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Thread: Gauging interest in reproduction of early style SWB muffler

  1. #11
    Senior Member
    Join Date
    Feb 2007
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    A couple of 7/67 dated NOS Leistritz for reference, both have a dark covering:
    Attached Images Attached Images      
    Tim

    Early 911S Registry #1167

  2. #12
    Bantam,

    Thanks for posting those pictures. The deeper you dive into these mufflers the more confusing it gets. There appears to be a progression in the part number assigned to the muffler. The early numbers (from a VII 11/67 parts book) I have been able to find are:

    - 901.111.011.03
    - 901.111.011.05
    - 901.111.011.08
    - 901.111.011.09
    - 901.111.011.10

    The parts book calls for different muffler clamps for the above systems:

    - 901.111.157.01 (for the .03 mufflers, 911)
    - 901.111.157.03 (for the .05 mufflers "up to model A", 911/911S)
    - 901.111.157.04 (for the .08/09 mufflers "from model A on", 911TU, 911L, 911S, 911 USA, 911L USA)

    I searched the forum and found several Leistritz mufflers offered for sale. The earliest dated muffler I was able to find is the .08 7/67 posted by Bantam. The earliest .10 system found is dated 2/68. My hypothesis is that the .03 and .05 mufflers were not dated nor did they have the part number stamped aside from the 901/1 designation and the Leistritz logo. Going one step further I would say that the "version 1" muffler referred to by me is the .03 and the "version 2&3" the .05. The mystery now remaining is why different clamps are called for. This most likely indicates the the diameter of the muffler changed. This makes sense as the early systems had the extra clam shell with the insulating material, however both the .03 and .05 are constructed this way so what is the difference between them?

    Any thoughts?

  3. #13
    Quote Originally Posted by 718RSK View Post
    The deeper you dive into these mufflers the more confusing it gets...

    The mystery now remaining is why different clamps are called for. This most likely indicates the the diameter of the muffler changed.
    This makes sense as the early systems had the extra clam shell with the insulating material, however both the .03 and .05 are constructed this way so what is the difference between them?
    Joris, does this help?

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    Jon B.
    Vista, CA

  4. #14
    Hi Jon,

    Thank you so much. Extremely helpful! Also a good reminder that I should be more pro-active in reviewing my bulletins when working on topics like these. This really helps to solve a number of key questions.

    Summarizing, the .03 muffler is the early version with asbestos shielding. There were probably a .01 and .02 version also which might denote the chromed tip "version 1" but so far I have not seen this mentioned in official factory literature. I will review my early bulletins (64) later today for mention. Another source might be the first print of the 911 parts book. I do not have one. If anybody out there does please let us know if any mention is made.

    The .04 muffler does not have the asbestos shield and uses the revised straps 901.111.157.03 and the early style muffler mount 901.111.014.01 and bracket 901.111.151.03. This muffler/mount/bracket combination was phased out with engine 909001. From engine 909001 onward the .05 muffler was used, again without the asbestos shield but now with a small recess to facilitate the new mount 901.111.014.04 and bracket, 901.111.151.03. It uses the same straps as the .04 muffler.

    Starting with the "A" series, '68 model year most likely, the .08/.09 was used which used a revised strap 901.111.157.04. Quick review of the M service bulletin section for '68 does not showcase any bulletins dealing with the muffler. ''67 bulletins not yet reviewed.

    All this being said, this leaves us with one conundrum, in my post #4 I posted a picture (courtesy of the revs institute) taken during a factory on april 13/14 of '67. I have found some more pictures of this visit in their library and the muffler shown on the engines appears to be some sort of intermediary version with what appears to be a shield or seam on only the top part of the motor
    Attached Images Attached Images    

  5. #15
    What does your clamp look like?

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    Richard
    searching for engine (case) 903742

  6. #16
    Richard,

    Attached spome pictures of mine. The best unexposed part of one strap shows very clear silver paint. The bracket and some other parts are darker making me believe that exposure probably darkens the look. This would also explain the darker remnants of paint found on my muffler. The silver pointed out by Ritchy is right. My suggestion would be to use my strap for a color match.

    JK
    Attached Images Attached Images   

  7. #17
    Quote Originally Posted by 718RSK View Post
    Summarizing, the .03 muffler is the early version with asbestos shielding... The .04 muffler does not have the asbestos shield and uses the revised straps...

    All this being said, this leaves us with one conundrum, in my post #4 I posted a picture (courtesy of the revs institute) taken during a factory on april 13/14 of '67. I have found some more pictures of this visit in their library and the muffler shown on the engines appears to be some sort of intermediary version with what appears to be a shield or seam on only the top part of the motor
    Joris, I think you meant to say "...what appears to be a shield or seam on only the top part of the muffler", not motor.

    The bulletin states "...exhaust mufflers without asbestos shielding on the underside, Part No. 901.111.011.04.", so on only the top part as I read it.
    It seems to imply the .05 muffler is similar, except for the small recess on top.

    Jon B.
    Vista, CA

  8. #18
    Quote Originally Posted by 718RSK View Post
    Richard,

    Attached spome pictures of mine. The best unexposed part of one strap shows very clear silver paint. The bracket and some other parts are darker making me believe that exposure probably darkens the look. This would also explain the darker remnants of paint found on my muffler. The silver pointed out by Ritchy is right. My suggestion would be to use my strap for a color match.

    JK
    Can you Shoot a picture like I did? Do they need to be Norma and /or straight or an arch?

    Richard
    searching for engine (case) 903742

  9. #19
    Quote Originally Posted by Jon B View Post
    Joris, I think you meant to say "...what appears to be a shield or seam on only the top part of the muffler", not motor.

    The bulletin states "...exhaust mufflers without asbestos shielding on the underside, Part No. 901.111.011.04.", so on only the top part as I read it.
    It seems to imply the .05 muffler is similar, except for the small recess on top.

    Jon B.
    Vista, CA
    You're absolutely right Jon, thanks for the clarification.

    @Richard, see attached
    Attached Images Attached Images  

  10. #20
    Quote Originally Posted by 718RSK View Post
    @Richard, see attached
    That reliefs

    BTW we can see some grey paint

    Richard
    searching for engine (case) 903742

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