Vacuum advance on 318

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Put the vacuum advance hose (carb end) up to your mouth and suck on it while the engine is running. It'll probably stall again. This means something is messed up in your distributor, probably the vacuum pot is pulling way to far (too much advance) under very little vacuum. If I were you I would replace the whole distributor with a remanufactured unit, and perhaps after some other upgrades also adjust the advance curve.
 
you borrowed a timing light... I don't see where you posted what the timing was... You can have a 700rpm idle with 12° initial, or with 10° retarded initial. which is it? I posted earlier that the port should not have vacuum present, but it might if the plates are open too far for you 700rpm idle. The stock idle speed should be slower than 700... closer to 550-600. A truck carb and ignition can be set up to give advance immediately, because trucks seldom go over 4K rpm, and do need max torque to pull and work. So where is your timing set now?
 
sorry for the late reaction. I was outta town.

My timing now is set at 10 degrees BTDC if I'm not mistaken it may be a few more.

I have a digital light, so I set the advance to 10, then zero out on the idler mark. That should give me 10 BTDC right?

The vac advance module isn't working right either way, it's response any vacuum is to stall out the engine.

I've tried a few different timing setups, like 20 BTDC this just makes things run worse.

My idle does drop to around 550/600 rpm when the vac hose is disconnected. It's 700rpm when connected.

I'm thinking of replacing the whole distributor for sanity's sake...it runs oke, mileage is garbage and it skips and misses here and there though. My gut tells me it's timing. Just a feeling though.

Perhaps I could post a vid of what and how I'm doing it Moper, you could observe for yourself? So many people over here trying to tell me how to set timing is getting me all confused. They work on computer controlled Europeans for Gods sake....

Just an idea
 
DQ81 said:
sorry for the late reaction. I was outta town.

My timing now is set at 10 degrees BTDC if I'm not mistaken it may be a few more.

I have a digital light, so I set the advance to 10, then zero out on the idler mark. That should give me 10 BTDC right?

The vac advance module isn't working right either way, it's response any vacuum is to stall out the engine.

I've tried a few different timing setups, like 20 BTDC this just makes things run worse.

My idle does drop to around 550/600 rpm when the vac hose is disconnected. It's 700rpm when connected.

I'm thinking of replacing the whole distributor for sanity's sake...it runs oke, mileage is garbage and it skips and misses here and there though. My gut tells me it's timing. Just a feeling though.

Perhaps I could post a vid of what and how I'm doing it Moper, you could observe for yourself? So many people over here trying to tell me how to set timing is getting me all confused. They work on computer controlled Europeans for Gods sake....

Just an idea
Click to expand...

Post as many pictures as you can with as much explanation as you can and we will try to help as much as possible.
 
Assuming you are running the factory Carter BBD 2 barrel carb, the vacuum port is on the right (passenger) side of the carb. There should be NO vacuum signal from this port at idle. Put a vacuum gauge on it to confirm (they are inexpensive tools and it's time you invested in one).

I believe any port on the rear of the carb is manifold vacuum, and designed to operate the choke pull-off dashpot.

Now, here's my theory as to why your engine stalls when you connect the advance: your carb is adjusted incorrectly.

After reading your earlier posts I am led to believe that the port you are attempting to connect the advance to is not plugged. Correct? If so do this: plug the port with your finger tip with the engine at idle. What happens? If the engine sputters and dies you should feel vacuum on your finger tip. This would indicate 2 things: first, that port is manifold vacuum and not ported; and second, your advance unit is OK and not leaking (if it were leaky, connecting it would have no effect).

A picture of your carb would help here!

If plugging the port stalls the engine, you are running with a fairly substantial vacuum leak and have somehow managed to adjust the carb to mask it at idle. You need to plug this port and readjust the carb for a smooth idle. I would expect you'll have to open the throttle plates 1-1 1/2 turns and possibly turn the mixture screws in a bit.

