The Mitsubishi Pajero Owners Club®

Phatwheels · Posted: Mon Apr 15, 2019 17:23 Post subject: vibrations/balance belt

OK so im running a 2004 2.5 4d56

been having a rather odd problem for a while now with vibrations - they are bad at idle, but disappear when engine is revving or moving, also vibrations get worse when the car door is fully open, weird i know.

I've read on here and elsewhere that the balance belt isn't needed.
also read that it should turn pretty freely - well i have the top half of the belts cover off so i have access to the top/right balance shaft just through the gap and i can't turn anything, its solid in place, is this normal or not?

Should i just cut the bloody thing off and see if it fixes these vibrations? or am I been daft and potentially screwing things up.

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Phatwheels · Posted: Mon Apr 15, 2019 17:24 Post subject:

100,00 miles on the clock. dunno if that has any bearing on whether the balance shaft gubbins might be ready to pack up...

2.25diesel · Posted: Mon Apr 15, 2019 18:53 Post subject:

The balance belt should not be able to be turned by hand on a stopped engine. It is a toothed belt which is driven by a sprocket on the crank shaft. However, the shafts themselves should turn freely when the belts are removed to be changed.

I have read before that the balance shafts have been known to seize on higher mileage engines. This will cause the belt to break, which can get tangled in the timing belt and cause that to jump teeth or break. The belts are also apparently prone to breakage as they run through more extreme angles than the timing belt.

The seizure issue is apparently is due to the bushes the shafts run in turning in the bores they are fitted into. This blocks the oil feed holes for the bush, which soon causes the shaft to seize.

I didn't fit a balance belt on my 1990 MK1 when I replaced the timing belt.

A word of warning is that I remember reading something about leaving the balance belt off causing trouble with a certain sensor on later 4D56 engines. This is not an issue with my MK1, but I am not sure about yours. I do not know this for certain, and would welcome a confirmation from someone familiar with the later engines.

Phatwheels · Posted: Mon Apr 15, 2019 19:03 Post subject:

Yeah i also read similar re the sensor, though it seems from this post that its okay to remove:

http://www.pocuk.com/forums/viewtopic.php?t=161205&sid=7519263f12563bcce87358b4cb931ea3

just can't figure out how to get it off without it pinging off into the bottom of the casing despite Trekkers explanation (not sure how he used that 3mm wire), ive not got much space to work with.

any suggestions of how to get it off?

2.25diesel · Posted: Mon Apr 15, 2019 20:17 Post subject:

That post was about a 1990s MK2 2.5, which would have an all mechanical fuel system without any sensors on the rotating engine parts.

Does your Shogun Sport have a mechanical injection pump or common rail? I do not know much about the common rail types.

Mark3 · Posted: Tue Apr 16, 2019 11:35 Post subject:

Personally i think 2.5s with no balance belts feel bloody awful Shocked

A few time at customers request i have left the balance belts off and it left a rather smooth engine (smooth for its age and the fact its an old diesel) with the most horrible vibration at lower revs i have come across Sad

If it was me i would definitely leave the belt on.

trekker · Posted: Wed Apr 17, 2019 9:10 Post subject:

My tool for holding the balance belt was a simple length of strong wire 3-5 mm diameter formed at one end to firmly slide over the width of the belt and grip it such that once cut through, the belt could be gently pulled out from the sprockets without fear of becoming detached from the tool. All worked well. I used a belt knife, the Stanley type, to cut across the width of the belt, adjacent to the holding tool.

trekker · Posted: Wed Apr 17, 2019 9:42 Post subject:

Further to Mark's experiences, I felt no difference in my engine vibrations from a slow cold idle through the full rev range. I conclude from this there are out of balance variables in the engine, some combining to offer little vibration whilst on other engines combining to the "horrible" vibrations felt by Mark. Perhaps engine and transmission mountings play a role in what is felt in the cab, also my older '88 being maybe less prone to vibes than a later model ?

I've always maintained my paj in original form, so it's had balance belts for 250 000 km. An oil weep from one of the balance shaft seals lead me to cut off the belt which was mid way into it's 80 000 km safe life.

2.25diesel · Posted: Thu Apr 18, 2019 19:10 Post subject:

assassin · Posted: Mon Apr 22, 2019 3:26 Post subject:

Is it a bottom pulley issue? check to see what type it has fitted as they are damped and they delaminate.