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Maserati Khamsin

Discussion in 'Maserati' started by Maeter, Feb 24, 2008.

  1. staatsof

    staatsof Six Time F1 World Champ
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    Mar 13, 2005
    63,579
    Fuggetaboutitland
    Full Name:
    Bob
    Here's the one for the Ghibli and I beleive the Indy and Khamsin have the same setup.

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  2. achimguenther1

    Nov 6, 2011
    15
    Germany, Baunatal
    Full Name:
    Achim Günther
    https://citroen-sm-club.de/club/index.php/de/forum/nur-sm-an/6001-suche-fliehkraftregler

    Hello,
    see link, this helped me to repair my steering hardener:
    story:
    My DIRAVI steering regulator had several problems.:
    1) because it turned without oil the little bearing was broken and the centrifugal wights could not push, because the small steel points in the lead weights were worn out.
    2) the valve piston was blocked in the cylinder by dirt and rust
    3) the rubber seal was broken
    I repaired the centrifugal part using small steel rivets and changed the small bearing.
    I made the valve movable and cleaned it
    I bought a new rubber seal from Citroen SM Club Germany
    I adjusted the pressure with the screw, I had to try out by driving the car and adjust again.
    After that it worked, but internal leakage was high. So I bought a good DIravi regulator from an Citroen CX. The regulator looks different, but the valve cylinder and piston is the same. I changed it, but that is another story: ...really difficult !
    Ma steering is much better now, but for my point of view too direct especially when I drive fast on the German Autobahn. My next idea is, to use an Howe Steering quickener ( upside down) to change that.
    Please excuse my bad English
    Best Regards
    Achim
     
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  3. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
    675
    New York and Norway
    Full Name:
    Art
    1977 Khamsin update..
    She runs!

    - Installed the temporary Bendix fuel pump powered with 12v from a switched Hot lead directly from the battery.
    - Installed temporary new fuel filter, hooked up all the hoses and oddball fittings at the pump.
    - Switched on the electric pump.
    - Waited for fuel to arrive at the rail.
    - Turned key to start and she fired up.... but..
    - The sound of splashing liquid made it a very short run time.

    Shut off engine and fuel pump.
    Observed fuel puddle on the floor from a persistent leak in the 3-way check valve at the inlet side of the pump. MIE says I have to find a way to seal it up, because they are NLA.

    Anyone recommend what method to re-seal, re-gasket, or bypass, the 3-way check valve? It doesn't appear on the Parts Tables.

    Molto grazie,
    - Art



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  4. Mexico074

    Mexico074 Formula 3

    Aug 14, 2008
    1,037
    Harriman, TN USA
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    Michael Demyanovich
    Hello Art...

    Interesting about the '3 way check valve' you found on the car you are working on.. I don't recall seeing this
    on my car, but it's been a while since I looked underneath the car, and I have never had any fuel delivery issues
    (so far!!!)…. Can you provide some guidance on how this was installed, as in where the hoses attached to it
    appear to be coming from or going to!

    Thanks in advance...

    Mike
     
  5. thecarnut

    thecarnut Formula 3
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    Apr 22, 2006
    2,293
    Atlanta
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    The Car Nut
    The Khamsin has two fuel tanks, but they are not independent as they are on the Ghibli and Indy. I must assume that both tanks somehow feed the fuel pump. What I do not understand is why would check valves be need on the input side of the pump; seems a standard "T" connection would be all that is needed. Perhaps if we understand what this gizmo was designed to do, building something that accomplished the same thing should not be that difficult.

    Ivan
     
  6. 010

    010 Karting
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    May 19, 2009
    70
    Toronto, Canada
    Full Name:
    Richard
    My limited understanding and viewing showed me that the upper little tank (right where you fill the fuel) simply feeds by gravity into the larger tank under the back trunk/boot floor.. I also have not seen that pump....but I know that it takes a short while for the fuel to flow from the upper to the lower tank..in my case I have a new hose between the two tanks.... But I suspect the air release is potentially a flow limiting factor.. never an issue when running/driving... But I do need to fill up at slightly less than full speed from the pump.
    Richard


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  7. khamsin433

    khamsin433 Formula Junior

    Jul 16, 2009
    262
    Birmingham, UK
    Full Name:
    Balbir
    I agree with Richard, top tank just feeds the lower tank. Main fuel pipe runs from lower tank to pump. From pump to filter/ pressure regulator and then to fuel rail.
    Oh and there’s an in-line filter near the fuel tank.

