[xj-s] warning for users of ac delco 214-552 instead of cbc7714

the charcoal canister pressure control valve cbc7714 , the one
which controls flow of gas fumes from gas tank to charcoal
canister has been discontinued , I bought a GM PART NUmber
17089068 ac delco 214-552 to replace it , what I noticed is
even both valves look 100 percent identical the input is
opposite , so if anybody decides to use the GM Rochester valve
should turn the valve upside down so the vacuum port would
face the ground–
5 speed 93 ,94gold 95BLK 95red 93coupe 93blue
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// please trim quoted text to context only

…if anybody decides to use the GM Rochester valve
should turn the valve upside down so the vacuum port would
face the ground

What difference will that make?

– Kirbert

// please trim quoted text to context onlyOn 20 Nov 2016 at 18:04, Gourgen wrote:

In reply to a message from Kirbert sent Mon 21 Nov 2016:

The difference is that the tank side of the vavle is
normally closed unless engine vacuum is applied to it , it
opens when vacuum is applied to it .
it has been designed to allow fuel vapors enter the carbon
canister from gas tank only when engine is running.
otherwise it will allow the gas fumes enter the carbon
canister all the time,
it does not make sense to me because what if the car does
not run for a long period of time , all the pressure buildup
in the tank is going to to some damage.
I am not saying that I am right , I am just saying that is
the way seems to me , if you have a good explanation please
share
clearly on one side of the valve is stamped can and the
other side is stamped tank , you can blow through can side
but you can not blow through the tank side unless vacuum is
applied .–
The original message included these comments:

What difference will that make?


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In reply to a message from Gourgen sent Mon 21 Nov 2016:

It seems to me that you’re over-thinking or have
misunderstood this.
Here is the Rochester valve:

http://www.jag-lovers.org/v.htm?id=1365397842

Jaguar does NOT make it, they re-package the very same AC
Delco part.

The valve is open to the charcoal canister when the car IS
NOT running (venting the tank so that pressure is not built
inside when temperature rises).
When the engine IS running, and the charcoal canister is
regenerated (evacuated), the Rochester valve MUST close so
that you are not applying vacuum to your gas tank.

The latter is a known failure mode, whereby the tank is
known to ‘collapse’

Steve

PS BTW, you are correct that the Rochester valve does have
the two ends labeled TANK and CAN

PPS Kirby has described the EVAP system very well here:
http://www.jag-lovers.org/books/xj-s/07-
Fuel.html#VaporRecoverySystem–
The original message included these comments:

The difference is that the tank side of the vavle is
normally closed unless engine vacuum is applied to it , it
opens when vacuum is applied to it .
it has been designed to allow fuel vapors enter the carbon
canister from gas tank only when engine is running.
otherwise it will allow the gas fumes enter the carbon
canister all the time,
it does not make sense to me because what if the car does
not run for a long period of time , all the pressure buildup
in the tank is going to to some damage.
I am not saying that I am right , I am just saying that is


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In reply to a message from Gourgen sent Mon 21 Nov 2016:

Yeah, me too??? My different car is using
the system that came from Brownslane,
but managed by the GM engine purge system.

Are you saying that the one way or restrictive
valve should be reversed. And to
accomplish that by point it the other way,
down vs up?

It isn’t a pressure thing in he tank
on a closed system. But, a vacuum thing.
As fuel is drawn off a ‘‘space’’ increases.
In olden days, air from the atmosphere
rushed. Nature abhors a vacuum.

And, as I see it, if the engine is not
consuming fuel, no change + or -
happens in the tank.

I’ve a cannster in my spares that came from
the donor Cadillac. Just like the one
that came with the Jaguar!!

