Hey all, New to the forums. I have been lingering around here for a couple of weeks since I got my 2006 Colorado. I got the truck for little to nothing with 344k miles, one owner still running. I noticed before I bought it that it had a pretty noticeable tick but the guy assured me that it had been there for the last 50k miles, figured it was just a lifter. It also had two engine codes, one related to vacuum being to low, and one related to timing. Fixed the vacuum issue, the airbox between the throttle body and MAF had a bad leak. The more I drove it the more it seemed to loose power until one day I almost didn't get home. I could barely get it to 35MPH. I figured it was time to just rebuild it or swap in a LS. I found a good deal on a rebuild kit so I tore into the motor and HOLY CRAP THE CARBON BUILD UP! Other than that though wow the inside the engine was still in spec, bearings all looked pretty good, except the balance shaft bearings. They looked horrible. I took the block to a machine shop cause I didn't see any way to get them out with the tools I have other than knocking them into the block then bending them up to get them out "Exactly what the engine shop did". He got them out but had a hell of a time finding a tool to put them in, So I made him a bushing which didn't end up working. The bearings got messed up trying to put them in and the shafts would not spin freely, not to mention the bushing would not allow him to even get them in far enough to even get good oil flow. I pumped oil through the block and got a trickle out of one bearing and the other was not getting any. This is where the fun part came in. I took my knowledge as a machinist and a mechanic and deleted them. Everyone on the forum said you cant do it, even though almost every inline I have worked on from Honda's to Ecotec's we always deleted them on high RPM builds. Misconception about balance shafts is they balance the engine which they do not, The create a negative balance to compensate for the slow and speed up of the crank/pistons during combustion. Its all for comfort of the driver, this being a old truck I just want to use as a truck, I was not expecting a Cadillac so I went through with it.
First of all, engine obviously has two, there is a larger diameter one that spins the same was as the engine, and a smaller one that spins the opposite direction. The larger one was easy to delete as it only gets oil from one spot in the block and feeds the back bearings through a hole in the shaft. For that all I did was pull the retainer plate/bearing piece off the shaft and make a replica without oil holes that was a very snug tap in fit, bolted it in and done. The smaller side was a little more difficult as it gets oil from all the bearings, I guess it was an after thought when they designed the engine and the oil galley was only on one side of the block. So for this side, the balance shaft had a metal plate with a set screw holding the front bearing for the shaft. I removed the plate and made a shaft about 11 inches long that was a very snug tap in into all the different size journals. No chain, No moving shafts. I just got the truck back together and have been driving it maybe a week and it runs great, The ride quality honestly has not even changed. The engine idle is high enough it does not really make a difference. The only time I notice a difference is if I almost stall it or I drop then engine speed down below idle. High RPMs no difference.
I wanted to make this post to let everyone know it can be done. All my research lead to it cant be done, and I have yet to find someone that has done it. To me they are just a hassle to deal with when rebuilding. I have worked on a lot of engines, and this engine by far has a ton of design flaws. Those balancer bearings being the top.
First of all, engine obviously has two, there is a larger diameter one that spins the same was as the engine, and a smaller one that spins the opposite direction. The larger one was easy to delete as it only gets oil from one spot in the block and feeds the back bearings through a hole in the shaft. For that all I did was pull the retainer plate/bearing piece off the shaft and make a replica without oil holes that was a very snug tap in fit, bolted it in and done. The smaller side was a little more difficult as it gets oil from all the bearings, I guess it was an after thought when they designed the engine and the oil galley was only on one side of the block. So for this side, the balance shaft had a metal plate with a set screw holding the front bearing for the shaft. I removed the plate and made a shaft about 11 inches long that was a very snug tap in into all the different size journals. No chain, No moving shafts. I just got the truck back together and have been driving it maybe a week and it runs great, The ride quality honestly has not even changed. The engine idle is high enough it does not really make a difference. The only time I notice a difference is if I almost stall it or I drop then engine speed down below idle. High RPMs no difference.
I wanted to make this post to let everyone know it can be done. All my research lead to it cant be done, and I have yet to find someone that has done it. To me they are just a hassle to deal with when rebuilding. I have worked on a lot of engines, and this engine by far has a ton of design flaws. Those balancer bearings being the top.