    Don’t recall the pictured item

    Bal
     
  8. Nembo1777

    Nembo1777 F1 Veteran

    Nov 4, 2006
    5,141
    opposite lock
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    Marc Sonnery
    #7583 Nembo1777, May 31, 2019
    Last edited: May 31, 2019
    Good morning,
    Sometimes you have to step back a bit to understand why something was made in a certain way. Like the cause for the SM Merak chain tensioner weakness not being sorted being... Political as I found out in research. The initial design of the Khamsin had a FULL SIZE spare wheel placed in the back. This was the case on the two first cars AM120-002 (crash test car destroyed December 1973) and AM120-004 (Turin show 1972 world premiere car). Once 002 (which had a longer tail) was ready it was decided to shorten the tail (purely a design tweak desired by Gandini and approved by Malleret and Alfieri) and to make room the full size spare was replaced by a space saver located in the car's nose. But typically of Maserati they would not have reengineered everything at that point. So in my humble opinion and as Bal mentioned the only reason there are two tanks was that it was easier in production terms to manufacture a big one and small one to maximise capacity as opposed to a complex shaped single large one.
    Art if it helps your understanding re three way check valve I can ask one of the top restorers here in Europe.
    Best of luck with getting sleeping beauty back on the road:)
     
  9. Mexico074

    Mexico074 Formula 3

    Aug 14, 2008
    1,037
    Harriman, TN USA
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    Michael Demyanovich
    I am in agreement with Ivan... Given that the two tanks are not independent of each other
    like they are on my Ghibli and Mexico, I can't specifically see a reason for a 3-way check valve, when a
    "T" connection would suffice.

    I am hoping Art can supply some additional info when he gets a chance...

    Mike
     
  10. abarth69

    abarth69 Karting

    Aug 16, 2011
    241
    Toronto
    Full Name:
    Mark
    I will post a picture of the pump and check valve set up on the weekend

    Art you have a PM

    Cheers

    Mark
     
  11. SMarc

    SMarc Rookie

    Mar 21, 2016
    18
    With a simple "T" tube, when the car is sloping you can run out of gas with a tank half full ;-)
     
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  12. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
    675
    New York and Norway
    Full Name:
    Art
    Thank you gentlemen, this is a long answer.

    The fitting seems unrelated to the arrangements two-tank fuel system. The valve is located behind the passenger front wheel, next to the fuel pump. There is only one main fuel feed going to the fuel pump. This valve sits between that main feed and the fuel pump.

    PROBLEM: Fuel is leaking from this valve out of the crimped edge of its housing.

    SOLUTION:
    1.) Can I replace it with a simple 'T' fitting?
    Below is a photo of the 3-way check valve in original position. The part is not shown in the Euro or US fuel system diagrams I found on Ivan's website (Thank You, Ivan). It may be useful to refer to an Indy or Ghibli diagram, which I have not done yet...

    It is my speculation that this valve receives the overflow fuel returning from the carburetor fuel rail.
    The top nipple seems to allow the overflow fuel back into circulation via the fuel pump without having to run a line back to the fuel tanks*. It is a mystery to me why this valve is not a simple T, but I'm sure Alfieri knows more about fluid dynamics than I do. It has some properties of a back-check valve. Maybe this avoids fuel flowing backwards in the fuel rail?

    *The Bora has the overflow fuel line return to the un-pressured fuel filler neck and back into the tank.

    GIVENS:
    - The valve mounted between the fuel pump and the main fuel feed from the two rear tanks.
    - The valve is oriented correctly in my original photo above with the fuel tank feed connecting into the right nipple and fuel flows from right-to-left into the fuel pump.
    - The right inlet nipple receives fuel from the rear tanks.
    - The top nipple I am almost certain receives the fuel return line from the carburetor fuel rail.
    - The left outlet nipple (see it has a flow-direction arrow), goes to the fuel pump.

    - The valve only permits fuel to be sucked by the pump:
    a.) If you put pressure into the top nipple, nothing is permitted to enter the valve.
    b.) If you put pressure into the nipple fed by the fuel tanks, nothing is permitted to enter the valve.
    c.) If you SUCK on the nipple going to the fuel pump, the valve PERMITS flow.
    Secondary observations:
    d.) If you SUCK on the nipple going to the fuel pump with the top nipple blocked, it draws easily from the fuel line.
    e.) If you SUCK on the nipple going to the fuel pump with the fuel feed nipple blocked, it does not draw from the upper fuel nipple but moves a diaphragm in the valve body that seems to open a supply from the fuel tank side.

