I don't have much motor experience under my belt so I need a little help. I have a vibration problem that is real noticable in the lower rpms I had suspected was from the driveshaft or u-joints, but I was messing with the throttle today while under the hood and noticed the vibration while in park. Is there a good way to tell if it is the balancer? I know its time for plugs and some tuning but it seems to run real well other than the vibration. I have barely run the motor at all since first noticing the virbation. I have another balancer on my project motor but I dont know if its any good.
Grab your water pump pulley and give it a few tugs. Make sure it is not coming apart before looking elsewhere.
like Brad said start grabbing things on the front of the engine and shaking them.... start with the fan blades ,,, to check the fan clutch and the water pump pulley shaft... the other thing to check is the harmonic balancer... on a nailhead in particular the hub of the balancer can crack down thru the keyway and then the balancer will viberate.... and wallow wear the nose of the crankshaft and destroy it... also the retainer bolt to the crank can be loose and cause a viberation..... and the ring on the balancer can come unvulcanised and the ring slips and gets out of sinc with the actual tdc.....
Did the vibration start suddenly, or did it come on gradually? Has there been any recent engine or transmission work? You didn't say what car and engine, but if it's carbureted, I would pull off each spark plug wire (one at a time) with the engine idling. If the idle is unaffected by the removal of one particular plug wire, the cylinder with the disconnected wire is the problem. I would suggest using a pair of plastic pliers for the wire removal - I hate electrical shocks. If the car has ported electronic fuel injection, I would unplug the injectors instead of pulling wires. This will set a trouble code which will have to be cleared. To check the harmonic balancer, bring #1 cylinder to TDC (Top Dead Center). I use the eraser end of a long pencil through the spark plug hole to be sure the piston is exactly at TDC. For this purpose, it doesn't matter whether the piston is on the compression or the exhaust stroke. At #1 TDC the timing mark on the balancer should be aligned with the 0 degree advance on the scale. If not, the harmonic balancer is messed up. Also check for vacuum leaks. An intake manifold vacuum leak will cause rougher operation at an idle then at higher RPM. If the car has an engine-driven fan, take a close look at the blades. Make sure that none are bent or damaged. If you have a viscous fan, check the fan clutch for binding or looseness. Go for the simple stuff first. Good luck.
Sorry, should have been clearer. It is the stock 401 in my Riviera. No recent work, but it needs some springtime TLC. I was able move the water pump pulley with the belt on. I will try running it breifly with the belts off. If there is no change I will try unplugging spark plugs one at at time. If that doesn't show anything then I will check TDC on the balancer. I did notice the idle change when I pressed on the brake. Does that mean vacuum leak?
Water pump pulley has about 1/8" of play when push/pulled on the top. I'm pretty sure thats bad. Is there a difference in water pumps between AC and non AC cars? Napa show them new for $75, is that a decent price? I would prefer new over reman. Taking the belts off helped, but there was still some vibration. Didn't find anything disconnecting the plug wires. FYI welding gloves work good for this. I was running out of time working outside so I messed with a few vaccum hoses and didn't check TDC yet. I think there is a vacuum leak from the (name?) vaccum tank on the passenger fender. When I plugged the hose from the intake the motor ran better, less vibration. I don't have a vacuum gauge. I plan to check the intake and carb base by spraying carb cleaner, unless anyone has a better way of doing it. Thank you all for your help getting this far.
If the vibration occured when you stepped on the brake pedal the 1st thing to check is the power brake booster since it is usually vacuum operated. Disconnect and plug the vaccum line running to the power brake booster.
Yup, And a smaller pulley, too. More blades, turns faster - moves more coolant. I would install an a/c pump whether the car has ice or not.
No vibration from brake being depressed, just an idle surge. Oh and the brakes were not working as good as before. After I plugged the vacuum line going to the canister the brakes are back to their touchy self and stopping good.
It may not really matter but if I'm putting an a/c water pump on a non a/c car and reusing the non a/c pulley (because thats what I have) the pump would not be spinning any faster, just have more blades in the pump. No problem with that right?
I wanted to thank you guys for your help and give ya'll an update. I really wanted to get everything done for a local car show on April 30th. I pulled the Riv out to swap the water pump in the beautiful weather last Saturday. Then I needed to move it so that I could drain the coolant and it wouldn't start. Had to push it, and I decided to go ahead and change the water pump and worry about the starting issue afterwards, since I knew it needed a tune up. Pump change went as planned. The motor turns over but just doesn't fire off. So I'm thinking spark or fuel. It has fuel and it is getting to the cylinders. I checked points, plugs, and timing. Points were not gaped right. Plugs were wet with gas but didn't look too bad, and timing was alittle off, I did check it with the vacuum advance unplugged. The rotor and cap looked good and only have about 2,500 miles on them, so I didn't replace them. So last night after work I changed the points and condenser, the plugs, and set the timing. Still no start. I checked both sides of the coil and that was good. Is there a way to check to make sure the spark I'm getting is strong enough? #1 cylinder is getting spark. I still need to check the others. I drove it about 3 weeks ago up and down the street and there was no lack of power or smoke, so I don't think compression is a problem. Yesterday was a long day, I know I made one mistake, I didn't disconnect the vacuum advance this time when I set the timing. Other than that I noticed the carb had a little seepage so it may be time for a rebuild. I'm at the end of my skill level. I don't have much $ or I would pay for help. Unfortunately my car guy friends don't do much of there own work. Any thoughts or suggestions?
You will need to re-time it. If you had the vacuum line attached when you first set the timing , it will be off (retarded).
