Delica Canada | Mitsubishi Van Club

HI gang,

I'm just in the middle of the timing belt/ water pump job on my 91 L300, and now that the front end is stripped, I've found some trouble. The balance belt looked slack, and when I grabbed it, the belt came out in a single strand...

It appears as though it was a quick wear situation, as several teeth are torn off and the belt is tapered thin around the break. The balance belt tensioner seems to be seized, but it's to be replaced anyhow.

My question is, how much resistance should be found on the balance shaft? I cannot rotate it by hand, and I have moderate difficulty rotating it by its 12mm bolt. I don't want to get into removing the shaft, and if it is seized I would be inclined to run without a balance belt. The engine runs bulletproof otherwise, and does not vibrate any more than any other 4 cylinder diesel I've dealt with.

Any help would be great.

-AC

The balance shaft should spin smoothly and effortlessly. They do seize, and it sounds like that's what's happened to yours. Repairing it probably isn't worth the hassle.

That's what I figured. It's been running fine as is, so I'll continue the job with one belt, sans balance shafts

Had the tensioner on my balance belt break and shoot bearings all inside the timing cover which caused my timing belt to jump a tooth. I managed to pull the front of the engine apart, clean out the bearings and re-time the engine while on the road. I've driven nearly 700 miles since the issue with no balance belt, but it has me worried...

What is the risk of running without it?

How has your experience been without a balance belt?

Thanks!

Myself, I notice zero issues running without the balance belt. The belt had been broken in the timing case before I had purchased the van (unknown until I did the timing belt), and I've had no uneasy feelings with the vibration encountered. Long term, I'm not certain, but for normal operation I feel that it's safe to run without it and it's one less item to fail and cause worse (catastrophic) damage.

AC's right. The balance shafts simply make the engine run smoother. Plenty of people run their Astron engines without the balance shafts (there's even a balance shaft delete kit) without issues.

Some people can feel the difference, others can't. I haven't done a back-to-back test, but I swear my engine runs smoother now it has a balance belt (it didn't when I first got it).

On teh internets there's a rumour that the lower balance shaft drives the piston oil squirters. This is incorrect. The balance shaft gearbox on the back of the oil pump is lubricated from the same gallery that feeds the oil squirters, but the oil squirters get the same amount of oil whether that gearbox is spinning or not. (I think people see the gearbox and presume it's some kind of auxiliary oil pump. It's built into the oil pump housing, after all. But it's not a pump.)

Thanks for the replies and making me feel a bit more comfortable with how the van is running.