I am about to refit the original ZS carbs, flange stamped
3305, and have a question regarding what appears to be a
vacuum fitting on the bottom of the front carb. For some
reason the OO had removed them and replaced with a
different model of the carb that did not have this fitting,
nor the breather fitting. I re-found them when clearing
off a shelf in the garage last fall, they were sitting
there for 20+ years, and they were rebuilt. The
distributor has a vacuum line attached that is T’d off the
vacuum line that goes to the air cleaner. I am thinking
the carb fitting is what should be used to the
distributor. Picture at link of the carb before rebuild,
showing the fitting in question. Car is an 11/69 build.
Checked the JCNA judges guide but no info other than the
carb numbers. Pix would be wonderful. TIA.
Ralph, 1970 FHC, 1R27295
Coastal NJ, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from RGK sent Sat 4 Apr 2015:
Ralph, I believe that the oe ZS carbs ( for a 1970 SII’‘E’’ )
did not have a vacuum advance…rather a vacuum retard…to
increase rate of warm up to reduce emissions! The air
cleaner warm air ‘‘flap’’, is actuated by vacuum from the
intake manifold up near the fire wall! I don’t know what yr
fitting is beneath the ZS carb. I am using a 1986 electronic
ignition system from an XJ car, and one ZS carb is modified
to provide a vacuum ( for the dizzy ) by a port close to the
butterfly valve.–
The original message included these comments:
I am about to refit the original ZS carbs, flange stamped
3305, and have a question regarding what appears to be a
vacuum fitting on the bottom of the front carb. For some
distributor has a vacuum line attached that is T’d off the
vacuum line that goes to the air cleaner. I am thinking
Ralph, 1970 FHC, 1R27295
Coastal NJ, United States
–
John M Holmes 1973 E Type SIII Supra 5Sp, 70 SII OTS 05XJ8L
Ontario, Canada
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from RGK sent Sat 4 Apr 2015:
By the photo, it looks like the vacuum fitting is below
(manifold side) the throttle plate, so it can connect to the
vacuum retard capsule on the distributor. As you open the
throttle, the vacuum to the retard capsule drops off and the
spring in the capsule advances the breaker plate in the
distributor. IF the rod seal in the retard capsule still
holds vacuum. If it doesn’t you may as well not even have
it connected.
My 70 E had the same thermostatic switch in the filter
housing between the carburetors that controlled the flapper
valve to bring hot air from around the exhaust manifolds to
help vaporize fuel when the engine was still warming up.
The vacuum retard capsule was Teed into the vacuum line from
a manifold fitting at the firewall.
When I fitted an electronic distributor from a Series III
XJ6, I drilled a sensing hole into the chamber between
shuttle and throttle for the advance capsule. There is a
blind hole on top of the mounting flange of the carburetor.–
The original message included these comments:
distributor has a vacuum line attached that is T’d off the
vacuum line that goes to the air cleaner. I am thinking
the carb fitting is what should be used to the
–
Pete Peterson 70E(193K) XJ40s(88-270K,89-97K, 94-122K)
Severna Park, Maryland, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Jaguarpete sent Sat 4 Apr 2015:
Thanks. That describes how the vacuum lines on mine
currently are. Apparently this fitting on the flange was
added for some reason. It was blocked off as shown in my
picture. I’ll just do the same.–
The original message included these comments:
My 70 E had the same thermostatic switch in the filter
housing between the carburetors that controlled the flapper
valve to bring hot air from around the exhaust manifolds to
help vaporize fuel when the engine was still warming up.
The vacuum retard capsule was Teed into the vacuum line from
a manifold fitting at the firewall.
–
Ralph, 1970 FHC, 1R27295
Coastal NJ, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from RGK sent Sat 4 Apr 2015:
On my 70 2+2,the vacuum line goes from
this port below the carb and tees to the
air cleaner and the vac retard on the
distributor. I have an available vacuum
port at the back of my manifold that is
capped. The one below the carb is
positioned perfectly for the purpose of
sending vacuum to distrib/ac. The other
one would take a lot of vac hose to do
the same job. I’m pretty sure mine is
factory.–
The original message included these comments:
In reply to a message from Jaguarpete sent Sat 4 Apr 2015:
–
Gary Devenney 1970 2+2
Amarillo/Texas, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
