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Harmonic Balancer dancing?
https://www.slantsix.org/forum/viewtopic.php?t=66573		 Page 1 of 1
Author:  René.G [ Fri May 06, 2022 1:18 am ]
Post subject:  Harmonic Balancer dancing?
Yester day i was doing anything to get our Valiant running, and it drives me crazy.
I did all the timing procedes our of „school book“. I got the engine running by only showing him the key.. :wink:
Now the problem is, as soon as the engine runs it only takes a minute an he dies.
In that minute the engine first is really good running, the rotation speed goes down and ends with a backfire trough the carb. While this minute i was looking at the timing mark on the damper with the timing lamp. There i could see, that the mark is moving by it’s self forward and backwards.. :?

I know there can be a problem with the outer damper which is slipping around the core..?
Any other ideas?

Greetings from Germany
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Author:  volaredon [ Fri May 06, 2022 5:17 am ]
Post subject:  Re: Harmonic Balancer dancing?
I'm thinking more along the lines of timing chain wear or problems in the distributor with the advance weights maybe?
Author:  René.G [ Fri May 06, 2022 5:32 am ]
Post subject:  Re: Harmonic Balancer dancing?
Oh no :? . Please not the timing chain. My idea is to get the damper to tdc again. So i can check if it‘s really the damper.
If that is ok, i will check the distributor..
But i will not spend more cash in that 170.
i have an offer for an reconditioned 195 with Clifford intake and headers.Trans included.
The guy is asking around 3K..
Author:  DadTruck [ Fri May 06, 2022 7:02 am ]
Post subject:  Re: Harmonic Balancer dancing?
I agree with Don, unless the damper was really shot I would not expect the ring to be slipping at idle. And when a damper ring does slip, it goes one way, probably the direction opposite of the rotation, not back and forth.
How much is the timing mark moving?
A couple of degrees at idle is not catastrophic.
I know you say the engine won’t keep running at idle, but will it continue to run at a higher ROM? Is so, does the ‘dancing’ stop if the rpm’s are raised to like 2000?
You should see the mechanical advance move the timing forward.

Also check the basics:
Sparkplug wires in the correct order.
Good coil connections
Distributor cap and rotor on firmly
Ballast resistor continues to send power to the coil with the key in the start and run position.
I have read that some of todays tune up kits condensers are junk, maybe try swapping it out.
Good Luck
Author:  volaredon [ Fri May 06, 2022 10:31 am ]
Post subject:  Re: Harmonic Balancer dancing?
Quote:
Oh no :? . Please not the timing chain. My idea is to get the damper to tdc again. So i can check if it‘s really the damper.
If that is ok, i will check the distributor..
But i will not spend more cash in that 170.
i have an offer for an reconditioned 195 with Clifford intake and headers.Trans included.
The guy is asking around 3K..
A "195" huh? And a timing chain isn't the end of the world on these// parts aren't all that much money. There are a few guys around here doing surprising things with a 170. And on buying someone else's "reconditioned" engine BEWARE! I've seen guys power wash, paint and maybe replace a few gaskets and call that "reconditioned".
And on my latest rebuild I was really awakened on some aspects of the process even though this one wasn't my 1st rodeo.
It was my 1st time actually measuring things like chamber CC size, piston "in the hole"" depth and such. If I go thru an engine I go completely thru it with machine shop help on boring and other machine shop duties, or I don't do it. But things like pistons intentionally made "shorter" so as to "guarantee " compression ratio doesn't change with overbore and replacement, which if not allowed for will actually reduce performance.... Combustion chambers bigger than specified, compression ratio lower than book spec, those sorts of things... Sometimes you're better with what you have.
Author:  SlantSixDan [ Fri May 06, 2022 11:43 am ]
Post subject:  Re: Harmonic Balancer dancing?
Check for a loose timing chain: remove the distributor cap, turn the engine by hand using the fan and fan belt in its normal direction of rotation until the distributor rotor starts to move and the timing mark on the crank pulley is at the lowermost mark on the timing tab. Then rotate the engine by hand the other direction until the distributor rotor once again begins to move. The timing marks will then give a direct reading, in crankshaft degrees, of how loose your timing chain is (or isn't).
Author:  René.G [ Fri May 06, 2022 3:09 pm ]
Post subject:  Re: Harmonic Balancer dancing?
Hey Guys.

Thanks for your answers.
I guess the mark goes up to 50degree beyond, only one way.
Of course it would be no problem to change the timing chain and the damper as well.. but..
To get those parts here in Germany is a mess :( .
If it was a V8- no matter.
I hope it is only the distributor. There i have a second one which came with the car.
Author:  Daddiojoe [ Sun May 08, 2022 6:36 am ]
Post subject:  Re: Harmonic Balancer dancing?
Slant Six Dan--

Good advice on checking how loose timing chain is by watching rotor spin. What are acceptable parameters?

Thanks,
Joe
Author:  Jase [ Mon May 09, 2022 9:50 am ]
Post subject:  Re: Harmonic Balancer dancing?
Quote:
Slant Six Dan--

Good advice on checking how loose timing chain is by watching rotor spin. What are acceptable parameters?

Thanks,
Joe
I can not exactly recall anymore.... But I checked mine and it showed something like 4 or 5 degrees... And the timing chain was somewhat loose on an 80,000 mile engine. I did not think until right now of checking it after the new timing chain was installed, so I can not offer a before and after for context.
Author:  SlantSixDan [ Tue May 10, 2022 10:39 pm ]
Post subject:  Re: Harmonic Balancer dancing?
You want as little slack as possible. A few degrees, okeh, engines don't stay new forever. But every little bit makes the engine run worse, so if you're looking at 4-5-6+ degrees of slop, you really need to put a timing chain swap on the to-do list.
Author:  Daddiojoe [ Wed May 11, 2022 11:18 am ]
Post subject:  Re: Harmonic Balancer dancing?
Thanks, Dan!


Joe
Author:  Rick Covalt [ Wed May 11, 2022 5:27 pm ]
Post subject:  Re: Harmonic Balancer dancing?
In this day and age don't be surprised if your brand new chain does not have more slop than it should! Ask me how I know. :(
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