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easy e Samba Member
Joined: May 28, 2008 Posts: 3931 Location: 1 hr north of Santa Barbara
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Posted: Fri Jan 27, 2017 2:05 pm Post subject: Fuel pump / carburetor fuel cutoff cut off valve when used? |
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Sometime the idle-cutoff solenoid was introduced on the side of the carb... and kept the engine from running on after shutoff.
There was also the anti-siphon valve... maybe the predecessor to the idle cutoff solenoid? Or, were there engines that ran both?
I don't know if the anti-siphon valve was used on beetle only or beetle, bus, ghia...
I think '66 came out with the square topped fuel pump with four screws... but not sure.... and I think that had some sort of modification that stopped engine run-on?
EDIT: found this poking around:
Eric&Barb wrote: |
Round shape top is 40 HP thru early 1500.
Pentagon shaped top is late 1500 thru 1600. |
So, for the round top, single screw on top (screw inlet) fuel pumps... when & on what... was the anti-siphon valve used? (40hp, 42hp, 44hp?) Part no. 113127405
I think the screw in anti-siphon valve ended (obviously with the end of the screw inlet fuel pumps).... totally disappeared for a while... and then a slip-fit one appeared in 1970.
_________________ aka: Evan
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Last edited by easy e on Fri Jan 27, 2017 11:28 pm; edited 1 time in total |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51153 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Fri Jan 27, 2017 4:26 pm Post subject: Re: Fuel pump / carburetor anti-siphon valve when used? Idle cutoff |
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It's an anti gravity feed valve, some pumps have it built in, others don't. It's not related to run on, it prevents flooding if the needle and seat weeps. Many engines used both. _________________ Rust NEVER sleeps and stock never goes out of style.
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easy e Samba Member
Joined: May 28, 2008 Posts: 3931 Location: 1 hr north of Santa Barbara
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Posted: Fri Jan 27, 2017 4:35 pm Post subject: Re: Fuel pump / carburetor anti-siphon valve when used? Idle cutoff |
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"... stops the flow of fuel to the carburetor when the engine is not running."
busdaddy wrote: |
It's an anti gravity feed valve |
I don't know if I believe in "anti gravity"... sounds like snake oil.
But, if you're selling... how much can I get a quarter oz. of anti gravity for?
I have a 'friend' that might be interested. _________________ aka: Evan
Spreadsheet for Bus RPM, based on gearing & tire size (Excel format)
Searchable, click-navigable 1958 Bus Parts List |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51153 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Fri Jan 27, 2017 4:47 pm Post subject: Re: Fuel pump / carburetor anti-siphon valve when used? Idle cutoff |
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easy e wrote: |
"... stops the flow of fuel to the carburetor when the engine is not running."
busdaddy wrote: |
It's an anti gravity feed valve |
I don't know if I believe in "anti gravity"... sounds like snake oil.
But, if you're selling... how much can I get a quarter oz. of anti gravity for?
I have a 'friend' that might be interested. |
Sadly all the makers of good quality antigravity were driven out of business by the Chinese, now all you can get is the watered down knockoff stuff, and since it's from the other side of the world it works in reverse here.
I had one NOS can of the good stuff left and I poured it over my head hoping to make me look 20 again, unfortunately it must have been past it's expiry date since it had no perceptible effect _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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kreemoweet Samba Member
Joined: March 13, 2008 Posts: 3899 Location: Seattle, WA
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Posted: Fri Jan 27, 2017 8:54 pm Post subject: Re: Fuel pump / carburetor anti-siphon valve when used? Idle cutoff |
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Those VW things are called "fuel cutoff valves". They are not anti-siphon valves. They shut the flow of fuel off (gravity flow) unless
there's pressure coming from the fuel pump, i.e. unless the engine is running. Some VW engines from the early 60's had in-line F.C.V.'s,
and the VW/Pierburg "square-top" (aka pentagonal-top) had one built-in. Those pumps were used up thru 1970 models on Type I. The
71-72 Type I's again had an in-line F.C.V. (see Fig. 4-5, Fuel System chapter, in 70-79 Type I Bentley manual). The 73-74 Type I's went back to a
"non-rebuildable" fuel pump with a built-in F.C.V. (as illustrated in Fig. 4-4, i.b.i.d.). As far as I can tell, F.C.V.'s were never used in the bus
until the 72-74 Type 4 engines with mechanical fuel pumps, and that part of the pump seems to be identical with that of the old Pierburg
square-tops. [EDIT: just noticed that the same pump used on 72-74 Type I's was used on Non-US bus with 1600 engine, presumably from 72- on.]
The reason F.C.V.'s were used, is because the carb needle valve was designed as a flow control valve, not a cutoff valve. The
endless posts here on thesamba about gas filling up the crankcase where the stock cutoff valve has not been installed pretty well tells the
story. Those problems are frequently attributed to a leaky fuel pump diaphragm, but that is likely not the case 98% of the time. _________________ '67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities
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Last edited by kreemoweet on Fri Jan 27, 2017 9:49 pm; edited 1 time in total |
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easy e Samba Member
Joined: May 28, 2008 Posts: 3931 Location: 1 hr north of Santa Barbara
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Posted: Fri Jan 27, 2017 9:37 pm Post subject: Re: Fuel pump / carburetor anti-siphon valve when used? Idle cutoff |
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^^ most excellent reply!
