Black smoke and loss of power = loose cam hold down bolt!

Does your Mitsubishi L300 make a strange noise? Need wheel alignment specs?
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delicat
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Vehicle: '92 Exeed '93 Safari '94 Pajero
Location: New Westminster, BC
Location: New Westminster, BC

Black smoke and loss of power = loose cam hold down bolt!

Post by delicat »

Original post from the UK site:
http://www.mdocuk.co.uk/forums/viewtopic.php?t=18608

And extract from the original post:

The bad news:
After travelling about 500k's over steep hills... We returned on what I suspeted was no oil... We arrived home fine, but then three days later a light ticking that had develoed on the trip...the tick got worse and on the way up a steep hil o the way home I started spewing black smoke and the power all but dissaperad. I limped home, the symtops getting worse and worse, now white smoke and black smoke, a harsh shuddering and clattering, and finally a sound that i was confinces was the crank shaft jumping in the holes where the burned up bearings used to be. I made it home! And after looking closer it seemed that there was a deep thudding and chuffing noise coming from the rear of the engine deep down...

BUT
The good news.
... I shoul check the rockers and see if the needle bearings in the rollers had shot themselfs...

So I took off the rocker cover and sure enough the tappet clearance was way(!!!) out on the 3rd and 4th cylendars (Ok I cant spell). In order to get the right clearance I had to take the lock nut off and put it on the reverse side, as I needed to screw the adjustor until it was inside the rocker arm for all four rockers... Then back on with the tappet cover and Voila!! It went! perfectly...

But alas the problem came back with a vengance... Limped home and took another look, the tappet clearance had all mysteriously changed... I then found the prices for new rockers. and confirmed with all the mechanics that this was most likely the problem.

But strangely when I had the rocker cover just resting in place wihtout bolts the engine went fine, it was just when it was tightened tat the problems developed again... from fine to eath like engine sound by tightening the tappet cover. weird. I took the rockers off to have a look and see if I could see any lobe damage, or whether these rolers on the rockers were really poked....
It turns out the bolts that hold the cam down were extreemly loose on no.3 and 4.

So I tightened them, put the rockers back, redid the tappet clearance, and now she goes bettter than ever before...

So the lessons here,
For terminaly death like negine noises it could easily be the rocker bearings, (which would have caused the same fault) or simply the bolts holding the cam down
'93 Nissan Patrol
'94 Mitsubishi Pajero
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