C2 Vibration when accelerating

[Tony S.]

Re: C2 Vibration when accelerating

You can certainly check your alignment to be sure. Front end toe in should be 0 to 1/8" toe in per wheel. I'd recheck your wheel and tire balance. I'll bet that is a culprit. Check that before you start spending alot of money on front end sub-assembly replacements.

[Paul J.]

Re: C2 Vibration when accelerating

Paul, Anthony, and Wayne,
Thank you for your additional suggestions. You're right Paul, there are a lot of things to check! I had a mechanic friend stop by last night and he checked the harmonic balancer and motor mounts and told me that they looked very good. With the rear suspension being completely overhauled recently (including driveshaft U-joints), and with a new clutch & pressure plate and various transmission bearings & bushings being replaced about 18 months ago (including the tranny & differential mounts), I am ruling out all of those items. With the vibration coming from the front and through the steering wheel, I am setting my focus on the front suspension. As you mentioned Paul, perhaps the tie rod ends or the ball joints as my mechanic friend suggested. I went for a long test ride this morning on I-95 and couldn't get the vibration to happen even one time, nor does it happen revving the engine in the driveway. Since it happens so infrequently, I will basically ignore the issue for now. However, I will purchase a front end rebuild kit and shocks from Eckler's and have my brother's shop R & R the parts during the winter. Hopefully, that will correct the occasional vibration problem that I have experienced during heavy acceleration. Once I change the front end parts, will I have to re-align the front tires? I just had a front & rear alignment done when the rear suspension job was finished (rear camber was set to about -0.38 deg.).

Thanks again for all your help,
Roger (50141)

Roger, while I haven't replaced many tie rod ends on vintage Vettes, I've replaced a lot recently on later model cars. As the joint wears, it will vibrate at certain speeds when the steering wheel is straight and there is no lateral load on the joint. Ball joints will make a clunk in a turn, but tie rod ends vibrate, and you'll get a hard vibration through the steering wheel. When you accelerate hard in a straight line, the vehicle weight is shifted to the rear, lightening the loading on the tie rod end. The vibration that you initially described sounds very much like what I have found. Several years ago, I was chasing this kind of vibration for a customer. The joints seemed tight, and I was lost until my buddies at the alignment shop told me about this. Since then, I've found its more common than you'd think. Certainly there are other things that can cause a vibration, but when you get tired of it check for play or loosness, or take it to your alignment shop. You can also take a shot at it and have your brother just replace them as you suggest. They're not very expensive.

And yes, I would realign the front end after the tie rod ends are replaced.

Paul

[Randy R.]

Re: C2 Vibration when accelerating

I heard a saying once: "If it doesn't work, check the last thing you fixed"

Tire balance, out of round tires, and a bent rim could be a possibilty.

Good luck.

[George C.]

Re: C2 Vibration when accelerating

I resurrected this post from the archives while looking for recommendations for an alignment shop. I read the posts from Anthony Stein about tire balance causing the vibration on hard acceleration, and thought I would throw in my $.02.
I also had a vibration on hard acceleration, easy acceleration no vibration, and had thought probably clutch or drive shaft out of balance. I have old KH made by Western Wheel knock offs, and the wonderful Coker Gold Lines. I also had a vibration in the steering wheel at about 65 MPH, and decided it was time to get the tires rebalanced.
Three years ago when I last had an alignment I had the road force balance done on all four wheels, but with all weights placed on the inside of the rims. This was doen with the Hunter machine.
So yesterday, yes Sunday I went off to the local Good Year store, and had all 4 wheels rebalanced and accepted that every one of them needed a weight on the outside of my knock off wheels. The technician offered me two options crappy balance with weight on the inside, the kind I already had, or a full balance with weights where they are needed. So I have to put up with the weights on the outside, until I replace the tires.
I CAN'T believe the difference; the vibration on acceleration is gone, as is the 65 MPH wheel shake.
I hope this helps someone else from replacing and rebuilding, before trying a rebalance on their tires, it sure worked wonders for me.
George

[Roger P.]