Carl

Carl
le–
The original message included these comments:

I am not saying that I am right , I am just saying that is
the way seems to me , if you have a good explanation please
share


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In reply to a message from sbobev sent Mon 21 Nov 2016:

I doubt if anybody actually read what I said about the valve
, I clearly understand that jaguar does not make rochester
valves , I also understand that jaguar uses gm parts .
I also mentioned they both look identical.
all I am saying is simply gm made the part for jaguar
slightly different.
very simple the side that is stamped can on jaguar rochester
valve is stamped tank on the other valve that I bought.
therefore the orientation of the valve has to be reversed
when installing , simple is that.
I do not think if it had not mattered what side or what port
to be hooked to can or to the tank , they would have bothere
to stamp it.
I have not read kirby’s book’s evaporative loss section but
I will read it , it could be different as I am not sure if
v12’s have the ecu controlled purge valve–
The original message included these comments:

Here is the Rochester valve:
Jaguar does NOT make it, they re-package the very same AC


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In reply to a message from Gourgen sent Mon 21 Nov 2016:

I suggest you read the Book and re-read your messages.
Verbatim from post #3 within this thread:
‘‘it has been designed to allow fuel vapors enter the carbon
canister from gas tank only when engine is running.’’

The gas tank venting is the same, REGARDLESS of whether it
is I6 or V12. Rochester valve is closed when engine runs and
open when it does not.

The purge scheme of the canister may be different, but the
Rochester valve is a simple, vacuum actuated ball-valve.
Nothing more to it.

Best regards,
Steve

PS BTW, I have a V12 and I was the one that corrected you
when you discussed the operation of the canister purge valve
here Jag-lovers Forums - Jag-lovers
The original message included these comments:

I doubt if anybody actually read what I said about the valve
, I clearly understand that jaguar does not make rochester
I have not read kirby’s book’s evaporative loss section but
I will read it , it could be different as I am not sure if
v12’s have the ecu controlled purge valve


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In reply to a message from sbobev sent Mon 21 Nov 2016:

Steve , I am not Bugslugger , I am Gourgen–
The original message included these comments:

PS BTW, I have a V12 and I was the one that corrected you
when you discussed the operation of the canister purge valve
here Jag-lovers Forums - Jag-lovers


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In reply to a message from Gourgen sent Mon 21 Nov 2016:

Gourgen,

My bad, I am sorry. Copied the wrong link, here is the
correct one (for the purge valve operation)

Best regards,
Steve–
The original message included these comments:

Steve , I am not Bugslugger , I am Gourgen


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In reply to a message from Kirbert sent Mon 21 Nov 2016:

The difference is that the tank side of the vavle is
normally closed unless engine vacuum is applied to it , it
opens when vacuum is applied to it .

That’s true of the Jag part. Is the GM part somehow different?

it has been designed to allow fuel vapors enter the carbon
canister from gas tank only when engine is running.
otherwise it will allow the gas fumes enter the carbon
canister all the time,

The Jag part only allows vapors to/from the canister with the engine off if the
psi in the tank exceeds 2 psi either positive or negative. When the engine is
running, vacuum pulls it open so the 2 psi is not required, it’s an open
passage to/from the canister.

it does not make sense to me because what if the car does
not run for a long period of time , all the pressure buildup
in the tank is going to to some damage.
I am not saying that I am right , I am just saying that is
the way seems to me , if you have a good explanation please
share

There MUST be a way for the tank to vent with the engine off, typically with
a 2 psi resistance. If this GM valve doesn’t provide that function, there will
need to be some OTHER component in the system that does.

clearly on one side of the valve is stamped can and the
other side is stamped tank , you can blow through can side
but you can not blow through the tank side unless vacuum is
applied .

Sounds like the 2 psi function may only work in one direction. In which case,
my suggestion would be to install two of these valves, one aimed in each
direction, plumbed in parallel. Only one of them needs a vacuum signal
connected to it.

– Kirbert

// please trim quoted text to context onlyOn 21 Nov 2016 at 3:20, Gourgen wrote:

The valve is open to the charcoal canister when the car IS
When the engine IS running, and the charcoal canister is
regenerated (evacuated), the Rochester valve MUST close so
that you are not applying vacuum to your gas tank.

