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View Full Version : S52 Cams w/ M52 Valve Springs??


AFDanHef
07-26-2018, 07:17 PM
Who all is running S52 cams in their M52 motor?? What valve springs are you using??

I recently read that the S52 uses different (stronger) valve springs because it revs higher and the cam has more lift/duration. That made since to me so I researched a little and according to Realoem.com, the S52 valve spring part number is not used in any m52s except for the E39 528i, which I could assume has a more aggressive cam because it's a 5 series that needs more power. The S52 valve springs are also used in just about every M42/44 engine made. I could assume that the 4 cylinder motors use the stronger springs because they rev higher.

All this said ... Will the stock M52 valve springs hold up under S52 camshafts?? :confused: I'm rebuilding my M52 right now, using S52 cams and I would HATE to swallow a valve because I broke a spring!! :mad::mad: Also, valve springs are $15 each!!!!! :eek::eek::mad::mad: $15x24=$360!!!!! :eek::eek::mad::mad::mad:

I did NOT expect them to be so expensive!!!! :mad::mad: .... Sooooo let me know if this is the worst idea in the world ... buuuttt I was thinking since the S52 springs are the same as the M44s ... I could go pull 24 of them from the junkyard?? :confused::confused: Is that a horrible idea?? :confused::confused:

EFoss28
07-27-2018, 04:33 AM
Most people do not swap the valve springs when doing the cam swap. I think it is a good idea to swap as the S52 spring is a little stiffer, but also a little bit shorter. You could be more prone to valve interference if you miss a shift or over-rev if you use the M52 springs. All of my experience is from a M52 race car that I rent to customers and I have a lot of experience with bent valves from them over revving the engine. I might suggest this kit as your best option if you decide to buy springs (I use it on my current race engine and have no issues). https://thmotorsports.com/538202-supertech-spring-retainer-kits