Help identify motor!

[Ooghee]

Hello everyone, I recently bought an e36 and the guy claimed it had an m3 motor that was swapped into it from the previous owner. So it’s a 328i with an s50/52 in it ( supposedly). The car didn’t steer but did turn on and transmission seemed fine. I made him an offer stating since he didn’t have proof it had an m3 engine in it I had to shoot him a much lower offer and he took it. The kid said he had to start school soon and didn’t wanna deal with it and his parents wanted it out. I towed it home and found out the steering joint was destroyed so I ordered and installed a new one. After driving the car I noticed it is pretty fast. I’m not familiar with either m powered e36 or regular so I’m not sure. I can’t find an engine block number and I honestly don’t even know where to look. I tried searching online on how to identify at a glance but I can’t find anything so I figured you guys should be able to help. I honestly don’t car either way especially considering what I paid. I’d like to know so I know what I’m ordering when I start getting parts. Thanks!! Here’s a few pics.


https://ibb.co/cEhNK8
https://ibb.co/dCQWCT
https://ibb.co/bAfnmo

[bluptgm3]

I think the S52 block has casting mark 1405513‬ on the side of the block behind the starter.

Potentially, there is a VIN sticker on the back of the head. “M” VIN contains/starts with code WBS.
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[shogun]

see page 30 where which number should be on the block http://www.m3-gt-racing.de/downloads...ena00399de.pdf

[mpost3r]

Looking at the pictures, it looks like a M52b28 or M52b28tu. That could just be beauty covers. All the S52s I've seen use the old oil filter housing with the 13mm on metal instead of the 36mm on plastic. Also, in the middle of the intake manifold, there is a cap with the BMW logo on it. I'm pretty sure this is something to do with the battery terminals (ground, maybe?). All the S52s I've seen don't have that either. It's definitely one of the two. Assuming it's not mismatched and the engine wasn't tampered with (like swapping heads, valve covers, etc) the position of the oil fill cap and the type of oil filter housing along with the ground thing on the intake manifold lead me to believe it's an M52.

[ed323i]

Won't be M52B28tu though because those have double vanos (the engine on the photo only has one) and other intake manifold (this is the stock M52 manifold, which I think is the same as the US S52 one).
Easiest way to see if it's faster than a 328i, is to time the 0-60mph acceleration and, a bit easier, for example a second gear pull from 1000 to 6000 rpm. And then compare it to known times. If it really is an S52, then your times should be a lot better than 328i's (240 horses versus 192 horses more or less).. Or find someone with a stock 328i and do a pull alongside with him.. You should be able to make some distance if it's an S52 or for example a modified M52, for example upgrade to 3.0 liters and better camshafts. Or make a video and post it on Youtube and post it here. I'm sure people with an S52 can easily see if yours is also an S52 or not.

[TostitoBandito]

Assuming he hasn't mucked with the internals, you can also take off the valve cover and look at the cams. You should be able to verify by the measurements and maybe the stamps/numbers whether they are S52 or M52 cams. Other than the bore/displacement, the cams and some other valvetrain parts are the only major differences.

Or, take it to a dyno. Any S52 should make over 200 rwhp, whereas a stock M52 won't be close to that.

And yeah, the pics don't look quite like my 10/98 build date S52. Mine has the metal oil filter housing. The oil fill cap is also wrong or not original, along with obviously the little bolt caps on the beauty cover as well.

Also, that is a pretty janky cold air intake, basically tied to the strut mount bolt with a twisted piece of metal.

[spyderg0d]

with how people upgrade or degrade parts on engiines with swaps. theres only 2 ways to tell. read the tune and compare to other base tunes or measure the pistons and stroke. a boroscope will be able to let you compare the piston shape and the hight of the piston at tdc. some just use a rod of some sort to measure the stroke with the spark plugs out. oil houseings are commonly swapped to plastic to fake a s52 look on even single vanos engines, and metal houseings are installed to replace brittle crappy plastic ones. im pretty sure s52 are double vanos, so you would either have a s50 or a non m3 engine. measureing cams wont help either as they are a commom mod. even ratings on power wont really help you identitify as even some kits like turners can put out m3 power on a 2.5l with cams, chip, headers, large tb. anyone one of those really could be sacrificed and be level with a s50.

[ed323i]

US S52 is basically a single vanos M52. Same engine block, same single Vanos cylinder head, same intake manifold, and I believe, same injectors and same MAF sensor (even 323i has same one). Main differences compared to the M52 are the bore, stroke, crank, camshafts and exhaust system. A completely different beast compared to the European S50B32 (with over 100 HP per liter).

It also wouldn't be the US S50B30, because that engine had the M50 (wider tubes) intake manifold. Would be extremely strange going through all the work downgrading the intake manifold to the M52 one, from the much better flowing M50 manifold.

So, it's either a stock M52, or it's a modified M52 (increased stroke, camshafts, etc, you'd have to check the internals to know) or it's an S52. If you can find the engine code, which probably isn't easy to find or to read, then you'd know for sure, if it's originally an M52 or an S52. An M52 can be upgraded to almost-S52 specs, but then you'd have to check the internals, and with the M52 manifold still on (they would normally upgrade to the M50 manifold if you're in a quest for horses), and the plastic oil filter house, my guess is that it's just a stock M52B28.

Codes you can find on the engine:
256S3 = M52 2.5 liter (323i / M52B25) (256S4 = M52TU)
286S1 = M52 2.8 liter (328i / M52b28) (286S2 = M52TU)

I'd expect the US S52B32 to have a code like 326S3, but I'm not sure.. Check the first two digits though, those will tell you the stock size of the engine in liters (28=2.8, 32=3.2, etc).
Update: found it. If it's a real E36 2nd generation US M3 engine, then it should have the code 326S2. Check page 30 of http://www.m3-gt-racing.de/downloads...ena00399de.pdf to see where to find this code. Thanks Shogun for the link.

[jc43089]

Get it up on jack stands for safety, crawl underneath and look up between the firewall and engine, you will be able to see the VIN tag on the back of the cylinder head. Only way to know for sure. Its either an M52 or S52 because the oil filter housing and valve cover are both the late style.

[MtekJosh]

Buried under the intake manifold there are numbers cast onto the block. They are hard as hell to see but you will be looking for either a 28 or 32 in the alphanumeric number. Disassembly is required to be able to see them.


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[gdavid]

Remove a coil and spark plug and then use a clean, long, thin scew driver or dowel rod to reach the top of the piston. Turn the engine over by hand and measure the highest and lowest piston height, the difference is your stroke. 75mm is a m50b25 or m52b25. 84mm is a m52b28. 85.8mm is a s50b30 motor. 89.6mm is a s52b32 motor.

As previously mentioned, it has the wrong intake for a s50b30 or m50b25 so those would be very unlikely but one final check for the location of the crank position sensor would settle it. m50 & s50 engines must have an external crank position sensor on the front of the engine while the m52 & s52 engines have an internal crank position sensor at the back of the block near the starter. The newer motors can be modified to an external crank sensor but the older motors cannot be modified to run an internal crank sensor. So bottom line, if your stroke measurement is around 84-86mm, don't get excited thinking it may be s50b30.

[ed323i]

Bit off topic because the engine very probably is a US engine, but in Europe the M52 engines (in Europe all of them are aluminum) have the crank sensor on the front of the engine, like the M50.

[MParallel]

It is a US engine. The Euro M50/M52 engines have the radiator cap on the right side (standing in front of the engine).

Euro's also don't have the secundairy airpump + related parts. And neither that emissions related label.

p.s. the bolt cover caps on the valve cover, are the smaller ones that should be fitted on the fuel rail cover.