Engine issues 292

[Vanspeed]

Hey guys. I picked up a 60 f100 back in September and I have been restoring parts of her to make her road worthy again. Engine ran great when I got it. I have driven it a few times and had plenty of power, pulled nice in all gears. Thursday I put a correct V-8 radiator in it (mine had a 6 cylinder radiator in it). I started it up to check for leaks and moved it a few feet to clean off the driveway. The next day I went to start it and it runs like crap. Will hardly idle, give it gas and it drops on it’s face. When I try to get the rpms up it backfired a few times. Real rough idle and will stall out. I pulled the carb and went through it and it was super clean inside. Fuel is pumping to the carb. What could have gone wrong? I did not touch anything like the timing, ignition, etc. tomorrow I am going to pull some plugs and see what they look like. Cap is clean inside, no cracks or moisture. Coil go bad? Could it have jumped a tooth on the timing chain? I don’t know how that could have happened as it ran fine the day before with no symptoms. Any help appreciated.

 

[40cpe]

I would put a timing light on the coil wire and see if it has a steady spark while running. That might point you to the ignition or something mechanical. If the ignition is erratic I would first change the condenser, then the coil.

 

[40 Deluxe]

Another possibility: Did it sit for a long time before you got it? If so, the gas in the tank evaporated and left behind a gummy residue. Fresh gas dissolves this stuff and carries it to the engine. However, it doesn't burn completely and instead deposits on the exhaust valve stems, causing them to stick. Surefire cure is to pull the heads and the valves and clean the stems and guides. Regular spray carb clean works good. Then get the gas tank flushed to remove all the gunk. Or you can try various kinds of mouse milk added to the gas to clean the valves. i have had success in airing up the cylinders and removing the valve springs, then releasing the air pressure and working the valve up and down while spraying with carb clean.

 

[dmsfrr]

My first guess is the problem may be in the ignition.
Double check the dwell of the points.
With a volt/ohm meter check the wire to the points from the coil for continuity or a short.
The wire style with a built-in rubber sleeve thru the housing can easily break inside the sleeve and be intermittent.
The type with a small bolt and ceramic & fiber insulators thru the housing, those parts can crack or break down and create a short.
Also, there should be a ground wire from the points to the distributor housing, check it's condition.
The ignition will be intermittent if that connection is bad.
Try another condenser or swap in a spare ignition coil.

 

[Daves55Sedan]

Based upon my experience, the engine won't run at all if it has jumped time, maybe fire one plug, cough and die. So that's probably not it. It is easy enough to check though. Just pull spark plug #1, rotate the crankshaft until #1 piston is at the top of the stroke with both valves closed. Then look at your crankshaft damper and see that the TDC mark is at the timing pointer. If it is not, that is a problem.

 

[56sedandelivery]

What is jumped time.

 

[dmsfrr]

What is jumped time.

Extreme wear of the timing chain and gears can allow the chain to 'jump', skip, slip out of position.
Which mis-aligns the rotation of the camshaft in relation to rotation of the crankshaft, a bad thing.
If a timing chain set gets that loose it will soon be followed by the engine becoming a pile of parts.

 

[56sedandelivery]

Got it.

 

[dmsfrr]

.... It is easy enough to check though. Just pull spark plug #1, rotate the crankshaft until #1 piston is at the top of the stroke with both valves closed. Then look at your crankshaft damper and see that the TDC mark is at the timing pointer. ....

Since the #1 piston and the crank damper are both connected to the crankshaft, wouldn't this usually be true? ...(unless the chain jumped a bunch and valve motion is 'out in left field', or the damper w/ timing marks has slipped)
Last time I tried this the #1 piston and crank pulley marks got to TDC about 1/4 turn of the crankshaft after the #1 intake valve closed.

How about this for a 'quick & dirty' slipped timing chain test??? Cautiously put the crankshaft at #1 TDC and look at the position of the distributor rotor.
Because the dist runs off of the rear camshaft gear, if the cam is out of sync with the crank the rotor wouldn't be close to pointing at #1 position.
.

 

[Ole Don]

One way to check for a very worn chain and gear set is to advance the engine with a long wrench and the dizzy cap off. Then turn it the opposite direction to see how far the crank turns before the rotor turns. The wide chain on a Y block makes it last much longer than some other engines.

 

[Vanspeed]

I am thinking it is spark. Pulled my plugs and they are all fouled. Heavy with gas so I am going to start looking at ignition/spark.

 

[40 Deluxe]

I am thinking it is spark. Pulled my plugs and they are all fouled. Heavy with gas so I am going to start looking at ignition/spark.

If gas fouled, there is a reason, like the carb may be flooding over. Causes include float leaking and full of gas, float set too high, bad needle and seat, ruptured power valve, or excessive fuel pressure.

 

[Fred Puhn]

Check the most common problems first before messing around with the cam drive. Most problems with not running or bad running are ignition. Condenser or coils can fail for no reason at any time. Check for good spark at a plug or the coil high voltage cable. Then do a quick check of the ignition timing. If spark is good check the fuel flow to the carb (you said you already did that). Usually one of those items will be the problem. The jumped timing is so rare I have only seen that once in 50 years of messing with cars, and that was a car with a rubber timing belt.