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Discussion Starter · #1 ·
I have a summit harmonic balancer that I'm putting on my new engine, however it does not fit. I measured both the crank snout and the ID of the harmonic balancer and they're almost exactly the same dimensions. I got the balancer a bout half way before I stopped because of extreme amount of force needed. I rented a h balancer puller and i stripped almost all the threads getting it off, I even heated up the balancer too. Besides sending it to a machinist, what can I do to hone out the balancer? I looked for a flap wheel for my drill but I couldnt find anything small enough.
 

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Rusty,
You did not mention what engine you have. This is pretty common on Big Blocks. It seems that most of the damper manufacturers make them a little small because some of the aftermarket crank snouts are a little small :( If you try to put them on a stock crank, or a replacement that is made properly, it just wont go. Now ....

The only correct way to fix the problem is to get a micrometer and measure the snout on your crankshaft. Then lock the micrometer so the reading wont cnahge and take it along with your damper to your machine shop and have them hone it on a Sunnen rod hone until you have the correct interferance fit. It is usually around .001" press fit on a big block.

Dont use a flap wheel .... you will ruin it.
 

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Discussion Starter · #3 ·
Rusty,
You did not mention what engine you have. This is pretty common on Big Blocks. It seems that most of the damper manufacturers make them a little small because some of the aftermarket crank snouts are a little small :( If you try to put them on a stock crank, or a replacement that is made properly, it just wont go. Now ....

The only correct way to fix the problem is to get a micrometer and measure the snout on your crankshaft. Then lock the micrometer so the reading wont cnahge and take it along with your damper to your machine shop and have them hone it on a Sunnen rod hone until you have the correct interferance fit. It is usually around .001" press fit on a big block.

Dont use a flap wheel .... you will ruin it.
I have a small block with a Scat 9000 crank, both the h.b. and crank are brand spanking new.
 

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Rusty,
You have to measure the fit with a micrometer and a good bore guage like the one on a Sunnen rod machine..... no way around it. I am betting that the "problem" is the Summit damper. Seems like lately I have been honing more dampers than I ever remember. By the way, I always use Permatex silver anti seize on the dampers and crank snout when I install them.
 

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Discussion Starter · #8 ·
Well I got my replacement in from Summit today, its actually smaller! I called Summit tech dept and they said I could hone out the hub of the balancer. They said since my crank is new its on the high side of the tolerance and that they make the balancer for cranks that have the snout worn out???? I wouldn't think that a crank snout gets a lot of wear, especially since nothing spins against it. I might try boiling it to see where it comes out at. :mad: If I heated the balancer up enough to get it on, would the balancer "mold" to the diameter of the crankshaft snout? I don't think getting it on would be a big big problem if I heated it up, but getting it off is another problem. I don't want it stuck on my crank.
 

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Rusty,

You just need to follow the advice you were already given ..... measure the crank and have the damper honed to fit it. The dampers are not made small to compensate for wear ... they are made small because there is a large difference in crank snout sizes depending on the manufacturer. You just happened to get a crankshaft with a large snout, so the damper needs to be honed. It probably will not matter which brand damper you get, you will have the same problem.

By the way ... it only takes a .001" (thats one thousanth) to make the difference between the damper going on easy and being nearly impossible to install, so unless you have a good micrometer, and a good bore gauge, you will have a hard time measuring for the correct press fit.
 

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We have to hone most of the new balancers we put on he engines we build and we have the proper Sunnen bore gauges and the proper mikes to measure with and the hone and mandrell to do the correct hone job.
 

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Rusty, I also bought a summit degreed balancer, and it would not go on my new scat crank.

I got a flapper sander at Menards. It was the smallest they sell, and I had to rip half the flaps off the get it in there! But it worked.

Bill & Carl, I know it ain't the "right" way, but it went on. It's still a good tight fit. It's been on there for 2 years and 6000 miles, including a couple dozen strip passes and countless runs to redline, Billings and back, and over the Beartooth pass, too. Ruin it? naaaa. Sometimes we just make do with what we have.
 

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Discussion Starter · #12 ·
I took it to my machinist today but he didn't feel comfortable boring out the hub. He said it would catch on the key way. I bought some emory cloth so I tried that but i think I need something with more grunt. I might try the flapper wheel and cut it down to size.
 

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Boring and honing are two totally different things. I wouldn't think a good machinist would ever say that. Might want to check out a new machinist.
 

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It is a press fit.
The parts also have a tolerance. If the crank is on the plus side and the balancer is on the minus, its an extra tight fit.

MAKE a flapper wheel with sandpaper and anything that is spit.
Even a big cotter pin.
Chuck it up in a drill and polish away.
Also try to polish the crank a little too.
And LUBE before mounting, the balancer.
 

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Discussion Starter · #15 ·
Boring and honing are two totally different things. I wouldn't think a good machinist would ever say that. Might want to check out a new machinist.

Ok wrong use of words, he was going to use his rod hone.
 

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Discussion Starter · #16 ·
Well I tried again today and no luck getting the balancer installed fully. I heated the balancer up and had about .003 clearance between the snout and the ID of the balancer. It started going on great, then it started getting tough and finally the install tool broke off in my crank snout. It did come out though so no worries there. My question is now how far is the h.b. supposed to go before its fully seated? I have noticed my balancer is a lot thinner than most of the other balancers I've ever seen. The hub of my h.b. is 2.40" deep. The distance between the end of the crankshaft, to the timing sprocket is 1.35". That being said, I found out when I measured the marks on the inside h.b. that its going on 1.35" and hitting the sprocket. I was fairly sure I had my sprocket all the way on and lined up with the upper sprocket but then again I could be off.
 

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Discussion Starter · #18 ·
If you are not going to hone , hand sand , can you return it and pay the differance for a good name brand balancer, Even maybe one from GM Performance parts?
I hand sanded .003 off the balancer with emory cloth. I went from 1.244 to 1.247. I boiled the balancer for 30 minutes which brought it up to 1.249 before I tried installing the balancer. I guess my new question would be is when the balancer is installed correctly, how much should the depth be from the end of the crank snout to the front of the balancer? I thought maybe i had it on correctly and it just looks like I don't since the balancer is a lot thinner than a factory balancer.
 

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The distance between the end of the crankshaft, to the timing sprocket is 1.35". That being said, I found out when I measured the marks on the inside h.b. that its going on 1.35" and hitting the sprocket. I was fairly sure I had my sprocket all the way on and lined up with the upper sprocket but then again I could be off.
The timing sprocket on the crank needs to be fully seated, right up against the filet where the crank gets larger.
The balancer goes on until it is against the sprocket, no further.
It is completely normal for there to be an inch or more of the balancer sticking out past the end of crank.
 
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