Official Cam Comparison Thread M52 vs S52 by 328iJunkie

By stevegolf
( 4 )

6 minute read

Official Cam Comparison Thread M52 vs S52

Compliments of 328iJunkie @

So at my shop Im often swapping cams and such around and had an issue telling the difference between M52 and a set of S52 cams i had purchased from a motor. I did this comparison to verify that these were in fact S52 cams i had purchased to go into my customers motor. 

Three cams shown. A used scored to hell M3 cam from my motor is on the left, a M52 cam from a customer motor is in the center, and a better condition cam i just purchased for another customers motor is on the right always...

Some things to note:

-You can see the major differences between the lobes.

-notice the high scoring sets of journals on each cam. All three cams have concentrated wear on only a few journals. 

-Wear is always significantly worse on the exhaust cam. 

-Note the TDC stamping differences on the cam block squares. The M52 is apart and the two S52s are together and offset to one side on both cams.

-Part Number stamping is of absolutely no significance. The M52 intake cam and the new S52 intake cam both have the same part number stamped on them in the same place where as my old intake cam(S52) has a different number stamped elsewhere

-Note the two different "BMW" stampings between my cam and the M52 and S52 cam

-All three appear to be from the exact same casting IE no differences between the balance cutouts and the wrench flat section

-The S52 Cams' squares' for the cam blocks appear trapezoidal, where as the M52 cam's is very square

-The stamping on the intake cam is in the same location for all three, but this time the two S52 part numbers match, including the letter("178F","890G","178F")

-All three intake cams have BMW stamped in the same location

-The stamping on the intake cams near the block squares is different for all three("R1","R4","R2")

-Also lastly notice the color differences between the three, the M52 cam is "bronzer" than the rest. This is prob caused by engine temps/oil choice between the motors and the fact that the bronze one was reciently run where as the other two have been sitting for a while

More Pictures:




This is useful info!

Posted by Diggymart on 11/21/19 @ 2:37:49 PM