fordtrucks-digest Monday, September 15 1997 Volume 01 : Number 216
Ford Truck Enthusiasts - 1979 And Older Trucks Digest
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In this issue:
Vacuum Switch ["Dale and Donna Carmine" ]
Vote results ["Payne, Kenneth" ]
Vibration at 30-35 [shoman p3.net]
On the Road (Almost) ["Don & Teresa Neighbors" ]
Re: Vote results [TNickolson aol.com]
Re: Vacuum Switch ["Donald R. Screen" ]
Throttle linkage fabrication ["Donald R. Screen" ]
Date: Sun, 14 Sep 1997 17:24:39 -0500
From: "Dale and Donna Carmine"
Subject: Vacuum Switch
My '79 F-150, 351M, has a thermostatic vacuum switch mounted on the
thermostat housing. It has...err had.... four vacuum nipples coming off
it. I assume that these are two separate vacuum circuits, one for the
distributor advance and one for the EGR. One of the nipples for the EGR
broke off. Being really cheap and not wanting to spring for a new switch
my inclination is to run the distributor straight off the carb and move the
EGR to the other circuit.
Anyone see any problems with doing this? We have no emissions inspection
I don't have a final count nor the comments ready as I've
been working all week (and administering the list from work)
with 78 hours put in so far (good thing I contract!) but
a quick glance at the vote emails shows about an 80% vote
in favor of the split. Voting participation was light,
with less than 100 votes.
I'll have the third list set up within a week, with details
of the list, the vote, etc. published when its all ready...
Heres a question,I have a BAD vibration at the speed of 30-35 in
any gear..Could this be a tire out of balance????Or a U joint?
Date: Sun, 14 Sep 1997 21:29:59 -0400
From: "Don & Teresa Neighbors"
Subject: On the Road (Almost)
We've had a brief moment of celebration at the Neighbors' place. I am
proud to announce that my '54 F-250, known as "Grover", today drove the
first mile that it has driven under its own power since being parked in a
shed in 1974.
Now if I can just figure out why the battery won't hold a charge, why the
turn signals don't work, and where that goshawful sqeaking noise is coming
Dale and Donna Carmine wrote:
> My '79 F-150, 351M, has a thermostatic vacuum switch mounted on the
> thermostat housing. It has...err had.... four vacuum nipples coming off
> it. I assume that these are two separate vacuum circuits, one for the
> distributor advance and one for the EGR. One of the nipples for the EGR
> broke off. Being really cheap and not wanting to spring for a new switch
> my inclination is to run the distributor straight off the carb and move the
> EGR to the other circuit.
> Anyone see any problems with doing this? We have no emissions inspection
> in Nebraska.
> +-------------- Ford Truck Enthusiasts - 1979 and Older --------------+
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Assuming the vacuum switch is a 235 degree switch...then vacuum would
normally flow from the carb spart port to the switch then on to the
distributor vacuum advance. If your engine got hotter than normal (>235
degrees) the switch would send full manifold vacuum to the distributor
port..this would further advance your timing...increase rpms and thus
cool your engine back down to normal levels..(At least that's the theory
behind this setup). I'd have to go pull my Mityvac book out to see
exactly which port is which on the switch and if EGR is hooked up
there. Seems to me Ford used a separate vacuum switch, usually a two
port thermal vacuum switch to control the EGR at a certain temp. The
switches were color coded depending on what temp they kicked in. IMO,
you could hookup the distributor vacuum advance directly to the carb
spark port. Vacuum at the spark port should be at or near zero at
idle...don't believe it will get quite as high as manifold vacuum even
when it does peak with the throttle open. You normally don't want to
run direct manifold vacuum to the distributor advance. Depending on
your carb...if you have two ports the other port should be for the EGR
hookup. You normally will see vacuum at idle on this port. At wide
open throttle it should be near zero vacuum on the EGR port. EGR valve
therefore would close whe you hit wide open throttle.
If you clean off the grease and dirt the vacuum switch on the thermostat
housing should be labeled. Something like 1,2,D,M
Do you have a vacuum gauge to check the ports and see how much vacuum is
be directed to the vacuum advance?
Hope this helps..will post the Mityvac 4 port description if I can find
it in my workshop tomorrow.
I would think the replacement vacuum switch wouldn't be terribly
expensive (I would guess around $15).
PS. I just cleaned up my thermostatic switch in my 1974 F100 XLT
Ranger. The switch was all metal with brass fittings...Shined up real
nice..looks brand new now. Sanded and cleaned the thermostat housing
and shot two coats of Ford Blue paint on it...it looks nice now too.
Gonna post a couple of pics of my truck and engine bay on my site in
about 2 weeks. See what ya think...
I recently went out to buy material to fabricate a new throttle rod
linkage for my 1974 F100 XLT Ranger. It's got a 390 intake manifold
with an Edelbrock 1406 carb with Ford Automatic Transmission adapter
installed. The original rod was a 3/16 inch steel rod. But I ran into
a problem. The threads on the original steel rod didn't match any
standard thread pattern. I tried #10-24 and 1/4-20 threaded
The threads appear to be coarse not fine and I'm sure are American not
Metric. I tried lower and higher sizes. Nothing worked I would like
to buy some new 3/16 steel rod, bend it in a vice and then use a die to
cut the appropriate threads for the screw on throttle linkage piece.
Does anybody know what thread size or pattern these 3/16 inch throttle
PS. While I'm asking..what do you think about switching over both the
throttle and transmission rod linkages to a cable operated setup.
Anybody done this? Should I just rob a linkage setup off of a later
1973-1979 series truck? Is it even possible to do this with the C-6
transmission currently setup with a kickdown rod not a cable?
I know I can't be the only one who has messed with this kinda mod.
Even tech support at Edelbrock just said good luck with the mod.....To access the rest of this feature you must be a logged in Registered User
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