I was putting my harmonic balancer on the new motor when I ran into a problem I hadn't seen before. I have only assembled about 6 or 7 small block chevy's and I don't remember this ever happening before and haven't been able to find the solution in any of my manuals or on the internet. I am hoping someone can shed some light on my situation.

I was putting a new stock 87 harmonic balancer on my internally balanced 406 with a Callies crank. I used a HB installer to pull the balancer on until it stopped, then proceeded to put the stud in and the crank pulley on. At this time I noticed that the balancer was about 1/8 (.125) back too far to line up with all the other pulleys on the motor. So first thing I figure is I have to make a spacer. As I am getting the materials together to do it I realize I have no idea just how far in the balancer is supposed to go in. I pull it off again and measured the distance from the end of the crank snout to the face of the lower timing gear, then measured the depth of the harmonic balancer itself. The difference was exactly 1 inch. When installed on the engine now the difference is about .9 or said a different way the snout face of the crank is a little less than an inch down from the front face of the balancer. I thought to myself, uh, oh, maybe I pushed the timing gear on a bit too far and put things out of alignment, that wouldn't be good. So then I started looking for some type of measurement as to how far in to install the balancer. Maybe a figure for how far down the crank snout should be or how far the balancer face should be from some reference point on the block. I haven't found any mention anywhere as yet. Because the block, crank and balancer are all from different years could it just be tolerances being off. I would much rather just pull the balancer out .125 than fabricate a spacer with the machine work required to have it done right. I can get the crank stud to the spec torque value with the crank out another .125 but if its supposed to be crushed up against the timing gear that would be bad. Thanks for any help or information you all can throw my way. Happy Holidays.

P.S. after spend a small fortune on this motor I wasn't that thrilled with using the stock harmonic balancer (new though), and was thinking of either the 6.25 Fluidampner or the 6.28 ATI rattler. Don't know which is better if anyone has a recommendation..thanks again.

http://www2.freepichosting.com/Images/84456/1.jpg


[Modified by Jaxian, 4:52 PM 1/3/2004]

 

It's been too many years and there's too many details, but here's my take as I recall it:

The crank gear is pressed on to a certain depth to align with the cam gear and the timing chain. The collar of the balancer is designed to snug up to the crank gear, which prevents any possibility of the gear walking forward as thrust is applied. It's then torqued in place.........the seal is on the timing cover around the balancer collar, no matter what the depth of the balancer is. The variable is in the design of the pulley (alignment in and out) depending on the accessories. If your pulley is too far rearward, you could use spacers under it against the balancer in the form of flat washers, etc.

If you used all stock components and have a problem, I'd want to know why before I called it a day and simply spaced things to alignment. Could it be the crank gear isn't fully pressed on and the chain is a little out of whack? If the timing gears line up, then I wouldn't worry too much about it.......heck, how did you find that 1/8" anyhow? :lol:

 

Thanks for the response. I tried to attach a picture but the pic hosting site is having issues, hopefully it will kick back in soon. The block is an old early 70's 400 block and the balancer is a new late model L98 piece, granted they are many years apart but still both factory. The crank is a pure aftermarket piece from Callies but I have heard only good things about them so wouldn't think there would be an issue there. The longblock was assembled professionally and sealed up so I can only assume the parts inside where set up correctly as far as the timing gear alignment goes. I thought it was just a matter of pressing the timing gear in until it hit the crank area that stops it.

As to how I noticed the .125. I had boltedt the crank pulley on and was looking at it from the side when I noticed it seeming to be off a bit. I layed a straight edge across the crank pulley and measured the difference in relation to the waterpump and other pulleys. Its noticeable because 1/8 (.125) is almost exactly one rib on a 6 rib factory belt setup. You can see the belt kind of deflecting over the little bit its off. Its not too critical on the water pump because that is driven by the back of the belt and has some extra slop space, I was more worried about the supercharger and alternator and A/C not being aligned correctly. Hopefully the timing gear is correctly aligned when it is up against the stop on the crankshaft, that would seem to make sense. I will try to get the pictures up again and hopefully the hosting site is working now. Thanks again.

 

I have a Fluidampner for a 400 sbc. If you would like you can take some measurements off it to see if its just a tolerance stack up issue. Oh and I'm just one town over from you so email or respond to this post if you want to contact me.


[Modified by Widebody, 7:00 PM 1/3/2004]

 

Jaxian, a little OT here, but who built your motor? I've got a 420 ready to go as well :cheers:
I tried to IM you, but it's disabled

 

Thanks for the offer Widebody, I don't think I need to measure the Fluidampner, my other old harmonic balancer has the same dimension as the new one so I dont think its a matter of that being out of spec. Just wish I knew if there was a set distance to push it in to or just until it hits the timing gear and stops as it did. I wish the photo post website would work, I have some photos of it I tried to post. I turned on the IM feature now Cabo, it should be working.