S50 Valve Q's

[Boyracer]

If you go down on valve stem size you must of course change the valve guides too. And that means you have to get valve seat job too because new guides most likely have bit different concentrity then original ones.

You most propably have to change the guides in any case, mine were worn outside of factory specification on development cylinder head. I bought it used and I have no idea how many km's it has been driven.

Also, use the opportunity to get bulleted guides instead of blunt ended stock guides, bulleted ones flow bit better on intake side and much better on exhaust side.

I think M42 and M50 use same diameter lifters/followers/tappets? And I think you want as small oil capacity in them as possible because oil does weight and weight is bad in valvetrain.

[Boyracer]

Furthermore on this topic, I chatted with the machinist today and he suspected that 35 mm valves might just fit stock 33 mm seats. I have to find this out, it would lower the costs big time if I can get away without buying new seats and then removing old ones and inserting new ones.

[Letsplayskatch]

If you go down on valve stem size you must of course change the valve guides too. And that means you have to get valve seat job too because new guides most likely have bit different concentrity then original ones.

So where would you get the valve guides from which have the smaller internal diameter? Concentricity shouldnt be an issue; surely lapping the valves into the head would sort this out.

Also, use the opportunity to get bulleted guides instead of blunt ended stock guides, bulleted ones flow bit better on intake side and much better on exhaust side.

Again, where would consider looking for these? Another BMW model? Or, can they be machined from OEM parts? Valve guides are a complete mystery to me - very little is ever said about them when talking about cylinder heads.

I think M42 and M50 use same diameter lifters/followers/tappets? And I think you want as small oil capacity in them as possible because oil does weight and weight is bad in valvetrain.

Yes the M50 ones are direct replacement for the M42 ones, and they flow more oil. Of course, id want solid lifters/followers/tappets (all the same thing) as theyre more reliable etc - but again...where to look? I read that someone on here (he has a white IS and is from the UK too I think) is using VW parts.
Sorry for the 'where to buy' Q's, but I just need to differentiate between what parts are from BMW (i.e another model), which are aftermarket/uprated from/for BMW, and what parts are from other manufacturers entireley (i.e. those S2000 valves metioned earlier).

Scott

[Boyracer]

So where would you get the valve guides from which have the smaller internal diameter? Concentricity shouldnt be an issue; surely lapping the valves into the head would sort this out.

It seems that BMW does not sell valve guides anymore, atleast not to E36. But they must be available elsewhere, I suspect ordinary places that fix engines can source them.

I think lapping only finishes the seal between valve and seat. After fitting new guides you probably need to grind the seats to suit new guides.

Again, where would consider looking for these? Another BMW model? Or, can they be machined from OEM parts? Valve guides are a complete mystery to me - very little is ever said about them when talking about cylinder heads.

If you find suitable stock M42 valve guides it should be possible to modify them in lathe, that's what I'm going to try

Race guides must be available somewhere too...

Yes the M50 ones are direct replacement for the M42 ones, and they flow more oil. Of course, id want solid lifters/followers/tappets (all the same thing) as theyre more reliable etc - but again...where to look? I read that someone on here (he has a white IS and is from the UK too I think) is using VW parts.
Sorry for the 'where to buy' Q's, but I just need to differentiate between what parts are from BMW (i.e another model), which are aftermarket/uprated from/for BMW, and what parts are from other manufacturers entireley (i.e. those S2000 valves metioned earlier).

You can convert stock lifter to be solids, just follow my build thread

[Letsplayskatch]

Will do, keep up the great info - its all much needed

Ill see what I can find out from BMW Whitehouse here in the uk, they must be able to source guides sureley. If not, ill have to call a few head companies I know to see what they reccomend.

[mkodama]

Got bored and did some research to all the possible candidate for valves.  I might have missed a few hidden in BMW's large amount of engines, but here are engines that are available in both US and the rest of the world.  All with 35-36 mm diameters and 5-6 mm diameter stems.  The only info that is needed still is the length of the stems!

2008 E92 M3 S65 Intake valve:
   part number: 11 34 7 838 293
   diameter: 35.7 mm
   stem: 4.97 mm
   weight: 43 gram
   cost: 15.00 euro

2005 E60 M5 S85 intake valve:
   part number: 11 34 7 833 775
   diameter: 35.0 mm
   stem: 4.97 mm
   weight: 36 gram
   cost: 16.40 euro

2004 E60 545i N62 intake valve:
   part number: 11 34 7 541 555
   diameter: 35.0 mm
   stem: 4.92 mm
   weight: 42 gram
   cost: 13.70 euro

2004 E46 M3 S54 intake valve:
   part number: 11 34 7 830 889
   diameter: 35.0 mm
   stem: 5.97 mm
   weight: 51 gram
   cost: 15.30 euro

2002 E39 M5 S62 intake valve:
   part number: 11 34 1 408 015
   diameter: 35.0 mm
   stem: 5.97 mm
   weight: 48 gram
   cost: 14.10 euro

2000 E39 540i M62 intake valve:
   part number: 11 34 1 435 480
   diameter: 35.0 mm
   stem: 5.94 mm
   weight: 50 gram
   cost: 13.50 euro

1990 E30 318is M42 intake valve:
   part number: 11 34 1 722 908
   diameter: 33.0 mm
   stem: 6.97 mm
   weight: 58 grams
   cost: 20.00 euro

Notes:
-Most(all?) gasoline engines sold by BMW today, use 5mm diameter valve stems.

-Just about all engines that use 35 mm intake valves use 30.5 mm exhaust valves, so I guess that's a good combination for low street useable torque and emissions?

-In all my research, the most amazing thing were the E30 M3 S14 intake valves, 37 mm in diamter, 7mm diameter stems, and 50 euros each!  and the 0.2 mm oversized valves were over 100 euros each!