lombardini ldw 1003m idle vibration

[magomerlino]

Hi folks, newby here, hope you can help.
new engines last winter. Launched January and had bad vibration throughout all rpm ranges. Lombardini had supplied shore 60 mountings ( should have shore 35 according to mounting manufacturers) So we fitted shore 35 and have no trouble at all EXCEPT at idle speed. Engine drops into some kind of spasm and shakes its self so badly it snaps mountings. Shaft drive and perfectly in line. We have four of these engines ( two boats)and all suffer the same. lombardini in italy,
completely useless! Help!

[model 10]

How high does the idle need to be so it won't go into freak out? It sounds like the mounts need to be stiffer or you need to add a shock absorber to keep it from doing that. If it were an airplane or something more engineered, you might have combination of soft and stiff mounts to keep the gyrations from starting.

[magomerlino]

hello and thanks for coming back. Engines are supposed to idle at 860 rpm. Very simple cone clutch gear boxes demand low rpm for engagement. 1150 rpm is the lowest we have achieved without this violent shaking.
Sure if we use the supplied engine mounts ( shore 60) the engine doesn't shake. The whole boat does!! The vibration is terrible throughout all rpm range with solid mounts.
With softer shore 35 mounts we get bad vibration at idle, but only at idle. All else is smooth running. Interestingly, when gear engaged we get terrible shaking, so we disengage. Perhaps you might think this would stop the shaking?, it doesn't. We have to increase revs in neutral to stop shaking. I thought perhaps she was over propped, but as she is a catamaran we tried same when she was aground ( no load on prop as no water) same trouble. It seems the engine does not have enough power at idle to keep its self running properly. fuel delivery ?

[Polux]

You mean you are not in Italy? If not I see any help as dificult. Where are you? I found a good Lombardini mecanico in Corfu, Greece but they are hard to come outside Italy.

[magomerlino]

Hi Polux, I am in UK and Lombardini have hardly any presence here at all on the marine side.

[Xthewater]

Sounds like one cylinder isn't firing which can become very pronounced at idle speed. Fuel injector or low compression maybe.

[magomerlino]

Xthewater, hi, None of the above I'm afraid. We have four of these engines. They all have exactly the same symptoms. They had the problem when they were brand new. no black smoke. Runs perfectly at higher revs. Loads of power after 1200 rpm. I'm at a loss!

[Xthewater]

Originally Posted by magomerlino

Xthewater, hi, None of the above I'm afraid. We have four of these engines. They all have exactly the same symptoms. They had the problem when they were brand new. no black smoke. Runs perfectly at higher revs. Loads of power after 1200 rpm. I'm at a loss!

Then the only thing I can think of is the timing is too advanced from the factory so at low rpms the flywheel is having a hard time pushing through the compression stroke causing counter torque and severe rocking. It can be tested by slightly retarding the timing on one and see if the problem goes away. Easier said than done I know if access is difficult. Slight shimming of the fuel pump will retard timing enough to verify.

[GrahamHO]

Originally Posted by Xthewater

Then the only thing I can think of is the timing is too advanced from the factory so at low rpms the flywheel is having a hard time pushing through the compression stroke causing counter torque and severe rocking. It can be tested by slightly retarding the timing on one and see if the problem goes away. Easier said than done I know if access is difficult. Slight shimming of the fuel pump will retard timing enough to verify.

I don't know those particular motors and you have 4 of them?!


You can easily slightly retard the valve timing by increasing the valve clearance by maybe + 2 thou". It won't harm anything and it's easy to do and reset if it doesn't help. Adjust each inlet when it's companion exhaust is fully open, and each exhaust likewise when it's inlet is fully open.


After my Yanmar was fully reconditioned the compression was higher as it had been bored +60 thou" and the head planed -8 thou". It shook around a bit on idle and kicked back on shut down. My cylinder head reconditioning specialist suggested increasing the valve clearance by +1,1/2 thou" from the factory recommended + 8 thou " to + 9, 1/2 thou "which I did, and now it runs like a Swiss watch. That was an increase by the thickness of a piece of paper.

[bikesherpa]

Hi,
I own a Lombardini LDW 2204 M (different model than yours, but maybe the same applies).
Accordingly to the owner's manual, the engine warm-up should be done at 1300-1500 rpm, not at idle.
Also, the ZF/Hurth mechanical gearbox is notorious to be noisy when putting in gear. If the engine is equipped with TwinDisc, it should be quieter.
To reduce the noise, I changed the original damper plate and it is much better now.

[magomerlino]

Hey bikesherpa and graham, thanks this is useful stuff!
We don't have four engines but there are two catamarans in our creek with exactly the same engines and same problem.
I see what you mean about about valve clearance. I'll try it thanks.
We have twin disc gear box but its pretty noisy due to engaging at 1150rpm. not the gearboxes fault, but its better than snapping mountings at correct idle speed under 1000rpm. i will report back. cheers, jim

[GrahamHO]

Originally Posted by magomerlino

Hey bikesherpa and graham, thanks this is useful stuff!
We don't have four engines but there are two catamarans in our creek with exactly the same engines and same problem.
I see what you mean about about valve clearance. I'll try it thanks.
We have twin disc gear box but its pretty noisy due to engaging at 1150rpm. not the gearboxes fault, but its better than snapping mountings at correct idle speed under 1000rpm. i will report back. cheers, jim

Thanks for the feedback Magomerlino. I hope the clearance adjustment works for you. As I'm sure you see, a valve opens a fraction later with more clearance. It can't hurt to try it on one engine first. I'm assuming they are adjustable and not the hydraulic type.

With 4 engines I was envisaging one of those low slung RIBs that run drugs across the Med from Africa.

[sotavento]

I had a vibration problem with a Yanmar 3 cylinder after I took it out for some overhaul. After many try including a new propeller it was the shift linkage not set prperly and the gearbox cone not engaging completely.