Balancer question

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Coyote Jack

Coyote Jack

Member #55, I'm old
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I recently had the harmonic balancer come of my 360 while it was running. There was no real damage visible so I decided to put it back together last night. When I put the balancer on it was not a tight fit ie: I didn't have to press it on. It just went on with the pressure from my hand. It does not wobble but it is not real tight. Is this normal? It does not appear to be scored in any way and there was still some silicon on it from when it was last installed.

Opinions please.


Jack
 
What do you mean it fell off? Like, the crank bolt loosened up and it walked off the crank?
 
That is correct moper. Bolt backed out and balancer followed soon afterward. I have never had it happen before but I talked to a couple of people that it happened to and they say I got off lucky with no real damage.

Jack
 
Whose balancer (brand)? What crank? Who balanced it? internal or external? Auto trans?
 
There was a time when the balancer and crank were a very tight fit and the bolt wasn't really needed. Some were never installed from the factory. The last egines I know of that left the factory without the bolt were 4 cyl in 80 Chevette. Those balancers were dropping off and running away like a loose wheel. LOL
Today that bolt is required with a heavy washer that is flat on one side, and should be torqued.
 
maybe just wasn't torqed correctly when installed? Believe that bolt is suppsed to be
torqued to 250psi when installed. Mine was a real pain to get loose on my 273.
 
Jack, I am suspect of harmonics in this case. Was the balancer installed with a tool? Was the bolt torqued? For sure? Check the flex plate bolts. If one or more is lose, ther may be a balance issue. Chances are the thing didnt just pop off. It rattled it's way off against the belts. So it probably beat up the dampener bore, and the crank snout. I would carefully measure both to see if they are now out of round too.
 
That's exactly what I am worried about moper. I didn't feel any vibrations from the engine until it came off, then it shook like crazy. What are the options if I do find a problem with the crank? The balancer is a lot easier to replace than a crank. LOL

Jack
 
It has to be a press fit in order for it to work properly, otherwise it will not be able to control crankshaft harmonics.
 
I'd say cross that bridge when you find out the damage. The crank my be fine and the balancer is damaged. I'd say that is the best case scenario.
 
Its not a press fit. Press fit is .003 difference between female I.D. and male O.D.
A hydrolic press would be required to put the 2 together. It is a snug slip fit though. You should be able to stand back and throw it one but if its lined up right it should slide on with little resistance. Just pecking with a rubber mallet should seat it.
Sure you'll neormally need a puller to get one back off but once its broke loose and starts moving you can almost pull it off by hand.
The fit of the key and key ways are similar in that a snug fit is required.
And by the way, Another member posted before about a problem with the bolt length, hole depth, washer thickness, something wasn't quite right. The bolt bottomed in the hole leaving the balancer and washer loose. I dont know what the solution was. I know just the thickness of the oil slinger between the timing gear and balancer could make some difference. Good luck with it.
 
I beg to differ. The balancer is not pressed on with a press persay (sp?).
But it is pressed on with the bolt,and should be a tight fit.
 
RedFish said:
Its not a press fit. Press fit is .003 difference between female I.D. and male O.D.
A hydrolic press would be required to put the 2 together. It is a snug slip fit though. You should be able to stand back and throw it one but if its lined up right it should slide on with little resistance. Just pecking with a rubber mallet should seat it.
Sure you'll neormally need a puller to get one back off but once its broke loose and starts moving you can almost pull it off by hand.
The fit of the key and key ways are similar in that a snug fit is required.
And by the way, Another member posted before about a problem with the bolt length, hole depth, washer thickness, something wasn't quite right. The bolt bottomed in the hole leaving the balancer and washer loose. I dont know what the solution was. I know just the thickness of the oil slinger between the timing gear and balancer could make some difference. Good luck with it.
Click to expand...

That is the exact problem I am finding right now. I can put it on by hitting it with the palm of my hand, but it does not wobble at all. Also the new bolt appears to be to long and will not snug against the balancer before it bottoms out.

Jack
 
From ATI Performance's site on instructions for installing a balancer:


3. Press fit of the hub to the crankshaft is vital to transfer harmonics to the damper assembly.
Recommended press is as follows:
1.0000" - 1.2500"------------.0009" to .0012"
1.2510" - 1.3750"------------.0008" to .0011"
1.3750" - 1.6000"------------.0007" to .0009"
1.6010" - 2.0000"------------.0006" to .0008"​
2.0010" - 2.5000"------------.0005" to .0007"
 
You say the bolts too long --Think the washer that goes under the bolt is probably around 3/16" thick. Might want to look in the hole on the crank to see if anything is
in there. When I was doing my timing chain the last time for some reason I stuck a
small socket in the hole so I couldn't screw the bolt in all the way - had to use a small
screwdriver to get it out.
 
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