[DeTomaso] Fuel tank ventilation - fuel spill

Julian Kift julian_kift at hotmail.com
Tue Mar 8 14:38:06 EST 2022


You are correct, the carbon simply absorbs the fuel vapor and eventually becomes loaded and cannot absorb more, it is really only designed for fuel vapor / fumes and not liquid fuel.

You need to prevent liquid fuel leaving the tank by installing an anti-slosh (or rollover) valve combined with some line elevation above the tank.

Julian
________________________________
From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of HARTWIG ASSHAUER via DeTomaso <detomaso at server.detomasolist.com>
Sent: Monday, March 7, 2022 9:38 AM
To: Mike Drew <mikeldrew at aol.com>
Cc: detomaso at server.detomasolist.com <detomaso at server.detomasolist.com>
Subject: Re: [DeTomaso] Fuel tank ventilation - fuel spill

I still do not realize how that canister fixes the issue. Fuel spillage
would go into the canister instead in front of the aft wheel. The bottom of
the canister is lower than the vent interface which means fuel will likely
accumulate in that canister and not flow back to the tank. Fuel stays there
until it is evaporated into the charcoal. Was thinking about a solution to
install in the vent line a kind of small reservoir located higher than the
vent interface that allows fuel to go back to the tank.
Cheers
Hartwig

On Mon, Mar 7, 2022 at 5:55 PM Mike Drew <mikeldrew at aol.com> wrote:

