M50 refresh opinions

[BenM]

In order to better match the awesome E36 M3 brake power and grip of 235/40/17s that I will have once I go 5-Lug, I have decided to do a budget refresh on the M50TU that I yanked out of my E34 Touring last fall.

The motor itself has 187K on it, with all documented oil changes at every 5K miles since new. The motor ran great on the 120 mile drive back from Rhode Island, with the only issue being a slight stumble when taking off, and the check engine light popping on and throwing the vacuum leak code.

Anyways, instead of spending money on an S50, I figured I could do a decent job on this motor for not much $$, and just upgrade to a low mileage S50 at a later point. Just picked up some S50 Cams for it, and plan on doing all the usual bolt-ons too (3.5" HFM, 21.5lb. Injectors, 8.5lb. flywheel). Here is what I have in mind so far:

- Headgasket and associated gaskets (Oil Pan, Valve Cover, Spark Plug, Timing Chain Covers, etc.)
- New Head bolts (obviously)
- Later style S50 conical valve springs and retainers (to go with the S50 cams)
- Cylinder head cleaned and reassembled
- Timing chain tensioner
- Loctite on Oil pump nut

Anything else I may be forgetting?

Thanks for any advice/comments/suggestions.

Ben

[hoveringuy]

-VANOS seals
-O-rings on the oil filter housing plugs

The last S50 was produced over 10 years ago. Are there still low mileage examples?

[Uber E30]

11621728983
Exhaust Manifold Gasket; At Cylinder Head


11611717259
Intake Manifold Gasket; Intake Manifold to Cylinder Head

11421719855
Oil Filter Gasket; Oil Filter Housing to Block


11421730389
Oil Filter Kit

12611277129
Oil Level Sender Gasket; O-Ring

11131437237
Oil Pan Gasket; Rubber/Metal

035121119
Thermostat Gasket/Seal; 60x3.5mm

11531740437
Thermostat Gasket/Seal; For Thermostat Housing

11531722531
Thermostat Housing/Water Outlet; Aluminum Update Replacement

11531712043
Thermostat; 92 Degree C; With Gasket


11141720639
Timing Cover Gasket; Lower Left


11141720638
Timing Cover Gasket; Lower Right

11121738701
Valve Cover Gasket

11121735721
Valve Cover Gasket; Spark Plug Hole Gasket

11511711484
Water Pump Gasket; O-Ring


11721437202
7mm Lock Nut; Exhaust Manifold to Head

[BenM]

-VANOS seals
-O-rings on the oil filter housing plugs

The last S50 was produced over 10 years ago. Are there still low mileage examples?

Good call on the VANOS seals. Completely forgot about those.

As far as S50s go, I guess I meant a lower mileage example would do. Something with around 100K, give or take a few miles would sound about right.

<snip>

Thanks for the part numbers, but I plan on doing all those things anyway. They are included with the Engine gasket set available at BMAparts, Autohas, etc. Thanks anyways.

Keep the suggestions coming.

[alexbaby88]

Might as well do a stroker conversion while you have the engine open.

[jrdeamicis]

I would just order a top and bottom end gasket set. Oil pump, primary timing, and secondary timing chain.

The top and bottom end gasket sets will have everything you need.

[Danny]

Think about turbo?

[BenM]

Ok, thanks again Stephen (hoveringguy) for the VANOS Seals. They will be going to good use.

So anyways, my dad decided he wanted to use the motor I was going to use, so I just went out and bought a wrecked '93 325is w/ 100K and most of the accessories. Not going to be doing the headgasket, but most of the other seals will be replaced.

However, I did recieve a seized '99 328i Shortblock (Alumninum block M52TU) with an enormous hole where the con rod #1 went through. #1 piston was cracked into many pieces, #4 con rod was bent as well, and the block is unusable. The crank is perfectly fine though, so I am in the process of sourcing a set of good M52 rods and pistons to match the crank, and then to put them together in the iron block'd M50TU.

Out of curiosity, does anyone know what sort of compression ratio an M52 crank w/ s50 pistons (86.1mm Bore) and S50 rods (135mm Length) would produce? I am thinking somwhere around 9-9.5:1 due to the reduced crank stroke, creating more piston clearance to valves. Can anyone confirm?

Thanks.

[PiercedE30]

http://bmwfans.info/parts/catalog/E36/Coupe/USA/325is-M50/LHD/M/1994/browse/engine/cylinder_head_attached_parts/

#2 Non-return valve - PN: 11 12 1 735 180

From when I was working in a shop, that was the main issue that we found to cause lifter bleed down and premature lifter failure. Most of the ones that you will find, the spring has worn and no longer has the tension that is needed, or the ball has worn enough to allow oil to bleed past it.

[jrdeamicis]

Just order a top end and bottom end gasket set and be done with it. Has everything you need for the most part include valve stem seals. Just make sure to get an Elring gasket set.

[e30this]

What about a Dr. Vanos stage 2 unit? I have heard some good things about them puppys and the price isnt all that bad.

In my M50 I ran M52 cam trays, listers and S52 cams, 21.5 pink tops, euro maf and TMS chip. I loved every minute of it till I blew a whole in the piston. :)

[StereoInstaller1]

The M/S 5* motors are a bit heavier than the stock M20.

In order to correct your weight balance, you should add a subwoofer.

Oddly enough, I know a great source for these.

[BenM]

The M/S 5* motors are a bit heavier than the stock M20.

In order to correct your weight balance, you should add a subwoofer.

Oddly enough, I know a great source for these.

Lol right on man. Unfortunately, audio equipment will be at a minimal for this car ('91 318i 4dr.) since I will be tracking it and am already planning on getting the coilovers corner-weighted.

I am however interested in one for my other E30!

[jrdeamicis]

What about a Dr. Vanos stage 2 unit? I have heard some good things about them puppys and the price isnt all that bad.

In my M50 I ran M52 cam trays, listers and S52 cams, 21.5 pink tops, euro maf and TMS chip. I loved every minute of it till I blew a whole in the piston. :)

The Dr. vanos stg 2 is really the only way to go. The stock stuff gets all bound up and does not transition nicely when advancing the cam. I have a Dr. Vanos stg 2 and its fantastic and I would not even think of just replacing the vanos after seeing what stock spring washers and washers look like.