Engine vibrations 1500 - 2000 rpm
Thread Starter
Instructor
Joined: Aug 2011
Posts: 109
Likes: 6
From: Hessen
Engine vibrations 1500 - 2000 rpm
Hi there,
my 350cui / MT Corvette has an engine vibration problem.
It is not related to driving the car it is related to the engine rpm... occurs around 1500 rmp and disappears above 2000 rpm.
The entire clutch assembly has been replaced already as well as the rear transmission mount/rubber cushion. The engine rubber mounts look ok. Also the balancing weights on the fly wheel are still there and the balancer/pulley seems to be ok as well.
Has anybody experienced the same, has an idea what the issue could be and/or fixed it!?!?!
Thanks in advance...
René
my 350cui / MT Corvette has an engine vibration problem.
It is not related to driving the car it is related to the engine rpm... occurs around 1500 rmp and disappears above 2000 rpm.
The entire clutch assembly has been replaced already as well as the rear transmission mount/rubber cushion. The engine rubber mounts look ok. Also the balancing weights on the fly wheel are still there and the balancer/pulley seems to be ok as well.
Has anybody experienced the same, has an idea what the issue could be and/or fixed it!?!?!
Thanks in advance...
René
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
I had a vibration that I could not find for the longest time. Then I replaced the transmission mount (my cars a A/T) and it went away. Turns out that my exhaust on my right side was laying (more like pinched between the hanger and cross member) against the cross member. The new mount lifted the exhaust up.
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
Hi there,
my 350cui / MT Corvette has an engine vibration problem.
Also the balancing weights on the fly wheel are still there and the balancer/pulley seems to be ok as well.
Has anybody experienced the same, has an idea what the issue could be and/or fixed it!?!?!
Thanks in advance...
René
my 350cui / MT Corvette has an engine vibration problem.
Also the balancing weights on the fly wheel are still there and the balancer/pulley seems to be ok as well.
Has anybody experienced the same, has an idea what the issue could be and/or fixed it!?!?!
Thanks in advance...
René
Pete
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Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
Years ago, my family's then brand new 79 Malibu with a 305 had a wobbly balancer. When you were idling in drive, the harmonic vibrations caused the steering wheel to almost blur. Brought it back to the Chevy dealer to complain, and the $%&* service manager offered to balance the front wheels and do a front end align to fix the problem.
Can you believe they are still in business?
Can you believe they are still in business?
Instructor
Joined: Mar 2013
Posts: 215
Likes: 0
From: Sunshine Coast Qld
If you have a 350cid engine it is or should be internally balanced. The flywheel should be neutrally balanced, no additional weights should be on the flywheel. Same for the harmonic balancer. Now if you have a 383, then I think you should have balance weights on the flywheel and harmonic balancer, 'cause that engine would be externally balanced
Pete
Pete
Thread Starter
Instructor
Joined: Aug 2011
Posts: 109
Likes: 6
From: Hessen
Hi folks,
thanks so much for all your comments!
All I can say is that the clutch system is entirely new... and that the vibrations have been there before the clutch exchange... but they have been much worse. However, the vibrations are annoying!
Unfortunately I cannot tell what has been done to the engine "invisibly" but from a first point of view everything looks original.
I do not know if AC Delco delivers poorely balanced Clutch Sets but I will check all related components.
If any new idea occurs what the root cause could be... just let me know!
Thanks...
René
thanks so much for all your comments!
All I can say is that the clutch system is entirely new... and that the vibrations have been there before the clutch exchange... but they have been much worse. However, the vibrations are annoying!
Unfortunately I cannot tell what has been done to the engine "invisibly" but from a first point of view everything looks original.
I do not know if AC Delco delivers poorely balanced Clutch Sets but I will check all related components.
If any new idea occurs what the root cause could be... just let me know!
Thanks...
René
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
Hi folks,
thanks so much for all your comments!
All I can say is that the clutch system is entirely new... and that the vibrations have been there before the clutch exchange... but they have been much worse. However, the vibrations are annoying!
