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I've been trying to get my truck back on the road for 3 full work days now and can't figure it out. If you have time to read my long *** post and offer me some advice/support, I'd appreciate it!
First off, my truck. It's a 1964 F100 manual 4 on the floor with a 223 engine. The engine has 20.000 on a rebuild. About half a year ago I got front disc brakes installed.
After about 5 months of smooth driving after the disc brake conversion, I started smelling gas beyond what I usually smell from the tank intake next to the drivers door and discovered a couple leaks on the carb. I took the carb off and cleaned it up (it was covered in oil bath gook) and found a crack in the body right where the vacuum hose connects. Found a local carb guy with an Autolite 1100 off a '63 that was a match to mine and he rebuilt it for me. I put the carb in and got a really rough idle. I removed the vacuum line checked the timing with a light and set it to 4 degrees BTDC. Still rough.
I discovered the vacuum advance diaphragm had torn so I replaced it. I also replaced the spark plugs (checked the gaps and they were within the window suggested by my manual) and got a new dist cap and rotar. Still rough but better.
I found an air leak at the manifold end of the hose coming from the valve cover and fixed it. I also swapped out the carb to manifold gasket with a thicker one. I've scanned the engine with carb cleaner (extinguisher nearby) and found nothing that would increase RPM's. I rechecked the timing and have the air mixture screw at 2 turns out. I also disconnected the brakes tube from the manifold and put on a vacuum gauge which held steady at around 22. The truck drives but struggles to stay alive. It also dies at stop signs.
Here are my questions:
When I use the timing light, my white spot bounces around a little. Is that normal? Or a sign of vacuum leak or some other troubles?
I hesitate to replace the points and condenser because I don't want to add to my list of possible problems. Could those be the issue?
I really feel like the carb should be dialed in as the rebuilder guy has been doing rebuilds since the 70's, owned his own shop, has a waiting list for his services, etc. but have read that an improper float setting can cause gas to spill over at stops.
I plan to try a quarter turn in on the air mixture screw next. Good move?
When I was setting the timing, there was a sweet spot turning the distributer where the idle smoothed out (which was a couple degrees PAST TDC) Not sure what that means.
Damn, that was a long *** post! Thanks for hanging in there! I miss my lil F100 and want to get it back on the road. If you have any thoughts about all this to share, I'd be very thankful!
OK, good info on symptoms. Was the crankshaft balancer rebuilt/replaced during rebuild? One thing about Tune-Ups, there are some things we need to check today that weren't a problem back then, so you won't find it in the manuals.
What you want to do generally speaking is check and verify everything, don't "assume" anything is good, i.e. "this part is brand new, therefore it has to be good."
It is common for the steel outer inertia ring weight to slip off axis, the rubber bonding material gets soaked in oil or dry rots due to heat. The timing marks then shift along with it. It's a good idea to always check this, even if new, because other errors are sometimes possible, maybe the crankshaft keyway was cut on a Tuesday after a 4 day weekend...
An inexpensive tool called a piston stop is the best way to accurately check this. All it is, is a long bolt that screws in place of the #1 spark plug. The engine is rolled over by hand twice, in each direction, until the piston is stopped. The balancer gets marked at both positions. Exactly halfway between the two marks is the true mechanical TDC point of the #1 piston. The pointer and "0" mark on the balancer ring should be perfectly aligned between the two marks made. It isn't unusual to see this off 20° when balancer rings slip.
This is a long winded answer, but I point this out because defects of this kind are now common, and cause no end to head-scratching and frustration. A methodical step by step approach to troubleshooting and tuning is important. And ignition timing looms large, because it will never run right if the timing is off at any point, from idle all the way to 4000 RPM and everything in between, and the carb won't flow right, etc. Even if the damper is OK, then the mechanical advance needs checked, the vacuum advance needs checked...
Points & Condenser are a whole nother nutroll. They have to be top quality ignition parts, except, electronic ignition replaced them 50 years ago, so the only replacements are generally el-cheapo imported junk. What you want to use are NOS points, Autolite or Motorcraft, Blue Streak, Standard, Echlin, from "back in the day". Ebay is a good source.
Not $2.95 points from Autozone from you know where. Same with the Condenser. This is a little trickier, because even good ones can go bad over time, just sitting on the shelf. They are a very important component.
