Only runs when advanced

[Jarrad]

Hi Guys,

I have been trying to get my F350 with 360 running right. It has been running rough and overheating. Compression is good. Here's what I have done.

- Electronic ignition, Ignition wires, Plugs
- Cleaned distributor, New vacuum advance
- Rebuilt Carburetor including throttle shaft bushings (Autolight 2100)
- New intake gasket (no vacuum leaks)
- Electric fuel pump with regulator

Runs great except only when the timing is off the scale advanced. I mean at about 50 deg advanced I get steady vacuum of 21 inHg. I can bring it down to about 30 deg advanced but it runs rough. I confirmed piston 1 is at the top of its stroke when at the TDC mark.

I checked the timing chain (new five years ago maby 1500 km) and found the marks were out 180 deg when at tdc. I turned the cam over to align the marks and turned it over two revolutions to confirm they were still aligned.

Still runs the same ? Sounds a little different but still needs to be way advanced to run at all.

At wits end. I have just timed it by ear and vacuum and am calling it done unless you have any ideas.

[Lee]

When you were checking the timing,... did you have the vacuum advance line disconnected and plugged?

Not sure what to say about the Cam...it ran fine those 1500km?

Lee

[colnago]

When you realigned the timing chain marks, did you pull the distributor out, or was it in and turned with the cam? I'm wondering if your distro is out 180 degrees.

Joseph

[sargentrs]

I wouldn't be overly concerned about what the timing light reads. Could be a slipped rubber insert in the harmonic balancer or false reading on the light. If you have 21Hg vacuum and she's not pinging, clattering or knocking at any time/rpm, then tighten the hold down clamp and call it done. I prefer to time by vacuum, driveability and max timing myself. My 302 was giving me fits with my points distributor. Ran fine up to 45 mph then cough and sputter. Advance the distributor then it would cough and sputter up to 45 mph then run fine. Drove around for an hour fiddling with the distributor and timing light, back and forth, etc. Gave up and swapped in a Duraspark ignition sytem and set the timing at 10* BTDC. Ran like crap. Monkeyed with it for an hour and a half then finally timed it to 38* at 2500 rpm and she ran like a champ. Clamped it down and checked it at idle, vac advance unplugged, and it was reading an initial timing with no advance at 22* reading 20-21 Hg vacuum. I thought "No Way!" so fiddled around some more till I finally gave up at set it back at 38* at 2500 rpm. Drove it at that timing for years before I began my build project and she loved it. After I tore down the original points distributor I discovered I had a broken advance spring which was the original problem the whole time. But hey, I got an electronic ignition as part of my learning curve.

[Beardlife]

I had a similar issue. I used a comp cams 4792 to find TDC on the balancer, the marks had walked. A little timing tape, and suddenly it runs fine at 10 degrees.

[Jarrad]

I don't know how it ran with the cam out of alignment. The only difference I have noticed since I turned it is that the starter seems to hit more resistance when starting. I took this as a good sign (more compression) I don't know about the balancer being out because tdc seems to be on the mark. I think I need to find a new timing light.

Vacuum advance hose was disconnected.

The weird thing about the distributer is that it was correct after I turned the cam.

I will find a new light and report back.

[Lee]

The only difference I have noticed since I turned it is that the starter seems to hit more resistance when starting. I took this as a good sign (more compression)

Hi,

The reason the Starter is laboring is because the spark is occurring very early on the compression stroke thus fighting the Stater.

Adjusting the timing does not effect the compression.

Take care,
Lee

[Jarrad]

Adjusting the timing does not effect the compression.
Lee

I realize this. I was talking about adjusting the cam. If valves are opening during compression stroke it would be easier to turn over.

[WarEagle]

If you are more interested in changing the number of degrees advanced by a large amount, try this: If your rotor turns clockwise, remove the dizzy hold down clamp, pull the dizzy up and turn the whole shaft clockwise an inch or so until the next gear tooth, then push back down. This should retard your timing around 22.5 degrees (360/16), putting you into the 27.5 range. 2 teeth is approx. 45 degrees, putting you around 5 degrees adv. Then you can tune from there. If its worse, then reverse the procedure.

[Jarrad]

I was wrong about the cam being 180 deg out. I was not at TDC when I changed the timing chain. I should have had the valve covers off.

Edit: This is not correct I have taken the cover off and the marks are aligned when the valves are closed. I guess I just wanted more practice taking the water pump off.