Austarion

This article sums up fairly succinctly why i DO NOT believe balance shafts should be removed in 99% of 4g6 and 4g5 engines..


http://www.jackstransmissions.com/pages ... nce-shafts

Interesting reading.

The factory did put them in there for a reason. And they spend mountains of money to figure this stuff out.

Thank you for this rather unpleasant read and I wish I had not read this article but it makes perfect sense. Next time I have to pull my engine out for something I will use my other block with the balance shafts in it and then I will find out what the real difference in my car will be between having balance shafts in or out.

Yeah I was originally going to remove mine as well, but decided on leaving them as I have had an engine balance shaft belt snap once and it was really unpleasant. That and everything needs to be perfectly balanced and remain that way. Thanks for the awesome read. Good to know I made up my mind right :) :beer :beer :beer

The unpleasantness was because only one shaft was spinning, so they were unbalanced. Mine snapped one day too as I was gunning it onto a freeway....felt horrid but I managed to limp home.

what caused your BS belts to fail ? ....not changing the belt, tensioner or worn bearings and shaft begining to bind up ?

I've never eliminated balance shafts. The smoothness always amazed me.... part of the charm

When shopping for a spare, any mitsu motor (2.0/2.6sohc or 2.0dohc) I viewed that had no bs, I left it

Yeah only 1 of mine snapped. Was so bad. I think they snap because people don't service them when they do the timing belt.

I think mine was old. Retard who worked on the engine around when I bought it probably didn't change any belts when the head etc was done. One of the numerous things I found wrong and had to fix.

Another was wondering why the gearbox was starting to get hard to put into first gear not long after the work was done. Apparently reinstalling all the bellhousing to engine bolts wasn't on his list of things to do :glare:

Yeah every place I've worked we have replaced both belts at the same time like you are supposed to. I can't understand mechanics who don't...

Good read, but my crank trigger goes where the balance shaft gear used to be, so begone with it! Motor is never going to be a super higher performer anyway, so I doubt I'll strike any issues.

This article, funnily enough about removing the balance shafts, has the best explanation of how they actually work that I've come across.

http://www.4g63turbo.com/tech/eclipse-b ... moval.html

I'm not even close to being a guru on the topic of vibration and engine dynamics, but I don't think the last paragraph is accurate from that article ProZac posted.. althought the first two paragraphs make perfect sense.

Firstly it is stated that there is a "potent" lubrication problem.. why is this considered to be the case? If due to the shafts spinning at twice engine rpm, then that doesn't make sense, given that a turbo spinning at perhaps 10 times balance shaft rpm doesn't seem to have these lubrication dramas due to rpm?

Secondly, countering a wave at a 180 degree phase IS balancing (or perhaps more appropriately, cancelling) it out, so it's not "merely masking" the vibration as the last paragraph claims. Perhaps a sound engineer can shed more light on this, because sound is basically vibrations through a medium such as air or water or a speaker cone. Masking the vibrations is essentially the same as balancing them.

The good - More oil pressure to the rest of the motor

The bad- More oil pressure to the rest of the motor, which is usually too much. Extra work to get the oil pressure back in spec.

rofl

ProZac wrote:Good read, but my crank trigger goes where the balance shaft gear used to be, so begone with it! Motor is never going to be a super higher performer anyway, so I doubt I'll strike any issues.

Stockish motors are the ones most likely to benefit from leaving then in!