S50 Engine Build Advice needed

[Shadye30]

Hello everyone,

I am in the process of picking up a 1995 US Spec S50 to swap into my 86 325e and wanted to ask for some advice on what parts/components to use.

The cylinder head was separated by the previous owner in preparation for a turbo build but he lost interest half way. The cylinder head is completely assembled as is the block but I figured why not freshen the motor up while everything is apart so here is my plan of attack:

• Upgrade to a euro 3.5 MAF and Intake Tube
• 24lb injectors
• Upgrade the cams but not sure which brand to go for..I was leaning towards Schrick 276/270?
• Upgrade the valve springs and retainers-Was thinking VAC's high Performance Titanium Spring and retainer set?
• New valve seals
• Slightly thinner head gasket-Any recommendations?
• ARP head bolt conversion
• Ported Head?
• VAC Shorty headers
• New Piston rings-Recommendations
• New Rod bearing and bolts-Recommendations?
• Oil pan baffle?
• Tune/Chip designed for all this-Recommendations? This is for a silver label 506 DME
• All new oil seals, water pump, timing/oil chains etc
• Oil Pump nut has already been safety wired :)
• Light/Medium weight flywheel and clutch assembly

This car will be a seasonal/weekend car at best and all I am looking for is a strong running motor making as close to 300hp as possible.

Thoughts/comments?

Thanks in advance

Freddy

[Northern]

I'd throw an oil pump chain tensioner on the build list. Either using S54 parts (ideally) or the cheaper VAG tensioner 06A115130.

I'd change the pump chain (IWIS one is cheap/fine), timing chain, and timing chain crank sprocket. Check your timing guides/main tensioner,

If you do a 3.5" MAF/intake, I'd also do a throttle body or else gains are questionable at best.

I think the Schrick 276/270 are great, definitely do springs/retainers. I like the supertech and PPF stuff for valvetrain - I'm not a fan of VAC, but that could be a "me" problem.

A fair number of people run stock headbolts even with boost and they seem to do fine even well beyond what an NA motor will make, so if you have any thoughts of cutting cost, I'd do it here unless you go MLS for the gasket

I would try to run an OE style gasket by someone not Victor Reinz, I don't know of any thinner gaskets other than MLS, which have a bad track record on the the M5x.
If you want the higher CR and can't do it with pistons/shaving the head, you need to get exactly the surface finish on the head & deck that the gasket calls for.
Those Schricks supposedly have PTV issues with stock pistons, so shimming VANOS/oversizing reliefs/aftermarket pistons will be something you have to experiment with/consider options.

I just went with glyco conrod bearings, but not for any particular reason. Bottom end bolts I'd stay stock unless you're willing to line hone things.

[moatilliatta]

If you want 300WHP just do stock S54. IT IS CHEAPER AND MORE RELIABLE. IT IS!


If you're hardheaded. One route:
Or Epic Race cams, Or bigger
Supertech valves
Epic or supertech Valve springs. NO titanium.
CP pistons, no need for stock ones. 11ish ~ CR, Spec out proper valve pockets. Stock pistons don't have enough valve relief for most all bigger cams and have to be band aid with vanos shim.
WPC KS bearings
ARP rod bolts Stock rods are probably fine.
Will need bigger headers.
I think the S50 Will need more than mild port work to hit 300WHP
MS41 makes it easy to tune on the dyno, MS41.3 is out, but not many seem to want to tune with it. I think If you're going over 270's on the cam and want it to drive well, go standalone.
Go find people who have tuned 300Hp S50's and go with their recipe. Or else it'll be more of a hassle.
YES baffle unless you're just hard parking.
Id do MLS on bigger bore S motor. ARP are reusable, You'll probably have the head off again.


If you are rebuilding the engine all the guides, seals chains are obvious. Iwis makes a "racing chain" which is less susceptible to stretchy.

[Shadye30]

Northern,

Thank you so much for the good advice.

Please see my comments in RED:

I'd throw an oil pump chain tensioner on the build list. Either using S54 parts (ideally) or the cheaper VAG tensioner 06A115130. Yes, I was intending on doing so.

I'd change the pump chain (IWIS one is cheap/fine), timing chain, and timing chain crank sprocket. Check your timing guides/main tensioner, Yup, planned on replacing every chain, tensioner, guides as well. Thank yo for suggestiing the crank sproket as well.

If you do a 3.5" MAF/intake, I'd also do a throttle body or else gains are questionable at best. Any suggestions on a TB?

I think the Schrick 276/270 are great, definitely do springs/retainers. I like the supertech and PPF stuff for valvetrain - I'm not a fan of VAC, but that could be a "me" problem. Care to share your issues with VAC?

A fair number of people run stock headbolts even with boost and they seem to do fine even well beyond what an NA motor will make, so if you have any thoughts of cutting cost, I'd do it here unless you go MLS for the gasket I'm not dead set on using ARP head bolts but just thought it would be a good upgrade but if stock works im ok with that.

I would try to run an OE style gasket by someone not Victor Reinz, I don't know of any thinner gaskets other than MLS, which have a bad track record on the the M5x.
If you want the higher CR and can't do it with pistons/shaving the head, you need to get exactly the surface finish on the head & deck that the gasket calls for.
Those Schricks supposedly have PTV issues with stock pistons, so shimming VANOS/oversizing reliefs/aftermarket pistons will be something you have to experiment with/consider options. Good to know. I much rather raise the CR via a head gasket vs shaving the head so if in the future I decide to run boost i can lower the CR easier

I just went with glyco conrod bearings, but not for any particular reason. Bottom end bolts I'd stay stock unless you're willing to line hone things. Interesting. I can't run ARP rod bolts by itself without honing?

