checking rpm on irrigation power units, we checked it against the tachs on our tractors and it was very accurate, don't remember the price but do know it wasn't real cheap.

r.man

I remember that thread and the cheap answer is a paper disk that can be printed off or bought. Affix it to the pulley and then look for the dashes that are not rotating when the pulley is turning at its full speed. Each series of dashes corresponds to an rpm so the one that is standing still like a carriage wheel is the rpm.
Life is too short or my list is too long, not sure which. Dec 2014

MartyParsons

Check the RPM with a tachometer after the first 20 hours of operation and every 200
hours thereafter. High-end RPM should be 2950 RPM and low-end RPM should be 1500
RPM.
Before checking the RPM, make sure belt and brake strap tensions are correct (See Sawmill
Maintenance). Also check oil, fuel, and coolant levels.
Make sure the throttle solenoid linkage is adjusted properly. With the clutch disengaged,
the throttle linkage should rest against the idle adjustment screw. With the clutch
engaged, the linkage should rest against the high-end adjustment screw and leave 0" to
1/32" of play in the linkage.
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

petefrom bearswamp

Thanks Marty.
I respect your posts and info.\ which are very helpful.
However, 2950 is still higher than Perkins/Cat says.
How about the service interval of 300 Hrs.
Seems high to me.
Oil and filters even at todays high prices are still cheaper than engines.
As an aside, Here in Central NY in the winter I have to "boost" the starting Idle speed with a thin piece of scrap or whatever is handy when starting or the engine will stall at idle.
This is even after cycling the glow plugs.
Pete
Kubota 8540 tractor, FEL bucket and forks, Farmi winch
Kubota 900 RTV
Polaris 570 Sportsman ATV
3 Huskies 1 gas Echo 1 cordless Echo vintage Homelite super xl12
57 acres of woodland

MartyParsons

Hello,
I checked the Cat manual I had here at the shop and it said rpm 3000 max. Most of these engines failed due to crank shaft failure. The argument is, customer tightening the drive belt to tight or weak cranks. We educate the owners as much as possible when we do the new mill training. It is also in the engine auto clutch book and the maintenance manual.
Spec for a 51 hp Cat is 18 lbs force with 7/16 movement. Check your manual for the proper procedure.
I have seen a few drive belts overtightened. I have even seen one Kohler engine with a rear pulley off ( the crank end was still in the pulley) and no auto clutch. I think the owner had big guns!
We have not seen this reciently.

I dont think any manufacture would design a failure so they could sell more parts. IMHO
Yes filters and oil are less expensive than engine parts and labor.
Thanks!
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

tyb525

With today's oils and engine technology, you can really go a bit longer than most specified intervals. The only reason service shop's still say every 3000mi is because they make more money that way. You can easily go 5-7k or more, especially with semi or full synthetic oils. Most manufacturers have changed their spec's to reflect this, and many service shops have not.
LT10G10, Stihl 038 Magnum, many woodworking tools. Currently a farm service applicator, trying to find time to saw!

hunz

I know this thread is quite old, but to me it seems there is mixed information without a verdict. First, from what I gather, Perkins made the engine, so they built the engine to operate a certain way. Is this where the 2850/3000 rpm question possibly arose from? I actually reset my idle rpm yesterday on my CAT as per my manual, and a verification call to Wood-Mizer Indiana. Both said/say 1500 low, 3100 high.

Marty,
Any idea why the discrepancy? Makes a guy feel a little uneasy running his $5,000 engine possibly out of its recommended rpm range. In order to achieve a 1500rpm idle speed, the high end came out at 3025. My engine has a tamper resistent set screw on the high end, so how is a guy supposed to adjust the WOT rpm? Possibly remove the tamper resistent screw, and install my own setup?

FYI, I also just installed the extra crankshaft support kit. Anyone else have one on their CAT?
Dream as if you'll saw forever; saw as if you'll die today.



2006 Woodmizer LT40D51RA, Husqvarna 372xp, Takeuchi TL140

hunz

Anyone with a definitive answer? Marty?

