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Balance shaft machining
http://www.4g61t.org/forum/viewtopic.php?f=22&t=33829		 Page 1 of 1
Author:  DarkHorse [ Tue Nov 23, 2010 10:29 pm ]
Post subject:  Balance shaft machining
Hey guys, I am finally getting around to working on the Mirage, and I am at the point of rebuilding the 6-bolt That I got. I have never been this far into a 4g before so I am a little out of my element. The last 63T-CSM I had was just a Craigslist 7-bolt and a donor turbo car, dumped into a GL... THis one I am trying to do thoroughly correct. I have a balance shaft removal kit but I am having a hard time figuring out how to knock out the bearing/knock a new one in. I, of course, have the VFAQ... but its less than clear so I was hoping for a few tips on how you guys did it.

The actual question I have is about the other balance shaft. I was wondering if it is usually messed with at all? I know AMS sells a "race balance shaft" but I dont know which one it replaces. I have a frined who is atalented machinist and I could get him to cut the shaft down, but I wanted to get your opinions first.

Thanks, for your time and patience I will pay you with this little bit of joy;


Image


~joe
Author:  CSM Shaun [ Wed Nov 24, 2010 8:47 am ]
Post subject:  Re: Balance shaft machining
I use large sockets on long extensions to knock the old bearings and push the new bearings into place.

I usually do not bother with purchasing a balance shaft delete kit as everything you need is already present on the car/engine. I simply press the bearings out, turn them to cover the oiling holes, then press them back in. For the stub shaft I cut the balance shaft, tap the oiling hole that runs down the center of it, then stick a bolt in the new threads and glue it in place with JB weld. If you have access to a welder you could just weld the oiling hole shut. To cover up the hole in the front cover where the seal for the end of the balance sat I use a freeze plug held in place with JB weld.

I would definitely remove both balance shafts rather than leaving one in the block that is essentially dead and not spinning.
Author:  LILEVO [ Wed Nov 24, 2010 4:45 pm ]
Post subject:  Re: Balance shaft machining
Image
Author:  89Mirageman [ Wed Nov 24, 2010 9:54 pm ]
Post subject:  Re: Balance shaft machining
I just flip the balance shaft around and use it as the tool to tap the bearings in/out with. If you buy the BSE kit use the oem part #'s found in the VFAQ, some of the ebay kits come with a stub shaft with no groove for oil so be sure to get oem mitsu parts.
Author:  CSM Shaun [ Fri Nov 26, 2010 10:48 pm ]
Post subject:  Re: Balance shaft machining
The pic that LILEVO provided would lighten the balance shaft and pretty much remove the "balancing" affect on the engine BUT it also allows the bearing to fail and ruin the rest of your engine. If someone is going to machine a balance shaft down to that then they really should just remove it and never have to worry about a balance shaft killing an engine ever again.

Of the four 4g63's I have destroyed three were due to balance shaft issues and one snapped the T-Belt....
Author:  whe3ls [ Thu Dec 16, 2010 2:41 am ]
Post subject:  Re: Balance shaft machining
the reason you machine the shaft down like that, is at high rpm the belt starts to deflect and more stress is put on the oil pump pulley and the gears start to dig in the case, with the stub shaft
Author:  CSM Shaun [ Thu Dec 16, 2010 2:59 am ]
Post subject:  Re: Balance shaft machining
How high of RPM? Are we talking factory rev limiter RPM or beyond?
Author:  whe3ls [ Thu Dec 16, 2010 8:19 pm ]
Post subject:  Re: Balance shaft machining
ive read people having issues at 5k all the way up 9k
Author:  CSM Shaun [ Thu Dec 16, 2010 8:27 pm ]
Post subject:  Re: Balance shaft machining
Wow. I have never had that problem myself. I am sure luck has a factor in that...
Author:  whe3ls [ Fri Dec 17, 2010 9:36 am ]
Post subject:  Re: Balance shaft machining
also big cams and stiff springs also play a part in it too.
Author:  biglady112 [ Fri Dec 17, 2010 1:54 pm ]
Post subject:  Re: Balance shaft machining
We are generally talking 9000rpm and more for the oil pumps to eat themselves.
Author:  CSM Shaun [ Fri Dec 17, 2010 8:34 pm ]
Post subject:  Re: Balance shaft machining
Quote:
We are generally talking 9000rpm and more for the oil pumps to eat themselves.
That is what I had in mind. I have never built an engine that needed to rev that high. The current engine, however, will have a much higher power band...
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