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Thread: 504 Question

  1. #1
    1000+ Posts BIGRR's Avatar
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    Default 504 Question

    I acquired a 504 GL-Ti (06.79-86) Manual.

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    504 Question-dsc00477.jpg

    See photo.

    Note:
    a) The back called the car 504 GT - 6 F.S.
    b) The white page, for Engine code (XNA AUST M4 & A3) (printed in France 07.78) is on the back of an
    Australian supplement 10.78-25.27 which was inside the manual.

    It notes VALVE ADJUSTMENT to set the Intake valves at different gaps?
    Cylinders No.s 2&3 set at 0.1mm

    Cylinders No.s 1&4 set at 0.2mm

    Exhaust gaps as usual all at 0.25.


    Does anyone know why?
    Present fleet:-
    Peugeot 93' 205 Gti 16v
    Peugeot 73' 504 Ti from new
    Peugeot 08' 407 Hdi Coupe from new

    Previous fleet:-
    Peugeot 95' 605 Sv
    Peugeot 92' 205 Gti
    Renault 72' 16TS from new
    Renault 69' 10
    Renault 71' 10s
    Renault 68' 10 from new

    "Be reasonable do it my way!"


  2. #2
    1000+ Posts PeterT's Avatar
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    Default

    Clearly to allow for differing rates of thermal expansion within such a finely tuned engine. This was even way ahead of F1 teams of the time.

    '92 205 Mi16
    '90 Mi16x4

  3. #3
    Demannu-facturing! Demannu's Avatar
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    Default

    I can't see all the details on the attachment, but here is some useless info that might help to make some sense of this.

    On 504s with the twin-carb round port engine, they found that due to different distances from the throttle plate to the valve face between the inner and outer cylinders, it was impossible to get the emissions under control, as the mixture was never consistent enough to prevent unburned hydrocarbons exiting the exhaust.

    So the solution was to use a camshaft that had longer intake lift duration on 1 & 4 than on 2 & 3. The result was emissions that passed the legal requirements of some of the more stringent markets (Australia, California).

    Having said that..... the XNA engine was the square port engine as used in very late 504s and 505s, and in Australia at least, were all a single twin-throat Solex carby.

    So I got nothin!
    Scotty

    Melbourne - Dandenong Ranges

    1956 Peugeot 403 - 'Francois' - resto project

    1969 Peugeot 504 - 'Pascal' - daily driver project

    1970 Peugeot 404 Utility - 'Brutus' - resto project

    1978 Peugeot 604 - as yet unnamed - V6 on straight LPG

    1987 Peugeot 505 - as yet unnamed - project car

    1999 Peugeot 406 Coupé - 'Chloe' - 5 speed manual

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  4. #4
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    Default

    Dave McBean said that the twin carb engine was called XNA.

    Quote Originally Posted by Demannu View Post
    I can't see all the details on the attachment, but here is some useless info that might help to make some sense of this.

    On 504s with the twin-carb round port engine, they found that due to different distances from the throttle plate to the valve face between the inner and outer cylinders, it was impossible to get the emissions under control, as the mixture was never consistent enough to prevent unburned hydrocarbons exiting the exhaust.

    So the solution was to use a camshaft that had longer intake lift duration on 1 & 4 than on 2 & 3. The result was emissions that passed the legal requirements of some of the more stringent markets (Australia, California).

    Having said that..... the XNA engine was the square port engine as used in very late 504s and 505s, and in Australia at least, were all a single twin-throat Solex carby.

    So I got nothin!

  5. #5
    1000+ Posts BIGRR's Avatar
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    Demannu,

    I think you are on the track, the heading on the white page is "VEHICLE EMISSION CONTROL INFORMATION".
    Carby: Solex 32-35 TMIMA.

    Obviously as Peter says "finely tuned engine" & "way ahead of F1 teams of the time".
    Present fleet:-
    Peugeot 93' 205 Gti 16v
    Peugeot 73' 504 Ti from new
    Peugeot 08' 407 Hdi Coupe from new

    Previous fleet:-
    Peugeot 95' 605 Sv
    Peugeot 92' 205 Gti
    Renault 72' 16TS from new
    Renault 69' 10
    Renault 71' 10s
    Renault 68' 10 from new

    "Be reasonable do it my way!"


  6. #6
    1000+ Posts Wildebeest's Avatar
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    Big R
    I'd assumed that it was because of the operation of the EGR valve and its effect on inlet valve temperatures.
    Having turfed out all the EGR plumbing on my previous and now current 504 I set the inlet valve clearance identical + .002".
    No additional noise evident.

    Following the thinking of my apprenticeship days, close set valves have a tendency to burn out quicker.

  7. #7
    Member Walshy's Avatar
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    Potentially to reduce flow to 2 and 3 thus preventing 1 and 4 leaning out?

  8. #8
    1000+ Posts BIGRR's Avatar
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    I will keep the Ti set up then!
    Present fleet:-
    Peugeot 93' 205 Gti 16v
    Peugeot 73' 504 Ti from new
    Peugeot 08' 407 Hdi Coupe from new

    Previous fleet:-
    Peugeot 95' 605 Sv
    Peugeot 92' 205 Gti
    Renault 72' 16TS from new
    Renault 69' 10
    Renault 71' 10s
    Renault 68' 10 from new

    "Be reasonable do it my way!"


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