Torsional vibration problems with a Hurth gearbox.

[Guest]

I have a Perkins 'Perama M30' engine in conjunction with a Hurth 100 gear box. I have had some problems with the gearbox "wearing'' and I have been told by two sources that the problem is associated with torsional vibration transmitted to the gear box from the engine and that there is no cure. I was told that Volvo cured the problem when they took over the engine and converted it to their 2030 model by increasing the fly wheel's inertia. Has anyone got a solution involving an alternative gearbox which is less prone to these vibrations?

 

[Johnjo]

Don't know about your engine, but on a boat I use to own, I fitted a
B.M/C 1,5 with a Hurth box, use to have a problem at low revs with the
engine kicking causing the gearbox to make a lot of noise,not keeping a
steady drive into the gearbox. think this is what you have!!!
only solution I could come up with was to increase the engine revs until
it all smoothed out, means going a bit faster, but saves the gearbox from
clattering,hope this helps,

regards mike

 

[Guest]

Mike Thank you for this but the problem is not one of vibration which impinges on the senses. As I understand it, it is caused by the vibrarion resulting from the three cylinders firing and there being insufficient damping between the output drive and the gearbox. This results in wear which causes a significant delay between engaging gear and the mechanical servo fully engaging the gear. I have been told that this will get worse. A larger flywheel damps out these torsional vibrations. As I do not want to nor can afford to re-engine, I am looking for a small but more robust gearbox which will fit onto the Perkins engine.

 

[mtb]

Have you thought about a mechanicle box !!
After that a PRM Hydraulic which one !! talk to Lancing Marine

Cheers
Mick

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[airbubble]

Re: Torsional vibration problems with a Hurth gear

In 12 years running a yacht service company here in NL, we have fitted and serviced several perana30/HBW100 installations in open launches that were built outside the EU and came with the otherwise unknown Perana, as VP had bought the rights to market them this side of the world. Although indeed the VP2030 has a modified cranckshaft and flywheel, we have not encountered any of the problems you describe. If I remember correctly, we even used HBW 50 on some installations, which has even less torque capacity. I think the problem lies in the 'clutch' ore dampening plate between engine and gearbox, or incorrect adjustment of the operating cable. Indeed an idle rpm that is too low will cause the gearbox to be noisy, as described by someone else. The PRM will only make that problem worse, specially the delta.
Check adjustment of the lever and clutch/spring plate first.
PM me if specific questions.
Best wishes,paul

 

[Johnjo]

Yes, understand that, which is why I suggested you increase the
engine tickover revs, this will, should! improve things,
Before spending lots of money, give it a try! think you might be
surprised. good luck
mike

 

[lauradee]

if it is really as serious as you think i would even go down the route of looking at the flywheel with the box off and seeing if you can bolt on some extra mass, usually there is some extra holes in the flywheel to allow for different installations and a decent machine shop could soon knock up a turned plate to fit onto shoulders and extra bolt holes?
it would appear that the prob is being caused by the uneven pulses in the firing order and the extra mass would damp out these pulses.
s

 

[mtb]

Interesting thing about the amount of cylinders and the effect this has re vibrations and movement of the engine in relation to other machinery.
The Audi Quattro and the sport ( OLD CARS !) had the five cylinder engines and talk about run smoothly , I had to test drive a sport after rebuilding the head and oooooooohhhhhhhh it was so fast the Quattro with the turbo must have been amazing especially with four wheel drive.

The BMC 1.5, I was surprised when some one said they had a problem with the engine not running smoothly, cos they are a wonderful engine and if kept well maintained run like sewing machines ,I agree re the clutch plate theory the springs do get worn.A lot of people don't maintain their gearboxes I think it's well worth keeping an eye on the box just as one would re the engine, re oil level and contamination cos hydraulic boxes do like clean oil, and the cable connections do need adjusting once in a while
cheers
Mick

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[Johnjo]

Sorry, I did not explain myself clearly,
did not have any mechanical problems with the B.M.C good enginethe point I was
trying to make was that the BMC also has a light flywheel, which if run at
a very slow idle speed results in gearbox clatter, by increasing the tickover
speed it balances out, some times the idle revs can drop over a period of
time and need the occasional adjustment,not neccasarily caused by a engine
problem, just vibration or wear on the adjuster, linkage etc.

happy new year
mike