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Harmonic Balancer

Matt Bachand

Matt Bachand

Depends on the 6.5
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Location
Worcester, MA
I felt vibration today, popped the hood and down by the crank I can see it wobble. I assume thats the harmonic balancer? Question is, what is needed to replace this, how hard, and will it hurt me to drive this for 2 days before the weekend?

It feels worse at idle, smooths out with RPM.

Sound like the harmonic?
 
Sure does sound like the HB, or crank pulley.
Won't hurt you to drive it for 2 days, but a bad harmonic balancer sure will break the crankshaft (destroying the engine) eventually... Probably won't take 2 days though.

In other words -- I would NOT run the engine till you are sure the problem is NOT the HB, or it's replaced.
Not even for a very short period of time -- You're really taking a chance at a sudden, catastrophic failure!
 
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Matt Bachand said:
I felt vibration today, popped the hood and down by the crank I can see it wobble. I assume thats the harmonic balancer? Question is, what is needed to replace this, how hard, and will it hurt me to drive this for 2 days before the weekend?

It feels worse at idle, smooths out with RPM.

Sound like the harmonic?
Click to expand...


Do not drive it. You will do more damage than is already done.

You need to remove it and see how bad the crank shaft snout is worn. You can use Loctite shaft repair to repair it up to 10 thousands on either side if the crank is worn that much. Some of the other Loctite shaft repair items work up to as much as 30 thousands. I have personally repaired shafts on two motors with this and they are still in operation.
 
I just took pictures, harmonic looks really good. Take a look, I will try to video record the wabble. I'll look at it from the bottom too...

That is from the bottom looking forward, it looks perfectly smooth with no dry cracks or chucks missing,... Going outside now to fire it up and look from the bottom...

Figures, I just bought a 93 AC-Delco Lift pump for her, and now this....

That and my Exhaust and guages are already ordered and awaiting delivery...

Try to do good to prevent these things... anyhow, i'm working on it as we speak (typing with greasy fingers) so if you can frequent back i'll be back and forth...

brb :) BTW, Thanks guys.
 

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I'm not sure if the camera picks up enough frames per second to catch it, but it defanately appears to wobble. Here is the clip, not sure why it's only 2 seconds long but here.

Damnit, can't upload that type of file... how can I put a .mov so you guys can see it?
 
Matt Bachand said:
I'm not sure if the camera picks up enough frames per second to catch it, but it defanately appears to wobble. Here is the clip, not sure why it's only 2 seconds long but here.

Damnit, can't upload that type of file... how can I put a .mov so you guys can see it?
Click to expand...


youtube.com
 
Ok... Now I need some other opinoins... I just took my socket and let it 'ride' the bottom of both the crank pully and the HB, and it was perfectly smooth, and like I said, look in good condition. It just appears to have a wobble due to the visual effect of it spinning?

I ddid then when running, and I started to grind my ratchet (not socket) like it was on a grinding wheel, perfectly smooth.

Here are more pix of the situation, i'm going to drop teh serp belt and see if still there.

These pix are ferom the front looking towards the rear (bed) from underneath.
 

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Pulled belt, vibration still there (it's NOT shaking, nor was it ever)...

I am starting to think the wobble was just an optical illusion (like a wheel with an imperfect drawing on it, it would appear to wobble) it was smooth as can be when i held the ratchet on it.

If it was wobbline I would have easily felt it witht he ratchet rubbing on it? It felt EXACTLY as smooth as a grinding wheel.
 
harmonic balancer pulley rubber starts coming apart in the middle ,grab your belt and push/pull on it,look down at the pulley on the right side of truck,your left while looking down,if it moves more then likely its your pulley,there was just a post a couple days ago with pics of a bad one
 
Will do, Here is U-tube http://www.youtube.com/watch?v=H1N0UNsc-Bg

Like I said it was super smooth with the ratchet... this may be stupid, but I have a hole in my muffler, and it got noticably louder... I think i'm feeling the 'drone' coming out of the muffler. I cover it with my hand and drone goes away , although I can't cover it and be in the cab at the same tiime..

If it was out of balance enough to vibrate the truck, I would HAVE to think I would have felt it when I was grinding my ratchet against the bottom of it. Like I said it felt just like using a grinding wheel. that smooth.

I think I'm good. I'm going to double check for movement since I just put the belt back on.

I think what you see in the video is an illusion.
 
an exhaust hole CAN make a vibration, you should feel my truck with it broken off after the downpipe! with that said, be CERTAIN it isnt your HB, cuz a new crank is not what you wanna get.
 
might wrap foil around exhaust ,not to fix of course but that way you can sit in cab and listen,how does it sound with belt on when you shut off engine,do you hear a clunk/clank ?
 
beaglehauler said:
might wrap foil around exhaust ,not to fix of course but that way you can sit in cab and listen,how does it sound with belt on when you shut off engine,do you hear a clunk/clank ?
Click to expand...

I have heard the clunk/clank for as long as I can remember when i turn her off...

After installing my new lift pump I fired her up again and I can instantly 'hear' the vibration now that I am aware of it. I first noticed it at idle, and when I peeked into the engine bay I seen what looked like a wobble...

If it was in fact wobbling/vibrating I would have felt it with the tool I put on the bottom side of the pully when it was running. It was silky smooth. Like I said it felt as smooth as sharpening a tool against a bench grinder. If it was wobbling (which is what made me think it was the culprit) I would DEFANATELY felt it.

Perhaps when they balance the pulley/harmonic they have to put more material at certain spots to make it true, and that's what made me think it was it.

Needless to say, if i'm wrong I'm screwed, but I now hear the vibration as well as feel it at the same time. I just panicked I guess.

And the visuals of my harmonic looked good, and I have 112k on the clock, so that's not terribly much... Recommended interval is 100k, ... We'll see.

Thanks again everyone for your prompt help. Some quick diagnosis and getting know new area's of my rig.

I need to start narrowing down the oil leaks under there... man i got oil, tranny fluid, and a rotted out fuel tank...

If I park nose down, i leak Tranny fluid, if I park nose up with 1/2 tank I leak Diesel fuel, If I overfill past 1/2 tank I leak diesel while level....

One thing at a time i guess. I know my oil cooler lines are leaking so i'll start with that one and see how much of the rest of the oil leaks is just blow-by off of the oil cooler lines.
 
I have heard the clunk/clank for as long as I can remember when i turn her off...
Click to expand...

Mine too -- New crank pulley fixed it. Took longer to get the belt off and back on than it did to change the pulley. Check 'em all while you have the belt off.
Oh yeah - Been reading that AutoZone's don't last long at all - Get a Dorman.
 
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this is the back side of a bad pulley,they will run straight so it seems,but cause a rattle,clunk,clank etc
 
Slim Shady said:
Do not drive it. You will do more damage than is already done.

You need to remove it and see how bad the crank shaft snout is worn. You can use Loctite shaft repair to repair it up to 10 thousands on either side if the crank is worn that much. Some of the other Loctite shaft repair items work up to as much as 30 thousands. I have personally repaired shafts on two motors with this and they are still in operation.
Click to expand...


How do these shaft repair kits work? I was able to press my new HB on way too easily.
 
I don't really remember having to fight too hard to install a HB. IIRC it went about halfway in and I brought it in with the bolt on one of my 6.2s and it was fine. I think you may be looking for problems you don't have. I mean did it literally feel loose and slide all the way on with no resistance ?
 
don't waste your money on G<M crank pulley either. I thought i was doing the smart thing spending top dollar on good factory parts. I was F'in pissed with the GM bag said made in China. In fact I think there is a pic of that somewhere over at DP.
 
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