Antomy of a bulletproof S52?

[kingston]

Hullo R3V track guys...

I think I am going to rebuild the S52 in my E30 over the winter.

More power, while I wouldn't say no to it, is not the primary goal here; what I am trying to do is add reliability. I want to know that I can hammer on the car now and forever, and she'll keep coming back for more.
I understand that using the car in this manner will cause more wear and tear on the motor, and I know that lack of maintenance, 'money-shifting' and time will still cause damage to motor, no matter how you build it. But, what I want to do is build the strongest S52 'endurance' engine that I can.

So, what areas should I be considering? Eagle rods? Solid lifters? Dual Valve Springs? Forged Pistons? Coated bearings? ARP head studs & crank studs?

Some history that may be relevant:

This is a normally aspirated S52, converted to OBD1. Stock cams. M50 intake manifold, OBD2 exhaust manifolds with the secondary O2 injection ports welded up. 413 red label DME running a TRM chip for 91 octane, M50 manifold, standard weight flywheel 21.5# injectors - all the things my car has.

Metric Mechanic did some minor work on the head a couple of years ago (skimmed it very slightly, added stronger valve retainers, new valve guides & seals, and replaced a couple of valves, as the motor had been left sitting and there was some corrosion/pitting on 2 of them).

The motor has standard pistons with oversize rings. A hone was done at a machine shop to clean up some minor pitting & corrosion on the cylinder walls.

I'm handy with a wrench, and know how to time VANOS, etc. I will not necessarily be building this motor myself. I figure at least getting the rotating assembly balanced is a good start.

Please give me your thoughts on this build! Thanks guys!
Kingston

[Artful Dodger]

hey, i have an S52 in my car. I feel pretty confident it is reliable for most abuse. I track the car and run it at autocross events. I also DD the car.
My main focus was preventative action. I pulled the head off and had it pressure tested and decked for flatness. installed a new head gasket.
I went with supertech valves and retainers to safely allow the engine to take an overrev. Not that I want to do that. just a precaution.
Cooling system is the weak point on these engines, in my opinion. I spent the money on a stewart water pump. installed an 80 degree thermostat, aluminum t-stat housing, diesel engine fan, new fan clutch, and wired my aux fan to be on all the time.
Oiling is also important. I made my own baffle for the oil pan to help resist oil starving the pump. Also, I heard the oil pump nut is a failure point. I welded mine on. most people buy one that has a saftey wire installed. If you are making a track car, a device like an accusump is pretty awesome.
After that, I feel the engines are pretty well built. If you expect to abuse the engine beyond what these item will protect against, you are going to need higher strength rods and possibly a better crankshaft, like one that has been professionally balanced. I hear the cranks have some harmonic issues and can break. i dont know if having them balanced fixes this or not.

hope this helps.

[kingston]

hey, i have an S52 in my car. I feel pretty confident it is reliable for most abuse. I track the car and run it at autocross events. I also DD the car.
My main focus was preventative action. I pulled the head off and had it pressure tested and decked for flatness. installed a new head gasket.
I went with supertech valves and retainers to safely allow the engine to take an overrev. Not that I want to do that. just a precaution.
Cooling system is the weak point on these engines, in my opinion. I spent the money on a stewart water pump. installed an 80 degree thermostat, aluminum t-stat housing, diesel engine fan, new fan clutch, and wired my aux fan to be on all the time.
Oiling is also important. I made my own baffle for the oil pan to help resist oil starving the pump. Also, I heard the oil pump nut is a failure point. I welded mine on. most people buy one that has a saftey wire installed. If you are making a track car, a device like an accusump is pretty awesome.
After that, I feel the engines are pretty well built. If you expect to abuse the engine beyond what these item will protect against, you are going to need higher strength rods and possibly a better crankshaft, like one that has been professionally balanced. I hear the cranks have some harmonic issues and can break. i dont know if having them balanced fixes this or not.

hope this helps.

