The Mitsubishi Pajero Owners Club®

boyoracer · Posted: Mon Dec 19, 2011 18:20 Post subject: 2.5 Bottom Pulley

Hi people
Yesterday I think I found the reason for the knocking on tickover - the outer bit of the bottom pulley is shaking abit. Not much probably a couple of mm on tickover. No play what so ever stationary.
What I want to know is am I damaging the timing belt crank pulley and what damage could happen if outer pulley goes for a walk. I need the truck for work for the next 4 nights about 100 miles. The engine runs smooth and only knocks on tickover.
I have got a new bottom pulley on order with bolt and washer and key.
Any thoughts folks?

Boyo

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dbamsey · ** Joined: 05 Feb 2011 Posts: 110 Location: Haverfordwest

Personally I wouldn't take the risk, however might be worth check the torque setting of the pulley bolt because if that has worked loose it will knacker your woodruff key. If its tight enough and its just the pulley delaminating then you could risk it, if it fails then then you could end up causing damage to the fan, radiator and anything else it smashes into. You could end up with it off the road longer waiting for parts you can't get fast. Your call Smile

Good luck.

vmaxsnoopy · Posted: Mon Dec 19, 2011 19:02 Post subject:

If your sure that the pulley itself is not loose on the crank, then it is delaminating (rubber vibration damper between centre and outer pulley) Will not affect the cam belt or the crankshaft end. Worst case scenario, the two halves will part, but dont usually do any harm aside from losing your alternator drive. I would put a paint line across the two halves and keep an eye on it for your 400 miles mate. The paint line will show up any additional movement.

Mitsibob · Posted: Tue Dec 20, 2011 9:56 Post subject:

Mine was like that and it wrecked the crankshaft.

boyoracer · Posted: Thu Dec 29, 2011 18:16 Post subject:

Update.....

Well it was deffo the bottom crank pulley. It somehow was rotating on the crank! The bolt was tight in the crank but the washer was loose. There was about 10 degrees radial movement and the keyway has worn in the pulley.
I thought not knowing what I'd find I would change all the belts and tensioners just to be on the safe side. I ordered new bottom pulley,bolt,washer,timing belt crank pulley,new belts and tensioners.
Forgot to get balance shaft oil seals,balance shaft crank pulley and flange-guess what bits I need to replace while its all off.

Anyhow got pulley off no problem - bolt undone no problem,got all covers off-saw a repair to the bottom cover. Also saw a few bits of an old belt wedged in the pulleys.Loads of shavings and gunk in the recesses. Guess a belt snapped at some point in the past!

Big problem I got at the moment is I can't get the timing belt crank pulley off. My 3 legged pullers get so far and then slip off. I am going to grind the feet to sit in the teeth a bit better.Should be able to get a better purchase on the flange. Will try abit of heat on the pulley as well.

My question is should the pulley be a press fit on the crankshaft as mine appears to be?

Any help much appreciated

ian lunn · Posted: Thu Dec 29, 2011 18:52 Post subject:

my bottom pulley just slides on/off once bolt is out.

dbamsey · ** Joined: 05 Feb 2011 Posts: 110 Location: Haverfordwest

I rebuilt my engine about 6 months ago, when I tried to remove to crank pulley and balance belt pulley they were on tight. I managed to get the crank pulley off without any damage but bent the plate inbetween the two pulleys and chipped a couple of teeth off the balance pulley trying to prize it off. Got replacements from Milners.

Nodge68 · Posted: Thu Dec 29, 2011 19:44 Post subject:

I'd guess that the loose pulley has slightly deformed the crank making it tight to shift the cam belt pulley!! If so the new pulley might never tighten correctly Sad

boyoracer · Posted: Thu Dec 29, 2011 19:57 Post subject:

dbamsey- I am getting my order ready from Milners now online. My balance belt crank pulley is 'loose' as is the flange,it's just the timing belt one. The new one I have also is a tight fit on the crank nose when I offered it up.
I will get my micrometers back from work on monday night and check the sizes properly to see if there is an interfence fit.

Anyone know what size the crank nose should be?

boyoracer · Posted: Fri Dec 30, 2011 12:13 Post subject:

Just been looking through the Mittsy workshop manual and they actually list a crankshaft sprocket removal puller. I have the new sprocket which I am going to take to work to measure but after seeing that tool I might make one up to use. Seems simple enough (page 11b-4-3 in use)
Unless of course someone knows where I can borrow or buy one.

old cottontop · Posted: Sat Dec 31, 2011 1:57 Post subject: 2.5 bottom pulley

The harmonic balancer on 4d56 engines are known to flog out.
the parts (harmonic balancer, belt pulleys and pump drive) are all a tight slide fit, however, because it's a well known problem, they are often installed with thread locking compounds or bearing mounting compounds, this makes the gears sometmes difficult to remove. Always fit a new key if the old one shows ANY signs of wear, it's just not worth not doing.
And as you found out, you can't check for the problem unless you unload the fan belts.

Old Cottontop