   Otto, the head engine man no longer works at Wood-Mizer, as per someone in tech support. It was somewhat made out to me, that all anyone knows is what's written in manuals.... which happens to be varying information depending on what revision # you have. No real hard evidence.
Dream as if you'll saw forever; saw as if you'll die today.



2006 Woodmizer LT40D51RA, Husqvarna 372xp, Takeuchi TL140

schmism

There is a metal tag on the side of the engine with the serial number.... send me the number and ill have my perkins guys look up the official high idle spec.   it might also list it on the plate.  fyi its its a perkins its 2 letters some numbers likely a U and some more numbers, if its CAT its 3 letters and some numbers.

as for extending oil service, unless your takeing SOS samples,  its ill advised.

039 Stihl 010AV  NH TC33D FEL, with toys

SawyerBrown

Well, the other thing to consider is that high idle is at high IDLE, ie without any load whatsoever (which is the way they'd be set in the factory), and warmed up to operating temp.  So even an alternator load can affect the speed they turn in the "overrun" (above rated speed at rated power).  Seems to me if you're going change the high idle setting, the alternator belt should be removed. (And maybe this is already in the manual?). Then when reconnected the speed will be slightly lower, and lower yet with blade engaged.
Pete Brown, Saw It There LLC.  Wood-mizer LT35HDG25, Farmall 'M', 16' trailer.  Custom sawing only (at this time).  Long-time woodworker ... short-time sawyer!

hunz

Sawyerbrown,
  Good point about the high end rpm set being with no load, I suppose even if a guy sets it at say 3025, it probably is actually turning somewhere in the 29s or 28s when cutting with debarker on.

Schmism,
  I appreciate that offer. I'll have to run down to the barn and check the tag, and get back with you. One thing I can tell you is it has a Perkins steel tag on the engine with "void" written all over it. The first owner recorded the idle rpm at 1373 when brand hammer new. Wonder if that is any indicator of where it should be.
Dream as if you'll saw forever; saw as if you'll die today.



2006 Woodmizer LT40D51RA, Husqvarna 372xp, Takeuchi TL140

Peter Drouin

 

  

  

  

 

It went well for me and no trouble. I did take the shield back off and left it that way.
A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

hunz

Peter,
  Let's hope that crank support kit is worth the coin we dropped on it. Have you ever checked your engine's rpm? Any insight to give?
Dream as if you'll saw forever; saw as if you'll die today.



2006 Woodmizer LT40D51RA, Husqvarna 372xp, Takeuchi TL140

Peter Drouin

Quote from: hunz on March 15, 2015, 12:36:32 PM
Peter,
  Let's hope that crank support kit is worth the coin we dropped on it. Have you ever checked your engine's rpm? Any insight to give?


No, The mill runs good the way it is. ;D
A&P saw Mill LLC.
45' of Wood Mizer, cutting since 1987.
License NH softwood grader.

drobertson

going off memory here, 1500 idle, 3000 running, have not checked since 08' and like peter's, running good here, it was mentioned back in 08' to me from a tech, that a slight tweek up or down on the idle can help reduce some of the vibrations that occur with these engines.
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

MartyParsons

The Wood Mizer manual states the high RPM at 3100 the low is 1500.
The low rpm is higher because WM needs the alternator to be charging while the hydraulics pumps are working.I highly recommend the crank support. I am assuming they WM are checking low rpm with the alternator belt on.
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

SawyerBrown

Quote from: hunz on March 15, 2015, 09:03:24 AM
One thing I can tell you is it has a Perkins steel tag on the engine with "void" written all over it.

I'm thinking since this is a yellow (Cat) engine, there should also be a Cat tag with high idle setting, but I'm not positive about the Perkins-built stuff
Pete Brown, Saw It There LLC.  Wood-mizer LT35HDG25, Farmall 'M', 16' trailer.  Custom sawing only (at this time).  Long-time woodworker ... short-time sawyer!

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