That is incorrect. The purge valves draw air through the carbon canister
when the engine is running, but there’s a great big opening to atmosphere in
the carbon canister so a vacuum simply cannot be applied to it. The
Rochester valve connects the tank to the carbon canister, not to the purge
plumbing, so it’s not possible for it to apply engine vacuum to the tank unless
someone replumbs it incorrectly. Meanwhile, the Rochester valve must be
OPEN when the engine is running lest the continuous drawing of fuel from
the tank causes a suction that sucks the tank flat.

– Kirbert

// please trim quoted text to context onlyOn 21 Nov 2016 at 7:20, sbobev wrote:

In reply to a message from Kirbert sent Tue 22 Nov 2016:

Oooops. I owe apologies to the OP. It appears that I have
poor understanding on the EVAP system. I always thought that
the spring/diaphragm inside the valve controls the pressure
(or vacuum), with the line venting freely in the direction
of the tank and having 1-2 psi in the other direction.

BTW, on my car, both the purge valves and the Rochester
valve are plumbed together at the canister inlet:

http://tinyurl.com/jtzl4am

Steve–
The original message included these comments:

That is incorrect. The purge valves draw air through the carbon canister
when the engine is running, but there’s a great big opening to atmosphere in
the carbon canister so a vacuum simply cannot be applied to it. The
Rochester valve connects the tank to the carbon canister, not to the purge
plumbing, so it’s not possible for it to apply engine vacuum to the tank unless
someone replumbs it incorrectly. Meanwhile, the Rochester valve must be
OPEN when the engine is running lest the continuous drawing of fuel from
the tank causes a suction that sucks the tank flat.


'95 XJS convertible - V12 6.0L
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In reply to a message from sbobev sent Tue 22 Nov 2016:

Link doesn’t work.–
The original message included these comments:

http://tinyurl.com/jtzl4am


1996 XJS 2+2 Convertible with 4.0L AJ16
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In reply to a message from Veekay sent Tue 22 Nov 2016:

http://www.jaguarclassicparts.com/uk/jaguar-xjs-v179737-
v226645-parts/engine-management-emission-
systems/evaporative-emission-control-system/carbon-canister-
6-0-litre-from-v-194775

or the tinyurl created anew

http://tinyurl.com/jeqq7vw--
The original message included these comments:

Link doesn’t work.


'95 XJS convertible - V12 6.0L
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In reply to a message from sbobev sent Mon 21 Nov 2016:

I think I finally got the warning Gourgen wanted to share
with us.

The OEM valve has the TANK port aligned with the vacuum
line, while the CAN port is in the opposite direction. Look
at pictures #4 and #5 in the album by Dr. Quail.

I am holding the AC Delco part in my hand now, and I see
that the CAN/TANK ports are at 180 degrees.
CAN port is aligned with the vacuum line, and one must
connect them properly.

This is what Gourgen meant by ‘‘upside down’’ in his original
post.

Steve–
The original message included these comments:

Here is the Rochester valve:
http://www.jag-lovers.org/v.htm?id=1365397842


'95 XJS convertible - V12 6.0L
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1 Like

In reply to a message from sbobev sent Tue 22 Nov 2016:

that is what I meant , It is very easy to make that simple
mistake–
The original message included these comments:

CAN port is aligned with the vacuum line, and one must
This is what Gourgen meant by ‘‘upside down’’ in his original


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On 22 Nov 2016 at 5:07, sbobev wrote:

BTW, on my car, both the purge valves and the Rochester
valve are plumbed together at the canister inlet:

Probably a difference in canisters. The canister in my '83 had four taps:
One to the tank, one to the float bowls, one to the purge line to the intakes,
and one big vent overboard. The tap to the float bowls was blanked off, but
that still leaves three connections to what is essentially a big box of carbon
granules. The connections for the tank and purge lines need to be on the
opposite side of the granules from the overboard vent, but that means they
could be close to one another. The only reason for them to be separate is
so you couldn’t accidentally apply intake vacuum to the tank.

http://tinyurl.com/jtzl4am

That link didn’t work for me. I got an error message saying the URL was too
long. I didn’t even know that was possible.

