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-   -   57 with 312 rough when accelerating (https://www.fordbarn.com/forum/showthread.php?t=316719)

Dude81 08-08-2022 12:46 PM

57 with 312 rough when accelerating
 

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?

dmsfrr 08-08-2022 01:38 PM

Re: 57 with 312 rough when accelerating
 

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
.

KULTULZ 08-08-2022 04:05 PM

Re: 57 with 312 rough when accelerating
 

- IMO -

You need to diagnose the engine as to tune.

What carb does it have and how long since any engine work.

paul2748 08-08-2022 08:13 PM

Re: 57 with 312 rough when accelerating
 

How about engine mounts ?

Dude81 01-22-2023 06:51 PM

Re: 57 with 312 rough when accelerating
 

Thanks for the advice. Currently preparing to rebuild or replace the Carb (came from a 58 332/352).

fordor41 01-22-2023 11:21 PM

Re: 57 with 312 rough when accelerating
 

Quote:

Originally Posted by dmsfrr (Post 2155428)
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
.

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.

dmsfrr 01-22-2023 11:51 PM

Re: 57 with 312 rough when accelerating
 

Quote:

Originally Posted by Dude81 (Post 2155405)
. . . Engine has always "ticked" on passenger side--worse when idle and cold. ...

Exhaust manifold leak?

40 Deluxe 01-22-2023 11:54 PM

Re: 57 with 312 rough when accelerating
 

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.

Flathead Fever 01-23-2023 12:22 AM

Re: 57 with 312 rough when accelerating
 

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.

scicala 01-23-2023 11:51 AM

Re: 57 with 312 rough when accelerating
 

It sounds more like a weak ignition problem to me.

Sal

dmsfrr 01-23-2023 01:25 PM

Re: 57 with 312 rough when accelerating
 

When did the car last have a basic tune-up?
Re-set the points & timing, clean or replace the sparkplugs, etc...

oldbugger 01-23-2023 01:29 PM

Re: 57 with 312 rough when accelerating
 

Always check the plugs first, look at the color, should be tan.

CSPIDY 01-25-2023 08:16 PM

Re: 57 with 312 rough when accelerating
 

Quote:

Originally Posted by oldbugger (Post 2198588)
Always check the plugs first, look at the color, should be tan.

I agree, ticking could be a bad plug

paul2748 01-25-2023 08:20 PM

Re: 57 with 312 rough when accelerating
 

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.

oldbugger 02-02-2023 10:37 AM

Re: 57 with 312 rough when accelerating
 

Any updates, we would like to know what you found

KULTULZ 02-02-2023 01:14 PM

Re: 57 with 312 rough when accelerating
 

You need to throw a vacuum gauge on it (IMO)

Ford blue blood 02-04-2023 09:55 AM

Re: 57 with 312 rough when accelerating
 

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.

KULTULZ 02-04-2023 07:47 PM

Re: 57 with 312 rough when accelerating
 

:D

- I Can Name That Tune In Ten Posts! -

oldbugger 02-15-2023 08:21 PM

Re: 57 with 312 rough when accelerating
 

HEY dude, whats up

Dude81 02-20-2023 07:04 PM

Re: 57 with 312 rough when accelerating
 

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.


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