Replace stock Harmonic Balancer?

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WSUTARD

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As some of you know, I'm in the process of digging into my 340. Or maybe screwing it up...yet to be seen.

Anyway, I yanked the stock harmonic balancer. I'm wondering if there is any benefit to going with an after market one instead?

I'm trying not to spend more money on the engine. However, it id makes sense then I can.

68 340, internal balanced.
IMG_1379.JPG
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Agree , the single important thing is safety . If you decide to purchase a SFI balancer it will have degree markings to make your life a little easier .
 
Deteriorating rubber (either hardened or cracked) makes them not do the intended job, which is to damp out torsional vibrations within the crankshaft itself. If you were grandma, and never drove it revved up at all, then it wouldn't much matter. But, as said having the outer ring come off when running would be bad, even for grandma.
 
Unless u plan to hit 6k+ rpms a good bit, there isnt much need for a high dollar balancer.

Use a paint marker for timing tape.
 
There's a place here in town that rebuilds those. machine shop would probably recommend refurbishing your American made one instead of buying Chinese junk like I did. My -2
 
As some of you know, I'm in the process of digging into my 340. Or maybe screwing it up...yet to be seen.

Anyway, I yanked the stock harmonic balancer. I'm wondering if there is any benefit to going with an after market one instead?

I'm trying not to spend more money on the engine. However, it id makes sense then I can.

68 340, internal balanced.
View attachment 1715030204 View attachment 1715030205


Your part is not useable. Replace it.
 
Even a really expensive one is cheaper than destroying your bottom end and then having to fix it. If that's the original, it's almost FIFTY year old rubber man!
 
I'm wondering if there is any benefit to going with an after market one instead?
just in case you're not convinced yet - YES, there are many - IMHO - #1 being your personal safety, #2 being protecting the investment you're making in the engine. Even a straight stock replacement would be fine. (if you're not looking to hit a race track with it) The one you got there is plumb wore out.
https://www.summitracing.com/parts/sum-163273/overview/year/1968/make/dodge/model/dart
 
Is there anything I need to do to the timing marks on he block or do I just use the 0 line now?
 
just in case you're not convinced yet - YES, there are many - IMHO - #1 being your personal safety, #2 being protecting the investment you're making in the engine. Even a straight stock replacement would be fine. (if you're not looking to hit a race track with it) The one you got there is plumb wore out.
https://www.summitracing.com/parts/sum-163273/overview/year/1968/make/dodge/model/dart

If you go with this one. Get some good clear coat on it asap. It will rust in no time, ask me how I know. :(
 
Is there anything I need to do to the timing marks on he block or do I just use the 0 line now?
You have a '68 340 right? That originally had the older water pump and timing cover with the timing mark on the cover over on the passenger side. Most (or all) of the newer dampers are for the '70 and up timing marks, which are on the driver's side. What you shows in the ad looks like it is for the later marks on the driver's side.

So 1st thing it to check on which side are the timing marks on the timing cover that you have. If on the driver's side, then you are basically set. If on the passenger side, then you are going to have to make a pointer on the driver's side, or make new marks on the damper to line up with the passenger side timing cover marks.

Either way, with your heads off the engine as the are you are going to have to find EXACT TDC on #1 cylinder. Use a dial indicator with the heads off on #1 piston to find exact TDC, and carefully locate your marks so that zero is EXACT TDC on #1. Since you are going to be messing with cams and/or timing them, you need to be spot on with this to have a solid, accurate reference.

Once you have that zero reference, then you just read the timing on the damper against you zero mark.

It may be confusing a bit, but hang in there; we're all pulling for ya.
 
You have a '68 340 right? That originally had the older water pump and timing cover with the timing mark on the cover over on the passenger side. Most (or all) of the newer dampers are for the '70 and up timing marks, which are on the driver's side. What you shows in the ad looks like it is for the later marks on the driver's side.

So 1st thing it to check on which side are the timing marks on the timing cover that you have. If on the driver's side, then you are basically set. If on the passenger side, then you are going to have to make a pointer on the driver's side, or make new marks on the damper to line up with the passenger side timing cover marks.

Either way, with your heads off the engine as the are you are going to have to find EXACT TDC on #1 cylinder. Use a dial indicator with the heads off on #1 piston to find exact TDC, and carefully locate your marks so that zero is EXACT TDC on #1. Since you are going to be messing with cams and/or timing them, you need to be spot on with this to have a solid, accurate reference.

Once you have that zero reference, then you just read the timing on the damper against you zero mark.

