Timing & Carb question...

[fordman]

well now you have lost me i don't know what an oriface tube does inside of a carb. ifits cracked that could be the problem. the heated carb spacer is for deicing of the carb during winter. it can also heat the carb too much when it gets warm. as far as the dist hoses. they should all be removed from the dist when settignthe timing and plugged off until your finished. manifold vacuum means nothing to me. i've never done that.

[peanutman]

I think i know what orfice tube you are talking about, if it's the twin one with multi holes that bolts inside the carb just behind the screw that hols the ball in that should not matter unless the crack goes below the gasket. Ford man is correct you should have both ports plugged on the dizzy vac lines when setting timing.

Also the chilton manual states your rpms need to be up per specs when you shoot it with your light. Where does each hose coming off your dizzy go one of those lines should go to a control valve and the other to a 1/4 port on the intake There are two different types, one you can see here, it is vacuum controlled from the intake manifold


the other type is temp controled and should be in a water jacket in the intake manifold or the thermostat housing.
From that control valve a 5/16 hose should run to a port in your intake and the other a 1/4 hose to the carb. Those two ports on the dizzy from what i read in the manual both advance your timing the one furthest from your dizzy acts as your main and the one i done away with keeps your timing advanced during de-acceleration to help burn excess gas, thus improving emission output.

The chilton manual did not talk about differences in fe vs small blocks and you may not have this setup at all but it was causing me problems. Someone correct me if im wrong but you do not need that secondary port on the dizzy,

You need to make sure your main vac advance line runs to a port on the carb that does not suck at idle but does during acceleration.
Im also thinking maybe you got some vac lines crossed during your reinstall after your engine rebuild since it started then. Robbie

[1968 Ford F-100]

The truck drove great this morning to work! 11 degrees of timing/3-3.5 turns out on mixture screws (still want to check plugs to make sure I'm not running lean)/still have 14-15" of vacuum though. Ran better than it ever has. I usually would have to run on choke till the truck got pretty warm. I got less than a half mile down the road from my driveway and I could shut off the choke and drive without hesitation. Doesn't seem to have a dead spot as it did before. I also didn't have to pump the gas 2 times and pull the choke to start it this morning. All I did was pull the choke and turn the key, she fired right up. Seems pretty decent as of now. Still wonder why I can only get 14-15" of vacuum.

I still get the fuel boiling. I really don't want to unhook the heater plate. I do have a spare if it ever develops a leak. I keep up on my maintenence but you never know...it could still have issues. When my fuel boils over...it doesn't come out of the vent tubes. It pushes it out of the venturi. Curious as to why. Has anyone else had this problem? It makes for difficult starting a few minutes after I shut the engine off. Plus it's putting all that raw fuel down my cylinders and into my oil I'm sure.

The orfice tube that I am speaking of is on the venturi assembly. You remove the straight slot screw and the venturi assembly comes out and for each venturi is a outter tube with the holes and inside that tube is a rod of some sort sticking out. The tube looks kinda yellowish and they both have a series of holes along the lengh. There is one tube on each side of the flat head screw that holds the venturi down. Hope that makes sense. Anyways, there is a crack going from the bottom of one of the tubes to about half way up the tube.

As for my timing and vacuum hookups to my distributer. I have the dual vacuum one that Peanutman shows at the bottom of his post. By the way the one he shows is a smallblock but same basic idea. I do not have a temp control on my manifold. The port closest to the distributer cap isn't hooked up as it is for deceleration timing retard and isn't needed (for better emissions only). The port furthest from the distributer cap is hooked to ported vacuum on the pasenger side of my carb. And eventhough it is only ported vacuum you ALWAYS disconnect and plug ALL vacuum lines from the distributer when adjusting your timing. As for the RPM's being up per specs when shooting it with your light....I'd be interested to know what RPM I am supposed to shoot the timing light at the pointer. I always thought the truck should be at idle as to not engage the flyweights in the distributer when timing the engine. Am I wrong. Please correct me if I am. Learn something new everyday.

Thanks again for all the input and the help. Always fun to learn more about these old trucks.

[peanutman]

Good to hear it's running well. I wouldn't worry about the vac and timing settings if she's running good. If you have a chilton or haynes manual it should give you all settings under tune up specs, each year model and engine is a little different. On my 302 it said set timing at 650/800 rpms which is basically idle, i just mentioned that in case you needed it.

