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Re: Balance Chain Question Posted by Gene N [Email] (#1094) [Profile/Gallery] (more from Gene N) on Mon, 31 Aug 2009 06:11:26 In Reply to: Re: Balance Chain Question, T. Christopher, Sun, 30 Aug 2009 17:21:06 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Let's start with some basics.
1. There are 4 sprockets in the balance shaft system and they all have the same tooth size to correctly mesh with the balance shaft chain.
2. One sprocket is on the crank and drives the system.
3. One sprocket is high on the intake side balance shaft (upper left).
4. One sprocket is low on the exhaust side balance shaft (lower right).
5. The last sprocket is on the idler shaft and is above and to the right of the exhaust side balance shaft.
6. The idler spins freely, with the chain off, and has some axial play (in and out).
7. The two balance shafts turn with chain off but not freely because they sit in lubricated sleeves in the block, not ball bearings like the idler.
8. The balance shafts spin at twice the speed of the crank shaft, and to be effective, they need to be specifically synchronized to the crank position.
OK, with that out of the way, is there any chance you are confusing the idler sprocket with exhaust balance shaft sprocket. The idler sprocket is more or less at the same height as the intake sprocket.
Could you post a picture of your engine, especially the of the sprockets?
There is a specific procedure for aligning the balance shafts. Set the crankshaft at TDC. Use the piston position, the flywheel, the camshaft marks, or temporarily put the timing cover and harmonic balancer (crank pulley) back on to do this. Rotate the two balance shafts until the mark on their sprockets are aligned with the lines on the plates that hold the balance shafts in the block. Put the balance shaft chain around the crank sprocket, then the intake sprocket, the idler, then the exhaust sprocket. The tensioner should be out for this to work. If you can't get the chain on, take the idler off of its shaft, mesh it with the chain, then put it back on the shaft. All the marks should line up at that point. Replace the tensioner and rotate the crankshaft one or two revolutions to see if the marks still line up.
That's it!
posted by 132.228.195...
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