Hello all, First time poster. I’m having issues with my 292 Y block. It sits and idles perfectly, but as soon as you start going it has a bad shake to it. The shake gets worse as rpm’s go up. Here’s a list of things I’ve checked or replaced: compression, timing, plugs wires and rotor, carburetor, fuel pump and filter. Any help or ideas would be appreciated.
Hmm, maybe you have a badly worn or even missing pilot bearing. That shake is only noticeable while driving or in gear?
Is it when the vehicle is moving, or is it there when the vehicle is stationary & you just "rev" the engine? If it is there with the vehicle stationary I suggest checking the harmonic balancer, but if not there & only when the vehicle is moving , check the drive shaft U-joints, the wheel bearings, & the wheel/tires
Oh I forgot I’ve done both front and rear motor mounts. I recently done clutch about a year ago. It’s a slight shutter as you rev the motor slowly. And if you’re actually driving it you have to rev it up to go or it bogs shutter and shakes.
Check your centrifugal advance in the distributor for excessive slack or broken or missing ground wire. Bones
So it isn't actually a vibration that comes in at a certain rpm but rough running when the motor speeds up slowly or when it is under load? What does it do at cruising speed on the highway, say a steady 55/60 Mph for a distance. Are there any vibrations then or does it smooth out once you reach and maintain a cruising speed?
hadnt checked that yet. Thank you. These motors are otherwise internally balanced correct? Im not sure about that fast but at 40-45 it still shutters, and seems like it’s down a little on power. And if I’m going down hill and let off the gas it vibrates shakes and slows down
Ok I checked my coil and the wires going to the distributor. The negative wire had a two ended connector on one end and a single on the other. The double ended one was hooked to the distributor and one was hanging. The other end went to the coil. It runs without it being hooked up. When I hook the loose wire up to a ground on the truck it does.
There shouldn't be any direct connections to ground on the distributor side of the the coil. The primary winding grounds though the points to build the magnetic field in the coil. Then when the points open that magnetic field collapses causing the high voltage spark from the secondary winding. That second wire may have gone to a tach at one time or another. You aren't trying to run a 55 292 with a six volt positive ground coil on 12 V negative ground? Still with any older stock engine without 900 odd ball factors to worry about it is still: Compression= Compression has to be within about 15 lbs high to low a**** all cylinders Firing order = Has to be correct for that engine Point gap has to be set correctly Plus the points need to be in decent shape. Condenser needs to be connected correctly and held tightly on the plate of the distributor. That will cause a similar issue. The vacuum advance if there is one needs to be working correctly along with the mechanical advance The timing needs to be right. Plugs need the correct gap Plug wires need to be in decent shape, ****py wires cause spark to jump where you don't want it to go causing a misfire. The carb needs to be decently clean inside with all internal pieces adjusted right and working right. It's pretty well a process of elimination and in you working on checking on it you probably already have checked a number of things off the list.
The OP doesn't say what year the motor is, but if it's a pre-57 he may be having issues with the Loadamatic distributor.
Thanks for the insight. It’s in a 60 model truck. It’s weird it literally idles as pretty as any V8 out there, but when you get above idle things get rough. Everything ignition wise is new; distributor, wires, points, etc, and plugs(checked gap). I had my neighbor check the timing and it close to spec. -Compression on the cylinders was between 100-108 psi with no leak down. -Carb is 2-3 years old Here is the 3 prong wire I’m talking about. One end was on the coil, the other going toward the distributor the other was hanging.
I'd be rechecking the firing order. Ford numbers their cylinders different than GM. Number one is on the right hand side (setting in the driver's seat) and the right bank of cylinders is 1-2-3-4, with the left bank being 5-6-7-8. If you recheck and the firing order is correct, 1-5-4-8-6-3-7-2, then I'd see if you can find someone with a scope to take a look at the secondary pattern. That will point you in the right direction quickly.
When you replaced the clutch did you change the pilot bearing? Was the engine ever working right after you replaced it? Did you check the flywheel/clutch ***embly for balance? I have a hard time understanding your description of the problem, but here goes -- A failing coil is a good possibility. It will run fine at low RPM but will start to "stutter" or "flutter"and lose power as you speed up or put a load on it. I have had this happen to me a number of times before I figured it out. Always on Fords for some reason. Also, very carefully inspect the coil tower for cracks or carbon tracking. Check the wires inside the distributor for chafed insulation. The earlier distributors had a big problem with this and the uninitiated could go nuts trying to figure it out. Check the vacuum advance to make sure the diaphragm isn't leaking. Recheck the firing order. A good way to check for leaking plug wires is to run the engine in the dark and see if there is any "lightning". Not knowing the history of this engine, this is the best I an give. Good luck.
I just replaced the coil today with no help to my situation. The motor has always ran good and been strong. When I did the clutch I replaced the pilot bearing The fork and had the flywheel resurfaced. I’m at a loss on what’s wrong with it.
When you installed the flywheel, are you sure it seated properly on the crankshaft flange? Even a small piece of debris between the mating surfaces can mean disaster. Flywheel bolts torqued to specs? There are some replacement pressure plates that can be way out of balance. If you can't find any other solution, I recommend taking the flywheel and clutch ***embly (***embled) to a machine shop and have them check the balance. Have them punch reference marks so you ***emble it correctly. To show how critical this balance is, I'll cite an old fashioned way of correcting it. In the 1946 Buick service specs it states that if you get a vibration after replacing clutch parts, add an extra lock washer under a bolt. Move it from one bolt to the next until vibration disappears. Bushwa, said me,until I tried it. It works for minor out of balance. That was my Buick, by the way. Your situation does not sound minor, though. Who resurfaced it? I'd have it checked for wobble, too. If they did it on a brake lathe they could have screwed it up. Don't wind up your engine while it's like this. You could damage it if this is as bad as you say.
Take a test light and clip the wire to ground. Stick the point into a plug wire at the distributor cap. Then drive the car. Do that with each wire. Maybe you can narrow it down to one cylinder
Problems like these are nigh impossible to diagnose easily through this medium. It's not the posters fault but it's not clear what the symptoms are. As this thread goes, more and more information comes out. Taking the above information as a whole it seems this may be a drivetrain issue rather than a engine issue. It could be a combination of both. ^^^^^^^ This suggests a drivetrain issue. ^^^^^ Again, a drivetrain issue. ^^^^ Drivetrain! It has? So what changed and when did it change? Did it change when you overhauled the clutch? I'm suspecting suspecting a well oiled clutch disk that grabs and slips. It also could be a poorly adjusted clutch. There's a possibility it could be further down the line, transmission ,U joint or the rear axle. Worn rear spring hangers, bushings and shackles will cause vibrations at the rear axle. The axle will shake if there is excessive clearance here. There's plenty of diagnostic tests you can do. With the truck parked.... The simplest is to rev the engine in neutral. Does it vibrate in neutral? Does it vibrate with the clutch depressed?
It shakes when in neutral with or without the clutch pressed in. I drove it again a few days ago. It honestly has plenty of power. I was driving between 55-65 and could accelerate at any point. But it shakes moving or sitting still. I let my dad drive it too so I could watch and listen. The vibration feels like it’s more in the floor pan and less vibration toward the fire wall.
Y blocks use a dampener not a balancer IIRC. When they slip or come apart either the timing reads wrong or the belts don't align. The flywheel in the garage off a truck y block is 6 equally spaced bolts. You might have some gunk in the carb that only affects the primary circuit and not the idle circuit. When you open the throttle you could be running on half a carb, and that will make the engine shake and/or go down on power. Maybe just in the transition circuit. It's a long shot, but with today's fuels I've seen some weird things happen.
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