balance shafts on a 600 horse power motor??

[drfinest1809]

heres my issue, my motor is geting assembled at a shop and the shop owner wants to install the balance shafts on the motor. he says that if i dont install them that eventually my oil pump will go out. they did dyno a gst that they built them selfs with a shaved down balance shaft, and with a gt42 it dyno 954 to the wheels. so i guess i want to no has any body used balance shafts on their high horse power, or dose any one no some one who has them.

 

[viperlp01]

Well with a ground down balance shaft only on the oil pump is technically a way to eliminate balance shafts. That is like AMS race shaft is sort of designed around that type of shaft. You will not have a balance shaft on the front of the engine anymore that is driven off its own belt. That is the main issue with balance shafts is that belt breaking and causing havoc.

 

[blackrosenova40]

Also the fact they spin twice the engine speed so if you redline at 9000, they are spinning at 18,000 rpm which seems to me would be really easy to spin a balance shaft bearing.

 

[TSIfreek]

As long as you use the OEM stub shaft in place of the balance shaft you will be fine. We have been building motors like this for years with out problems. Make sure who is doing your motor to have them turn the balance shaft bearings to block the oil ports in the block.

The shaved down rear shaft is also another option as this also deletes the front balance shaft that causes the problems.
Personally I dont see the need for the race shaft supporting the oil pump gear any more than the stub shaft. Using the race shaft adds the use of 1 balance shaft bearing that could fail.
90% of the rebuilt 4g63 race motors you see run just the stub shaft.

Also the fact they spin twice the engine speed so if you redline at 9000, they are spinning at 18,000 rpm which seems to me would be really easy to spin a balance shaft bearing.

Very true

 

[habitatguy187]

The only real problem with having balance shafts is the risk of the belt breaking and taking out your t-belt, but if you do regular maintenance you shouldn't have a problem with them. I will never remove balance shafts from any dsm I ever own.

 

[spydergotboost]

I say this you cant argue with a proven fact of eliminating the balance shafts it is Tried and Proven True. several hundred times over.

 

[habitatguy187]

TunaTalon kills this thread.


http://www.dsmtuners.com/forums/newbie-forum/336296-balance-shafts-no-balance-shafts.html

 

[JusMX141]

Use the OEM stub shaft, a new OEM front case, and the '90 straight-cut gears for high-revving applications. I've yet to see one of these setups fail.

Do not use a TopLine front case!

 

[cookmeup272]

I just had this overhaul done on my talon. New OEM case, BSEK, Crank/Rod bearings, Timing belt/tensioner/pulleys and a whole bunch of miscellaneous crap. Do the Balance Shafts. You will be happy later on.

 

[TunaTalon]

Using the race shaft adds the use of 1 balance shaft bearing that could fail.

90% of the rebuilt 4g63 race motors you see run just the stub shaft.

Balance shaft bearings are heavily loaded by the eccentric weights on the shaft. If the shaft is turned down there will be much less loading on the bearings. They could still fail but less likely than with the OE shafts.

The only real problem with having balance shafts is the risk of the belt breaking and taking out your t-belt, but if you do regular maintenance you shouldn't have a problem with them. I will never remove balance shafts from any dsm I ever own.

The balance shaft belt will fail when the balance shaft bearing seizes. Changing the belt will not stop the bearings from failing. If you keep the balance shafts then replace their bearings on every rebuild. My Talon's balance shaft bearings were near end of life at 183,000 miles while the main and rod bearings were like new.


I kept the balance shafts on my Talon but then I'm and old phart who thinks all engine vibration is bad.

For what it's worth, after way too much surfing about balance shafts and the Mitsubishi factory racing program I found that the 4G63 Dakar race engines had their balance shafts removed. Bah I said; vibration bad, torque good.

 

[DSMunknown]

For whoever this offends, I don't give a sh** - I side with Maurice on this one.

 

[donniekak]

Balance shaft bearings are heavily loaded by the eccentric weights on the shaft. If the shaft is turned down there will be much less loading on the bearings. They could still fail but less likely than with the OE shafts.

This. Picture cutting half of the counterweights off of your crank, then spinning it at 18,000 rpm's. This is very hard on bearings. You are spinning a shaft at high speeds, that is as off balance as possible, by design. The #1 cause of spun rod bearings in stock engines, is contamination of the oil from worn balance shaft bearings.

 

[jrohner]

The only real problem with having balance shafts is the risk of the belt breaking and taking out your t-belt, but if you do regular maintenance you shouldn't have a problem with them. I will never remove balance shafts from any dsm I ever own.

The other issue is the balance shaft bearings going out, sending parts out the side of the block. On a well-maintained car, that's the issue, not the belt. I wouldn't run balance shafts because of this issue, not because of the belt issue (although that IS a very common problem).