– Kirbert

On 22 Nov 2016 at 7:32, sbobev wrote:

http://tinyurl.com/jeqq7vw

Yeah, that link works better. And that canister doesn’t look anything like the
one in my '83, although the purge and Rochester valves look similar.

I see what you mean about the purge and vent systems coming together at
the connector at the top of the canister. One can only hope that the little
siamesed fitting is designed so vacuum cannot possibly be applied to the
tank. It’d make me nervous unless that little fitting actually had a divider in
the center keeping those two systems separate.

#2 is a “purge inlet”. Is that the port that’s open to atmosphere?

BTW, one other possible failure mode would be for the diaphram inside the
Rochester valve to fail and the line from the carbon canister to the
Rochester valve to get clogged, possibly with a carbon granule right at the
port in the Rochester valve. It would seem that such a dual failure could
apply intake vacuum to the tank.

I have been suggesting for some time adding a solenoid valve to this system
that opens when ignition is on and provides an alternate, clear path from
tank vent to canister. The above hypothetical failure mode would be another
good reason to make that mod.

I have also suggested that inline fuel filters should be installed in two places:
Between the tank and the Rochester valve to keep rust particles from the
tank and vent lines out of the Rochester valve, and between the Rochester
valve and the carbon canister to keep carbon particles out of the Rochester
valve. Can’t hurt.

– Kirbert

1 Like

On 22 Nov 2016 at 7:35, sbobev wrote:

The OEM valve has the TANK port aligned with the vacuum
line, while the CAN port is in the opposite direction. Look
at pictures #4 and #5 in the album by Dr. Quail.

I am holding the AC Delco part in my hand now, and I see
that the CAN/TANK ports are at 180 degrees.
CAN port is aligned with the vacuum line, and one must
connect them properly.

All well and good, but with the original Jaguar valve that wouldn’t make any
difference. The flow from either CAN to TANK or from TANK to CAN
requires 2 psi of pressure when there is no vacuum signal (engine is off) and
should be a clear, unrestricted passage when there is a vacuum signal
(engine is running). I can report from experience that, blowing through a 2
psi valve with your mouth, you can barely notice a 2 psi restriction; it feels
like it’s just open. So this valve should feel open whether you’re blowing on
the CAN port or the TANK port.

From an earlier description, it sounds like this is NOT true for the GM/Delco
Rochester valve, that it only flows one way like a check valve. If this is true,
it is NOT a suitable replacement for the original Jaguar part. However, TWO
of them, plumbed in parallel and in opposite directions, might be!

I hasten to point out that you may not be able to judge these Rochester
valves by looking at them. A few years ago somebody reported that there
were scads of different part numbers for Rochester valves, all of which
looked similar but were apparently different somehow. Perhaps some allow
2-way venting while others only 1-way.

This is what Gourgen meant by ‘‘upside down’’ in his original
post.

Yeah, “upside down” makes more sense looking at that image. In my '83,
the Rochester valve was arranged horizontally rather than vertically. But it
still wouldn’t make any difference if this valve worked the way the original
Jaguar valve worked.

– Kirbert

When I was messing with my charcoal canister I noticed that the hose going from canister to electronically controlled purge valve was completely blocked , I took the hose off to blow in it and clean it , no luck , even air compressor did not help.
I ended up buying a new hose . long story short the charcoal will get in the hose going from canister to purge valve to the point that it will block it.it may ruin the purge valve too.
this made me realize that my other cars may have been suffering from the same issue , i checked my other 93 and it had the same blocked hose however the purge valve seemed to be ok.
I ended up rebuilding both charcoal canisters with activated charcoal that I bought from amazon .com to stop the flow of tiny charcoal particles in my purge valves.
I am guessing overtime the charcoal brakes down to smaller pieces which makes it easy to travel through the round aluminum separator at the bottom of the canister , the aluminum plate has many 1/8 " holes , I cut some round stainless steel mesh filter and placed it on the factory separator to act as a filter .
I used high strength clear 2 part jb weld epoxy to glue the canister lid back .