If I'm right here's what's happening. At idle a significant portion of the engine's air requirement comes through that unplugged port. To compensate for the extra air, your throttle plates must be far more closed. Also the mixture must be rich to compensate for the non-metered air and resultant weakened signal. So when you plug the port (or connect the advance) you cut off the air the engine is using for idle. The throttle blades are too far closed to admit adequate air for idle and the engine stalls. Also the idle metering circuit now gets a full signal and is suddenly really rich which could also make it stall. As a side issue to a vacuum leak, the signal at the metering rod piston is greatly reduced. The rods raise prematurely and ride higher at cruise killing MPG. A stock 318 should get about 20 MPG.
 
Get a new dizzy in there and honestly, get rid of the Carter BBD POS. That thing gave me SO much trouble on my '70 318, almost got me (and my mom) into a couple accidents! You probably have the dreaded worn throttle shaft that's making a massive vacuum leak.
 
Carter it is indeed. And it has definately seen better days...

I knew the choke was crap as it's all disconnected except for the vacuum hose, which I'll admit, is the port I was trying to use...this doesn't explain why my distributor will kill the engine when I apply suction to the hose though, just the slightest bit=shutoff.

The only way to start the car is with starter fluid, once it's warm/started and run for 3 minutes it starts immediatly no hesitations...
But it never runs perfect. It's pretty smooth through the RPM band, doesn't hesitate of the line ever, just skips and misses every so often, predominantly at idle, maybe at higher RPM it's just not noticable.
I'm the kind of person who gets irritated by an even slightly poor idle.

Anyway as the picture shows, the vacuum advance port has been crudely sealed. The whole carb is a mess, I don't trust it one bit. By the looks of my distributor it's in about as a good a shape.

C130 Chief and others make a very good point, the carb is obviously set up to compensate for it's own shortcomings and that of the distributor. I replaced my plugs the today, ran the car 5 miles and pulled #2 and #5, they were both black. It's set up way rich.

As the trans needs to be pulled and replaced anyway I'm just going to have to save for a new 4bbl and intake like I wanted and a new distributor. This whole thing is a mess I don't think is possible to save/get running right with these parts on there...It's so frustrating, I wanna drive the damn thing already!

Thanks for your help anyways...

Pictures of the hunk o' junk:


120220091106.jpg


120220091105.jpg

The current "hookup" for the vac advance, God only knows how long it's been like that and what kind of moisture has gotten into the pot which could cause all kinds of mayhem with an electronic ignition like mine...

120220091107.jpg


The distributor with cap off:

090120091051.jpg
 
Those are pretty good carbs.... for a flathead I-6 made in 1954! Best course of action would be a ThermoQuad carb on an old iron 4-bbl. or Eddy Performer intake, a new double roller timing set, and a reman'd distributor. What was weird about my old carb was that it would stumble off idle ALL the time. Bumping up the initial advance and rebuilding the carb helped a little, but I knew there had to be something fatally wrong with that carb to make it act the way it did. Even to add insult to injury I got pretty crappy gas mileage and it ran way too lean to make any decent power.
 
The second pic shows your problem, somebody has PLUGGED the timed vacuum port, as you have correctly noted. The problem is primarily your carb, not the distributor.

As an interim repair, plug the port you are attempting to connect the distributor to, and readjust he carb to idle in that configuration. This will likely require opening the throttle plates at idle a little more. It is the carb that is killing the engine, NOT the distributor.

Now, here's my advice: I agree that it would be foolish to spend any more money on that carb, it is JUNK! It has been hacked and wasn't all that great when new.

1. Order an Edelbrock Performer intake and an Edelbrock 1406 carb. Both Summitt and Jegs offer good prices and will ship internationally. I suggest all NEW parts due to your geographic separation from the US. Also, even though the ThermoQuad is a fine carb the newest one is over 25 years old. Parts can be a challenge in the US, and would mean no end to frustration overseas.

2. While you have the intake off, consider a cam swap. I suggest this for a few reasons: the intake will be off already, the original cam is not exactly a performance piece, and you'll get the chance to replace the original timing chain and sprockets (which WILL fail, potentially bending valves).

3. A rebuilt distributor may nor be a bad idea either, but yours might be OK. You need to verify that the mechanical advance is operating correctly (twist the rotor clockwise and it should turn freely and spring back when released).

Good luck with your "foreign car". I've seen American mechanics do some pretty diabolical stuff to European carburetors.
 
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