> Hartwig,
>
> I think you’ve hit upon the solution.
>
> That vent hose originally went to a charcoal canister, which experienced
> vacuum from a second hose that went from the canister to the air cleaner.
> The hose was higher than the tank. Fumes would be neutralized by the
> charcoal in the canister.
>
> Now your hose just goes to the ground. It will therefore just vent fumes
> directly to the atmosphere, and if the tank is filled to the brim, it may
> drool a bit of fuel onto the ground.
>
> The obvious thing to do would be to reintroduce the canister to the mix.
> Short of that, perhaps routing the hose so that it climbs a little bit
> before descending might help matters?
>
> I have a similar issue and my garage smells of fuel for a day or two each
> time I drive my Pantera.
>
> I like it. :)
>
> Mike
>
> Sent from my iPad
>
> On Mar 7, 2022, at 08:31, HARTWIG ASSHAUER <hartwig.asshauer at airbus.com>
> wrote:
>
> 
> Hi Mike,
>
> I checked the interface between the vent and the top of the tank. There is
> plenty of dust in that area and no signs of any fluid. I think that
> interface is 100% tight. However, when shaking the vent hose, there are
> fuel droplets dripping out.
> Cheers
> Hartwig
>
> On Sun, Mar 6, 2022 at 10:28 PM Mike Drew <mikeldrew at aol.com> wrote:
>
>> Hartwig,
>>
>> The non-linear movement of the fuel gauge is simply explained by the
>> shape of the tank. It’s not a simple box. Philosophically it’s more akin to
>> a pyramid.  Because it’s much smaller at the top, the fuel sender float
>> sinks much more quickly at first.  So your gauge will go from full to 3/4
>> relatively fast. It will move a bit more slowly from 3/4 to half, and then
>> at a constant (and arguably ‘correct’) rate from half to empty.
>>
>> It’s probably best to return to the canister system if you can,  it it’s
>> not strictly necessary.
>>
>> Have you determined where exactly the fuel is leaking from? I always
>> assumed my tank was cracked near the top, and it would leak at least one or
>> two gallons immediately if I completely filled it, which led to much
>> embarrassment at the gas station. Eventually I realized that the problem
>> lay with the interface between the vent and the top of the tank. The early
>> aluminum tank is heavily reinforced where the filler neck and fuel level
>> sender attach, but inexplicably where the vent attaches its very thin.
>>
>> Mine had the vent attached and reattached several times which distorted
>> it.  Although I considered various means of rectifying the situation,
>> because I happened to have a spare steel tank from a later car, instead I
>> just replaced it.
>>
>> My aluminum tank has been at a Pantera buddy’s house for several years,
>> awaiting us to get the energy to fabricate a reinforcing ring which would
>> affix to the inside of the tank and enable the vent to be properly secured.
>>
>> If you pop your gas tank cover off, fill the tank to the brim and find
>> gas pouring from between the top of the tank and the vent flange, that just
>> might be the impetus we need to develop a fix for you, using my tank as the
>> guide.
>>
>> The problem is detailed at length in the April 2018 PCNC newsletter,
>> available to all at www.Panteraclubnorcal.com<http://www.Panteraclubnorcal.com>
>>
>> Let me know what you find out!
>>
>> Mike
>>
>> Sent from my iPad
>>
>> On Mar 6, 2022, at 13:13, HARTWIG ASSHAUER <hartwig.asshauer at airbus.com>
>> wrote:
>>
>> 
>> Hi Mike,
>> Yes, my tank is wrapped in fibreglass. The car is from 1971 (VIN 1571).
>> When I bought the car it had the canister installed but there was no vent
>> hose connected to it and I removed the canister. The tank vent is connected
>> to a simple rubber tube that goes straight in front of the left aft wheel.
>> From the beginning I had noticed that the first quarter (fuel gauge)
>> empties quite quickly. I always thought that this is due to the
>> Italien non-precision instruments installed but it seems that my car is
>> equipped with a fuel jettison system. Should I go back to the canister
>> setup or is there a smarter way?
>> Cheers
>> Hartwig
>>
>> On Sun, Mar 6, 2022 at 5:23 PM Mike Drew <mikeldrew at aol.com> wrote:
>>
>>> Hartwig,
>>>
>>> The vent hose originally ran across the engine bay beneath the rear
>>> window, into a charcoal canister.  Another hose ran from that canister to
>>> the engine, although at the moment I can’t quite remember what the scheme
>>> was. Was the engine also vented to the canister? Or was the canister
>>> providing vacuum that drew fumes from the tank, through the canister and
>>> into the engine, as modern cars do?
>>>
>>> In any case, if you disconnect the vent hose from the canister and
>>> instead just point it at the ground, in certain rare circumstances, when
>>> the tank is completely filled, it can actually siphon the engine tire
>>> contents onto the ground! (I’ve only heard of that happening once).
>>>
>>> My car had an aluminum 1971 tank in it and used to dump fuel all the
>>> time. I discovered that the top of the tank where the vent is attached was