Re: C2 Vibration when accelerating

Hi George,
Thanks for resurrecting my post! I was just thinking about this post a few days ago after taking the Vette out for a weekend spin. Although I still get an occasional vibration on hard acceleration, I don't get any vibrations at all cruising and passing speeds. For that reason, I left things alone and decided that I would look into it further down the road when I need to replace the tires. My brother's shop installed my tires a couple of years ago, and I, too, instructed them to put the weights only on the inside of my knock-offs. As you said, it looks like Anthony's idea to check the tire balance is most likely the cause of the vibration. Since my tires are still near-new, and my knock-offs are hammered tight, I was wondering if there is a way to balance the tires without removing them from the car? Also, I was curious about your comment, "so I have to put up with the weights on the outside until I replace the tires". I assume that you will still have weights on the outside of the rims even with new tires in order to get the "full balance" vs. another "crappy balance". Am I missing something?

Roger (50141)

[Joe L.]

Re: C2 Vibration when accelerating

I resurrected this post from the archives while looking for recommendations for an alignment shop. I read the posts from Anthony Stein about tire balance causing the vibration on hard acceleration, and thought I would throw in my $.02.
I also had a vibration on hard acceleration, easy acceleration no vibration, and had thought probably clutch or drive shaft out of balance. I have old KH made by Western Wheel knock offs, and the wonderful Coker Gold Lines. I also had a vibration in the steering wheel at about 65 MPH, and decided it was time to get the tires rebalanced.
Three years ago when I last had an alignment I had the road force balance done on all four wheels, but with all weights placed on the inside of the rims. This was doen with the Hunter machine.
So yesterday, yes Sunday I went off to the local Good Year store, and had all 4 wheels rebalanced and accepted that every one of them needed a weight on the outside of my knock off wheels. The technician offered me two options crappy balance with weight on the inside, the kind I already had, or a full balance with weights where they are needed. So I have to put up with the weights on the outside, until I replace the tires.
I CAN'T believe the difference; the vibration on acceleration is gone, as is the 65 MPH wheel shake.
I hope this helps someone else from replacing and rebuilding, before trying a rebalance on their tires, it sure worked wonders for me.
George

George------

The same effect can be achieved by using adhesive-backed-type balance weights and placing them at the centerline of the wheel. Using this method, a very good, DYNAMIC balance can achieved. This way, you don't have weights on either side of the wheel. If the wheel surface where the weights are placed is properly cleaned and "scuffed", the weights will not come off.

[Joe L.]

Re: C2 Vibration when accelerating

Hi George,
Thanks for resurrecting my post! I was just thinking about this post a few days ago after taking the Vette out for a weekend spin. Although I still get an occasional vibration on hard acceleration, I don't get any vibrations at all cruising and passing speeds. For that reason, I left things alone and decided that I would look into it further down the road when I need to replace the tires. My brother's shop installed my tires a couple of years ago, and I, too, instructed them to put the weights only on the inside of my knock-offs. As you said, it looks like Anthony's idea to check the tire balance is most likely the cause of the vibration. Since my tires are still near-new, and my knock-offs are hammered tight, I was wondering if there is a way to balance the tires without removing them from the car? Also, I was curious about your comment, "so I have to put up with the weights on the outside until I replace the tires". I assume that you will still have weights on the outside of the rims even with new tires in order to get the "full balance" vs. another "crappy balance". Am I missing something?

Roger (50141)

Roger-----


Sometimes the problem can be in the tires. If you note that more than 5 ounces of weight is required to balance a tire and wheel, that's a pretty good clue that there is a problem with the tire. The only way to correct this sort of problem is to replace the tire.

Also, have you ever replaced your front hub/rotor assemblies or have you ever replaced a front rotor on an existing hub?

[Chuck B.]

Re: C2 Vibration when accelerating

Roger,

Just a suggestion.

I had a similar vibration in my '66 coupe after rebuilding the rear suspension and replacing the steel spring with a fiberglass one. The car had over 150K miles and I was concerned about the integrity of the steel spring. The vibration could be felt in the steering wheel and gas pedal area upon strong acceleration from 40-60 MPH and from a standing start. Since the U-joints were new, I started thinking about the operating angle of the u-joints. I replaced the stock spring bolt with a 8" adjustable spring bolt and started lowering the rear of the car until the vibration went away. This was trial and error but I believe less than 1" solved the problem. I assume that by lowering the rear I brought the two 1/2 shaft u-joints back on the same plane so they were back in phase. Replacing the old worn out spring with the new fiberglass spring must have changed the ride height enough to throw those 1/2 shaft u-joints out of phase.

