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Replacing Harmonic Balancer On 1974 Blazer with SBC 350

Chief Brody

Chief Brody

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I think I asked this in a thread somewhere, but thought I would just create a thread to make it easy. These are Noob 101 questions I know:

Stock engine, replacing with stock harmonic damper / balancer

1. Is it necessary to find TDC before removing, because these things are keyed with a Woodruff key aren't they?

2. If it is necessary to find TDC, what's the best way to do it without removing valve cover to see number one cylinder valves?

3. Is there room to do this without removing anything from core support area?
 
Having it at TDC just makes it easier to see where the marks are in relation to the tab. There are a bunch of different clcokings between the key cut and the markings

If you can turn it over to look as it you were setting the timing should be sufficient. But removing the valve cover is confirming. If the engine isn’t going to get turned over while the damper is off, just stick with the first paragraph. So not 100% necessary, but easier to not have a mistake

The clearance to the radiator is tight. I think the last ones I did, I pulled the belts, fan, and the shroud
 
Also make sure to compare new damper to old. There are many different diameters as well as clockings
 
Do you do this from the top or the bottom? If removing the radiator shroud and fan, I assume you do this from the top.
 
Also, if I lined it up TDC, it would move on me when I was breaking the bolt loose wouldn't it?
 
I left the radiator in, but you have to be careful not to get into it with your tools. From the top
 
I am trying to get enough information to get motivated to do it. I have all the parts, the puller / installer. The TDC thing was bothering me.
 
Chief Brody said:
Also, if I lined it up TDC, it would move on me when I was breaking the bolt loose wouldn't it?
Click to expand...
Lining it up is more for peace of mind. The ignition timing won’t move. Once you reinstall the new damper, it will be fine. Just really watch that the new and old are identical
 
I have a vacuum gauge, I think I have a spark plug hole adapter for it. I should be able to find TDC on compression stroke with that, right?
 
Correct

be very mindful of that seal around the damper. When you reinstall, make sure the lip goes outside the damper or you will push the spring out of the seal. Then you’ll have a new project
 
I really think you are getting hung up on TDC. with the woodruff key it will only go on in the same position as the old one. like bent said; most important is to make sure the balancers are the same.
 
Also, if I am loosening the crankshaft bolt, is it normal "lefty loosy" or is it backwards because of the direction the crankshaft spins?
 
Bent77 said:
Correct

be very mindful of that seal around the damper. When you reinstall, make sure the lip goes outside the damper or you will push the spring out of the seal. Then you’ll have a new project
Click to expand...

Does the balancer make contact with the seal before the "pressing on" begins? How the heck do you see in there?
 
As long as the timing mark is exactly in the same position on both dampers and they are the same diameter, the key way aligns it.
Use a removal tool and a installation tool. You will have to remove the fan and the shroud. like bend mentioned careful with the seal.
 
Chief Brody said:
Also, if I am loosening the crankshaft bolt, is it normal "lefty loosy" or is it backwards because of the direction the crankshaft spins?
Click to expand...
Correct. Does your puller kit come with the reinstall tool? You don’t want to use the main bolt to pull it back on. That’s how the threads get destroyed
 
Bent77 said:
Correct. Does your puller kit come with the reinstall tool? You don’t want to use the main bolt to pull it back on. That’s how the threads get destroyed
Click to expand...
Yep. I bought the removal / installer kit last year
 
So right at the moment the only thing I have questions about is the seal. How do you see it and see what you are doing while installing the balancer? Do you suggest lubing the balancer shaft before installing on the surface that touches the seal?
 
A little coat of oil is fine. When you reinstall, pull it in to where it’s barely touching the seal, then slow down and make sure it’s right.
 
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