Balancer to Sensor Interference

M

MichBC3

Member
Joined
Aug 1, 2008
Here I am playing around again with aftermarket parts that don't seem to work together.

I have a BHJ balancer and a brand new Chinese crankshaft. When I put the balancer on and torqued the retaining bolt, the teeth on the sensor wheel are in too deep and are physically contacting the crankshaft position sensor. I can't even get the end of a paperclip in there. No clearance.

Does anybody sell a crankshaft shim to space out the balancer about 0.050" to 0.100"? An alternative solution might be to shave down the aluminum sensor mount to gain some tooth clearance.

Anybody else run into this? If so, what did you do?

Thanks.
 
MichBC3 said:
Here I am playing around again with aftermarket parts that don't seem to work together.

I have a BHJ balancer and a brand new Chinese crankshaft. When I put the balancer on and torqued the retaining bolt, the teeth on the sensor wheel are in too deep and are physically contacting the crankshaft position sensor. I can't even get the end of a paperclip in there. No clearance.

Does anybody sell a crankshaft shim to space out the balancer about 0.050" to 0.100"? An alternative solution might be to shave down the aluminum sensor mount to gain some tooth clearance.

Anybody else run into this? If so, what did you do?

Thanks.
Click to expand...
Ive ran into it and done both things you suggested. I like shimming since your not removing metal though.
 
MichBC3 said:
Here I am playing around again with aftermarket parts that don't seem to work together.

I have a BHJ balancer and a brand new Chinese crankshaft. When I put the balancer on and torqued the retaining bolt, the teeth on the sensor wheel are in too deep and are physically contacting the crankshaft position sensor. I can't even get the end of a paperclip in there. No clearance.

Does anybody sell a crankshaft shim to space out the balancer about 0.050" to 0.100"? An alternative solution might be to shave down the aluminum sensor mount to gain some tooth clearance.

Anybody else run into this? If so, what did you do?

Thanks.
Click to expand...


Take a grinder to the back of the crank sensor bracket. I had this problem a few weeks back.
 
Thanks for all the advice. I think that a shim would be best of course, but don't know where to get one.

So here's another approach. I took it to my local machine shop. First, we made sure that the wheel was pushed on to the balancer as far as it would go with a press. Didn't move. This also insured that the wheel was on there tight. Then we marked the wheel to hub position with a scribe. Then they very slowly, carefully took about 0.020" off the top of each "tooth" using a lathe. The key is to do this very slowly so as not to distort the tooth dimension or accidentally move the position of the wheel on the balancer hub. I reinstalled the balancer, checked sensor clearance and now should be good to go.

I kidded my machinist that he was a pretty good dentist - working on these sensor teeth. Hope this helps others.
 
MichBC3 said:
Thanks for all the advice. I think that a shim would be best of course, but don't know where to get one.

So here's another approach. I took it to my local machine shop. First, we made sure that the wheel was pushed on to the balancer as far as it would go with a press. Didn't move. This also insured that the wheel was on there tight. Then we marked the wheel to hub position with a scribe. Then they very slowly, carefully took about 0.020" off the top of each "tooth" using a lathe. The key is to do this very slowly so as not to distort the tooth dimension or accidentally move the position of the wheel on the balancer hub. I reinstalled the balancer, checked sensor clearance and now should be good to go.

I kidded my machinist that he was a pretty good dentist - working on these sensor teeth. Hope this helps others.
Click to expand...

LOL! Thats making a mountain out of a mole hill.
 
This may sound dumb but did you put the seal sheild back on the crank before you installed the cover? I remember someone else had this isssue and had forgotten to put it back on before he installed the cover.
 
Check the belt alingment before you go ant farther. If the balancer is in too far it will chew up the belt and can cause ignition related issues. I had a timing set once that had a thinner crank gear than normal. Fought ignition problems before i figured it out. If that's the case the best thing to do is have a shim made to space the balancer out.
 
