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Vibration

Explorer

Bronco Guru
Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
Got the "77" running fine, but had a vibration in it even in park or neutral. Tranny was bad so had it rebuilt w/ new flywheel, torque converter. Still has the vibration, not quite as bad, but gets worse under load. We'll check the motor mounts tomorrow. Looking for other things to check. Engine is of unknown pedigree, appears to be "86" 5.0 w/ Holley 4160 and HB part# matches up to that year. Very few miles on it, but internals are unknown. How can I tell if the HB is good or not? Any suggestions appreciated. A guy over on FTE has same problem, but no solution yet.
 

bax

Contributor
Old Member
Joined
Aug 22, 2005
Messages
14,491
Check the balancer. It may have spun putting the motor out of balance. Check the ring on the outside and the rubber.
 

brewchief

Sr. Member
Joined
Feb 11, 2007
Messages
871
Got the "77" running fine, but had a vibration in it even in park or neutral. Tranny was bad so had it rebuilt w/ new flywheel, torque converter. Still has the vibration, not quite as bad, but gets worse under load. We'll check the motor mounts tomorrow. Looking for other things to check. Engine is of unknown pedigree, appears to be "86" 5.0 w/ Holley 4160 and HB part# matches up to that year. Very few miles on it, but internals are unknown. How can I tell if the HB is good or not? Any suggestions appreciated. A guy over on FTE has same problem, but no solution yet.

Proper imbalance on the flywheel? A flywheel or flexplate for a 77 motor will be setup for 28oz imbalance, 86 motor needs 50oz imbalance.

Brewchief;D
 

bax

Contributor
Old Member
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Aug 22, 2005
Messages
14,491
Brewchief may be on to something. Good catch
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
Proper imbalance on the flywheel? A flywheel or flexplate for a 77 motor will be setup for 28oz imbalance, 86 motor needs 50oz imbalance.

Brewchief;D

The same is true for the balancer too, in case it may have been swapped out too.
 
OP
OP
Explorer

Explorer

Bronco Guru
Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
Yea, I told the tranny guy that. HB part# matches "86" engine. "Supposibly" he put the right flywheel/flexplate in. We'll check the HB today, how do I tell if ring has slipped? Any marks, keyway to look for? Never had one in my hands to look at. Pic of proper alignment would be nice if anyone has one handy.

Was just researching a little and was wondering "if" tranny guy installed 28oz, can I just change the HB to match?
 
Last edited:

fstik

Full Member
Joined
Feb 7, 2004
Messages
311
Yea, I told the tranny guy that. HB part# matches "86" engine. "Supposibly" he put the right flywheel/flexplate in. We'll check the HB today, how do I tell if ring has slipped? Any marks, keyway to look for? Never had one in my hands to look at. Pic of proper alignment would be nice if anyone has one handy.

Was just researching a little and was wondering "if" tranny guy installed 28oz, can I just change the HB to match?

Nope, The different weights are specific for the crankshaft you are running. I have been down this road before, you will have to install the right flexplate.

As far as checking the HB to see if it spun, I would think you could pull the spark plug on cylinder #1 and bring it to top dead center, then check to see if your timing marks line up.

fstik
 
OP
OP
Explorer

Explorer

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Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
Will do. Thanks for quick response. Should have known it wouldn't be that easy. I'll double check with tranny guy Monday. I told him, but you never know.
 
OP
OP
Explorer

Explorer

Bronco Guru
Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
Just caught tranny guy in shop. His supplier told him it was the same flexplate for both. Like that's never happened before. So 99% sure thats the problem. I'll double check all the numbers again and check the other stuff. I'll post again when it's right. Thats why I like to do everything myself, but tranny's are not in my job skills. Thanks again guy's for all the help, I'm slowly getting trained.
 
OP
OP
Explorer

Explorer

Bronco Guru
Joined
Mar 2, 2008
Messages
4,390
Loc.
Raphine, Virginia
Ok guy's, it's right. Put the 50oz flywheel in and life is good. Vibration gone, running great. I love the stuff previous owners do. For anyone swapping out their 302 for a 5.0. 1982 is when they went to 50oz balancer and flywheel, hope this saves someone else some problems. Time will tell how much damage was done to bearings, have no idea how long it was driven before tranny went out.
 
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