Balance Shaft Elimination Questions
 

I have purchased the GSC Race Balance Shaft for my Evo 8 and I have a few questions about installing it. I have watched these videos already: and
I am going to take my block to a machine shop and have my old bearings removed and the new ones pressed in. I want them to press all three new ones in, but do I want them to simply press them all in in such a way that the oil flow holes will be covered by the bearings, as stated in the second video?

The third video has him opening the oil pump to install that stub, however, the GSC Race Shaft is a full shaft, so can I just bolt it in without opening the oil pump?

My last question is: do I still keep the other balance shaft with this delete?

Thank you!

The shaft in front of the block that's attached to the oil pump gear is fed oil from the shaft. The rear shaft is removed and the bearings are used to block the oil feeds so you don't lose a ton of oil pressure.

Awesome, thank you! Is there any way to completely combat the oil pressure drop?

You completely combat it by installing the rear bearings to block off the oil supply to the rear shaft.

Can a balance shaft delete be performed with the motor still in the bay?

Yeah, it's a lot of work though. If you're going to leave the motor in the car, I would only remove the front shaft (the oil pump driven one), then leave the rear shaft installed just don't install the belt so it doesn't spin.

I would agree with him. Also, by leaving it in there you won't have to deal with the increased oil pressure many deal with. The 4g63 already makes a ton of pressure and actually most would like to shoot for the 10psi per 1000rpm rule . This leaves more oil in the pan .

You guys consider the potential harmonic vibration damage incurred by deleting the shafts?
Im of the opinion, its better to leave them as designed by the Mitsu engineers

http://www.jackstransmissions.com/pa...balance-shafts

Its a controversial topic :beer:

That does not cause any issues in the multiple cars I've helped build.

The jacks article is a good one but anytime you go with aftermarket pistons/rods or crank the harmonics of the engine will change. This may lead to the balance shafts doing more harm then good and causing a BS front cover bearing issue or belt issue on the upper shaft.

Stock engine, keep them and do the maintenance and don't rev it to the moon.

Built, delete them using the method you prefer. Either way make sure the timing belt tension is correct or it can lead to premature oil pump failure .

The reason the balance shaft delete practice began wasn't because the balance shaft belt was likely to break (although that occasionally occurred), or because people were looking to eliminate a small horse power loss. It was because twenty five years ago the 4G63 liked to spin balance shaft bearings. Hear a noise, remove the pan and find a balance shaft bearing. If you owned a DSM back then you eventually would hear balance shaft buzz. When an engine was rebuilt, rather that risk that again, the balance shafts were removed. When was the last time you heard of an Evo 8 or 9 throwing a balance shaft bearing?

Two guys I know In the Vegas Evo community lost a b-shaft belt last year (2016), resulting in the timing belt falling part, causing catastrophic engine failure. One of them was at 175k miles and had all the parts and an appointment to do the 60k interval timing service. There was nothing wrong with the shaft or bearings on teardown. Losing the belt within the maintenance time frame is a real thing. I think they come loose. I retensioned my bshaft belt when it hit 25k miles, it was loose.

^^^ I agree with that. The balance shaft belt needs a tensioner just like the timing belt. Its one of the few remaining weak points of the design. Replacing both belts at 60K and going back in and resetting the bbelt tension 30K later I suggest is good practice.

I still prefer the belt driven design over some of the newer engines with chains where you have chain guides and tensioners powered by oil pressure that wear out and are all internal to the engine. Its like first having to tear the engine apart and then repairing a bicycle.

Based on your notes above, what is your opinion of Jacks article?

Thanks, Joe

http://www.jackstransmissions.com/pa...balance-shafts

Only some engines have issues with chains. And a lot of times it's due to consistently late oil changes. Nissan/Infiniti has an issue with this. The Evo X with the revised chain doesn't seem to have any problems.