'

Artful Dodger,

Thanks for the reply. You raise a couple of very good points. The Accusump is absolutely something I will do, and I hadn't thought of that. I already have a baffle in a new oil pan that will be installed soon. I am considering going with Eagle rods, although I will stay with the stock crankshaft. It's forged, so I think it's plenty strong. I will get the rotating assembly balanced, though if I do get aftermarket rods and/or pistons. As I'm not trying to rev the engine past 7K, I think that will suffice.

The Stewart water pump is a good call. I already have the metal thermostat housing, and I have a Spal pusher fan mounted directly to the radiator I am still using the stock fan clutch and a stock radiator. I have a DD car that has an Aluminum Zionsville Motorsports radiator, so I will probably pop that into the track car.

Thanks again for the well-thought out reply!

Cheers!
Kingston

[Bimmerman325i]

Beisan vanos, stewart pump, oil pump nut, z3 oil pickup tube, radiator ducting, and for the adventurous/paranoid, oil cooler and s54 oil pan/pump.

Accusump is not needed, these engines are quite robust and tolerant of oil pressure fluctuations. S54 pan solves that issue, e34 pan is already an improvement from the stock e36 under braking.

Oil cooler isn't really necessary unless competition is in the cards. Only needed things are stewart pump and vanos seals when they start to rattle. An s50/52 is already a pretty reliable and durable track motor. Killing one is usually due to operator error, not engine failure.

Case in point: many friends have put 100k track miles on bone stock s50/52, my car has had a good 50k of track miles over its last few owners. You only need to 'build' it if you have money to burn. Fill it a little over full with 5-40 or 15-50 oil, address cooling, and enjoy it.

Now if you're looking to add power reliably beyond the scope of typical intake/exhaust or rev beyond 7200rpm, that's a different story and would make sense to change rods and pistons and valves and cams. Until that point, it's a waste.

[kingston]

Bimmerman325i, thanks for the response.

I did the VANOS rebuild about a year ago. Definitely want to do a Stewart water pump. Also the VAC oil pump nut kit.

I've never heard of the Z3 pickup tube mod before. Can you give me anymore info on this?

I've got an S54 oil filter housing, and will probably do an oil cooler system, just for peace of mind.

Radiator ducting is something I hadn't considered. I will be looking into that.

Thanks again!!

[Bimmerman325i]

Z3 pickup tube might not work with e34 pan, come to think about it. Basically it has a stronger bracket as the s52 one tends to shear off with elevated rpm, causing most of the oil issues in the first place. If you're regularly hitting 7200 and above and dont have a balanced rotating assembly and/or an ATI superdamper, the oil pressure fluctuations from the pickup tube shearing off its (brazed) bracket is the early warning sign of impending doom. Simple solution is to spend as little time above 7000 and to upgrade that pickup bracket to prolong high rpm life before likely failure.

The issue is the rotational harmonics of the engine, above 7200 the s52 has a nasty harmonic that basically causes the damn thing to wobble itself apart. Balanced, lightened, and fancy components only prolong the inevitable. Keeping under 7200 saves the engine. S50s do NOT have the same issue, their harmonic is well into the 7500ish area where you're floating valves anyway. And, unless you've got wild cams and tons of head work, the engine doesnt make any power that high. Long story slightly shorter: keep rpm below a hard max of 7200.

Oil cooler doesn't hurt. I would recommend the s54 oil cooler flow valve mod that BW sells, in tandem with an external oil cooler thermostat because the stock valve never diverts more than 40-50% of oil flow through the cooler circuit.

VAC oil pump kit is something I'd like to do. That and a baffle will be good for a long time of sub-7200rpm.


Radiator ducting will keep the car happy longer, and I'd be surprised if you don't see a consistent drop in temps from it. A pusher fan won't do any good, nor a puller at track speeds. I'd just do one of them wired to the temp switch on the radiator or a cockpit switch/button for cooling in the pits.

If you run the zionsville, make sure to take off the aluminum shroud on the back if yours has that. It is good for a street car, awful for track car where cooling demands require lots of cfm through the rad. Also try to rig the ducting to have the oil cooler in the same pathway.

