Results 1 to 12 of 12

Thread: Camshaft 921 928

  1. #1
    Registered User Simonrex's Avatar
    Join Date
    Oct 2016
    Posts
    255

    Camshaft 921 928

    How do you differentiate between the early and later Cams, I know one is solid and the other is a Hollow core, but can you tell the difference from the outside and do they have a different part number?

    Thanks in advance

  2. #2
    Administrator JimVillers's Avatar
    Join Date
    Aug 2001
    Location
    Virginia Beach, VA
    Posts
    5,923

    Re: Camshaft 921 928

    Rex .... There is a number engraved on the rear end of the shaft. I believe that a "14" is the early cam and "15" is the later cam. See page M3a2 of the Supplement manual.
    Jim Villers
    1961 190SL, 230SL 5-speed, MGB 5-speed, Porsche 356C; 1967 Porsche 911; 1950 Jeep CJ3A

  3. #3
    Registered User Simonrex's Avatar
    Join Date
    Oct 2016
    Posts
    255

    Re: Camshaft 921 928

    Quote Originally Posted by JimVillers View Post
    Rex .... There is a number engraved on the rear end of the shaft. I believe that a "14" is the early cam and "15" is the later cam. See page M3a2 of the Supplement manual.
    I see the engraving 15 I dont have a copy of the manual....so the hollow cam came on the newer SLs or older SLs?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	26D799A3-AF83-4F61-A1F4-3FFC224D735A.jpeg 
Views:	5 
Size:	69.9 KB 
ID:	31612  

  4. #4
    Administrator wpuryear's Avatar
    Join Date
    Aug 2001
    Posts
    3,728
    The cam lobes on the 921 engine are lubricated through drilled passages (not hollow) while the lobes on the 928 use external lubrication. The 928, like the 921, does have drilled passages for bearings lubrication.

  5. #5
    Registered User Simonrex's Avatar
    Join Date
    Oct 2016
    Posts
    255

    Re: Camshaft 921 928

    Is this an NOS or an aftermarket part?

    KPAT

    No 14 or 15
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	4B25CC0B-FB38-4D1D-8BC3-1C828E19BBB7.jpg 
Views:	8 
Size:	202.9 KB 
ID:	31616  

  6. #6
    Registered User Simonrex's Avatar
    Join Date
    Oct 2016
    Posts
    255

    Re: Camshaft 921 928

    So I have a 921 engine and a 921 head. Im trying to buy a cam from a vendor and theyre not able to confirm which cam it is. The 14 15 marking are not there, but the KPAT engraving is present. Im going to attach a couple pictures of the cam and see if we can solve this puzzle.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	256CABE1-151D-4524-B064-8E73BA0E54F5.jpg 
Views:	8 
Size:	262.2 KB 
ID:	31617   Click image for larger version. 

Name:	979FE99A-64D8-4145-8671-5872B69E5308.jpg 
Views:	8 
Size:	288.3 KB 
ID:	31618  

  7. #7
    Registered User Simonrex's Avatar
    Join Date
    Oct 2016
    Posts
    255

    Re: Camshaft 921 928

    Quote Originally Posted by wpuryear View Post
    The cam lobes on the 921 engine are lubricated through drilled passages (not hollow) while the lobes on the 928 use external lubrication. The 928, like the 921, does have drilled passages for bearings lubrication.
    Walt, that makes this cam a 921 by your Definition. Other then how the lobes are lubed, is there any other differences?

  8. #8
    Administrator wpuryear's Avatar
    Join Date
    Aug 2001
    Posts
    3,728
    The lobes are sufficient to differentiate. Your photo appears to be an aftermarket cam with the number 121 050 01 01 cast into it which is a camshaft part number used up to chassis 550183.

    A Mercedes camshaft, however, would have a casting number not a part number. In your case the casting number desired would be 121 051 15 01. Who knows what specs the aftermarket supplier used. The sure way to know is by measuring the valve opening and closing angles as detailed in the Supplement Manual.

    Walt

  9. #9
    Registered User Simonrex's Avatar
    Join Date
    Oct 2016
    Posts
    255

    Re: Camshaft 921 928

    Quote Originally Posted by wpuryear View Post
    The lobes are sufficient to differentiate. Your photo appears to be an aftermarket cam with the number 121 050 01 01 cast into it which is a camshaft part number used up to chassis 550183.

    A Mercedes camshaft, however, would have a casting number not a part number. In your case the casting number desired would be 121 051 15 01. Who knows what specs the aftermarket supplier used. The sure way to know is by measuring the valve opening and closing angles as detailed in the Supplement Manual.

    Walt
    Thanks for the lesson Walt! This is my old cam.

  10. #10
    Registered User Simonrex's Avatar
    Join Date
    Oct 2016
    Posts
    255

    Re: Camshaft 921 928

    Heres the pic
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	A2E06FA6-6E4A-493D-82C7-5B710E31048D.jpg 
Views:	11 
Size:	1.54 MB 
ID:	31622  

  11. #11
    Administrator wpuryear's Avatar
    Join Date
    Aug 2001
    Posts
    3,728

    Re: Camshaft 921 928

    So why are you not using your old cam?

    Walt

  12. #12
    Registered User Simonrex's Avatar
    Join Date
    Oct 2016
    Posts
    255

    Re: Camshaft 921 928

    Quote Originally Posted by wpuryear View Post
    So why are you not using your old cam?

    Walt
    Too embarrassed to type that answer Walt. Lol.

Posting Permissions

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