Diesel Engine Vibration Issue

<...cold condition...>

OK. Try this:

• It's an Unidentified Frozen Object [UFO] - something in it or on it is frozen-up, causing out-of-balance operation when it is cold. Once the engine has warmed-up, the UFO melts, and disappears into a fluid phase.

Seriously, it is not possible to determine this without carrying out a fault-finding exercise on the equipment, which cannot be seen from here.

First, change the crankcase oil. Maybe it is contaminated.

Or, put strip heaters around the crankcase to determine.

Change things, one at a time, (take notes) until it quits vibrating or self destructs.

Or tear it down and correct the problem, once it is identified.

It sounds fine from here.

What did Mitsubishi have to say when you called them?

do you observe black smoke from the exhaust during this time of vibration?

Does the engine develop full power during this time, go to peak revs if commanded?

What is the period of the vibration, does it change with engine rpm, what is the engine driving?

vibration is the result of something being out of balance.

How are you measuring this vibration?

What condition are the shock mountings in? New, worn?

when you say cold, how cold? Is there ice, is there snow? What country are we talking about?

when did you service the engine?

What is it powering? Gen Set?

Yep, Or one of the pistons have worn or sticking rings.....Thus compression too low and compressed air still too cold to ignite diesel. Does the engine knock when cold?....Diesel ignite too late? Same story if valves are leaking.

Yes; Grease on exhaust manifold to see which cylinder does not fire propperly[Injector or low compression leaking valves etc]

If it is very cold and you hear loud knocking at start-up, add 250ml of any clean oil and 10% petrol to the fuel. this should fix knocking and vibration at cold start if the engine is not too much worn out.

It will NOT harm the engine, fuel pump etc.

I would keep an eye on fuel and oil qualities. Double check fuel is being purified correctly and the fuel being used is at the correct viscosity for this engine. Do a full analysis on your oil in your sump and do it a few times to make sure. If traditional coolant is used, double check the operating characteristics of that and if jacket water is used I would double check the temperature going in. Open up a crankcase door and look for obvious damage or water. I would next look to exhaust gas temps and try and look for a cylinder that is not pulling its weight. Also, timing may be off, causing slight problems to amplify on the cold weather. If any specific cylinder seems to be the problem, I would perform a condom test and change the fuel pump. Like previous posters said, it is hard to understand what is going on without being there.