S50 Cams in an m52?!?

[Uber E30]

Is it as simple as the s52 cam swap? I searched and all i could find was reference that the trays are the same for the s50 and m/s52. Any info would be helpful.

The S52 and S50 cams are the same for lift (10.3/9.7mm) and duration (252/244).

The only difference is the cams are built from different cam cores, although they are both hollow cores. The S50 (M50 family) cams are built from "round" cores and the S52 (M52 family) cams have areas where there is additional material on the cam between the lobes and this material is squared off instead of round. I would assume that if the cores are the same material and core thickness, the S50's would be lighter in weight because they have less material in the areas between the lobes.

The reason M/S52 cams won't fit the cam trays for the M50 (only) is the square cores of the cams interfere with the tray. The S50 trays are unique to that motor, and M/S52 cams will fit an S50 tray ONLY. The S50 tray and M/S52 tray are the same P/N.

The whole reason I know all this is I've been swimming in cam details for the last few weeks. I was sold an S50 motor that actually contained M52 (2.8L) cams. The situation has recently been addressed and the appropriate cams (S50) are now making themselves at home in my motor.

Be careful out there when buying cams. Don't assume what cam you have by the casting number on it. You have to measure the lift to know for sure.

Just as an example, a 1718888 cam casting correlates to a S50 exhaust cam. It is precisely the same p/n stamped on the Group N 2.5 cam. These two cams have the same casting#, but different lifts and durations.

The Schrick 2.5L non vanos cam has 1738369 stamped on it, and so does the S50 intake cam.

You gotta measure the cams to know for sure.

Ed

[asubimmer]

yes they will fit in there w/ your stock trays

[e30polak]

Is it true that s50 cams have a better profile for peak power???

[Uber E30]

From the guy i quoted, no, but i have no idea. Im only asking because i have had a hell of a time the past month trying to find s52 ones but there is an s50 local to me.

[ed94r]

There are some folks that say the S50 and S52 cams are the same in Lift/Duration, some say differently. I say the difference is negligible. If you have M52 trays, use whatever camset you can find. I didn't weight them, but the S50 cams have to be lighter than the S52 set;the S52 set definately has more material on the cores. Add: double check and make sure whatever camset you run, that the update thrust washer design is used/is present on the intake side cam. Ask me how I know....

Don't snap the cams on the way in. I would worry about that more than what camset to run btw the S50/52.

Ed

[Uber E30]

double check and make sure whatever camset you run, that the update thrust washer design is used/is present on the intake side cam. Ask me how I know....

What is this that you speak of?

[ed94r]

I don't remember the exact details..other than the 94 and up Vanos engines had a different set of "cam gears" on the intake cam..not the actual gear itself, but the washers and thrust plate design was different. I believe the updated design was done mostly to cure a "rustling" sound that sounds much like Vanos rattle.

Realoem the 93 camset, paying attention to the gears on the intake cam. Print the diagram.
Realoem any 95 on up camset. Notice gears. Compare the 2. See Difference. Make sure you have 95 and up thrust washer/plate.

Ed

[Uber E30]

Shouldnt the s50 have that be default since it was made in 95?

[ed94r]

Yes.

Don't make any assumptions tho. Check it to make sure. Not all cams will come with the gears attached.

Ed