Unfortunately I cannot tell what has been done to the engine "invisibly" but from a first point of view everything looks original.
I do not know if AC Delco delivers poorely balanced Clutch Sets but I will check all related components.
If any new idea occurs what the root cause could be... just let me know!
Thanks...
René
thanks so much for all your comments!
All I can say is that the clutch system is entirely new... and that the vibrations have been there before the clutch exchange... but they have been much worse. However, the vibrations are annoying!
Unfortunately I cannot tell what has been done to the engine "invisibly" but from a first point of view everything looks original.
I do not know if AC Delco delivers poorely balanced Clutch Sets but I will check all related components.
If any new idea occurs what the root cause could be... just let me know!
Thanks...
René
If you replaced it I wound move up to the harmonic balancer.
Thread Starter
Instructor
Joined: Aug 2011
Posts: 109
Likes: 6
From: Hessen
I did not do or check anything the last days because I was busy. However, I would again like to thank all of you for your comments.
Back to the car... the flywheel was not changed nor reworked... it was not touched at all but the surface looked ok... no marks no heat marks... nothing. The spark wires have been replaced a few years ago... together with the coil, Petronix ignition and Edelbrock carb & intake.
I will check PS, WP, Fan, Alt... and also all the belts. We will see...
Have a great weekend!!!
Cheers...
René
Back to the car... the flywheel was not changed nor reworked... it was not touched at all but the surface looked ok... no marks no heat marks... nothing. The spark wires have been replaced a few years ago... together with the coil, Petronix ignition and Edelbrock carb & intake.
I will check PS, WP, Fan, Alt... and also all the belts. We will see...
Have a great weekend!!!
Cheers...
René
Thread Starter
Instructor
Joined: Aug 2011
Posts: 109
Likes: 6
From: Hessen
Hi guys, this is the German Guy again!
I did some investigation and found out the following...
There are small "rubber-pieces" squeezing out of the area in between the inner and outer ring of the balancer... so this might be one reason for vibrations due to movement of the balancing weight!?! If this is the case the ignition timing might be misaligned as well!?! In addition, I found out that there is kind of a vacuum leak (at least I would guess it is a small one) between the carburator, the brake booster and the small round die-cast distribution-connector (one "in"... two "out") for the other vacuum controlled systems. So, with an Edelbrock Performer carburator and intake manifold where would you connect the vacuum for the brake booster and the "rest"... both on the carburator or one on the manifold and the other on the carburator!?!
Thanks again so much for all your help!
Best regards from (meanwhile cold and rainy) Germany!!!
Cheers...
René
I did some investigation and found out the following...
There are small "rubber-pieces" squeezing out of the area in between the inner and outer ring of the balancer... so this might be one reason for vibrations due to movement of the balancing weight!?! If this is the case the ignition timing might be misaligned as well!?! In addition, I found out that there is kind of a vacuum leak (at least I would guess it is a small one) between the carburator, the brake booster and the small round die-cast distribution-connector (one "in"... two "out") for the other vacuum controlled systems. So, with an Edelbrock Performer carburator and intake manifold where would you connect the vacuum for the brake booster and the "rest"... both on the carburator or one on the manifold and the other on the carburator!?!
Thanks again so much for all your help!
Best regards from (meanwhile cold and rainy) Germany!!!
Cheers...
René
Thread Starter
Instructor
Joined: Aug 2011
Posts: 109
Likes: 6
From: Hessen
Today I had the chance to take a picture of the pulley/balancer. There is a piece of rubber squeezing out from the gap in between. Could this be an indication for a worn balancer... and ultimately causing vibrations.
I know, a SB is an internally balanced engine... but is it possible, that a balancer with a moving weight could have a negative impact to the internal balance!?!
Thanks again for all you help so far!
Cheers...
René
I know, a SB is an internally balanced engine... but is it possible, that a balancer with a moving weight could have a negative impact to the internal balance!?!
Thanks again for all you help so far!
Cheers...
René
Oh wait they don't make 383 cranks, do they
Thread Starter
Instructor
Joined: Aug 2011
Posts: 109
Likes: 6
From: Hessen