57 with 312 rough when accelerating

D

Dude81

Junior Member
57 Fairlane Sunliner with 312, Ford 4-barrel, and auto trans runs very rough when accelerating, especially at low speed. Causes car to shake. Does not occur unless car is in gear. Installed new U-joints and rear trans mount (engine mounts appear OK). No improvement. Engine has always "ticked" on passenger side--worse when idle and cold. Non ethanol 91 used. Suggestions?
 
- IMO -​

You need to diagnose the engine as to tune.

What carb does it have and how long since any engine work.
 
dmsfrr said:
Could the transmission be slipping, not engaging properly?

Ticking noise on the passenger side...
Have the pushrods and valves been checked & adjusted recently?
See this link...
https://www.youtube.com/watch?v=SqG-Q_kVI3s
.
Click to expand...
so I watched the video but he didn't start the engine. I scrolled down to another video he had where he adj. the valves on a for pick-up and started it up. OMG, if our Y-block sounded like that I'd s**t. other than a small tick on the pass. side when cold , our 292 Y-block sounds like a hyd. lifter engine. close the hood and can barely hear it run.
 
Sounds like misfire under load. Coil could be weak. It only takes 5,000 volts or less to fire a plug at idle, whereas it will take 25,000 or more volts to fire a plug under load. The plug wires could be bad and leaking some of that higher voltage needed under load. Could be a bad condenser. Someone could have put too small main jets in the carb, or float level could be too low. Jets or passages in the carb could be plugged. Point gap could be off. Fuel pump could be weak. Fuel filter or fuel lines could be partially plugged.
Do a thorough tune-up. Do not assume anything. Make a check list and mark off every item until it runs smooth.
 
It's hard for me to know what shaking means. Is it shaking in the steering wheel? Where does the shaking feel like it's coming from? How bad is this shake? Is it an actual shake, a vibration or an engine running bad. A ticking lifter is not going to cause a shake in the chassis. A video would helpful. Did it always have this shake, did it start after something was changed?

Under acceleration the engine could torque to one side enough to allow metal to metal contact between the engine and something, and you could feel a vibration. Like if you had tight fitting headers that move far enough to touch part of the chassis. Can you have somebody you trust, put it in gear, set the parking brake and hold the brakes on while you stand to the "side" and give it a little gas and see if that engine is moving enough to make contact with something. Don't' you dare walk in front of it during the test.
 
When did the car last have a basic tune-up?
Re-set the points & timing, clean or replace the sparkplugs, etc...
 
How about a bad vacuum hose or a disconnected vacuum hose? Check ll the hoses to make sure hey are in good condition. There are vacuum hoses under the dash.
 
I'm going with week spark. At idle the fire makers don't much care how hot the spark is, under load a week spark will cause multiple mis-fires.
 
Update: not so good. Sent the carb (a 1958 Ford 4100) off for a rebuild. Installed when it came back. Engine very hard to start and when finally did, it coughed, sputtered, backfired and then died. I tested the fuel pump by removing a line and watching the flow--looked good. Tested one spark plug and it fired ok once per revolution. Plug was slightly sooty, probably from over rich carb before the rebuild. Multimeter test on coil (Pertronix Flamethrower 3.0 ohm) showed 3.5 ohms between primary contacts, and 78000 ohms between contact and output (is that bad? I don't know what it should be). Coil is getting the full 12V needed. Distributor cap looks clean and solid. Points have been replaced by a Pertronix Igniter module. I'm researching how to test this. Any advice is appreciated. Also, if I decide to replace the coil and/or igniter, does anyone have suggestions? Thanks again.
 
You must log in or register to reply here.
Back
Top