engine break in and balance shaft questions - Toyota Nation Forum : Toyota Car and Truck Forums

bennington28 · 12-06-2003, 09:34 AM

I had an 2.2l camry engine installed and the camry would not start on the initial start up. I took it to a shop and they said the cam timing was off a bit. They reinstalled the cams and the car started. The problem is the idle is rough and there is a slight knock coming from the bottom end. They seem to think that the idle is rough because some valves may be haging open and the valve lash may be off a bit. They suggest that I take car of that.

Do if I need to "reinstall" the balance shaft and realign it to the "new/correct engine timing". What is the purpose of the balance shaft? Would a balance shaft that is installed incorrectly(not set to TDC) cause a car to knock? The lower end was rebuilt, so I cannot see what else would cause bottom end knocking on a newer engine.

Whatever the problem is , I am going to fix it because I am not spending another "$450"

Flashmn · 12-06-2003, 09:56 AM

I think you should of overhauled that engine to begin with, it could literally be anything. But as far a I know, the balance shafts are gear driven so you wouldnt have to align them unless you took out the crank.

bennington28 · 12-06-2003, 10:14 AM

I stripped the engine of everything and had a shop rebuild the whole damn thing( they removed the crank, put in rods, rings, etc. rebuilt the head). I got the head and block back with the innards installed. I put it back together- including reinstall the balance shaft.

I am sure that cars run rough for a while after the initial start up. Hopefully this is the case. I feel like driving this "project car" into a river.

Flashmn · 12-06-2003, 10:56 AM

Well they shouldnt run really rough after the first start. You sure you got everything aligned correctly inside the engine when you put it together, I mean it could be that the balance shafts are off by a tooth and causing this problem. Hmm. howbout the valves? the valve clearance is within specs?

alltrac165 · 12-06-2003, 12:19 PM

Sounds like you need to call the shop that did the rebuild and see what they have to say. If they put it together wrong, they should fix it. Verify that it's not anything you or the installer(if it wasn't the same shop installing that did the rebuild) did wrong first, of course.

jd1990 · 03-28-2011, 09:04 PM

The balance shaft shouldn't be out of allignment if it was it would be locked up. I work at otics USA and build the shafts and housing for Toyota if it was out of alignment it would fault a machine out so it can't be that. As far rebuilding it that would be tough cause the gears come from otics Japan and are pressed on by machine once you remove and old gear the shaft is bad. You can by the whole assembly from an auto parts store though. As far as your knocking though its not the balancer. You can go to oticsusa.com and see the old AZ balancer they haven't updated the new ar balancer though. Good luck on your problem.

crash81 · 05-11-2012, 06:31 PM

bennington28, hello. I am not sure if you have solved your problem or not but I own a 1997 Toyota Camry and I have done a complete overhaul to my car. It is my experience that the lower end knocking is a result of the engine balancer or commonly called balance shaft( located in the oil pan attached to the lower portion of the engine) is the cause of this knocking sound. Here's why I say that, When I started the car the first time after rebuild, also I to had someone rework the heads but I did everything else, including replacing the balance shaft unit as a whole, and ordered new shims as well after furture inspection I desided the balance shaft was not sounding so good so I pulled the balancer off the car and the sound was gone when I started my car. Bearings and little crank type shaft are inside, bearing can wear out. The point I am getting at is when I removed it the knocking was completely gone quiet as any new car. With the proper adjusting spacers or shims you can get spacer to small and get a whinning or to loose and get a knocking sound. Look up Balance shaft under wikipeddia to get a detailed explanation of this device they were first invented and patented by British engineer Frederick Lanchester in 1904. You might try removing it but I would not recommend normal usage without it in place, just to see if the knowing has stopped. Worn out balancer or shims may be a issue as well. This is not the spoken word just something I experience and wanted to share it with you. Note getting the shims right are not as easy as it sounds it does space the gear in the balancer to the crank gear so it is hard to know just the right shim.
Good luck.