I have milled .050-.060 off the crank sensor pedestal to provide adequate clearance.

Shimming the balancer out may cause pulley alignment problems and you may have belt noise/wear issues.

I never considered trimming the teeth on the balancer!! Good idea. I'll remember that for the future.
 
Ran into this a few times

steve hughes said:
Check the belt alingment before you go ant farther. If the balancer is in too far it will chew up the belt and can cause ignition related issues. I had a timing set once that had a thinner crank gear than normal. Fought ignition problems before i figured it out. If that's the case the best thing to do is have a shim made to space the balancer out.
Click to expand...

Steve is dead on--some crank gears are thinner than they should be. This seems to be cominy up a lot lately. Take an extra slinger--trim the cup part off with tin snips then using a grinder clean up the edges--presto you have a .045 shim that will go through the front seal. No need to remove cover. This will also put the balancer back in line with the other pulleys.
 
The problem with trimming the teeth on the reluctor is the crank sensor may not always see the opening in the windows when it needs to. This can cause a very hard to find intrmitant ignition miss. I'm speaking from experince here.
 
When I built my current Stage 2 engine, I was using a Buick Motorsports balancer with the trigger wheels. That balancer had two trigger wheels and sat too deep into the sensor. I needed to mill the sensor to provide clearance.

I switched over to a new BHJ balancer a few years back and that balancer did not have the same issue. I installed a new unmodified sensor bracket and alignment/clearance was correct.

Both balancers provided the correct spacing for the pulleys.....never had a belt alignment issue with either one.

I can see where trimming the trigger wheel could run into other issues, but if the wheel is buried in the sensor, you need to do something to provide clearance. As long as belt alignment is correct, I'd stick to milling the sensor pedestal, easy fix.
 
steve hughes said:
The problem with trimming the teeth on the reluctor is the crank sensor may not always see the opening in the windows when it needs to. This can cause a very hard to find intrmitant ignition miss. I'm speaking from experince here.
Click to expand...

Exactly!

Thats why trimming the teeth is not the best solution.
 
The best way to correct this is to shim the balancer out - which was my preference from the beginning. But nobody could direct me to a source for such a thing. After trimming the teeth on the reluctor I later indpendently thought of a way to make a shim by cutting up a slinger -which I saw later suggested in this thread. I'd definitely do that if I ever had a problem like this again.

No need to panic. I trimmed the teeth only 0.020". There is still plenty of window depth left. Now about belts. The offset of this balancer from where it should be to where it is is probably only 0.050". That's less than a tenth of an inch. That small change is not going to throw a belt on an engine that won't spin any faster than 6000 RPM.
 
Also worth mentioning is that one tooth was almost 0.020" taller than the other two. So I'm pretty confident that we did not remove too much metal. Thanks for all the great ideas though.
 
Wow. If your belt was sensitive to a constant 0.060" error (in or out), that absolutely amazes me. I found the serpentine belt system on this car to be quite robust and forgiving - and here is why: After I had my car for a few months, I noticed that the belt was not running smooth with the belt tensioner working like crazy. Got under the car and noticed the pulley was not running smooth. Started removing parts and ultimately discovered that the crankshaft was damaged on the snout with 0.030" runout. The balancer and spacer multiplied this runout to about 0.100" by the time it got to the pulley. This alternately pulled and relaxed the belt by 0.100" and also dynamically changed the in-out dimension on the pulley with every single engine revolution. Talk about a stress test... Even so, the belt never came off. How did this happen? The previous owner changed the cam and didn't tighten the balancer bolt enough. So the balancer walked off the front when the engine was running - wrecking the crankshaft snout. But he just jammed everything back on there and called it "good". Of course it wasn't. What a sheister. Anyway, that engine has been pulled and I decided to build another separate one. So that problem has nothing to do with what I'm dealing with today.
 
Just FYI. I also double checked that the slinger is indeed inside the timing cover. But if it wasn't in there, that certainly could have been the problem.
 
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