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1963 buick electra engine shakes


philipjohnsen

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Sounds like it is mis-firing on one or more cylinders. Check the firing order and make sure the wires are going to the right plugs. Another thing to do is pull the plug wires one at a time to see if it makes a difference. If not, you know that cylinder is not contributing anything. You can go from there to diagnose the cause of the problem.

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If it was recently rebuilt, it may be out of balance. The available replacement pistons are extremely crude and there will be a large variation in weight comparing the the lightest and heaviest in a set. Also the engine may have been "balanced" and the operator did not take into consideration that nailheads are externally balanced.

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the engine runs on all 8. the shaking starts when i hit the trottel, and is worst around 40miles. the engine is not shaking when the car is running on idle. starts when i hit the trottel. it seems to vibrate from flywheel, converter on the tranney???

I think that you're looking in the right spot. I could be wrong, but I think that engines and torque converters may have been balanced as a unit from the factory. Remove the flywheel cover and mark the torque converter's location in relation to the flywheel, and then remove the bolts that connect the two units. Rotate the torque converter until the next set of bolt holes line up again and re-install the bolts. Go for a test ride and note any change in the vibration. If the problem persists, repeat the process at the next location. If the vibration is gone or greatly diminished, then you've rectified the problem. Let us know the result.

Edited by Larry W (see edit history)
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Step one: always do a complete compression test. Then proceed through a logical procedure of diagnostic steps with the ignition system, fuel system, and then major mechanicals. Develop your own personal details for your method and always follow the same steps.

When others do work, trust but verify.

I knew a guy, not me, who bought a car with a match book stuffed in the corner of a dashboard panel. When he took it out there was a rattle. He disassembled the dash, put in rubber bumpers, and ended up with a new match pack. A few years later the car got a major tune up and the guy who did the tune up saw the matches during a test drive. He threw them aside because he didn't know about the rattle until the owner asked about the match pack. The rattle was gone. I think they are still lying around on a shelf somewhere in my garage.

Be careful to check all the simple details and make no assumptions.

Bernie

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From my experiences, a "shake under load" is not a balance issue, but a performance issue. As in a "dead cylinder" via a burnt valve or similar. Might even be a spark plug wire that's internally defective OR two plug wires that happened to get "swapped" as to which cylinder they are attached to. When you throttle into the engine, it increases the cylinder pressure and also increases the voltage required for the spark to jump the gaps(!) in the spark plug and also between the distributor rotor and distributor cap. If not enough voltage is available, the spark plug will not fire.

Rather than a compression test (AND the related variable results!), I'd recommend hooking a vacuum gage to the motor and watch the needle movements. NOT the numbers where the needle is, but the needle movements. When a dead cylinder "fires", it'll cause the needle to quickly move downward and then return to its prior level, for example.

Roy's recommendation of sequentially-removing plug wires from spark plugs is valid. If you might have access to a large engine analyzer, it might have a similar "cylinder kill" capability. But by simply pushing a button which corresponds to each cylinder. A little simpler, easier, and "safer" than handling working plug wires.

With a "balance problem", the magnitude of the shake will increase with rpm and not be affected by engine loading or acceleration.

As you noted the "under load" shake issue, one other place to look is the driveshaft u-joints, especially the center joints mechanism AND the related angularity of the shaft to the transmission and rear axle. In this scenario, when you take off from a stop, the vibration will continue as long as you're accelerating, then possibly decrease when cruising speed is attained. The position and adjustment of the carrier bearing, plus the condition of the "double-jointed" center "joint" mechanism, can result in a "drive line shudder". The center carrier bearing is rubber mounted. Rubber deteriorates and the angularity of the drive shaft will change, as a result.

So, first do the vacuum gauge check and watch for a "steady needle" or a "jumpy needle". The latter indicating an engine problem. If the "steady needle" happens, then put the car on an overhead lift and check the looseness of each of the u-joints on the driveshaft. Then grasp the center section and check it for looseness, plus the condition of the carrier bearing mechanism. If you find ANY looseness in those areas of the driveshaft, then that could well be were your "vibration under load" problem is coming from.

On one-piece drive shafts, it's usually the front u-joint that causes the vibration. On our '66 Chrysler, it was a squeak when taking off from idle, plus a small vibration. The vibration at 70mph was not much worse than a tire needing a little more balance weight, but with a new front u-joint, that car was vibration-free at 70mph and no more low-speed squeeks or vibrations. I suspect your car has a two-piece driveshaft with a "2-joint" center u-joint assembly that could well need rebuilding, plus a new center carrier bearing.

Please advise of your progress.

Take care,

NTX5467

Edited by NTX5467 (see edit history)
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