1960s 1960 Annoying Vibration

[60eldo]

   I got the dr side bolt out yesterday. So the problem was, 1st of all laying on my back, car up on ramps NO ROOM. Its so hard to see this bolt so what was happening was when I slid my extension through hole in frame it wasnt quite on the nut so it felt like it was stripped. Then I tryed a swivel and I got it. Unless youve done this before you wont understand. Its so complicated.

[Steve Lomas]

That's good, curious to know if the new mounts fix the vibration- let us know.

[60eldo]

 New mounts are in, NO CHANGE. After 15hrs of work. I will never do that again, without a hoist. Now back to the drawing board.

[60eldo]

So after 10 or 12 hrs more, Im done, the new mounts are in. Just some advice to others wanting to do this with car on ramps. DONT EVEN TRY< you will regret it. Anyway mounts are in, NO CHANGE

[Chopper1942]

I know it will cost some money for diag time, but I would take it to a GM dealer that has that has a Pico scope and the GM NVH software and get some data on the source of the vibration.

[60eldo]

I googled pico scope, says it measures electricity

[Cadman-iac]

 If you have had the tires balanced multiple times and your wheels are not bent, then it's most likely something else that rotates at the same speed as the tires, that being your drums and hubs.
 There is a way to check the balance of the drums by using a balancer that spins the wheels on the car, and can balance the rotating mass as a unit.
 I have seen it before, a drum is warped from being overheated, causing a pulsating pedal, and someone will turn the drum in an effort to "correct" the warpage, which leaves the drum out of balance.
 This can be corrected by one of two ways. Either by replacing the drum, or by balancing the entire rotating assembly as a unit.
 Good luck with your car. I hope you find out what the problem is.

 Rick

[60eldo]

Yes a possibility. Im also now thinking of harmonic balancer,but it looks good while spinning. How can that be out of balance?  And I can feel the same vibration when car is in Park while slowly reving the engine, so makes me think its something there.  I thought of something else, a long shot, but years ago I removed the A/C belt, cause A/C doesnt work, could that have created a wobble in the H  balancer?

[Cadman-iac]

Yes a possibility. Im also now thinking of harmonic balancer,but it looks good while spinning. How can that be out of balance?

 I'm not familiar with that year, but if it's assembled anything like the small block Chevrolet balancer, if that outer ring should rotate on the rubber insulator between the hub and the ring, it will throw off the balance, but it normally starts at a low speed and just gets worse as the speed increases.

 Have you had the drums off before to check the brakes? Are any of them turned to the maximum diameter?

 Also, to balance the drums at the factory, sometimes they used weights that were welded to the outer face of the drums.  I've had some with as many as 4 big weights on them.
 If you have a drum with multiple weights, and it's been turned multiple times and is just about worn out, I'm willing to bet it's not balanced anymore.
 If it's a front drum, you will feel it in the steering wheel and your seat, if it's a rear drum, you will usually only feel it in your seat.

 Rick

[60eldo]

 Remember, The car vibrates while not moving by just slowly reving the engine. Also I just put the ac belt back on,,,,no change

[Chopper1942]

You have an engine vibration.  Remove all the belts and see if the vibration goes away. If so, now put back on 1 belt and see if the vibration returns. If so, observe what is now turning. One of those items is the culprit. If it still vibrates with all the belts off, it is either internal or an external rotating component, like the balancer, flywheel, or converter.

I was working on another post when this one popped up. It talks about several other items that could be the source of your vibrations, but I also talked about checking the balancer and internal issues. Here is that attempted post.

Lets try this again. My post just disappeared.

A Pico Scope is either a 2 or 4 channel oscilloscope. It measures electrical signals. It must be connected to a laptop computer with the correct software to view the signal from the scope.  With the GM NVH kit that includes an interface box, cables, optical sensor, software, and an accelerometer, when connected to a vehicle it can determine if a vibration is caused by tires (T vibrations), engine (E vibrations), or propeller shaft (P vibration). The accelerometer changes a vibration frequency into an electrical signal whcih the software can interpert.

