ChefDeadpool

Where do I start diagnosing issues with the engine if it makes the car vibrate too much? It's not an uneven vibration, just normal engine vibration. As far as I know, this car does not have a built motor - it was just driven, according to all the dated receipts I got and the previous owner.

The carburetor needs a rebuild pretty bad, but I have a hard time thinking that's what's causing this.

The only thing I did notice here, was that the car has aftermarket dual exhaust. Is there anything int he exhaust that could cause additional vibration to be felt inside the car?

You can actually see the one side of the hood that has worn rubber bumpers vibrate pretty radically at idle.

Help!

BlackGold

Poor fuel mixture at idle or fouled spark plugs will cause a rough idle. So will a vacuum leak. Start with a simple tune-up before looking for something more complicated.

NorTown Olds

Agree! Carb rebuild COULD be a GOOD start to allow you to properly diagnose and hunt down the root cause -- especially for trying to find Vacuum Leaks! What year is this engine again?? (Mid 70s w/ all the "new pollution control stuff" really made it TOUGH for those engines to run smoothly! even when they were brand new! it was very interesting reading an old Consumer Reports from like 1973 last month, they were actually writing about how "MANY of these cars brand-new just did NOT idle smoothly!" How FAR we've come! TONS of Vacuum lines and connections on those 70s Era ones too! GOOD LUCK and let us know!

OldCar_Mechanic

Are all the blades on the fan?

Ron

greenslade

worn eng/trans mounts can transfer normal eng vibration into the body

Lady72nRob71

Something is truely wrong here - good advice given already.
The stock 350 in my 72 with 155K miles runs so smoothly and quietly at idle, i have to look at the tach to see if it IS running! It has points, so every now and then i will sense a small misfire.

Check your points and condenser if you have them. Replce if you do not know when they were last changed. Keeping the ignition on to run the radio or whatever can cause points to burn and then make poor contact - a common issue that not many know about.

bulldog

Check to see if your exhaust system is touching the frame of the car as this will cause regular engine vibrations to be transfered into the body and give the feeling of a poor idle.

ChefDeadpool

Thanks, these are all great suggestions. I need to lower the rear tailppes, they seem to be touching the bumper...which I know can rot it out, so I'm going to try and do something about that this weekend.

The fan blades are in good shape, and all there.

I'm going to check for more vacuum leaks.

I just replaced the points and condenser, distributor cap, and coil. I'll pull a few plugs and see how they look.

I'm currently working on adjusting the fuel mixture. It was poorly adjusted to begin with.

OLD SKL 69

I agree with all the advice given here and I will add a little more. Make sure all the fan blades, pulleys are straight and true with no wobbling when the engine is running. That will give you a vibration.

If you have a vacuum gauge, hook it up and see what readings your getting. It should be steady and somewhere between 16 to 20. When I had a garage shop, a customer brought in a 66 Ford with a 289. The owner complained of a vibration but what it ended up being was a burnt valve, which showed up with the vacuum gauge.

ChefDeadpool

Well, it was me doing something retarded - literally. I'd forgotten where 0 was on the timing marker, and set it to -8

Fixed it this morning, and it runs much better.

Still, there is an issue of vacuum drop, which I assume is something to do with a leak somewhere.