Okay so my 292 has always had an inconsistent misfire (I think) at idle, and it runs kinda rough. I can hear quiet random popping coming out of both exhaust pipes, and the motor will idle really smooth for a moment, and then bog down a little for a second and then come back up. It also makes the entire truck rumble a little when it does that. I ran a compression test tonight and all cylinders were within 10 psi of each other with the highest reading at 150 on #5 cyl.

Then I checked the spark plug wires by turning off all the lights so it was pitch black, firing it up, and looking for little blue sparks or glowing from the wires. All were fine. (They are new wires after all, along with the plugs.)

Oh, and by the way, the radio has some static at idle, but goes away at a higher RPM. The misfiring/popping also seems to go away at higher RPMs too, which might have some link between the two...

I'd like to get this fixed so it'll run smoother, idle better, etc. etc. duh!

Anybody have any ideas or advice? All help is appreciated. Thanks! --Matt

 

It looks like you have made quite a few posts about the problem. Maybe it is time to pull the heads and examine their condition. Also look for bent pushrods. Keep pushrods in their same respective location in the engine. Should the heads need rebuilt I have a set of new rebuilds cheep, C1TEs.

 

Oh thanks for the advice. I'll definitaly check that out today when I get home. It seems to me when I did the valve lash adjustment that I recall all the pushrods were rotating, but my memory is vague whether I checked them all or not.

Why do should the pushrods be kept in their same respective locations?
And is it easy to replace pushrods? Can I just pull them out of the hole and stick new ones in there? (obviously then re-adjusting the valves) Or is there a proper procedure? I'm new at working on engine internals...

What's the right procedure to pull the heads and later reinstall them? Obviously I should use new head gaskets, right? Anything else I should check while I have them off? To reinstall them is it a simple matter of torquing the bolts down the right amount and I'm done? I'm new at this you see!

Thanks for the help. I appreciate it. I posted multiple times on some forums to maximize responses. --Matt

 

Before you get too crazy with pulling heads, etc. you might want to make sure the ignition is up to snuff.

Questions;

6 volt or 12 volt?

How old is the distributor?

Points or electronic?

Do you have ground strap between
the battery and the engine block,
the engine block and the firewall,
and the engine block and the frame,
and are all the ground connections clean?

With the car running, what voltage do you see on the ignition?

If you have a points distributor, make sure there is a little ground strap running from the points plate to the base of the distributor.

If you have sticking valves, you might want to look around for a 'top-end-lubricant'. Auto parts stores used to sell this product.

Good luck.

 

12v. New distributor since about two years ago. I put in a Pertronix Ignitor I and one of their Flamethrower I coils...

How do I check the voltage on the ignition while the car's running?

How do I tell if I have 'sticking valves'?

Thanks --Matt

 

Measure between the + terminal on the coil and chassis ground. A voltmeter will work, but an oscilloscope would show noise/transients.

The fact that it goes away at higher RPMs makes me wonder if you don't have some sort of power supply problem. Bad grounds, bad connections, and similar.

Generator or alternator?

 

Alternator.

 

Have you checked the timing lately?? It sounds like too much timing at idle. Is your vacuum advance hooked to ported or manifold vacuum? Try disconnecting the vacuum advance and see how it idles. Let us know how it goes.
Just some thoughts---------Hotwrench

 

MY 61 FORD DOES the same thing but keeps poping

 

hello, you just responded to a thread over a year old.... but I was reading too, hoping to hear the moral of the story.... I guess he never finished it or told the group what happened...

mine does something similar, i'm going to check the ground straps tonight...

 

Has anyone gotten any closer to solving this mystery? My 56 just started doing the exact same thing last week, I've done all the basic checks, I'm wondering if it could be some kind of vacum gremlin?

 

hey gentalmen, mabey it's time to rebuild that carb. sounds like it might be rich at idle. try turning your idle screws in all the way, if it doesn't stall the engine or at least make a huge differents then it needs rebuilt. the air bleeds get pluged up and make it run rich at idle. a slite vacume leak will do the same thing.