I'd try a different condenser for sure if it's a no name generic piece. A junk box condenser is fine, you know, something manufactured at a time when it was still OK to smoke on elevators. Check out the quality of the spark from the coil wire held about a 1/2" from a headbolt while cranking over the engine. It should be able to jump a 1/2" gap with a nice blue spark. Make sure to test it again after everything is warmed up, both ignition coils and ignition condensers get hot - and can sometimes work OK when cold but the heat of operation will expose internal defects.
Even if you have good quality ignition points, there is a learning curve to them, and a lot of little "gotchas" and details to be mindful of. I'd suggest getting some period Tune-Up manuals and study them, and definitely pick up a reprint of the Ford Truck Shop Manual for your truck. It has everything on troubleshooting and repair, fluid specs, quantities, torque specs, etc.
If you're like me, after say 20 years or so, you'll get it running pretty good!
You're looking at the right things with fuel and spark. Check your points, cap and rotor for wear and make sure that your points are gapped correctly. Wiggle the shaft of the dizzy to check for play. Check the lobes on the shaft of the dizzy for wear. Check for vacuum leaks in and around the carb. Take your time, and do one job at a time, so that you can identify the problem. Good looking truck.
The balancer was replaced during rebuild. I took it to a mechanic to have the engine removed/installed and the engine was rebuilt by a shop here in Portland who does nothing but so i doubt it's the balancer. I have also checked the TDC three times now and it really seems to line up with the TDC mark on the balancer. The truck really wants to purr but something is disrupting that. Today a got a new condencer and carefully swapped it out. No changes. If I pull the choke out a bit (maybe a 3rd of the way) it'll idle high with slight bumpiness. If I push the choke all the way in, it'll want to die.
The cap and rotor are new and I don't feel wiggle in the dist. shaft.
Pretty sure it's a Load-O-Matic.
One thing I thought of today is that the vacuum advance line has been removed and installed with pliers to the point that the end nuts are warn down. I don't see any ovaling but ordered a replacement just in case.
Another telltale diagnostic is the vacuum test. A good basic stock engine with serviceable innards, all the big pieces still there, in good sharp tune will always pull 19" to 21" on the gauge at factory idle and timing specification. Have you done this?
If you happen to live at altitude, at higher elevations it will pull somewhat less vacuum, but the same principle applies. If it doesn't reach factory spec with this simple check - there is a defect somewhere, and often the characteristics of the gauge needle will tell you what's going on. Every Tune-Up manual has the vacuum test.
OK, so we're not talking about any major engine derangements here in ignition or valve timing, vacuum leaks, etc., that's good info.
So we're certain the correct factory carburetor is paired with the Load-O-Matic, because they use the funky spark control valve and both manifold and venturi vacuum? Recall that there is no mechanical or centrifugal timing advance with these units, it is exclusively vacuum operated timing. So you'll want to dive into that, and make sure everything is working as it should.
Well, this would prompt me to ask the question; is there a difference between the 1963 Autolite 1100 and the 1964 Autolite 1100? I guess I have some more researching to do...
Yep, that I don't know. I do know for a fact the correct carburetor must be paired with the Load-O-Matic distributor. Even when setup right, they weren't universally loved. They need the special combination of carb venturi and manifold sourced engine vacuum to work right.
An alternative is to find a more modern style dual advance distributor (if possible) then you can use whatever carburetor you want. But I don't know what kind of contortions that requires. I doubt there's anything plug and play. Maybe.
I got the truck back in shape today! I replaced the points with some good ones and re-timed the engine. Still a rough idle. Decided to turn the idle mix screw all the way in with the engine running. No change. Then started turning it out with no change at 1, 2, 3, 4 and finally at 4 1/2 turns everything fell into place. I got my truck back! Turns out the new carb wants 4 1/2 360 turns! Hooked up the vac meter and fine tuned it a little and she purrs just like I remember her doing from so long ago! I always find it frustrating when the solution doesn't get posted so I thought someone out there might get some direction from my experiences!
Not sure if it applies here necessarily but, the standard diagnostic test for a blown power valve (economiser) is bottoming out the idle mixture screw(s). Doing so should stall the engine, if not suspect the power valve.
Today's gasoline seems to be hard on rubber fuel system components, and the power valve has a rubber diaphragm. The generic no-name valves in the kits seem not to last very long.
02-23-2020, 10:31 AM
