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Can The Speed be Increased on a Low Speed GenSet Engine?

ssmithfam

Registered
Hi All

I'm a longtime member and periodic lurker, but haven't posted much.

I refurbish vintage garden tractors as a hobby. As such, I sometimes repower the machines with an updated engine.

I have a Bolens HT23 with a front end loader and a Kohler K582 with a hole in the block.

I want to repower it with a diesel engine, and have found a Lombardini 9LD561-2L in a light tower genset. The Lomba is a 2 cylinder inline air-cooled diesel. It has a Bosch style injection pump that is timed by shims between the inj pump and cam, and fuel output changed by shims in the individual pumps.

The problem is the Bolens has a hydrostatic transmission and needs to run in the 3,000-3,600 rpm range while the Lombardini runs at 1,500 rpm. The same model Lomba engine is also available in a 3,600 rpm version.

My question:

What would be involved in getting the Lomba to run at higher rpms--at least 3,000 rpm?

Can it be adjusted by adding or removing shims on the injector pumps, or do I need to buy a new pump?

Thanks,

Smitty
 

AngrySailor

Subscriber
Last Subscription Date
01/31/2020
I don’t think it will like running at double rated speed. Aside from damage it will probably be way past it’s torque peak. You would be better off to use a step up gearing arrangement.
 

ssmithfam

Registered
I don’t think it will like running at double rated speed. Aside from damage it will probably be way past it’s torque peak. You would be better off to use a step up gearing arrangement.
Thanks for the input. Lombardini also makes an LD561-2 which runs at 3,600 rpm, so I'm hoping that increasing the speed is a simple adjustment of some type, or minimal parts replacement.

Smitty
 

Birken Vogt

Email NOT Working
I would guess the opposite, that it mostly could run at 3000+ RPM.

But if it was built as a 1500 RPM generator engine then the only way to know for sure would be to get the parts list of this existing engine and the parts list of the high speed engine and compare to make sure they are right.

Rods, pistons, camshaft, injectors, pumps, timing would be the things to look closest at.
 

I like oldstuff

Registered
Last Subscription Date
11/09/2015
Don't forget that those aluminum diesels are quite noisy. I wouldn't want to be sitting with it hammering away 3 feet in front of me for a few hours.

If it was me, I'd find another 582.
 

Thaumaturge

In Memory Of
Age
68
Last Subscription Date
07/12/2019
Speed change would not involve the shims, which set timing. On single cylinder Lombardinis the speed is set on govenor assembly. Lombardini is now owned by Kohler. I'd try running your model number on the Kohler site to see if they offer an operators or service manual pdf file, which should cover speed adjustment.
Doc
 

Thaumaturge

In Memory Of
Age
68
Last Subscription Date
07/12/2019
Sadly that manual specifically state for 9LD561-2L an RPM of 2000. So no go on 3000 RPM, at least by direct drive. Is there room to provide for 0.66:1 (2:3) belt ratio?
Doc
 

ssmithfam

Registered
I would guess the opposite, that it mostly could run at 3000+ RPM.

But if it was built as a 1500 RPM generator engine then the only way to know for sure would be to get the parts list of this existing engine and the parts list of the high speed engine and compare to make sure they are right.

Rods, pistons, camshaft, injectors, pumps, timing would be the things to look closest at.
I stand corrected. The 9LD561-2 is 3,000 rpm as you stated.

I got a workshop manual last week, and a parts manual. The only differences I've found noted, aside from the rpm, are that the LD561-2 timing is 24 - 26 degrees, while the LD561-2L timing is 22-24 degrees.

I haven't found any parts listed that are specific to the 9LD561-2L, though one would assume that at least the injection pump, and possibly the injectors, are different.

Per the workshop manual, timing is changed by adding or removing shims from the area where the injection pump mates to the engine block--thus increasing or decreasing the distance from the plunger to the cam.

There also is a mechanical governor, which controls speed through a flyweight that is opposed by springs. I suspect that replacing the springs with lighter springs would allow higher speeds.

At any rate, thank you for the response.

Smitty

---------- Post added at 09:55:24 PM ---------- Previous post was at 09:51:10 PM ----------

Speed change would not involve the shims, which set timing. On single cylinder Lombardinis the speed is set on govenor assembly. Lombardini is now owned by Kohler. I'd try running your model number on the Kohler site to see if they offer an operators or service manual pdf file, which should cover speed adjustment.
Doc
Thanks. I was able to download a service manual and parts manual last week. I haven't been able to find anything that shows different part numbers between the "normal" and the "slow" version of the 9LD561-2.

Smitty

---------- Post added at 09:58:32 PM ---------- Previous post was at 09:55:24 PM ----------

Sadly that manual specifically state for 9LD561-2L an RPM of 2000. So no go on 3000 RPM, at least by direct drive. Is there room to provide for 0.66:1 (2:3) belt ratio?
Doc
Thanks for the suggestion. Unfortunately there isn't room for speed reduction.

I'm looking to use the engine to repower a vintage garden tractor. I have a couple candidates, a Bolens HT23, and a MTD995. Both are shaft drive to the hydrostatic rear end and there isn't room to squeeze in a gear reduction gear box of any size, not to mentoin one capable of handling 18-20 hp.

Regards,

Smitty

---------- Post added at 10:00:07 PM ---------- Previous post was at 09:58:32 PM ----------

Thanks. I failed to mention that I already have a service manual and parts manual for the engine.

Smitty
 

Birken Vogt

Email NOT Working
Yes, you are right that all the governor parts would have to be checked for commonality.

Also the crankshaft or fan drive pulley might be different so as not to overspeed the fan, and so the water pump is going the right speed.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Interesting. I'm surprised the timing difference isn't greater. But then again, they may want to make it still tolerate being overloaded at low speed- "lugged".
 

J.B. Castagnos

Registered
Last Subscription Date
01/01/2006
I don't think they would have made a special engine for lower speed, they just ran it slower, timing may have been changed for maximum efficiency at lower speed. I would run it, should be a throttle lever with high and low speed stops.
 

ssmithfam

Registered
Also the crankshaft or fan drive pulley might be different so as not to overspeed the fan, and so the water pump is going the right speed.
That's a good point I hadn't thought of.

BTW, how do you do a "Thanks" on other people's posts? I haven't found a button to click?

Smitty

---------- Post added at 09:50:31 PM ---------- Previous post was at 09:48:31 PM ----------

I don't think they would have made a special engine for lower speed, they just ran it slower, timing may have been changed for maximum efficiency at lower speed. I would run it, should be a throttle lever with high and low speed stops.
Yes, there is. I haven't seen the actual engine, it's just listed for sale in a local online classifieds, but my Ruggerini uses a couple screws with locking nuts to adjust speed. Ditto with my (now stolen) Kohler.

Smitty
 
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