Chuck Banks

[Gerard F.]

Re: C2 Vibration when accelerating

Roger,

If you have power steering, check the belt and position of the pump to the chassis. With a worn belt, the pump pulley is very close to the front suspension, and any movement of the motor in the mount could cause it to rub on the suspension or chassis.

Just a thought, if you have power steering.

[Ronald L.]

Re: C2 Vibration when accelerating

On balancing those coker gold lines... watch them when on the spin machine to be sure they are NOT egg shaped, most are slightly out of round and can be balanced by piling on the weights, however an egg is still and egg by anoother name and it won't go down the road smooth.

The other thing is that if they sit for any period of time, they get a flat spot thats not easy to remove. I had that from 55 - 65 or so and the tire shop was smart enough to say they really could not balance them.

As one of the guys mentioned - check the last thing you changed or took off the car to change something else. You have changed a lot of things that separately each one on a mis-install could cause this issue.

[George C.]

Re: C2 Vibration when accelerating

Roger,
Hi, in response to;
Also, I was curious about your comment, "so I have to put up with the weights on the outside until I replace the tires". I assume that you will still have weights on the outside of the rims even with new tires in order to get the "full balance" vs. another "crappy balance". Am I missing something?

No, you didn't miss anything, but the Cokers seem to be so far out out that they need allot of weights.

I think as Joe pointed out the tires could be balanced with stick on weights from the inside if they didn't need so much weight.

Anyway it is a whole lot better now than it was, so I can live with the weights on the outside until I decide on new tires.
Thanks,
George

[George C.]

Re: C2 Vibration when accelerating

Joe,
Do you think that these Coker tires could be balanced, using the road force Hunter machine by just putting stick on weights on the inside of the tires?

One other question, as was mentioned these tires tend to flat spot from sitting and I only drove the car about 12 miles before I had them balanced.
If I had driven 40 or 50 miles and then had them balanced would you expect any different results?
Thank you,
George

[Joe L.]

Re: C2 Vibration when accelerating

Joe,
Do you think that these Coker tires could be balanced, using the road force Hunter machine by just putting stick on weights on the inside of the tires?

One other question, as was mentioned these tires tend to flat spot from sitting and I only drove the car about 12 miles before I had them balanced.
If I had driven 40 or 50 miles and then had them balanced would you expect any different results?
Thank you,
George

George-----

I am not particularly familiar with the Hunter balancing system. However, an excellent dynamic balance can be achieved using adhesive wheel weights IF the weights are placed at the centerline of the wheel's rim width.

In fact, I recently had this done on the original wheels on my 1992 and I believe the tire shop used a Hunter machine. I had it done many times in years long-gone-by on mag wheels, too.

I would not expect any different balancing results after 40 or 50 miles than at 12.

[Roger P.]

Re: C2 Vibration when accelerating

Joe, Charles, Jerry, Ron, and George,
Thank you all for your suggestions! I really think that collectively you have located the problem. Jerry, I don't have power steering, so I can rule out that possibility. Ron, I make sure to drive my car nearly every weekend to avoid tire flat spots and component deterioration (I'm lucky to live in South Florida with year-round driving weather). After looking closer at my tires, I see that the adhesive-backed balance weights are near the centerline of the rims and not toward the outer edge. That makes sense because I don't get any vibration, at any speed, other than during very hard acceleration... typically in 2nd or 3rd gear when I'm pushing 0 to 60+ . Joe, I didn't change anything on the front end yet; including the hubs or rotors as I was told that everything was in good condition. However, as Charles mentioned, my rear ride height is a little higher than spec since I replaced the entire rear suspension. I was going to replace the spring bolts with the longer adjustable bolts, too, but I figured that the rubber cushions would settle down from the weight of the car after a while. I will check the dimensions per the manual and will definitely consider replacing the bolts to bring the half-shaft U-joints in phase. Between tire balancing and longer spring bolts, I am confident that the issue will be resolved. Unlike rebuilding the rear suspension, this repair won't break the bank !!

Thanks again to all,
Roger (50141)