>>> very thin, and it was distorted by the attaching rivets, preventing a
>>> proper seal. As the vent is below the top of the tank (which is stupid), it
>>> is submerged when the tank is completely full. I know you have a 1971
>>> car—is it early enough to have an aluminum tank also? (They are wrapped in
>>> fiberglass, ostensibly to prevent leaks).
>>>
>>> Mike
>>>
>>> Sent from my iPad
>>>
>>> > On Mar 6, 2022, at 07:41, HARTWIG ASSHAUER via DeTomaso <
>>> detomaso at server.detomasolist.com> wrote:
>>> >
>>> >    Hi fromA Toulouse (France),
>>> >   I noticed for quite some time that there is often a significant fuel
>>> >   smell in the garage after having driven my Pantera. After some recent
>>> >   investigation I found that the underside of the car was partially wet
>>> >   from fuel that was releasedA from the fuel tank venting hose. That
>>> does
>>> >   not look normal, right? Does the fuel tank venting have some device
>>> >   installed that prevents liquid fuel leaving the tank?
>>> >   Cheers
>>> >   Hartwig
>>> >
>>> >   The information in this e-mail is confidential. The contents may not
>>> be
>>> >   disclosed or used by anyone other than the addressee. Access to this
>>> >   e-mail by anyone else is unauthorised.
>>> >   If you are not the intended recipient, please notify Airbus
>>> immediately
>>> >   and delete this e-mail.
>>> >   Airbus cannot accept any responsibility for the accuracy or
>>> >   completeness of this e-mail as it has been sent over public networks.
>>> >   If you have any concerns over the content of this message or its
>>> >   Accuracy or Integrity, please contact Airbus immediately.
>>> >   All outgoing e-mails from Airbus are checked using regularly updated
>>> >   virus scanning software but you should take whatever measures you
>>> deem
>>> >   to be appropriate to ensure that this message and any attachments are
>>> >   virus free.
>>> > _______________________________________________
>>> >
>>> >
>>> > Detomaso Email List is not managed by POCA
>>> > Posted emails must not exceed 1.5 Megabytes
>>> > DeTomaso mailing list
>>> > DeTomaso at server.detomasolist.com
>>> > http://server.detomasolist.com/mailman/listinfo/detomaso
>>> >
>>> > To manage your subscription (change email address, unsubscribe, etc.)
>>> use the links above.
>>> >
>>> > Members who post to this list grant license to the list to forward any
>>> message posted here to all past, current, or future members of the list.
>>> They also grant the list owner permission to maintain an archive or approve
>>> the archiving of list messages.
>>>
>>> The information in this e-mail is confidential. The contents may not be
>> disclosed or used by anyone other than the addressee. Access to this e-mail
>> by anyone else is unauthorised.
>> If you are not the intended recipient, please notify Airbus immediately
>> and delete this e-mail.
>> Airbus cannot accept any responsibility for the accuracy or completeness
>> of this e-mail as it has been sent over public networks. If you have any
>> concerns over the content of this message or its Accuracy or Integrity,
>> please contact Airbus immediately.
>> All outgoing e-mails from Airbus are checked using regularly updated
>> virus scanning software but you should take whatever measures you deem to
>> be appropriate to ensure that this message and any attachments are virus
>> free.
>>
>> The information in this e-mail is confidential. The contents may not be
> disclosed or used by anyone other than the addressee. Access to this e-mail
> by anyone else is unauthorised.
> If you are not the intended recipient, please notify Airbus immediately
> and delete this e-mail.
> Airbus cannot accept any responsibility for the accuracy or completeness
> of this e-mail as it has been sent over public networks. If you have any
> concerns over the content of this message or its Accuracy or Integrity,
> please contact Airbus immediately.
> All outgoing e-mails from Airbus are checked using regularly updated virus
> scanning software but you should take whatever measures you deem to be
> appropriate to ensure that this message and any attachments are virus free.
>
>
The information in this e-mail is confidential. The contents may not be disclosed or used by anyone other than the addressee. Access to this e-mail by anyone else is unauthorised.
If you are not the intended recipient, please notify Airbus immediately and delete this e-mail.
Airbus cannot accept any responsibility for the accuracy or completeness of this e-mail as it has been sent over public networks. If you have any concerns over the content of this message or its Accuracy or Integrity, please contact Airbus immediately.
All outgoing e-mails from Airbus are checked using regularly updated virus scanning software but you should take whatever measures you deem to be appropriate to ensure that this message and any attachments are virus free.
-------------- next part --------------
   You are correct, the carbon simply absorbs the fuel vapor and
   eventually becomes loaded and cannot absorb more, it is really only
   designed for fuel vapor / fumes and not liquid fuel.

