Page 4 of 4 FirstFirst 1234
Results 46 to 57 of 57

Thread: Carburetor bolts and gasket

  1. #46
    Registered User
    Join Date
    Feb 2004
    Location
    Boise, ID
    Posts
    304

    Re: Carburetor bolts and gasket

    Gerry sent me a set of his 3d printed prototypes. I tested them with the spare pair of mikunis I had on the self. I can confirm that they fit fine. The only pair of manifolds I have however are on the car and so I couldn't check all three of them together without a lot more work.

    While I've had the carbs off and on a dozen times, I have only once removed the intake manifolds. My comfort level with doing that is a lot less as it means also messing with the exhaust manifolds. With these prototypes I see the long term merit of installing the bolts with the heads towards the engine block. Unfortunately, I currently have my bolts installed with heads away from the block. I am trying (and failing) to come up with a good argument for simply having these things threaded like in the example Walt showed. I I think I'm just going to have to work up the courage to pull my intake manifold off again.

    The prototypes look a little crooked in the picture, but that's just because of my camera angle.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	carb_nuts.jpg 
Views:	32 
Size:	1.53 MB 
ID:	30968  
    Frank Stutzman
    '56 190sl (chassis 01186)
    Done with paint, let the wild re-assembly begin!!!
    Boise, id

  2. #47
    Administrator JimVillers's Avatar
    Join Date
    Aug 2001
    Location
    Virginia Beach, VA
    Posts
    5,934

    Re: Carburetor bolts and gasket

    Frank ..... Walt and I have spare manifolds and have reviewed the existing 3D printed sample. Both Walt and I had some issues with the pressed bushings of the current plate and Gerry is revising the design and printing up another version.

    I am confident that anything that will work with both Weber and Solex carburetors will work the Mikuni.
    Jim Villers
    1961 190SL, 230SL 5-speed, MGB 5-speed, Porsche 356C; 1967 Porsche 911; 1950 Jeep CJ3A

  3. #48
    Registered User totÚpt's Avatar
    Join Date
    Jul 2016
    Location
    Pistoia, Italy
    Posts
    213

    Re: Carburetor bolts and gasket

    Goodmorning all!!
    I follow your project with interest and I cannot help you given the distance that separates us ... but I follow you ..
    What kind of problems did you encounter with the bushings?
    Francesco
    Francesco
    190 SL 1961 - (ex US OZF-810)
    Sorry for my "Google" English...

  4. #49
    Administrator JimVillers's Avatar
    Join Date
    Aug 2001
    Location
    Virginia Beach, VA
    Posts
    5,934

    Re: Carburetor bolts and gasket

    Francisco .... The problems with the bushings were in the installing the bolts or removing the plate. with the bushing installed in the plate, the plate could not be installed in one of my spare manifolds. I installing the bushings with the plate and bolt installed made it impossible to remove the bolts or plates from the carburetor. That is the value of prototyping in plastic; you get a feel of what works and what will not work on the car with an installed manifold.
    Jim Villers
    1961 190SL, 230SL 5-speed, MGB 5-speed, Porsche 356C; 1967 Porsche 911; 1950 Jeep CJ3A

  5. #50
    Registered User totÚpt's Avatar
    Join Date
    Jul 2016
    Location
    Pistoia, Italy
    Posts
    213

    Re: Carburetor bolts and gasket

    Goodmorning!!
    does anyone know how much the rear carburetor is lower than the front one?
    Thanks!!
    Francesco
    190 SL 1961 - (ex US OZF-810)
    Sorry for my "Google" English...

  6. #51
    Registered User totÚpt's Avatar
    Join Date
    Jul 2016
    Location
    Pistoia, Italy
    Posts
    213

    Re: Carburetor bolts and gasket

    Jim good morning,
    I take this post again for clarification.... I'm still thinking about mounting the rubber seals between the intake manifold and the carburetors!
    My question is What is the function of bushing # 4 on the design posted by Walt?
    Is it necessary to make it beat against the flange of the carburetor (with the spring washer) or must it NOT beat and the bolt must be tightened with a sufficient force 'X' not to leak air?
    I ask you this because the thickness of the flange of my intake manifold is different hole by hole. Should I therefore change the bushing length for each hole? (I have 2 to 4 mm of draft left before the spacer touches the carburetor flange)
    Thanks!!
    Francesco
    Francesco
    190 SL 1961 - (ex US OZF-810)
    Sorry for my "Google" English...

  7. #52
    Administrator wpuryear's Avatar
    Join Date
    Aug 2001
    Posts
    3,748
    The purpose of the bushing, I assume, is to prevent over tightening which would result in the rubber gasket squeezing out and creating an air leak. As an experiment I once used gasket sealer on both sides of the rubber. Even with the steel bushings, the sealer lubricated the junction enough for the gasket to squirt out with only moderate tightening.

    I do the final tightening of the bolts, one by one with a 1/4Ē ratchet, until the torque on each feels the same.

    I donít think you need to adjust the bushing length but with 2 to 4mm remaining, they might be under sized. What length are they?

    Walt

  8. #53
    Registered User totÚpt's Avatar
    Join Date
    Jul 2016
    Location
    Pistoia, Italy
    Posts
    213

    Re: Carburetor bolts and gasket

    Hi!
    the spacers are 17.4 mm, but what worries me is the difference in the thickness of the manifold die flanges (the minimum is 10.2 mm and the maximum 11.88 mm)
    How shorter they should be than the flange / gasket pack.
    I thought I'd put a little bit of silicone grease on the face of the seal to limit air leakage ... but do you think it's a bad thing?
    Francesco
    Francesco
    190 SL 1961 - (ex US OZF-810)
    Sorry for my "Google" English...

  9. #54
    Administrator wpuryear's Avatar
    Join Date
    Aug 2001
    Posts
    3,748
    Francesco,

    My flanges are 10.1 to 10.6mm. I thought the spacers were shorter than 17.4mm but measuring a test setup seems to indicate it is not. The parts manual doesn't specify the length. You might measure the rubber gasket thickness and adjust from there.

    The one set of aftermarket gaskets I purchased proved to be too soft to stay in place, so went with Mercedes parts. I definitely would not use any grease.

    Walt

  10. #55
    Registered User totÚpt's Avatar
    Join Date
    Jul 2016
    Location
    Pistoia, Italy
    Posts
    213

    Re: Carburetor bolts and gasket

    Quote Originally Posted by wpuryear View Post
    ......
    ..... You might measure the rubber gasket thickness and adjust from there.....
    Walt
    Hi, my doubt is just this ... how much shorter the spacer must be than the seal/flange assembly? How much draft should you leave?
    thanks!!
    Francesco
    Francesco
    190 SL 1961 - (ex US OZF-810)
    Sorry for my "Google" English...

  11. #56
    Administrator wpuryear's Avatar
    Join Date
    Aug 2001
    Posts
    3,748
    Francesco,

    Pulled one of my spacers this morning and length is 17.4mm. I can't give a definitive answer as to how much clearance is needed but it appears to be about 1mm or less. I would certainly rather have too much clearance rather than not enough. One item I did observe when re-installing was the rear grommet bulge created during tightening with no noticeable change in the large gasket. Hope this is of some help.

    Walt

  12. #57
    Registered User totÚpt's Avatar
    Join Date
    Jul 2016
    Location
    Pistoia, Italy
    Posts
    213

    Re: Carburetor bolts and gasket

    Thanks!!
    Francesco
    Francesco
    190 SL 1961 - (ex US OZF-810)
    Sorry for my "Google" English...

Page 4 of 4 FirstFirst 1234

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •