Im building my motor and cant find a how to eliminate the balance shafts. I searched and only found info on kits.

 

I just did this with the engine in the car. Basically you remove the rear one, knock out the bearings and install new ones to block the oil holes. Then use a freeze out plug to plug the hole. The front one needs either a stubby shaft which is included in the kit or a turned down full shaft. AMS will charge you about $300 for kit that included turned down shaft. A local machine shop will charge you about $40 to turn down the shaft. Best bet is to buy a kit from RRE. I would howeve ditch the stubby shaft and have yours turned down and reinstalled. It provides better support for the oil pump this way. I have seen 2 Evo's lately with destroyed oil pumps. Both were using a stubby shaft. It worked fine on the DSM's, but it may casuse a problem when run hard on an Evo. Both cars see a lot of time racing and both make 600 + WHP.

BTW. This is not a fun job with the engine in the car. There are how to's on ClubDSM. Good luck.

 

don’t worry about turning down the shaft. We have ran them both ways with success and on the other hand seen them both fail. Less parts = less things to brake

 

im building a spare shortblock. This is my first time doing this and I have a couple other questions. which one is the rear and front shaft and what do you mean turn down?

 

The back one is the one that has it's own belt/gear drive that you can see behind the timming belt. The foward one is bolted to one of the oil pump gears, and is not externaly accesable. You have to pull the oil pump to get it. Turnning the shaft is having the counterweight lathed off of the shaft so that shaft is neutral and balanced.

 

It is a good idea to take these things out if you plan on reving the car high. I have seen a few cars break the balance shaft belt which then takes out the timing belt and then things start to break. As gr8evo said, it's just one less thing to break. I am always looking to minimize the weak links and this is one of them. There are a few ways to do this. Some people leave the belt driven rear shaft in place, lock it down and cap it. I prefer to get it out completly, but that is your choice. If the engine is out of the car, it is a no brainer to take it out. No mater what way you go, you are going to have to order a kit to get the bearings and the cap. It is up to you if you use the stubby shaft, but, I would not. A local machine shop can take the weights off and and you are good to go and the oil pump will be supported as it was originally. I am also guessing that doing it this way it will reduce the excessive oil pressure that this mod tends to create. You will need to make a tool to knock out the bearings w/o damaging the journals. Sometimes a big socket works, but I ended up making a tool with some pipe.

 

With the engine out of the car, this mod is cake. I too did it the hard way and did it with the engine still in the car, and it took quite a while as I had to fabricate a tool to ge the bearings out. Mitsubishi had a special tool for this but had discontinued it and was in teh process of replacing it with another one. Don't know if that tool ever came out.

 

The spare block I have has the balance shafts eliminated and one of the holes are capped off already (back one?) If I get the shaft I have turned what do I need to do to get it to work? Do I put it back in the block with the gear and leave it like that?

 

No. All you need to do is put that shaft back on. The gear is no longer necessary as it won't be driving anything without the belt.

 

You have to remove the front cover to do this project, which is a pain to do in the car. With some DSMs, you also have to tilt the motor to give enough clearance to pull the shaft out of the motor. Much easier to do with the motor out of the car.

Even with the motor out of the car, this is not quite as easy a process to do properly as some would suggest. With the engine out of the car, there are two bearings to remove. The one closest to the outside of the motor is the first; the second is about 8-10" deep into the middle of the block. On a DSM you can turn the balance shaft around and use it to knock out the second one, but a journal bearing must be reinstalled 180 degrees rotated, so as to block off the oil hole that lubricated the shaft while it was in there. That takes a bit of work, and the best way to reinstall it without damaging anything requires a tool that pulls the bearing back in like a V-8 cam installation tool. If you don't get it installed properly, you'll lose ALOT of oil pressure. Unless you have very small hands, the crank needs to be out for this job to be pleasant.

The other balance shaft is attached to the back of the oil pump and is internally lubricated. Some people believe that the back bearing of that shaft can provide additional stability to the rear of the oil pump, and so they turn the eccentric weights off of the shaft and thus leave it a straight round bar. Others use the stubby shaft -- there are two kinds -- and the one with the factory groove is the preferred one.

Enjoy

 

You can get a factory Mitsu stubby shaft. I'm not 100% sure, but I believe it is from the 1.6L Mirage motor.

 

i'll post pics of what I have so far shortly

 

here's the plug in the back shaft hole



Here's the shaft in the front cover how much of it has to come off?

 

bump

 

Bring that shaft to a machine shop and have them turn it down. It is cheap to have done and I doubt anyone would argue that a stubby shaft is better than a full shaft supporting the oil pump. AMS suggests and runs a turned down shaft in all of their high HP cars. They also sell one, but it is really expensive and you can easily have it done at a local machine shop.