Harmonic balancer comes off

-
7

74 dart sport

Kameron
Joined
Jul 7, 2015
Messages
171
Reaction score
1
Location
Southern California
Recently, our 318 started making noise when running. Ever since we got it running , the timing has been weird. After starting it up one day, the car shook more than normal , and was making a funny noise. When we took all the belts off, to get to the harmonic balancer, we saw it was loose (that was our first thought when we heard that noise. I was under the impression that a tool was needed to take off / install the harmonic balancer, but the harmonic balancer can right off. What should be our next step? Thanks!
 
Find the inch and a quarter bolt and put it back on with likely a new balancer?
This is easy to check but I think a hundred and thirty-five foot pounds of torque and of course a big *** washer.
 
Inspect tof make sure your crank snout is OK. Running loose like probably damaged the key way. Yes it should not come off with out a puller. Is it a factory balance or aftermarket? When you put the new one on it should be pulled on with a balancer installer. I know people use the bolt and a block of wood with a bfh. Proper way is with an installer.
 
Measure the snout and the hole. One,or both,of them is bad. I would not depend on the key or the bolt tightness to keep it on there. You will need precision measuring tools.
 
Time to remove the timing cover and inspect the crankshaft. If it was run loose for very long at all you will likely need another crankshaft and balancer.
 
RustyRatRod said:
Time to remove the timing cover and inspect the crankshaft. If it was run loose for very long at all you will likely need another crankshaft and balancer.
Click to expand...


Exactly. The bolt doesn't hold the damper on, press fit does. You should have had to use a tool to install it, unless you used the BFH method, which I know is popular in some circles.

If it was loose for very long, chance are you will need a new crank. Or, you can have the snout welded up and sized to spec. But that is probably more than a new crank.

Bummer.
 
yellow rose said:
Exactly. The bolt doesn't hold the damper on, press fit does. You should have had to use a tool to install it, unless you used the BFH method, which I know is popular in some circles.

If it was loose for very long, chance are you will need a new crank. Or, you can have the snout welded up and sized to spec. But that is probably more than a new crank.

Bummer.
Click to expand...
The bolt dosnt hold the balancer on? I had a thread about putting the sucker on around Thanksgiving last year where I was trying to put it in the oven while my wife was cooking to heat it up LOL then of course the forum bitched me out for doing that let alone my wife she said- now where are you going with that thing and why are you opening up my oven? But it's just shade tree garage mechanic kind of stuff that I shouldn't have been doing in the first place obviously.
 
The replacement will likely go on easier than normal. If that worries you there are several formulas of Loc-tite that can ease your mind and help fill small voids and secure the bolt. If it's not a high RPM race engine and it doesn't vibrate run the sucker. Most likely you will need to replace the front cover seal. The Loc-tite should be allowed to cure before installing belts etc.... Just to be sure it was the whole balancer or just the outer ring?
 
I just put on a slant balancer with the almost correct tool
Damper install procedure
And there is no way you could do it any other way than using a jackscrew/installer unless heat expands ot a few thou.
 
We did not install it, so I do not know how it was done. The engine was out of the car and has less than 50 miles on it since we had it . The crank looked great when we opened the oil pan. And the balancer has maybe ran 1 minute since it started getting weird.
 
Well it's good you didn't run it very long. I'm sure a good inspection of the Cotter key and also like some are saying making sure the outside didn't separate from the inside. That will tell its own tale. of course the nut holding everything on is that there? or was it just the outer ring slip? On my car just the outer ring went inwards and scraped the timing cover, luckily I caught it before it went through the timing cover or went the other way and flung out and did a lot of damage.
 
Also, when we dry fit it and it's pushed on all the way, it wiggles left a bit . (Wiggles as in turns maybe 1/20th of an inch, moving in a way a steering wheel does). Is that a problem?
 
I'm trying to upload photos but I can't. Can I get cell phone numbers so I can send pics. (Sorry this is so informal, but it's not allowing me to upload pictures
 
It's just that I really need your help to figure this out guys. I got my permit today and my first car isn't ready, and it's kinda a let down. I really wanted it to be ready today
 
Marcohotrod said:
old Pontiac V8 dampers were not a press fit, they had a bolt, and ran fine for years
Click to expand...
As above.... FWIW, the bolt is what clamps the damper to the crank for the case of a SBM. The purpose is make sure all of the higher frequency vibrations are coupled into the damper so it can do its job. With the 135 ft-lbs torque on a 3/4" thread bolt, the clamping force is somewhere in the range of the 10,000-12,000 lbs. The interference fit can't come anywhere near to that 'locking' force and is not reliable anyway for higher vibration levels, due to variations in the fit. (It is obviously adequate for the /6.)

OP, make sure the bolt has the very thick stock washer (approximately 3/16" thick) under the bolt head. That HAS to be there so that the bolt can apply the above level of clamping force. A thinner washer will just distort and release the clamping force.
 
Also, one of the 6 outer bolts is different . There are 5 bolts with spiky washers and 1 longer bolt with a flat head screwdriver slot. Is this important?
 
Geebus guys come on, we are NOT discussing a Pontiac here. You should have .001-.0015 PRESS FIT and no more than .002.

If you had to heat up the damper to put it on it has too much press. Can't tell you how many dampeners I had to hone to get them correct. In fact, most good dampeners come undersized so you can fit them because the Chinese have trouble machining to a blue print. Fluidamper got burned by this very thing years ago. No one measured their ****, they too much press fit and the crank snout would fail and the damper got blamed.

FWIW many early SBC's had a damper that was passed on and th cranks were not drilled.
 
The washers are kinda rough looking from the factory. If it is essentially flat, then it should be OK.

The longer bolt sounds like it was put in there because somebody in the past lost the 6th bolt with the 'spikey' star washer. I'd make them all the same. Won't hurt you to get a new set of 6 new grade 5 bolts of the right length and star washer for each.
 
I think the dent you are referring to is the counterbalance system.
The 5 little bolts may or may not be correct. The 6th one with the screwdriver slot should not be there, nor should the spiky washers.There should be 6 hexhead bolts with spring washers or Belvilles. The factory bolts had special captive washers. It's not real critical, until the pully comes off at 6000 rpm.
The 1/20 side wiggle, if I understand it correctly, says you have a junk part there, or maybe two.The damper should absolutely not slide onto the crank and then wiggle. Time to measure both.
Here's the thing; this interface is pretty important to the life of the engine, and so it makes me wonder where else corners were cut with this engine. I'm not trying to scare you, but this stuff IS scary.
 
Last edited:
You must log in or register to reply here.
-

Back
Top