Balance shaft stuck after oil pump install??
Sep 15, 2010, 08:06 AM
#1
Balance shaft stuck after oil pump install??
I'm a bit confused here. And I'm trying to find any answers as to why and how this could happen. The first thing I noticed upon taking the timing belt covers off is that the belt tentioner (the pulley not the hydraulic tensioner) was turned upward, so the two holes were on top of the bolt for the belt tentioner. I thought that was a little wierd since I've never seen it in that position before, but I don't know if that's relavent here. I removed the oil pump gear using the old timing to stop it from moving. (didn't over tighten the belt for support, just left it as it was) I also used the old balance shaft belt to remove the gear off the rear balance shaft. Upon removal of the oil pump and shafts, I noticed some dark blue and what seemed to be heat marks on the front balance shaft.
For the installation of the front balance shaft, I used a cresent wrench on one of the weights to hold it as I torqued the bolt of the driven gear to 27lbs. Here is where I put the new oil pump on, then tightened the rear balance shaft using the old balance shaft belt again. The front balance shaft spins just fine along the bearing, but when I bolted down the oil pump, the front balance shaft won't move, but the rear one still spins fine!
So I looked around for any type of obstruction around the front balance shaft, but I can't find anything. I then re-loosened the bolts for the oil pump and it spins like it should. I took the front balance shaft out and looked up; the bearing is all scraped along the center in a full circle. How did this happen? Has this happened to anyone before? Did i do something wrong? Thanks for any help.
Sep 17, 2010, 06:04 PM
#6
I see what you mean. Thanks, but this is a brand new pump that comes pre-assemled from the factory, and was untouched until I found that it was sticking. I only opened the oil pump to be sure that the gears were on timing, but it still locked up even after re-assembly.
Sep 17, 2010, 07:35 PM
#7
Did you install the balance shaft into the driven gear? I know no oil pumps come with the balance shafts installed from the factory. If you have the front case off you should just eliminate the balance shafts. It is better and since you are having an issue with the shafts it is more likely they are going to fail. Post a pic of the pump assembly.
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Sep 18, 2010, 01:45 PM
#8
Did you install the balance shaft into the driven gear? I know no oil pumps come with the balance shafts installed from the factory. If you have the front case off you should just eliminate the balance shafts. It is better and since you are having an issue with the shafts it is more likely they are going to fail. Post a pic of the pump assembly.
OK. This is the back side and front side of the oil pump respectively. You see how you can't accidentally flip the driven gear because its inside the pump. Even if I did eliminate the balance shafts, I don't have a tool to remove the balance shaft bearings. So, the balance shafts have to go back in.
Last edited by D-VO; Sep 18, 2010 at 01:54 PM.
Sep 19, 2010, 06:13 PM
#10
The damaged bearing part was the in the original post. The "But why?" part is the question. Is this a common problem? I can't find any information on this. The bearing looked pretty messed up, and I can't imagine that I did it. Iss there any way to remove and replace the bearing without purchasing the special tool(or spending any money).
Sep 19, 2010, 08:02 PM
#11
If you use the balance shaft that is not run by the oil pump turned around you can pound out the bearing then put in a new block off bearing also using the BS as a driver. It is MUCH easier than trying to install them again with the oil hole lined up perfectly without damaging a new BS bearing. I would NEVER build a motor using balance shafts and I certainly wouldnt spend time fixing them when removal is cheaper, easier and better. Good Luck!
Sep 19, 2010, 10:30 PM
#12
OK. Thanks for the help man. I'd love to take them out, but the guy doesn't want to. Also, I won't be able to get the rear balance shaft bearings out because the engine is still in car, so I have no space. I have them deleted in my car as well, but my engine is balanced.
Sep 19, 2010, 10:47 PM
#13
if you can't fix the problem with the engine in the car, obviously it will have to come out. Tell your client that. If he/she wants to pay for that, then so be it. If not, there is nothing wrong with a stubby shaft.
Sep 20, 2010, 04:23 AM
#14
The balance shafts come out with the engine in the car. You just have to lower it by removing the front and side engine mounts while using a hoist or fender horse to hold the engine then lower it to the proper height to get it out. The replacement of the bearings in order to use the B/S is much harder to do right in the car than out so it would save a lot of time and money to remove them. If he want to keep the shafts you would need the tool to install the bearings correctly and you would most likely need to pull the motor. Good luck with the situation as it is a tough one.
Sep 20, 2010, 04:56 AM
#15
If you use the balance shaft that is not run by the oil pump turned around you can pound out the bearing then put in a new block off bearing also using the BS as a driver. It is MUCH easier than trying to install them again with the oil hole lined up perfectly without damaging a new BS bearing. I would NEVER build a motor using balance shafts and I certainly wouldnt spend time fixing them when removal is cheaper, easier and better. Good Luck!
as been discussed many many times, it doesn't matter if your rotating assembly is balanced or not, the engine produces vibration by design. the balance shafts dont eliminate the vibration, they just mask it.
if you can't fix the problem with the engine in the car, obviously it will have to come out. Tell your client that. If he/she wants to pay for that, then so be it. If not, there is nothing wrong with a stubby shaft.
if you can't fix the problem with the engine in the car, obviously it will have to come out. Tell your client that. If he/she wants to pay for that, then so be it. If not, there is nothing wrong with a stubby shaft.
I agree with both of these posters. The balance shaft is not a necessary component in an interference engine like the 4G63. Our cars are going to transmit vibrations by design, it is just a fact of life. The balance shaft is just there to hide these vibrations and noises by rotating themselves in opposite directions, and MMNA wanted to do this to make the Evo a little more tolerable on the street. Who knows if it was mandated from the US or if it is just a common practice (it is on most inline 4-cylinders).
I would tell the client (or whomevers car it is) that rebuilding it to work correctly with the balance shafts will not only cost a little more, but it will also cost them some power in the process. Most people who remove them can barely tell the difference anyways, I have even read of some removing them on a stock motor with unchecked balance on the internals.
Good luck