Your flooding sounds like to much fuel pressure to me but seems like everyone with the autolite carbs are having this same hot flood problem. I don't know if it is a heat, timing, carb or fuel pressure problem. All i can say when i done away with my emmision stuff which wasn't much and put 3 wooden clothes pins on my fuel line my flooding/heat soak problem stopped.

No one has been able to give me a solution to heat soak other than put a holley carb on it, which in my opinoin no offense to any other readers but holleys have there own unique problems.
Robbie

[1968 Ford F-100]

I pinched off my fuel line after shutting off the engine and I still had a issue with the fuel boiling and coming out the venturi. You can see the fuel bubbling if you open up the fuel bowl. So I am quite certain that it isn't an issue with my fuel pump. So I beleive that the fuel is getting hot through the carb. Maybe I should bypass the heat spacer and see where that leads me.

[peanutman]

I would think that your water cooled spacer would help. With proper mix of coolant it should keep it under the boil point for water. I don't know what the boil point for gas is plus most gas now has alcohol in it. You may post that question but but iv'e heard some say unhook it and others say leave it. Mine doesen't have that, i don't think small blocks came with the water cooled spacer so i have no experience with them.
I can tell you that heat soak is a common problem on the old ford engines-not sure why.
Robbie

[1968 Ford F-100]

I have a 50/50 mix right now. I went through the entire cooling system when I got the engine rebuilt. New rad hoses as well as heater hoses and heater core, elbows and heater valve. Flushed the radiator as well. Nice and green and used distilled water just for kicks..ha. I think I'll give a try at bypassing the spacer....although I think it won't matter because of the spacer and carb being ontop of a cast iron intake manifold. Right now my idiot gauge is right at the middle when warm. Only time it gets hot is if I sit for too long in gear somewhere. Again, no fan shroud so I can't complain and I have great heat in the cab. I'll drive it for a couple days and get a length of hose to bypass the spacer.

Thanks again.

[peanutman]

[Wes]

With your low vacuum reading, on a rebuilt engine, did you get a new cam ? It seems these days a lot of cam grinders are grinding their cam @4 degrees retarded. so even w/ the timing gears straight up, your cam is @ 4 degrees behind the crank. You could remedy this with and after market timing gear set that has multiple timing marks. This might not worth the trouble if you've got the truck running good and don't need the vacuum for brakes.

[fordman]

you could also try to cut the metal line going to the carb and putting a piece of rubber hose between the two pieces of metal line. they say that helps to do that. or evena inline filter will help the heat from boling the fuel.

[1968 Ford F-100]

Wes

Yes, I got a new cam because the old one was wiped out. It is a stock replacement. I didn't have the cash at the time to get a better cam or to put the 390 crank/rods & pistons in. It seems to be running pretty well today. I definately don't need vacuum for brakes considering I have the original "FoMoCo" drums and manual brakes.

Fordman

I have a steel line going from my fuel pump up and around the distributer and I have a 5" peice of rubber line between that and the line coming from the carb. I don't have a inline filter. I have the original style fuel canister/fuel pump design.

Good points though. Appreciate the input. Can always use more knowledge.

[Alfred Lord Tenniscourt]

I don't know if this will help you at all, but I might check to see if the mechanical advance is working. It doesn't explain the low vacuum, but if you were running that much advance on it with no pings, it seems like there must be something wrong. My theory is that you would compensate for a stuck mechanical advance by advancing the timing at idle, then, at higher revs the timing would be closer to correct explaining why the truck ran better with the timing advanced so far.
It sounds like you have a lot of little problems more than any one big one.
Good luck.

[fordman]

Fordman

I have a steel line going from my fuel pump up and around the distributer and I have a 5" peice of rubber line between that and the line coming from the carb. I don't have a inline filter. I have the original style fuel canister/fuel pump design.

Good points though. Appreciate the input. Can always use more knowledge.

sorry about that. the way you talked sounded like it was a soild line.

[SteveC]

not that this is it but is the gauge its self off? i know mine thats made clear back in 67 ish is off about 4 pounds

[1968 Ford F-100]

It was a good point Fordman. I really didn't specify as to whether or not I had a solid line from the pump to the carb.

SteveC....if your talking about my vacuum gauge....it is brand new. Not that a new one couldn't be off. But a good point none the less.