Freddy

[Shadye30]

If you want 300WHP just do stock S54. IT IS CHEAPER AND MORE RELIABLE. IT IS! As much sense as that makes I really rather see a S50 in my engine bay-Just a personal preference :)


If you're hardheaded. One route: Super Hard-headed lol
Or Epic Race cams, Or bigger
Supertech valves
Epic or supertech Valve springs. NO titanium. Understood
CP pistons, no need for stock ones. 11ish ~ CR, Spec out proper valve pockets. Stock pistons don't have enough valve relief for most all bigger cams and have to be band aid with vanos shim. Good to know
WPC KS bearings ok
ARP rod bolts Stock rods are probably fine. ok
Will need bigger headers. Any suggestions?
I think the S50 Will need more than mild port work to hit 300WHP I don't absolutely need 300whp..250 plus is ok..
MS41 makes it easy to tune on the dyno, MS41.3 is out, but not many seem to want to tune with it. I think If you're going over 270's on the cam and want it to drive well, go standalone. So Kassel and SSSquid are no good?
Go find people who have tuned 300Hp S50's and go with their recipe. Or else it'll be more of a hassle.
YES baffle unless you're just hard parking. Gotcha
Id do MLS on bigger bore S motor. ARP are reusable, You'll probably have the head off again. ok


If you are rebuilding the engine all the guides, seals chains are obvious. Iwis makes a "racing chain" which is less susceptible to stretchy. That was my intention..Thank you for the good advice..

[moatilliatta]

There is a big jump from 250 to 300.

[Northern]

Any suggestions on a TB?

I can't really recommend one, but there are options from Dinan, Achilles, Riot Racing. I think people have run M60 TB with adapters as well.

Care to share your issues with VAC?

A local racecar blew up from a failed part from them, also people used to simp for their 24v turbo cams for ages on the forums, until someone bought them and revealed there is no cam card, install instructions, or anything. They basically know nothing about these cams they supposedly make themselves.

Good to know. I much rather raise the CR via a head gasket vs shaving the head so if in the future I decide to run boost i can lower the CR easier

Yeah it all comes down to PTV clearances, between thinning the gasket and increasing the lift. I agree that shimming vanos is a half-ass move.

Interesting. I can't run ARP rod bolts by itself without honing?

Changing the torque/force holding the rod (or main) together should theoretically cause it to deform differently, so if you change it, I'd at least have them checked for out of round

[jbontke]

I recently read on a z3 forum that a guy went with an M62 swap instead of the s54. The M62 makes more power than the s54, costs much less to acquire, and weighs less (also puts weight further back in the chassis). East way to have reliable NA 300hp.

Something else to think about is where the engine makes power. The mods you list move the power up in the RPM band. So driving around town you will have to spin the engine up to get that power. The m62 will make more power at lower RPM. Makes for a more fun drive.

Food for thought.

[Shadye30]

I recently read on a z3 forum that a guy went with an M62 swap instead of the s54. The M62 makes more power than the s54, costs much less to acquire, and weighs less (also puts weight further back in the chassis). East way to have reliable NA 300hp.

Something else to think about is where the engine makes power. The mods you list move the power up in the RPM band. So driving around town you will have to spin the engine up to get that power. The m62 will make more power at lower RPM. Makes for a more fun drive.

Food for thought.

Thank you for the helpful suggestion but i would personally never go with an M62 for several reasons:

1. An E30 needs to remain an inline 6. Period. This is a personal preference and also coming from someone who owned an E30 M3.
2. The M62 is far from reliable as stretched timing chains and leaking exhaust valve stem seals are a given. I worked for BMW of Manhattan's service department for many years to know the failure rate of those.

Freddy

[jbontke]

Thank you for the helpful suggestion but i would personally never go with an M62 for several reasons:

1. An E30 needs to remain an inline 6. Period. This is a personal preference and also coming from someone who owned an E30 M3.
2. The M62 is far from reliable as stretched timing chains and leaking exhaust valve stem seals are a given. I worked for BMW of Manhattan's service department for many years to know the failure rate of those.

Freddy

1.) I don't disagree. Others may not... I plan an s85 for my 1956 F100.

2.) I would disagree on an M62 being unreliable. Timing chains and valve guides are serviceable items. If you service the engine as intended, it's fine.

All timing chains stretch. The ford 4.6 that came in many patrol cars and taxis require replacement at some point. I had an 540i wagon with 162k miles that never gave me any issues. If you don't service any engine, it will become unreliable. And I wouldn't call replacing the s54 rod bearings "normal service". Does the m62 lose its oil pump nut and terminate the engine or is that m52 territory only?

I am not trying to start a debate about reliability on any BMW engine. Since its a seasonal/weekend car, any well serviced BMW engine would be reliable.

[hasa]

I'd just put ITB setup, standalone engine management, cams, headers and send it. ITB is important when you are chasing power with hot cams.

[Shadye30]

I'd just put ITB setup, standalone engine management, cams, headers and send it. ITB is important when you are chasing power with hot cams.

Any particular ITB setup that you would recommend?

I have read that the one or 2 aftermarket kits out there were notoriously difficult to tune/tame..

[jbontke]

I have read that the one or 2 aftermarket kits out there were notoriously difficult to tune/tame..

I have heard this about ITBs on any engine.

[Shadye30]

I have heard this about ITBs on any engine.

My only experience with ITB's were on my previous E30 M3 and E46 M3's but I guess being a factory item the DME's were matched perfectly to them..

[digger]

Itb are straight forward to tune with a modern standalone once setup properly mechanically . I know RHD, Jenvey have kits and there are the adopter kits for s54 that also exist.