So, just to clarify and summarize.... (please clarify inconsistency)
The FCV was used from whenever it was introduced.... to the end of the round top... and on ALL VW models? _________________ aka: Evan
Spreadsheet for Bus RPM, based on gearing & tire size (Excel format)
Searchable, click-navigable 1958 Bus Parts List |
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kreemoweet Samba Member
Joined: March 13, 2008 Posts: 3899 Location: Seattle, WA
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Posted: Fri Jan 27, 2017 10:06 pm Post subject: Re: Fuel pump / carburetor anti-siphon valve when used? Idle cutoff |
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Note Edit to my post above -
Not seeing any inconsistency ... unless you're wondering why VW put 'em on some vehicles but not on others ... I do not usually find it rewarding to
speculate on the motivations of the ancient VW organization that built these aircooled rigs.
I do not know the usage of F.C.V. except as I mentioned above. I cannot find any mention of their use in Type 2's except for those with carbed
Type 4 engine, and, as per my edit, on some later non-US late bay busses equipped with 1600 carb engines. It seems all those earlier Type 2's
had some variant of the Pierburg round-top pump (which of course has no F.C.V.), or the later "non-rebuildable" pump with no F.C.V. (as my '71 bus
was equipped with). _________________ '67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities
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easy e Samba Member
Joined: May 28, 2008 Posts: 3931 Location: 1 hr north of Santa Barbara
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Posted: Fri Jan 27, 2017 10:42 pm Post subject: Re: Fuel pump / carburetor anti-siphon valve when used? Idle cutoff |
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Hmmm... seems strange to have a Type 1 fuel pump/carb on a Type 2 (which is the case).... and use the FCV only on Type 1.
Absent of further input...
I'll try to look for some survivor Typ 2 40hp - early 1500 pics of fuel pumps. _________________ aka: Evan
Spreadsheet for Bus RPM, based on gearing & tire size (Excel format)
Searchable, click-navigable 1958 Bus Parts List |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51153 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat Jan 28, 2017 11:05 am Post subject: Re: Fuel pump / carburetor fuel cutoff cut off valve when used? |
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You can add type 3's into the mix as well.
_________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
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EverettB Administrator
Joined: April 11, 2000 Posts: 69827 Location: Phoenix Metro
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Posted: Sat Jan 28, 2017 6:13 pm Post subject: Re: Fuel pump / carburetor fuel cutoff cut off valve when used? |
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Adding to what is already posted:
For Bugs and Type 3s the cutoff valves are 1965 only because in 1966 VW changed to the fuel pump with the 4 screws on top, which had this shut-off built into the pump.
I am not sure why Buses didn't use it or why they used the screw-in pump so much later. _________________ How to Post Photos
Everett Barnes - [email protected] | My wanted ads
"Water is the only drink for a wise man" | "Communication prevents complaints"
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bobnorman Samba Newfoundlander
Joined: August 09, 2010 Posts: 1389 Location: Newfoundland
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Posted: Tue Jul 30, 2019 9:47 am Post subject: Re: Fuel pump / carburetor fuel cutoff cut off valve when used? |
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EverettB wrote: |
Adding to what is already posted:
For Bugs and Type 3s the cutoff valves are 1965 only because in 1966 VW changed to the fuel pump with the 4 screws on top, which had this shut-off built into the pump.
I am not sure why Buses didn't use it or why they used the screw-in pump so much later. |
Old thread, but if on the Type 3s it was 65 only, what did they do for the 62-64 cars? _________________ Air does not freeze. Air does not boil.
http://www.thesamba.com/vw/forum/viewtopic.php?t=289807 |
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EverettB Administrator
Joined: April 11, 2000 Posts: 69827 Location: Phoenix Metro
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Posted: Tue Jul 30, 2019 4:34 pm Post subject: Re: Fuel pump / carburetor fuel cutoff cut off valve when used? |
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bobnorman wrote: |
EverettB wrote: |
Adding to what is already posted:
For Bugs and Type 3s the cutoff valves are 1965 only because in 1966 VW changed to the fuel pump with the 4 screws on top, which had this shut-off built into the pump.
I am not sure why Buses didn't use it or why they used the screw-in pump so much later. |
Old thread, but if on the Type 3s it was 65 only, what did they do for the 62-64 cars? |
Nothing, the engine ran on if there was an issue. _________________ How to Post Photos
Everett Barnes - [email protected] | My wanted ads
"Water is the only drink for a wise man" | "Communication prevents complaints"
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bobnorman Samba Newfoundlander
Joined: August 09, 2010 Posts: 1389 Location: Newfoundland
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Posted: Wed Jul 31, 2019 7:32 am Post subject: Re: Fuel pump / carburetor fuel cutoff cut off valve when used? |
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EverettB wrote: |
bobnorman wrote: |
EverettB wrote: |
Adding to what is already posted:
For Bugs and Type 3s the cutoff valves are 1965 only because in 1966 VW changed to the fuel pump with the 4 screws on top, which had this shut-off built into the pump.
I am not sure why Buses didn't use it or why they used the screw-in pump so much later. |
Old thread, but if on the Type 3s it was 65 only, what did they do for the 62-64 cars? |
Nothing, the engine ran on if there was an issue. |
Thanks for the reply. I thought the electromagnetic cut off valve was for a running-on issue, and the fuel cut off valves were to stop the gas flow from the pump when not running. _________________ Air does not freeze. Air does not boil.
http://www.thesamba.com/vw/forum/viewtopic.php?t=289807 |
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