    THEORY:
    - The 3-way valve balances the rate of fuel flow between the overflow from the fuel rail and main fuel feed from the tanks.

    ASSUMPTION:
    - I can replace it with a simple T fitting.

    If the T fitting fails for some reason, the OTHER SOLUTIONS remain:
    2.) Did this valve rely on the crimped edge for a seal, like 1960's fuel pumps? If so, what is a good way to re-seal the edge of this valve body? It leaks fuel from the upper circular crimped edge. I'm researching whether cyanoacrylate is fuel-proof.
    3.) Is it suffering an internal gasket failure? If so, I am soaking it in fuel to see if an internal gasket simply dried out and needs to "re-expand" into place.

    Thank you for enduring my lengthy treatise.
    - Art




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  13. Froggie

    Froggie Karting

    Sep 27, 2017
    151
    Belgium
    #7588 Froggie, May 31, 2019
    Last edited: May 31, 2019
    Art, if it can be of any help as you are asking for the Indy fuel diagram, here is the fuel pumps arrangement on my Indy before I started its restoration.
    I think that the fitting seen on the pics may be original as the car was on storage for 30 years beforehand.
    No visible 3-way valve around the two fuel pumps.
    Serge

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  14. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
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    Art
    PS - Cyanoacrylate turns out to be an outstanding fuel-resistant adhesive. And with the otherwise leaky (i.e. useless) valve body, there is nothing to lose in the attempt at trying CA as a sealant.
    - Art
     
  15. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
    675
    New York and Norway
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    Art
    Thank you very much, Froggie,
    I love the 2 pumps like the Bora! Do you have the selector switch in the engine bay too?
    Very good photos. It seems to make sense your Indy does not have the 3-way, when the Fuel Pumps are mounted back near the tank. I wonder how the hoses are arranged, where does the overflow fuel go from the carburetor fuel rail? I wonder if it goes all the way back to the fuel tank?

    It is your style fuel pump that I am using temporarily now, a Bendix. The original AEG is going out to be rebuilt.
    Cheers,
    - Art
     
  16. barnfieldman

    barnfieldman Rookie

    Apr 18, 2006
    20
    Hi Art
    I would bet that its not an original piece, the fuel return line should go directly to the upper of the two fuel tanks and is routed through the sill.
    Regards
    Paul
     
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  17. Froggie

    Froggie Karting

    Sep 27, 2017
    151
    Belgium
    Actually I don't know where is located the selector switch (I have not driven the car yet).
    I thought it was under the dashboard...

    Nor do I know how the overflow fuel may go back from the fuel rail to the fuel tank.
    On this pic during the reassembly of the carbs, you can see the carburetor rail.
    Not sure whether the device under the rail on the far left (with a hose attached to it, close to the cabin shield) may be a valve for the overflow return back to one of the fuel tanks...


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    The two pumps have now been replaced with Facet fuel pumps and protected with relays.
    At first only one non working pump was replaced, but it appeared preferable to change both because the fuel feeding was not stable, and to wire both of them through relays as suggested (by Ivan?) because of the high current required:

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  18. thecarnut

    thecarnut Formula 3
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    Apr 22, 2006
    2,293
    Atlanta
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    The Car Nut
    I think the fuel systems in the different Maserati models might be causing some confused. Let me try to explain the differences. .

    Many of the six cylinder Maseratis (3500GT, Sebring , Mistral) had two tanks which were interconnected and would feed one fuel pump. The tanks would be placed in the right and left rear fenders and a big rubber hose ran along the back of the trunk connecting the tanks. Not the safest thing to do, but it works.

    The Mexico, Indy and Ghibli have two independent fuel tanks with two fuel pumps. Each tank has an associated fuel pump and works independently from each other. Think of it as two separate fuel delivery systems. If one pump or tank was to fail you can still use the car with the other tank/pump. The tanks were located in the right and left rear fenders. A dash switch is used to select which tank/pump supplies fuel to the carbs. The fuel gauge indicates the level of the tank selected.

