Is there an easy way to identify cylinder capacity and camshafts for S50/M50 ?

[CMG]

My car has M50 swap and I know drivetrain was originally from 1995 bmw 525i, but I am wondering if it had any frankengine things done to it. Is there any easy way to determine cylinder capacity and what cams are in it visually, other than doing a bunch of measuring? I am changing plugs out and replacing valve cover gasket at the moment that's what made me think of it. Reason I am asking is that it seems a bit peppy for a m50b25.

[82eye]

aftermarket and regrind cams are engraved on the ends so future builders can find the spec. i'm not sure you can get a peak at them though.

[mtech325]

Not sure if you've had the ECU opened up, but if not, maybe they're a custom chip installed with a label indicating the setup? Most of the reputable chip tuners I have purchased from usually have the engine, injector, and octane info listed on a sticker on the chip itself.

[CMG]

I know I do not have aftermarket cams and block is 2.5. I thought that s50 cams were a common upgrade but I could be mistaken, and I'm not sure if there were other possible oem cam options. I do have a chip, but is a tune always required if just swapping between mild oem cams? Engine is peppy and performs well and has good external upgrades, and eventually will be FBO. Just trying to identify cams because that would be the only other possible upgrade. How could I identify my cams in general if they were stock m50b25 cams, I know the numbers stamped on them?

[digger]

only way to be 100% sure is measure the stroke or possibly id the crank, it will be 75, 84, 85.8 or 89.6mm , possibly the torque figure on a reliable dyno will reveal some about the likely capacity. its easy to measure the stroke on the 4V m50 based engines as the plug is direclty above the piston so remove a plug and at TDC insert a long wooden dowel that touches pistons doweland measure how far it sticks out and then remove the dowel and it rotate to bdc and repeat and the difference is the stroke.

[CMG]

K, Digger, thanks for the info. I just did the plugs and vcg a while back so I will check it out next time I pop the top. At the moment trying to through on a couple parts to complete the FBO aspect. I have a Dinan BBTB and 3.5" Bosch - 800 MAF to add and gonna try to set up intake to draw outside air thru hood louvres. Totally unneccessary and overkill, but I have the parts in hand so figure might as well. I know performance will benefit just from cooler air. I can't think of any other way to get cooler air into the engine