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Harmonic Balancer replacement

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Old Apr 21, 2012 | 12:18 AM
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Default Harmonic Balancer replacement

My harmonic balancer / dampener was shot due to the outer ring slipping, so I bought a replacement: SUM-161350 from Summit, looks identical dimensionally to my 1980 L-48 HB. I also picked up a removal/installation tool: Proform 66514 Harmonic Damper Installer/Puller from Jegs.

I removed the HB this evening, with the Proform tool it could not have gone smoother. The hardest part of the whole process so far has been removing the power steering belt, the power steering pump did not want to pivot out of the way.

After researching this forum for the HB and tool that I bought, I also found that I would not have to remove the fan shroud to get the HB out. There is plenty of room to use the tool. When I first started cranking (pun intended) on the removal tool collar, I let the 3/4 wrench turn with the crank until it was lodged against the fan shroud, holding it in place. This made the rest of the removal a one-handed process.


Also from this forum (the Search button is my friend!) I saw the front main seal can be removed leaving the timing cover in place. I was concerned about damaging the cover trying to pry the seal out, so I tried cutting it out. It worked pretty well, took less than 10 minutes, including stops to take a few pictures. Since I could not find any step-by-step tips, here is how I did it.

First, I cut across the front-facing surface of the seal with large diagonal cutters. I cut on the bottom edge of the seal, careful to ensure any metal fragments fell to the ground and not into the cover:


Then I made a second cut about an inch away from the first cut, and removed the face of the seal between cuts using the diagonal cutters. This left a flat surface between the cuts that easily bent upward, reducing the OD of the seal and allowing it to pop out.



I did leave a few scratches on the face of the timing cover, but no deformation of the cover, and no scratches where the new seal will sit.

Last edited by indydoug; Apr 21, 2012 at 12:27 AM. Reason: I type too fast
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Old Apr 21, 2012 | 12:23 AM
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Now a question for the engine builders: Before removing the HB, I noticed what looks like black RTV gooped around the key:


Is this recommended for installing a new HB? Or has Bubba been here trying (in vain) to stop an oil leak?

I need to stop at AutoZone tomorrow for a new seal and fan belt, and would like to know if I should also get black RTV. Thanks in advance for your sage advice!

Last edited by indydoug; Apr 21, 2012 at 12:29 AM. Reason: Still can't type
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Old Apr 21, 2012 | 07:19 AM
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I am no engine builder but have taken off more HB's than I can count and have never seen RTV. My guess is Bubba has been trying to help you...
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Old Apr 21, 2012 | 07:30 AM
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I don't think its a good idea to put some RTV sealant in that area, also I can't think of any kind of fluid that would leak from it, its just a solid peace of a crankshaft.

Very good job indeed, I'll be doing the same very soon, the only problem is I have a big block, so the working space will be much less!
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Old Apr 21, 2012 | 09:22 AM
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I've never used sealant on the harmonic balancer, and I've never had one leak. (Although most of my engines develop leaks just about everywhere else. ) And in theory they could leak between the damper and the crank, just never heard of anyone doing this.
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Old Apr 21, 2012 | 09:38 AM
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Originally Posted by themetalman03886
I am no engine builder but have taken off more HB's than I can count and have never seen RTV. My guess is Bubba has been trying to help you...
No sealant needed.
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Old Apr 21, 2012 | 11:45 AM
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Engine oil can wick along the crank keyway and slowly, over time, result in oil seepage. A small dab of RTV in the keyway groove will prevent this.
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Old Apr 21, 2012 | 11:47 AM
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BTW, a good HD will show the TDC mark aligned with the keyway for pre'69 dampers, or will be 10 degrees counter-clockwise from the keyway on later dampers.
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Old Apr 24, 2012 | 12:36 AM
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Originally Posted by larrywalk
Engine oil can wick along the crank keyway and slowly, over time, result in oil seepage. A small dab of RTV in the keyway groove will prevent this.
That's what I've always done just before I install the HB bolt.
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Old Apr 24, 2012 | 06:09 AM
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Thanks to all for the feedback.

Another question - the Shop Manual indicates the HB bolt should be torqued to 60 ft-lbs. How do you keep the engine from turning to get the bolt tight enough?
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Old Apr 24, 2012 | 07:57 AM
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Easiest way to keep the engine from turning is to pull one plug and stuff some cotton rope into that cylinder. When it gets close to TDC, the rope will jam between the piston and head and stop the piston from moving, holding the crank so you can torque away.
Next time you swap the front seal, try this: use a nail to knock a small hole in the wide metal band of seal material. Thread a small machine screw into this hole (I use one with a hex head and use a 1/4" ratchet and socket) and use the screw as a grab or pry spot.
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Old Apr 24, 2012 | 09:34 AM
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Originally Posted by indydoug
How do you keep the engine from turning to get the bolt tight enough?
For my manual gearbox, I simply put the trans in high gear. For a slushbox trans, try jamming something into the flywheel ringgear teeth.
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