    The Bora has a single tank but with two pumps ... a Bendix (as the Ghibli/Indy/Mexico) and the APG pump which was used on the Khamsin. A switch is provide in the engine bay to select which pump operates. These pumps are connected in parallel and both feed from the same fuel tank. The purpose of providing two pumps was for redundancy. If you own a Bora it is a good idea to switch pumps every so often to make sure they both work. Not all Boras might have had this dual pump layout, but most did.

    The Khamsin has two interconnected fuel tanks which feed to a single APG fuel pump. It is useless to compare the Khamsin and Indy fuel system as they are vastly different.

    Since around 1970 carbureated Maserati engines were provided with a return path to the fuel tank for any excess fuel. Lucas fuel injected engines always had a return fuel path, but that is a different story. The fuel return path was a way of avoiding vapor lock by keeping the fuel always flowing and therefore cooler. I am not familiar enough with the Khamsin fuel system to know if on this car fuel returned to the pump instead of the tank .... although returning to the pump would seem rather odd as I doubt it would have time to cool.

    Ivan
     
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  19. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
    675
    New York and Norway
    Full Name:
    Art
    Yeah, this fitting is a bit of a mystery, but i've sealed it back up and will reinstall it as I found it.
    The fitting is as old as the fuel pump and surrounding hoses - and MIE was familiar enough with the fitting they immediately knew what I was talking about..

    From official sources there appear to be both non-recirculating Khamsins and re-circulating Khamsins:
    - Khamsin owners manual Fig21 page 73, and Euro parts catalog Table 27 show no fuel recirculation return line from the carbs at all.
    - Khamsin US parts catalog Table 2 shows items 17, 33 and 18 - "Manicotti dal tube di ream al primo carb per ricircolo" and "tubo di rame per ricircolo di benzina" - fuel recirculation lines - which do go all the way back to the main fuel tank - as Paul mentions. I'll scrutinize where the hose into the upper nipple originates.

    Molto grazie,
    - Art
     
  20. khamsin433

    khamsin433 Formula Junior

    Jul 16, 2009
    262
    Birmingham, UK
    Full Name:
    Balbir
    I was going to ask If this may be a US market difference. As per table 27 in parts manual item 26 is the next item after the pump and IIRC that’s a filter King combined filter and pressure regulator. The lower bowl item 51 is a clear glass bowl.

    Best of luck getting this working.

    Bal
     
  21. Froggie

    Froggie Karting

    Sep 27, 2017
    151
    Belgium
    #7596 Froggie, Jun 1, 2019
    Last edited: Jun 1, 2019
    On the late Indy's (EU spec), there is indeed a King fuel filter/regulator in the engine bay before the fuel carb rail.
    Would that justify maybe absence of a fuel return line to the tank?

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    Also here under on this better view of the fuel pumps, one can see that at least there is no return fuel line to the pump(s), which seems logical.
    The fuel circuit looks clear, with inlets from the two left and right fuel tanks at the bottom and the two exits on top.
    One can also see on top of this pic the T joining the two fuel exits into the common line that goes into the fuel filter/regulator in the engine bay.
    It is not clear however if this T includes some kind of one-way valve on its top to avoid fuel back-recirculation in the pump not in use (my understanding is that in the Indy, only one pumps is activated at each time, electrically selected by the switch under the dash board)

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    Hoping that it helps clarifying the various fuel systems, not polluting this Khamsin thread.
    Serge
     
  22. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
    675
    New York and Norway
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    Art
    Can't wait to get this K out on the road a few miles, feel what it's like. The seats and driving position are really nice. Definitely needs new tires. Brakes seem to have reliable pressure.. I'll report more the coming week, goal is to get a video of it up on YouTube.
    - Art
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  23. abarth69

    abarth69 Karting

    Aug 16, 2011
    241
    Toronto
    Full Name:
    Mark
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  24. 71Satisfaction

    71Satisfaction Formula Junior

    Jul 15, 2012
    675
    New York and Norway
    Full Name:
    Art
    Thanks for the photo Mark.. I have re-sealed the original and will test it the next couple of days.
    - Art

    This makes sense with the "one-way" feature of the valve.
    - Art
     
  25. SMarc

    SMarc Rookie

    Mar 21, 2016
    18

    Humm... see manual parts it doesn't seem to be an original K. pump (AEG) and/or tubes system

    Perhaps this pump have a too high pressure level for carburators so they put a regulator on the pipe

    On some other cars the carburetor is drained when you stop the motor to avoid the vaporlock at restart
     

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