Besides tire balance, the biggest issue we have with tire like balance vibrations is Force Variation/Road Force variation in the tires. You can have perfectly balanced tires and still have a vibration in the steering wheel if the Force Variation is too high. This is caused by the difference in stiffness in different places of the tire's sidewalls. All tires have some force variation. Sometimes the force variation can be reduced to acceptable levels by repositioning the tire on the wheel and then rebalancing the assembly.

Tire beads not properly seated on the wheel causes lateral runout which will feel like tire balance. The same for wheel runout, hub runout, and wheel stud runout.

When I do a Force Variation balance of a wheel/tire assembly, the first thing the balancer does is check wheel centering, then is spins the wheel and checks runout. It then put a roller with 700-1200# pressure on the tire while it spins. This checks the stiffness of the sidewall variation and acts like the wheel/tire is running on the road.
When it is finished, it displays the force variation, runout, and balance weights needed if the force variation is OK. If force matching is needed it predicts what the final reading will be and if it can even be force matched because the tire is bad.

A quick check if there is a balancer issue is to check the timing.  If the engine runs OK and the timing mark is way off, the outer ring of the balancer has slipped and you need a new one. You can have other engine vibrations caused by a cylinder with low compression, an internal component was changed and its weight is different than the part it replaced, etc.

A prop shaft out of balance or with too much runout, a u-joint out of phase, or we have even found ring gears made with excessive runout that caused vibrations.

Sure it will cost some money for diag time, but if you want to find the type and maybe the source of your vibration, and possibly save you money in the long run, and not throwing a lot of parts at it and not accomplishing anything, I would take it to a GM dealership and ask what it would cost to diag your vibration problem with a Pico Scoe and NVH diagnostic hardware. If it's within your budget at this time, you will probably find out where it is and possibly what is the source of your vibration.

[Cadman-iac]

I should also say that while driving and she starts to vibrate at 40 mph, when I throw it into neutral or shut off the car, it continues to vibrate,. Update I just tried leting the car idle at 600 rpm and hooked up a rpm gauge, I slowly , while in neutral, revd the car to 900 and it started shaking the same way and stoped around 1100,,mmmmm, is this my problem? And whats doing it, the crankshaft bolt, motor mounts? bad cylinder

  From what you're saying here, you are chasing two vibrations, one in the engine, and another in the rotating mass of the rest of the drive train.

[60eldo]

 Im chasing anything that moves, but if the steering wheel vibrates when in park as I slowly rev it, the engine some how seems to be the culprate. But I just installed new motor mounts, so shouldnt they take out most vibration

[Dave Shepherd]

Trans mount also? Exhaust has good quality hangers, also not touching the body or frame anywhere?

[60eldo]

 New exhaust last week, and it was vibrating with the old one too. Trans mount I have not done.

[35-709]

"You have an engine vibration.  Remove all the belts and see if the vibration goes away. If so, now put back on 1 belt and see if the vibration returns. If so, observe what is now turning. One of those items is the culprit. If it still vibrates with all the belts off, it is either internal or an external rotating component, like the balancer, flywheel, or converter."

I would go with this advice from "Chopper 1942".  If you get the vibration just by running the RPMs up, car not moving, something in or on the engine, as he listed, is causing the problem.

[Cadman-iac]

I should also say that while driving and she starts to vibrate at 40 mph, when I throw it into neutral or shut off the car, it continues to vibrate

 This statement is why I have suggested that you might have a drum issue.
 Good luck with your car.

   Rick

[E Masters]

Things which have caused vibration for my 67 when in neutral and light reving have included

Loose power steering pump pulley
Leaking vacuum advance
Sticking distributor weights
Vacuum leaks
Misfire
Bad pcv valve
Lean mixture idle/transition

[Chopper1942]

From what he is describing his 1st issue is in the engine or parts that rotate at engine speed with the trans in park or neutral. This can also reappear at higher vehicle speed that match the rpm where he is feeling it in neutral. But, I also believe he still has a T or P type vibration that is speed related. Best bet is have an NVH analysis performed.

[60eldo]

   Just a thought. If the new motor mounts didnt help, Im at a loss. If vibration is coming from the engine ie harmonic balancer or pulleys. Wouldnt the rubber in the mounts absorb that? The H balancer is not worpped that I can see, might it be wobbling inside cause the rubber has slipped.  Also can someone tell me. Should the 2 stubs from motor mounts be resting on the bottom of the slots, or should they be up a bit.