bad vibrations
Thread Starter
Melting Slicks
Joined: Dec 2000
Posts: 2,130
Likes: 1
From: mesa,az
bad vibrations
o i dropped the new built 327 in my 65 vette the other day. finally got it all hooked up this AM. Take it out for a spin and duh. large vibration. it gets more severe with revs. hardly feel it in neutral, pretty strong under load and acceleration very strong when engine braking. it increases in frequency with RPM s but not so often as crank rotation. I didn't remove the transmission during the engine swap. tomorrow I will raise the car on jacks and get under it with the motor running try to see whats going on. any ideas.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
With the trans in 'N' and the engine revving...does the car vibrate?
Does it only vibrate when the car is in gear or moving?
Does the vibration coincide directly with either car speed or engine speed?
Does it only vibrate when the car is in gear or moving?
Does the vibration coincide directly with either car speed or engine speed?
Last edited by Durango_Boy; Mar 10, 2007 at 11:30 PM.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
With the trans in 'N' and the engine revving...does the car vibrate?
Does it only vibrate when the car is in gear or moving?
Does the vibration coincide directly with either car speed or engine speed?
Instructor
Joined: Jan 2007
Posts: 152
Likes: 0
o i dropped the new built 327 in my 65 vette the other day. finally got it all hooked up this AM. Take it out for a spin and duh. large vibration. it gets more severe with revs. hardly feel it in neutral, pretty strong under load and acceleration very strong when engine braking. it increases in frequency with RPM s but not so often as crank rotation. I didn't remove the transmission during the engine swap. tomorrow I will raise the car on jacks and get under it with the motor running try to see whats going on. any ideas.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Check the stuff D_boy suggested. If no vibrations when revving engine in the driveway, take to the road and get your vibrations going. Put the car in neutral, take foot off the gas, and coast at speed. Still got vibrations? If so, it's likely a U-joint...or if you changed driveshafts for some reason, the d-shaft was not balanced correctly.
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Thread Starter
Melting Slicks
Joined: Dec 2000
Posts: 2,130
Likes: 1
From: mesa,az
as i sit here thinking. I am using the same flywheel / clutch I used on the previous engine. I had sent that flywheel out with the clutch and crank to be balanced for that combo. I had assumed they zero balanced it and just bolted it onto this engine. I wonder if they balanced it to the LJ cast crank in the last engine. Maybe I will rotate my clutch on the flywheel. see if that changes anything.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
That is a likely suspicion. When a shop balances crank and flywheel, it's best to do flywheel separately, first...then as a set. That way, both are well balanced to begin with. If the balance was done as a set and material only taken out of the crank, that could well be your problem. Look for any balance drilling on your flywheel. If you don't see any, have it balanced and re-install. Good luck.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
I re-read your last post.... If you are re-installing the crank, flywheel, clutch set from your prior engine, are the flywheel and crank still indexed as they were before? If not, see if you can match up any "wear/rub patterns" on the crank/flywheel mating surfaces to get them oriented the same as they were.