M52B28 Race Engine

[Gleb]

Looking for some maintenance info. Keep in in mind, it's a race only motor.

Picked up a 60k miles aluminium block M52 for a song. It already has S52 cams. It's been sitting on a shop floor for a few years, and the only info I have, is that it was overheating when it was pulled out of the 1998 Z3 in favour of an S50. The block is fine and the head will be sent to a machine shop for a thorough inspection.

So, I took it all apart, down to the last washer, just to educate myself, it is going to be rebuilt anyway, by a real mechanic, and it got me thinking of what should be replaced/upgraded.

I am not looking for big power. I am thinking that S52 cams, M50 manifold and a tune will do the trick in order to get around 200HP at the wheels.

What I want to know is what should I replace/upgrade "while I am in there".

So far the short list consists of:

Forged Pistons
Baffle Pan
Crank Scraper
Stewart Water Pump
Bearings
------------------------------------

What else? Don't really know much about problematic areas on these engines.
Which head gasket - stock, aftermarket?
Not sure if the chain and tensioner need to be replaced.
Etc...

Basically, what should be done to make it as reliable as possible?

Thank you.

[mtlbloodshot]

Depends what your intentions are. Depends your budget. Depends if your the type of person that rather spend a little extra money and time but be sure that the motor is on top order.
I just finished rebuilding my M52 with S52 cams. Here's a few things that I did.

Timing chains, guide rails ( since the motor is out, just do the chains )
Vanos seal - thermostat - thermostat housing
Replace all valve seals, resurface head
Thinner profile head gasket part #(11121726617) Victor Reinz does the job.
The timing case has 2 gaskets, change them.

I basically rebuild the engine, A-Z.. every gasket is new, chains, rails, water pump etc;
Check my build for infos

[Bimmerman325i]

Don't waste your time with a crank scraper. I don't know of a single fast BMW racer that uses one on the m/s5x. You also don't need fancy pistons unless you plan on running ridiculous cams, or lighting money on fire. You would put the $1k to better use with bolt on mods, not pistons. Baffled pan is a good idea, as is the stewart pump.

For 200 at the wheels, you don't need S52 cams.

You need all the other bolt ons though-- 3.5" intake, good solid CAI, silicone boot, m50 manifold, 21.5s, a good header, and a 3" exhaust. A SOLID tune is also required(TRM, AA, Epic).

There are a few local cars with this setup on M52s with >200whp. With the S52 cams you can expect less midrange but more top end, maybe 210-215whp.

If you don't do all the bolt ons, and just do M50/S52 cams/tune, you might crack 200, depending how restrictive the exhaust is.

[frankie591]

why do people still think the 3.5 afm is an upgrade. Your throttle body is barely 2" diameter, so the stock afm is not a restriction.

[Gleb]

Depends what your intentions are. Depends your budget. Depends if your the type of person that rather spend a little extra money and time but be sure that the motor is on top order.
I just finished rebuilding my M52 with S52 cams. Here's a few things that I did.

Timing chains, guide rails ( since the motor is out, just do the chains )
Vanos seal - thermostat - thermostat housing
Replace all valve seals, resurface head
Thinner profile head gasket part #(11121726617) Victor Reinz does the job.
The timing case has 2 gaskets, change them.

I basically rebuild the engine, A-Z.. every gasket is new, chains, rails, water pump etc;
Check my build for infos

Intentions are to have a reliable motor first and fast second. Yeah, I am that guy - I'd rather do it right the first time.
For VANOS, I was thinking using Dr. VANOS... thoughts?
What about cooling, any upgrades required there?

Don't waste your time with a crank scraper. I don't know of a single fast BMW racer that uses one on the m/s5x. You also don't need fancy pistons unless you plan on running ridiculous cams, or lighting money on fire. You would put the $1k to better use with bolt on mods, not pistons. Baffled pan is a good idea, as is the stewart pump.

For 200 at the wheels, you don't need S52 cams.

You need all the other bolt ons though-- 3.5" intake, good solid CAI, silicone boot, m50 manifold, 21.5s, a good header, and a 3" exhaust. A SOLID tune is also required(TRM, AA, Epic).

There are a few local cars with this setup on M52s with >200whp. With the S52 cams you can expect less midrange but more top end, maybe 210-215whp.

If you don't do all the bolt ons, and just do M50/S52 cams/tune, you might crack 200, depending how restrictive the exhaust is.

Well, the cams already came with the engine.
I was told by someone that built a few of these engines for race application, that pistons are a must, believe me, I don't really want to spend the money on them.

why do people still think the 3.5 afm is an upgrade. Your throttle body is barely 2" diameter, so the stock afm is not a restriction.

Doing some research on it, and you seem to be right.

[dcskate102]

why do people still think the 3.5 afm is an upgrade. Your throttle body is barely 2" diameter, so the stock afm is not a restriction.

A 3.5'' afm with a retune and 19lb injectors netted me ~20hp peak with atleast 10 across the graph...

[VinniE30]

A 3.5'' afm with a retune and 19lb injectors netted me ~20hp peak with atleast 10 across the graph...

So you had a bad tune for your setup and had old, clogged injectors?
Not surprising you would have those gains from fixing your problems.

It's basically the equivalent of saying "Hey I had a clogged air filter and replaced it with a cone filter and gained 50hp! so cone filter mod gives you +50hp!"

[!kid]

if this is a race engine, getting a WPC surface treatment on your bearings,pistons and rings could be a wise choice.

[MaksV]

Let me know when your ready for some injectors. I will get you sorted.