Anatomy of a bulletproof S52?

[Wanganstyle]

This is a post that I have great interest in, realize it is only 4 years old. I figure my question in this thread would give those who are planning on running a bullet proof M52 a pretty definitive idea of what a racer is looking at to build a bullet proof M52 endurance racing motor.

I am preparing my Spec E30 to go World League Racing (WRL) in the Texas area. So far my 10 years racing has been in as “near” to stock powered cars, Spec Miata and Spec E30. The WRL classes my Spec E30 as it sits in GP2. The rules will allow an engine swap and keep me in the GP2 class. To stay in the class the swapped motor has to dyno out at 197 HP without adding ballast and if I add up to 150 lbs of ballast and stay out of the ballast modifier points. If it is a stock engine I can produce the HP numbers from the manufacture and I am not required to do a dyno. So... I believe a stock M52TU28 becomes the right engine to swap.

Of course finding one to do the swap means an engine with over 100K, with questionable maintenance. Hence an engine rebuild I most likely required. Again going WRL racing and have a HP goal of stock and a reliability goal of 8 hours of straight racing one day and 8 the next. I see that a few folks in this thread have racing experience and understand the environment. I don't have experience with a M52 in an endurance environment, nor do the friends I race with.

So stock everything or selective aftermarket parts, like rods, bearings, valves or different springs or???

Thanks in advance.

Not sure of your exact needs; here is some data that might be useful though

Ran the m52 in anE30 chassis for 52hrs till failure

Failure point was valve spring retainer cracking and collets pulling through

Valve dropped destroyed piston and head.

Rpm limit was set to 7500 with an aftermarket chip; stock I believe is 6500

Solid aluminum aftermarket engine mounts were also ran; these had a lot of nvh and the oil pump Pickup was breaking down at the casting seams.

if was to build one myself today I’d probably use new stock s52 valvespring and retainers; supposedly they are more updated for the cams and rpm max of the s52.

Wpc all the moving parts and oil pump bits

Run stock ecu and rev limit for more durability