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Still getting powerful vibration
https://slantsix.org/forum/viewtopic.php?t=54267		 Page 2 of 2
Author:  Danarchy [ Thu Jan 09, 2014 2:19 pm ]
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Would a flexplate with stress cracking or loose bolts vibrate louder at low idle vs. high idle?
I would pull the inspection plate and have a look. Bent flex plate, missing a bolt???
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What about the torque converter - would a leaking or low-fluid torque converter vibrate due to imbalance at low idle more than high?
Both Torque Converters that I have installed on my car have had balancing weights*(simular to a car wheel, but welded on), I don't know if this is common or normal, but you might see if you have them or if it looks like something is missing.

* one was original to the car, the other was a New replacement.
Author:  robertob [ Fri Jan 10, 2014 11:39 am ]
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It's Drive that's the issue. The second I punch Drive, idle drops and there's low-end vibration. Step on the gas, the vibration goes away completely.
Sounds transmission related to me. Torque Converter, Flexplate, Mounting Bolts??? As RPM's go up it balances it self and vibration goes away. Just guessing.
I agree with your idea.

Would a flexplate with stress cracking or loose bolts vibrate louder at low idle vs. high idle?

What about the torque converter - would a leaking or low-fluid torque converter vibrate due to imbalance at low idle more than high?

Those problems would vary with RPM - I had a '64 Dart that someone swapped later engine or crankshaft without using the bushing. Basically the same as an unbalanced torque converter. Anyway, at idle it had a bad vibration that would smooth out at higher rpms. but then the vibration came back even worse at high speeds, like 70 mph or faster.
Author:  Eatkinson [ Sat May 10, 2014 9:45 pm ]
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I think the hard poly mount is the problem. Do we have anyone else here using those mounts?

The mounts can be reversed and if the rubber one is turned around it transmits an obnoxious level of vibration into the car.
Josh, you were correct, the source of my low-idle vibration was indeed the hard poly mounts. Doc confirmed it as well and advised me to switch them. Swapped the original rubber mounts back in and the vibration completely went away, now the car runs silent inside.

I still have a poly transmission mount - hear a little noise that might be coming from this mount. I may replace it with a traditional rubber mount if it starts bugging me but I'm enjoying the newfound silence at idle too much right now to care.

Wish I hadn't sprung for those poly mounts with my rebuild after all. They came so highly-rated. Had no idea they'd transfer so much vibration inside. A word of caution to anyone who plans to use them for their street vehicle and likes the quiet stock ride of the slant. I wouldn't use these.
Author:  1930 [ Sun May 11, 2014 3:30 am ]
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Quote:
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I think the hard poly mount is the problem. Do we have anyone else here using those mounts?

The mounts can be reversed and if the rubber one is turned around it transmits an obnoxious level of vibration into the car.
Josh, you were correct, the source of my low-idle vibration was indeed the hard poly mounts. Doc confirmed it as well and advised me to switch them. Swapped the original rubber mounts back in and the vibration completely went away, now the car runs silent inside.

I still have a poly transmission mount - hear a little noise that might be coming from this mount. I may replace it with a traditional rubber mount if it starts bugging me but I'm enjoying the newfound silence at idle too much right now to care.

Wish I hadn't sprung for those poly mounts with my rebuild after all. They came so highly-rated. Had no idea they'd transfer so much vibration inside. A word of caution to anyone who plans to use them for their street vehicle and likes the quiet stock ride of the slant. I wouldn't use these.
If you would like to get rid of them let me know. I wish that I had used them instead of the new rubbers in my W-100 but at the time did not bother to take the time to take my time and ask the questions I should have asked.

P.M no good but E-mail is jhason2@yahoo.com
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