Hey all. I tried unhooking the vacuum advance. The vibration is still there. I also tried removing the fan and power steering belt and still there. It will do it in Drive or Park and when driving as well. So that eliminates driveshaft. The Harmonic balancer looks very good - no wobble or damaged in any way. Vibration starts at about 1100 RPM - 1400 RPM. If I go above that RPM its still there but hardly noticeable. When in park at idle (500 RPM) the engine has a smooth but slight soft rocking movement. Engine vacuum is a steady 19. Plugs all have a nice burn (slight tan colour) A local engine rebuilder commented that my engine is too quiet for solid lifters. You cannot hear the lifters clatter at all. He felt the valve lash is too tight.

Anyone agree with this before I proceed. I wouldnt bother with this but the city driving is in that RPM range.



Thanks all

It won't hurt to check the lash. You should be able to hear it but it shouldn't be loud. But regardless, if you check it and it's right, then don't worry about any valve noise or a lack thereof.


Lawrenceville, GA

If the engine is not dancing around I would start with the trans and move forward, maybe disconnect the trans and isolate the engine and see what happens

Mike Rizzo

1963 F100 "Rudy"

Daniel Island, SC

Nat,

You've had you leads off recently chasing that vacuum leak check your firing order.

cheers

Warren

Grizzly (Aussie Mainline)

Please do not take this wrong but not knowing your mechanical experience, a couple things come to mind.  Spark plug wires in good physical condition and properly seated?  Recent ignition service?  Did this vibration start suddenly or?  Have you examined the spark plugs?  Their color and condition may narrow your search.

Please do not take this wrong but not knowing your mechanical experience, a couple things come to mind.  Spark plug wires in good physical condition and properly seated?  Recent ignition service?  Did this vibration start suddenly or?  Have you examined the spark plugs?  Their color and condition may narrow your search.

Is there any way to tell if the harmonic balancer is at fault here? Would I be able to move or turn it. I am assuming that when a harmonic balancer fails it has rotated shifting the counter weight. It is sitting approx 3/4" away from the crankshaft pulley. Does that sound correct? It is annoying to drive because it is right at city speeds (30-35 mph)

Nat, check these two things...



1) The first is the vibration damper mentioned by others previously. The 'donut' behind the pulleys on these is very prone to moving back toward the timing chain cover. The rubber gets hard with time and engine heat and allows the 'donut' to slip, moving toward the timing chain cover. When viewed from above, or even from the side, it appears that there is no interference, that is, the 'donut' seemingly has not moved back enough to contact anything that it shouldn't. However if you can observe the 'donut' at its lower side rear edge, you may see that the lower edge is potentially just touching the front steel engine support that is attached to the timing chain cover. SOMETIMES, you'll get a random tweet from the 'donut' brushing the curve of the front engine support at idle.



Also, between the 'donut' and the pulley are two 180 degree apart openings. The side of the openings closest to the 'donut' have center points that are closer to the 'donut' than the ends of the openings. Using an INSIDE (correction!) caliper, the space between the center of either of the openings to the face of the 'donut' should be between 5/16 and 3/8 of an inch. This dimension was taken from a damper I ordered from Ford that has not been used (yet).



2) On the 'Birds, the side engine steady rests are riveted to the frame. I've seen more than one of these where the rivets are loose. The ones I've seen have been loose on the driver's side. They will not 'look' loose, but if you remove the rod between the frame bracket and the engine bracket, you'll be able to test them by trying to wiggle them. These can be fixed by welding the bracket to the frame or by removing the rivet and bolting through the frame outer and inner box sides. While doing this check, consider also removing the steel brackets from the sides of the engine block. I've also seen these brackets cracked from the twisting action of the engine.



All the previously mentioned thoughts from others are sound, too. Vibrations are a challenge to find. Let us know how you make out.


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Is it possible that the cam chain could cause this vibration, Maybe throwing things out a little till it "loads up"? Ted, Tim?



"Came too close to dying to stop living now!"

I inspected the harmonic balancer. It has not moved backward toward the timing cover. It was pretty much spot on with the dimensions you gave me. Maybe it has spun? The engine steady rest brackets are tight. Checked my plugs for misfire- All my spark plugs are relatively close on burn (Light to Medium tan). #8 is a bit lighter. Vacuum measured with car in drive is a steady 19 1/2 inches. Ted described it best as a shudder. At 500 rpm in neutral or park the engine has a subtle side to side soft rocking motion - 1200 -1400 rpm is where it is at its worst. It comes up through the steering column-anything above that I think its still there but again subtle. Thanks all