   You need to prevent liquid fuel leaving the tank by installing an
   anti-slosh (or rollover) valve combined with some line elevation above
   the tank.

   Julian
     __________________________________________________________________

   From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of
   HARTWIG ASSHAUER via DeTomaso <detomaso at server.detomasolist.com>
   Sent: Monday, March 7, 2022 9:38 AM
   To: Mike Drew <mikeldrew at aol.com>
   Cc: detomaso at server.detomasolist.com <detomaso at server.detomasolist.com>
   Subject: Re: [DeTomaso] Fuel tank ventilation - fuel spill

   I still do not realize how that canister fixes the issue. Fuel spillage
   would go into the canister instead in front of the aft wheel. The
   bottom of
   the canister is lower than the vent interface which means fuel will
   likely
   accumulate in that canister and not flow back to the tank. Fuel stays
   there
   until it is evaporated into the charcoal. Was thinking about a solution
   to
   install in the vent line a kind of small reservoir located higher than
   the
   vent interface that allows fuel to go back to the tank.
   Cheers
   Hartwig
   On Mon, Mar 7, 2022 at 5:55 PM Mike Drew <mikeldrew at aol.com> wrote:
   > Hartwig,
   >
   > I think you've hit upon the solution.
   >
   > That vent hose originally went to a charcoal canister, which
   experienced
   > vacuum from a second hose that went from the canister to the air
   cleaner.
   > The hose was higher than the tank. Fumes would be neutralized by the
   > charcoal in the canister.
   >
   > Now your hose just goes to the ground. It will therefore just vent
   fumes
   > directly to the atmosphere, and if the tank is filled to the brim, it
   may
   > drool a bit of fuel onto the ground.
   >
   > The obvious thing to do would be to reintroduce the canister to the
   mix.
   > Short of that, perhaps routing the hose so that it climbs a little
   bit
   > before descending might help matters?
   >
   > I have a similar issue and my garage smells of fuel for a day or two
   each
   > time I drive my Pantera.
   >
   > I like it. :)
   >
   > Mike
   >
   > Sent from my iPad
   >
   > On Mar 7, 2022, at 08:31, HARTWIG ASSHAUER
   <hartwig.asshauer at airbus.com>
   > wrote:
   >
   >
   > Hi Mike,
   >
   > I checked the interface between the vent and the top of the tank.
   There is
   > plenty of dust in that area and no signs of any fluid. I think that
   > interface is 100% tight. However, when shaking the vent hose, there
   are
   > fuel droplets dripping out.
   > Cheers
   > Hartwig
   >
   > On Sun, Mar 6, 2022 at 10:28 PM Mike Drew <mikeldrew at aol.com> wrote:
   >
   >> Hartwig,
   >>
   >> The non-linear movement of the fuel gauge is simply explained by the
   >> shape of the tank. It's not a simple box. Philosophically it's more
   akin to
   >> a pyramid.  Because it's much smaller at the top, the fuel sender
   float
   >> sinks much more quickly at first.  So your gauge will go from full
   to 3/4
   >> relatively fast. It will move a bit more slowly from 3/4 to half,
   and then
   >> at a constant (and arguably `correct') rate from half to empty.
   >>
   >> It's probably best to return to the canister system if you can,  it
   it's
   >> not strictly necessary.
   >>
   >> Have you determined where exactly the fuel is leaking from? I always
   >> assumed my tank was cracked near the top, and it would leak at least
   one or
   >> two gallons immediately if I completely filled it, which led to much
   >> embarrassment at the gas station. Eventually I realized that the
   problem
   >> lay with the interface between the vent and the top of the tank. The
   early
   >> aluminum tank is heavily reinforced where the filler neck and fuel
   level
   >> sender attach, but inexplicably where the vent attaches its very
   thin.
   >>
   >> Mine had the vent attached and reattached several times which
   distorted
   >> it.  Although I considered various means of rectifying the
   situation,
   >> because I happened to have a spare steel tank from a later car,
   instead I
   >> just replaced it.
   >>
   >> My aluminum tank has been at a Pantera buddy's house for several
   years,
   >> awaiting us to get the energy to fabricate a reinforcing ring which
   would
   >> affix to the inside of the tank and enable the vent to be properly
   secured.
   >>
   >> If you pop your gas tank cover off, fill the tank to the brim and
   find
   >> gas pouring from between the top of the tank and the vent flange,
   that just
   >> might be the impetus we need to develop a fix for you, using my tank
   as the
   >> guide.
   >>
   >> The problem is detailed at length in the April 2018 PCNC newsletter,
   >> available to all at [1]www.Panteraclubnorcal.com
   >>
   >> Let me know what you find out!
   >>
   >> Mike
   >>
   >> Sent from my iPad
   >>
   >> On Mar 6, 2022, at 13:13, HARTWIG ASSHAUER
   <hartwig.asshauer at airbus.com>
   >> wrote:
   >>
   >>
   >> Hi Mike,
   >> Yes, my tank is wrapped in fibreglass. The car is from 1971 (VIN
   1571).
   >> When I bought the car it had the canister installed but there was no
   vent
   >> hose connected to it and I removed the canister. The tank vent is
   connected
   >> to a simple rubber tube that goes straight in front of the left aft
   wheel.
   >> From the beginning I had noticed that the first quarter (fuel gauge)
   >> empties quite quickly. I always thought that this is due to the
   >> Italien non-precision instruments installed but it seems that my car
   is
   >> equipped with a fuel jettison system. Should I go back to the
   canister
   >> setup or is there a smarter way?
   >> Cheers
   >> Hartwig
   >>
   >> On Sun, Mar 6, 2022 at 5:23 PM Mike Drew <mikeldrew at aol.com> wrote:
   >>
   >>> Hartwig,
   >>>
   >>> The vent hose originally ran across the engine bay beneath the rear
   >>> window, into a charcoal canister.  Another hose ran from that
   canister to
   >>> the engine, although at the moment I can't quite remember what the
   scheme
   >>> was. Was the engine also vented to the canister? Or was the
