90 Pajero with a broken rocker shaft

[Pajero90]

Hi All 1990 Pajero, 2.5 diesel turbo intercooler

I was driving down the highway and boom, sudden loss of power and running on fewer cylinders. I spent way too much time driving it after that trying to find the cause of the power loss until she just suddenly stopped, after a few metallic noises!

Took the cover off and discovered the rocker shaft in 3 pieces! Not sure what caused it, but, does anyone have any experience putting a new shaft and cam caps in (the last two cam caps near the firewall were damaged.

After reading on a few forums, I've heard some horror stories about trying to get the new cam caps to fit and having a whole series of horrible things happen to the engine after that.

I'd like to avoid any problems and was thinking of ordering a new head, built up. I don't really want to take the head off because it's a lot more work than I want to do right now.

The truck only has 100, 000 k, and the body and everything is in top condition.

Thanks, for any suggestions you could give me!

[.:FoRuM56:.]

Timing might have jumped, it's an interference engine so pistons and valves will make contact. The rocker shafts seems to be the weak link in the head, save other components. Honestly, it would be beneficial to pull it apart and check the timing first and then pull the head for inspection.

[Growlerbearnz]

The rockers are usually the first things to break (they're deliberately weaker to protect your pistons), and if it were just a broken rocker or two then it's usually ok- but if the shaft goes you know there's more serious damage lurking somewhere. I wouldn't trust any of the rockers, and I wouldn't be surprised if some of your valves are bent too. The cam caps are probably irreplaceable unless you have a huge pile of caps to test fit: during manufacture the caps are bolted onto the posts, and the cam bearings bored all at once- making each cap unique to its post. Misalignment is very, very bad. It's also likely that your cam is damaged or bent- breaking the cam caps takes a lot of force.

Basically, I'd get a new head. Replacing all the damaged bits on your existing head is going to be very, very expensive.

Also, you need to figure out what happened so it doesn't happen again- probably timing belt failure, which means new timing belts and tensioners. If the old belt is oily, then you're going to have to change the crank and balance shaft oil seals too, which isn't too difficult while the head is off.

[Datsubishi]

I had the same thing happen to my Pajero while climbing a steepish hill on the #1 in BC. Overspeeding the engine could've been a factor as I didn't have a working tach at the time. I was trying to make good time as mine maxes out at about 110km on the highway, I'm guessing it's extremely low geared. The timing belt was fine besides being aged, but I didn't do the work myself so I'm not sure if timing had slipped. I ended up having the whole head replaced to avoid any possible future issues. Mine had about 160,000km at the time.

[PHIL]

I had the same thing happen to my Pajero while climbing a steepish hill on the #1 in BC. Overspeeding the engine could've been a factor as I didn't have a working tach at the time. I was trying to make good time as mine maxes out at about 110km on the highway, I'm guessing it's extremely low geared. The timing belt was fine besides being aged, but I didn't do the work myself so I'm not sure if timing had slipped. I ended up having the whole head replaced to avoid any possible future issues. Mine had about 160,000km at the time.

It'd be interesting to know your diff gears... if you check the plate on the firewall it will tell up. Stock with the 2.5 was 4.88s - probably says 4875 on the tag (which are already low compared to most rigs. But there was an option for 5.29s which are extremely low, and puts your revs way up there at highway speed. LOL - throw some bigger tires on and call it "maintenance"?