It may be confusing a bit, but hang in there; we're all pulling for ya.
The previous owner swapped out the pump and timing cover for the one with the marks on the driver side. I guess I don't follow with finding the zero mark. Once I find TDC will the 0 mark on my timing cover point to 0 on the dampener? Or are you saying it might point to a different number on the dampener and then I use that as zero from that point forward?
 
The previous owner swapped out the pump and timing cover for the one with the marks on the driver side. I guess I don't follow with finding the zero mark. Once I find TDC will the 0 mark on my timing cover point to 0 on the dampener? Or are you saying it might point to a different number on the dampener and then I use that as zero from that point forward?
Good that you know all of that. If things are perfect on all parts, then the 0 on the new damper will line up on the 0 on the timing cover marks. If they are off a bit, then the 0 on the damper will line up on some other timing cover mark. Use that other mark as your new reference, and read the timing tape numbers on the new damper against that new reference point.

BTW, I can't emphasize enough to use a tool like a dial indicator to find exact TDC; eyeballing it is iffy at best. This is the baseline for everything else so it needs to be spot on. 3-4 degrees off on cam timing will show right up in the engine's performance.
 
Ok you guys convinced me. I went with this one. Professional Products 80012 7.25" Damper for Chrysler 318/340/360 Amazon.com: Professional Products 80012 7.25" Damper for Chrysler 318/340/360: Automotive

I'm assuming all the cheap ones are going to be made in china.

You're right! This one is made in China, but they do make a SFI approved one. If that's any help.

http://www.corvetteforum.com/forums/c6-corvette-general-discussion/3452723-
ati-balancer-vs-summit-sfi-harmonic-dampers-sum-c2501.html
Professional Products Harmonic Dampers... Any good? • Speed Talk
Here's some failures on this subject.
Hope this helps.
 
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You're right! This one is made in China, but they do make a SFI approved one. If that's any help.

Professional Products Harmonic Dampers... Any good? • Speed Talk
Here's some failures on this subject.
Hope this helps.
Hmm, that thread makes me question my decision. Im not going to be racing, just a street/cruise vehicle looking for low end performance. If I get up to 6k rpm I'm doing something wrong...

Anyone know of a sub $100 US made one that is reliable?
 
Hmm, that thread makes me question my decision. Im not going to be racing, just a street/cruise vehicle looking for low end performance. If I get up to 6k rpm I'm doing something wrong...

Anyone know of a sub $100 US made one that is reliable?


Again, it's not a place to skimp. What does RPM have to do with it? You can have frequency issues at any RPM. Not just high RPM. Don't step over a donut to pick up a dog turd. You see what happens to rubber over years. Now, change the bob weight, change the RPM, change the load. All those change the frequency where issues can occur. The harder you work the rubber, the quicker it becomes hard and fails.
 
Again, it's not a place to skimp. What does RPM have to do with it? You can have frequency issues at any RPM. Not just high RPM. Don't step over a donut to pick up a dog turd. You see what happens to rubber over years. Now, change the bob weight, change the RPM, change the load. All those change the frequency where issues can occur. The harder you work the rubber, the quicker it becomes hard and fails.
Do they make single piece ones? Maybe I should go for that.

What if I'm on a diet and don't want the donut but I need to get the turd off the lawn?
 
No single piece ones... the outer ring connected through the rubber ring is what makes the damper actually damp.

I suspect there are a lot of the PP dampers running OK out there. The issue is what gets damaged IF they fail. Other damper brands have problem from time to time.

The stock ones can be rebuilt as suggested earlier....it is all in the rubber used, and the care of installation of the ring to keep it centered.
 
I think I will keep running my Chrysler made in USA 340 damper, maybe someday I can afford an ATI
DSCF0179.JPG
 
Do they make single piece ones? Maybe I should go for that.

What if I'm on a diet and don't want the donut but I need to get the turd off the lawn?


See post 23.

In 2002 I was still replacing cranks that were junk from Moroso single piece dampers. And I'm talking nice, aftermarket cranks.

The two biggest deals with dampers like you are using is overall diameter (weight) and the durometer of the rubber used between the outer ring and the hub.
I would rather have what you have rebuilt if and its a big IF they can tell you the durometer of the rubber is OE.
I've never seen an OE Chrysler damper fail, but I did see a couple of GM ones fail back in the early 80's and it was a hell of a mess. Not as bad as a clutch but bad enough and that's where the SFI damper rule came from. NHRA had to decide when you use an SFI damper they picked 9.90 at the beginning. I don't know where it is now but I think it's slower than that.
 
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