[whitebulat22]

Anecdotal evidence of bulletproofness, but I have a bud with a stock one outside of exhaust and computer work which has survived more than 400k non gentle miles without a rebuild outside of rings. It's in it's original home of an E36 M3 chassis which has received mechanic owner maintenance. As long as it's taken care of and not doing too much more than it did from the factory it might already be as bulletproof as bulletproof gets.

[athayer187]

Another suggestion - prevent a money shift with some good, hard motor and trans mounts.

[Northern]

Another suggestion - prevent a money shift with some good, hard motor and trans mounts.

New shifter detent pin bushings and a rebuilt shifter would help with that as well.

[kingston]

Thanks for all the thoughts, guys!

I keep the motor at 7K, maximum.

The car has AKG Motor & transmission mounts. (The motor mounts are the 24V E30 ones to keep everything where it should be.) Shift detents were done on the ZF when the trans & S52 were installed. The shifter is a solid-mount shifter, similar to the AKG DTM one.

I remain on the fence about the oil cooler. Seems like the thing to do is install an oil temp gauge and see what temps I'm hitting at the track...

I will be doing the Stewart water pump & the VAC oil pump kit.

Thanks again for all the replies!!

[aventari]

Accusump is not needed, these engines are quite robust and tolerant of oil pressure fluctuations. S54 pan solves that issue, e34 pan is already an improvement from the stock e36 under braking.

I like everything in this thread, but I have to take issue with this...

Oil pressure issues will kill any engine, doesn't matter how built or "bulletproof" it is.

I don't actually track an S52 (yet), but anything you can do to keep oil pressure in hard [left] corners will help gain reliability.

My M20 has a baffle, windage tray, and I fill it around 1.5 quarts over. Because the suspension is good and tires are so incredibly sticky nowdays, I still get minor pressure drops in a few select left-handers on the track

I never even notice the pressure dropping when on track, but when I go back and look at the in-car video, I see the gauge needle flicking around a bit.

I don't like the complication of Accusump and I don't really want to run one, but it might be my next step for keeping my motor alive.

If the S52 has a better option, like S54 pan/pump like was mentioned, I would do that in a heartbeat.

[theevildoodlebob]

I would second the oil cooler and ducting to the cooler and radiator. I worked on an e36 M3 bmwcca race car and when it was originally built we put full shrouding on top, bottom, and sides that went all the way into the contours of the bumper for it. Later that season a different mechanic did some maintenance to it and they removed everything and threw it away. Next time out the car was running hot both coolant and oil.

[M-technik-3]

We added a s54 oil pan and dual oil pick up similar to this write up. Then added a oil cooler.

http://www.eatsleeptinker.com/2013/07/10/bmw-s54-oil-pan-and-dual-pick-up-pump-conversion-for-s50s52-engines/

[TobyB]

shit, that M54 pump has a scavenge pump on the back of it, doesn't it???

that's... kinda cool...

t

[B1mmer]

I like everything in this thread, but I have to take issue with this...

Oil pressure issues will kill any engine, doesn't matter how built or "bulletproof" it is.

I don't actually track an S52 (yet), but anything you can do to keep oil pressure in hard [left] corners will help gain reliability.

My M20 has a baffle, windage tray, and I fill it around 1.5 quarts over. Because the suspension is good and tires are so incredibly sticky nowdays, I still get minor pressure drops in a few select left-handers on the track

I never even notice the pressure dropping when on track, but when I go back and look at the in-car video, I see the gauge needle flicking around a bit.

I don't like the complication of Accusump and I don't really want to run one, but it might be my next step for keeping my motor alive.

If the S52 has a better option, like S54 pan/pump like was mentioned, I would do that in a heartbeat.

For an M20, a better solution is to run a Paul Poore oil pan. It has spring loaded internal baffles. I see zero pressure loss (video confirmed) since switching to this pan. It's about $550 and you have to wait in line for Paul to build a batch, but it's worth it. - AB