Timing and Balance Belt

Haileybut

Haileybut

Member
Getting ready to order a timing belt and balance belt from Delica USA. I've been reading that some people are deleting the balance belt cause it could fail and take out the timing belt. Has anyone done or heard of this? Very new to these vans. Also, this is the first car I've ever worked on. I found a diesel mechanic thats going to teach me how to install.

Thanks in advance,
Haileybut
 
If the balance belt is in good condition there is no reason for it to be prone to failure... It's not required as such, but I wouldn't delete it.
 
If the Balance shaft belt breaks it can cause your timing belt to break!! Belts should be changed including water pump and seals while its apart.
Belt and kits are the same as the mid 80s mightymax and dodge D50 2.3L diesels. FYI
 
Update: I replaced all the belts Saturday March 31st. Had a diesel mechanic do the timing and balance belt to make sure all the notches were lined up. Took it on a road test, and the balance belt jumped off. He tore it down and put it back on, yet it jump again. We removed the balance belt, and I've been driving with out it for just over two weeks. Not sure if there was a flaw in the new one or what. The only thing I've noticed is the engine is a lot noisier. Not terrible, but definitely can tell the difference. Still not sure if I should order another one or just run without it. I like the way it runs with the balance belt, but worried it will jump again and take out my timing belt.

Any Thoughts, and is anyone running with out the balance belt? Last time it was changed was 3/28/201


Thanks all,
Haileybut
 
Bump... Any new thoughts here? I'm guessing that this is the noise I'm hearing about 2500rpm or so on accel/decel. Thought it might be big end rod knock, but typically you'd hear that at lower rpms...
 
You can run without the balance belt, it won't cause any harm, it just makes the engine that much noisier. I think the balance belt has a reputation for failing because sometimes people are cheap/lazy and don't replace both belts. I've seen a couple of 4D56 engines now with new timing belts and very old balance belts.

The balance belt shouldn't jump off if installed as per the engine service workshop manual. The tensioner has a spring on it to set the initial tension, it kind of looks like the tensioner should be left loose so the spring does the work, but that's incorrect. Once the belt is in place and you've checked the tensions you need to tighten the lock bolt to stop the tensioner moving. You also need to tighten the tensioner bolt and nut in the correct order or it messes everything up.


iliketowalk said:
Bump... Any new thoughts here? I'm guessing that this is the noise I'm hearing about 2500rpm or so on accel/decel. Thought it might be big end rod knock, but typically you'd hear that at lower rpms...
Click to expand...

Balance belt failure is hard to spot, there aren't any particular harmonics that stand out just a general engine coarseness. If you suspect balance belt failure you should immediately remove the top timing belt cover and check that the balance belt is still in place (you'll need a flashlight). Sometimes they break and just lay there doing nothing, waiting until you're in the middle of nowhere to jump out and break the main timing belt.
 
Thanks for the epic reply!

I should have been more clear, I don't think my belt has failed, I'm guessing that it was left off when the timing belt was last done and that may explain the noise I'm hearing. (The van is new to me)

Will pull the timing cover and report back if belt is MIA.

Coarseness is a good way to describe what I'm hearing...
 
Haileybut said:
Update: I replaced all the belts Saturday March 31st. Had a diesel mechanic do the timing and balance belt to make sure all the notches were lined up. Took it on a road test, and the balance belt jumped off.
Click to expand...

Another thought- the timing belts changed after April 1993. You might have received the wrong belts- but DelicaUSA is usually pretty good. You can check the belt part numbers specific to your Delica by putting the chassis number into https://mitsubishi.epc-data.com/ but as a general guide:

Pre-04/1993 engines: Balance MD363481, Timing MD197153
Post-04/1993 engines: Balance MD310484, Timing MD306981

(If your Delica is a 1993 then you need to check the chassis number for sure).
 
iliketowalk said:
Thanks for the epic reply!
I should have been more clear, I don't think my belt has failed, I'm guessing that it was left off when the timing belt was last done and that may explain the noise I'm hearing. (The van is new to me)
Will pull the timing cover and report back if belt is MIA.
Coarseness is a good way to describe what I'm hearing...
Click to expand...
More thoughts: If the noise only shows up when accelerating or decelerating (not when cruising) check out the engine and gearbox mounts, it could be the drivetrain shifting around under load. Also try checking/greasing the rear driveshaft universal and centre sliding joints- a bad universal joint can make all sorts of weird vibrations, and if it lets go the driveshaft will tear the belly out of the rear fuel tank. Not fun.
 
I've been meaning to find out whether or not the engine loses more energy to vibration without the balance shafts turning or to friction loss due to them turning. (It might seem counterintuitive for an engine to lose energy just by vibration but that's exactly what happens; kinetic energy is lost in the form of vibration conducted into the chassis (and a miniscule part to air) that would otherwise remain within the reciprocating and rotating masses in the engine). If the balance shafts are operating, the forces between pistons/rods and the balance shafts couple and cancel and there is now no second order vibration in the form of vertical vibration of the engine. This would be easiest to test on an engine dynamometer in the form a fuel efficiency test.
 
I know this is an older thread. I'm a new guy here. I have a 4d55 that I swapped into my Mazda b2600i. I have learned a bit about balance shafts in my time with that motor.

You can run without it. It may work.

The thing is, the lower balance shaft that runs through the oil pump actually runs an auxiliary oil pump that pushes oil to the squirters on the bottom of the pistons. This is essential for thermal protection of the motor.

I'm sure you've gotten whatever taken care of by now.
But I wanted to make sure that the info about the true function of the lower balance shaft was out there.

You may not feel significant vibrations. But your pistons will see excess heat.
 
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