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Distributor vacuum lines

thinman666

thinman666

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Jun 19, 2021
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Location
Georgia
I need help with the routing of the vacuum lines to the distributor on my 1969 F100 240hp standard transmission 2 wheel drive one barrel carb.
There are three vacuum supply points. One on the intake manifold, one on the base of the carb. and one higher up on the carb.
The distributor has two vacuum chambers. One hose outlet pointing up nearest the distributor and one outlet pointing straight away from the distributor on the very end.
I sure do need help with this.
Thanks,
Russell
 
Ok. Have never seen a distributor with a vacuum advance like that. What engine and carburetor? 240 hp and single barrel carb rings no bells here.
 
Your location says Georgia. 3.9L in 69, makes it difficult for us old timers. 238 cu. inch. This is an in line 6.
So finally getting some where. 240 cu. inch straight 6. 150 hp / 234 ft lbs torque. Is this correct?
 
I see in my post I made a type-o and wrote 240hp instead of ci. All I can confirm is that and it is a straight 6.
 
I also didn’t say that the two vacuum ports on the carb both are located on the base of the carb.
 
The port on the carb will be the one above the throttle plate. You made have to spray some penitrating oil or carb cleaner into the vacuum port to see which it is. The dual lines on the can on the distributor will take more research. Have you messed with them to see what they actually do? One would advance the timing. The other??
 
Both of the vacuum ports on the carb are located at the base below the throttle plate but that doesn’t mean that they enter the carb throat at that point.
I pulled a vacuum on the distributor vacuum chamber farthest from the distributor and the points plate assembly moved in the opposite direction that the distributor shaft turns. That would imply that’s advance but a timing light will verify.
My issue is really which carb port to use. I’ll experiment.
Thanks
 
That is why the suggestion of spraying cleaner or lubricant threw the ports while looking threw the top of the carb. You should be able to see it come out the slot above the throttle plate when the right one has been found.
 
Okay, that worked. I now know which is which.
I tried using the manifold vacuum port, the carb. port below the throttle plate and the port above the plate all with the retard vacuum chamber on the distributor inactive. Results was varying degrees of rough running when connected to the advance chamber of the distributor. The distributor shaft is not loose nor is any part of the points plate.
I’m definitely at a loss. It runs smooth with nothing connected to the distributor but I know it should have an advance. There is no mechanical weight mechanism. The dwell is 34 and the timing is 6 deg
 
I put the new distributor in today. It’s the single advance vacuum chamber. No retard chamber. And connected to port vacuum. It seems to run fine now but I’m a little confused about the point gap I should be using. The gap is preset in the new distributor at .017. But everything I’ve been able to find on line is .027.
My truck is the 1969 F100 3.9L 240ci 6 cyl standard trans 2 wheel drive basic model.
Does anyone know what is correct or have a link to such info? Sure would be very thankful.
 
I will check my old timing chart tomorrow it should have all the timing information on it.
 
Almost forgot but here we go.
Year: 66-71
Engine: 240; 300 LD/HD standard transmission
No. Of Cyl: 6
Spark plugs gap LD/HD: .034 note for HD use .030
Distributor
Point gap: .025
Cam angle deg.: 37-42
Spring tension (oz): 17-21
Timing
Mark: 6BTDC. California vehicles use TDC
On: VD (vacuum distributor)
Firing order code: A
Valve Tappet Clearance
Int: HYD
Exh: HYD

Hoping you know what the LD/HD is in the engine type. The chart give no discription.
IMG_20210801_194309.jpg
IMG_20210801_194309.jpg
 
This is great information. As I understand it the LD/HD has to do with the rear axle and gross vehicle weight. I’m not sure what the specifics are though.
Thanks very much for digging up this material. It’s a great help.
 
That makes since light duty and heavy duty. Your F100 would be light duty. Glad I could help.
 
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