   canister
   >>> providing vacuum that drew fumes from the tank, through the
   canister and
   >>> into the engine, as modern cars do?
   >>>
   >>> In any case, if you disconnect the vent hose from the canister and
   >>> instead just point it at the ground, in certain rare circumstances,
   when
   >>> the tank is completely filled, it can actually siphon the engine
   tire
   >>> contents onto the ground! (I've only heard of that happening once).
   >>>
   >>> My car had an aluminum 1971 tank in it and used to dump fuel all
   the
   >>> time. I discovered that the top of the tank where the vent is
   attached was
   >>> very thin, and it was distorted by the attaching rivets, preventing
   a
   >>> proper seal. As the vent is below the top of the tank (which is
   stupid), it
   >>> is submerged when the tank is completely full. I know you have a
   1971
   >>> car--is it early enough to have an aluminum tank also? (They are
   wrapped in
   >>> fiberglass, ostensibly to prevent leaks).
   >>>
   >>> Mike
   >>>
   >>> Sent from my iPad
   >>>
   >>> > On Mar 6, 2022, at 07:41, HARTWIG ASSHAUER via DeTomaso <
   >>> detomaso at server.detomasolist.com> wrote:
   >>> >
   >>> >    Hi fromA Toulouse (France),
   >>> >   I noticed for quite some time that there is often a significant
   fuel
   >>> >   smell in the garage after having driven my Pantera. After some
   recent
   >>> >   investigation I found that the underside of the car was
   partially wet
   >>> >   from fuel that was releasedA from the fuel tank venting hose.
   That
   >>> does
   >>> >   not look normal, right? Does the fuel tank venting have some
   device
   >>> >   installed that prevents liquid fuel leaving the tank?
   >>> >   Cheers
   >>> >   Hartwig
   >>> >
   >>> >   The information in this e-mail is confidential. The contents
   may not
   >>> be
   >>> >   disclosed or used by anyone other than the addressee. Access to
   this
   >>> >   e-mail by anyone else is unauthorised.
   >>> >   If you are not the intended recipient, please notify Airbus
   >>> immediately
   >>> >   and delete this e-mail.
   >>> >   Airbus cannot accept any responsibility for the accuracy or
   >>> >   completeness of this e-mail as it has been sent over public
   networks.
   >>> >   If you have any concerns over the content of this message or
   its
   >>> >   Accuracy or Integrity, please contact Airbus immediately.
   >>> >   All outgoing e-mails from Airbus are checked using regularly
   updated
   >>> >   virus scanning software but you should take whatever measures
   you
   >>> deem
   >>> >   to be appropriate to ensure that this message and any
   attachments are
   >>> >   virus free.
   >>> > _______________________________________________
   >>> >
   >>> >
   >>> > Detomaso Email List is not managed by POCA
   >>> > Posted emails must not exceed 1.5 Megabytes
   >>> > DeTomaso mailing list
   >>> > DeTomaso at server.detomasolist.com
   >>> > [2]http://server.detomasolist.com/mailman/listinfo/detomaso
   >>> >
   >>> > To manage your subscription (change email address, unsubscribe,
   etc.)
   >>> use the links above.
   >>> >
   >>> > Members who post to this list grant license to the list to
   forward any
   >>> message posted here to all past, current, or future members of the
   list.
   >>> They also grant the list owner permission to maintain an archive or
   approve
   >>> the archiving of list messages.
   >>>
   >>> The information in this e-mail is confidential. The contents may
   not be
   >> disclosed or used by anyone other than the addressee. Access to this
   e-mail
   >> by anyone else is unauthorised.
   >> If you are not the intended recipient, please notify Airbus
   immediately
   >> and delete this e-mail.
   >> Airbus cannot accept any responsibility for the accuracy or
   completeness
   >> of this e-mail as it has been sent over public networks. If you have
   any
   >> concerns over the content of this message or its Accuracy or
   Integrity,
   >> please contact Airbus immediately.
   >> All outgoing e-mails from Airbus are checked using regularly updated
   >> virus scanning software but you should take whatever measures you
   deem to
   >> be appropriate to ensure that this message and any attachments are
   virus
   >> free.
   >>
   >> The information in this e-mail is confidential. The contents may not
   be
   > disclosed or used by anyone other than the addressee. Access to this
   e-mail
   > by anyone else is unauthorised.
   > If you are not the intended recipient, please notify Airbus
   immediately
   > and delete this e-mail.
   > Airbus cannot accept any responsibility for the accuracy or
   completeness
   > of this e-mail as it has been sent over public networks. If you have
   any
   > concerns over the content of this message or its Accuracy or
   Integrity,
   > please contact Airbus immediately.
   > All outgoing e-mails from Airbus are checked using regularly updated
   virus
   > scanning software but you should take whatever measures you deem to
   be
   > appropriate to ensure that this message and any attachments are virus
   free.
   >
   >
   The information in this e-mail is confidential. The contents may not be
   disclosed or used by anyone other than the addressee. Access to this
   e-mail by anyone else is unauthorised.
   If you are not the intended recipient, please notify Airbus immediately
   and delete this e-mail.
   Airbus cannot accept any responsibility for the accuracy or
   completeness of this e-mail as it has been sent over public networks.
   If you have any concerns over the content of this message or its
   Accuracy or Integrity, please contact Airbus immediately.
   All outgoing e-mails from Airbus are checked using regularly updated
   virus scanning software but you should take whatever measures you deem
   to be appropriate to ensure that this message and any attachments are
   virus free.

References

   1. http://www.Panteraclubnorcal.com/
   2. http://server.detomasolist.com/mailman/listinfo/detomaso


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