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425 Harmonic Balancer Help Please

425 Harmonic Balancer Help Please

Old February 6th, 2019, 03:46 PM
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425 Harmonic Balancer Help Please

Hi Everyone.
I could really use your help.
I have a 1966 Toronado with a 425 4-bbl. While trying to figure out why it has no where close to the power it should, I got into the timing. With #1 piston at the top of the cylinder in a compression stroke, my timing mark on the balancer was no where close to my degree pointer. Of course I tried this at 180 degrees on the crankshaft. Same issue.

In researching possible causes, one thing stands out. The outer portion of the balancer may have slipped on the inner portion due to the rubber deteriorating. It is after all stock and 53 years old.
The stock 425 engine was rebuilt over 10 years ago and has about 50 miles on it. The numbers match the car as original and the timing gears and chain were replaced then..The car starts up, idles & revs fine with no run on or at shutdown, but i when on the street.very little power..
We have a few options for parts in our area. Rock Auto, Advance Auto parts and Autozone. The all come up with the same part number-Dorman 594-117. I ordered one from Advance and it came in today. I wish I had taken a picture of it in hindsight for comparison. It will sit there for a couple days until this gets resolved.

Here is a picture of the stock original. .Please note the position of the crankshaft key-way and the location of the timing mark.

Note key-way position and timing mark. Approx. 170 degrees.

This stock harmonic balancer has the following characteristics:.
7" Diameter
5/8" thick
Weighs 7 lbs.

Dorman # 594-117
6 1/2" Diameter
1" thick
Weight 8.25 lbs.

If you were to put the Dorman in the same key-way position, the timing mark on the outside is directly in line with the key-way straight up and not 170 degrees off like the stock one.

Could this Dorman's dimensions and weight be some kind of upgrade? My big concern is the difference in weight.
and
Has the original balancer slipped?
Again, thank you for your help.
streets
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Old February 6th, 2019, 04:04 PM
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I would say you found the problem. You may want to get the original harmonic balancer rebuilt. Several places do it and some on here can provide names. Your accessories will run at the same speed if you get it rebuilt, the Dorman would under drive your accessories.
..........Just my two cents worth
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Old February 6th, 2019, 04:05 PM
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I think your right, that likely the outer ring has slipped. The correct location on the 425 is with the key way. Since you don't know the history of the engine there's also a balancer used on the 1964 330 that looks similar but with a different timing mark, its closer to the 9:00 O'clock position from the keyway. Can you post some photos of the replacement damper you purchased? John
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Old February 6th, 2019, 04:18 PM
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Originally Posted by OLDSter Ralph View Post
Your accessories will run at the same speed if you get it rebuilt, the Dorman would under drive your accessories.
That's just the hub diameter, not the pulley diameter, so there shouldn't be a change in speeds.
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Old February 6th, 2019, 04:21 PM
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FYI- if you choose not to have it rebuilt and buy a new modern one, you will need to update the timing pointer, been there done that.....
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Old February 6th, 2019, 04:28 PM
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Originally Posted by Fun71 View Post
That's just the hub diameter, not the pulley diameter, so there shouldn't be a change in speeds.
OOOOPS, good catch. Thanks for correcting me.
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Old February 6th, 2019, 04:36 PM
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Your fast replies are greatly appreciated and I hope I'm going the right direction. If memory serves I vaguely remember the timing mark is in line with the key-way as John mentioned. John would that timing mark be to the closest side of the key-way?

I will go back and pick the Dorman up tomorrow and post a picture of it. The parts guy also mentioned that Dorman # also fits a 330 cu. in. and 455 to mention just a few.

I'll attempt to get a list of the years and applications. I also learned it is suggested the Dorman balancer come with an optional sleeve, as there was a 0.20 difference in the outside shaft that goes into the timing cover.

Thanks again,
Dave
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Old February 7th, 2019, 06:13 AM
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I highly recommend Damper Doctor if you are going to rebuild yours. I have had two rebuilt by them and excellent results on both.
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Old February 7th, 2019, 06:49 AM
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Get yours rebuilt. The Dorman is for a 68-up 350-455 engine and is counterbalanced differently from the 64-67 dampers. The later damper has the timing notch in a different position and would require using the later timing tab. You can use the later part if you get it re-balanced to the earlier spec.

Last edited by Run to Rund; February 7th, 2019 at 06:37 PM. Reason: typo
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Old February 7th, 2019, 05:18 PM
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Thanks Guys for the help. I didn't get to the parts store today too take a picture of the Dorman, but I will tomorrow and post it. If they made these to almost duplicate an original 425 balancer, it is my hope the relationship of the crank key way and the timing notch are in line or concurrent. That would definitely tell me it slipped.
I'm thinking like Rund to Rund, whoever assigned that Dorman part number didn't do any research.So the correct one is unavailable.
Emailed Damper Doctor several days ago and got no response. I'll call them tomorrow and see if they can do a fast turn around. I read they close at different months of the year and March is one of them.
Anybody have any insight of how much they charge?
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Old February 8th, 2019, 06:10 AM
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Originally Posted by streets View Post
Anybody have any insight of how much they charge?
I can try to find my old receipts. It was many years ago but I will try to find it. Prices may have changed. I remember both of mine came back looking like factory dampers.
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Old February 8th, 2019, 09:00 AM
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I had (might still have) an NOS damper, would have to search for it. PM me if you can't contact a rebuilder.
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Old February 9th, 2019, 09:49 AM
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425 Harmonic Balancer Help Please

Originally Posted by Run to Rund View Post
Get yours rebuilt. The Dorman is for a 68-up 350-455 engine and is counterbalanced differently from the 64-67 dampers. The later damper has the timing notch in a different position and would require using the later timing tab. You can use the later part if you get it re-balanced to the earlier spec.
Rund to Rund was dead on.
Made a 2nd trip to Advance Auto Parts and took this comparison picture.
I didn't call Damper Doctor but did talk to Ron at Damper Dudes 1800-413-2673. He was very knowledgeable about Olds 425 Harmonic Balancers (HB). The HB for a 1966 Toronado 425 was only made from 1965-67. I am guessing Dorman has it listed wrong.

If the crank shaft key-way is in the 12:00 position then the timing mark should be as well. So my HB has slipped and explains the out-of sink problem with the HB and #1 TDC. In checking this company's references they seem to have a great reputation. Ron said the turn around time is one day.

The cost for the rebuild is about $98. Shipping to Anderson, CA was $36 from central Illinois. So I expect the same for the return shipping. Total should be around $170.00.

I thank everyone on here for your help and offer of a replacement. Hopefully this post will help some other member.

Dave

Key-way to Timing Mark difference. Original has slipped.

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