Larger valves

[745turbo]

Anybody know where to get larger (+1mm) valves for b35 head? Can't find them anywhere. I've know several places that have m10 39mm and 48mm valves, but I'm not sure if they fit M30!

JV

[Skeen]

I can't say with certainty, but I would guess the M10 valves would fit.

[90e34535i]

I remember Korman having a good price on Stainless oversize Valves for the m30 a litte while ago.

[745turbo]

Thanks!
Sent email to Korman. Will see what they say.

Any other possiblities?

JV

[Azure]

Ireland Engineering:

http://www.bmw2002.com

Catalog > BMW E28 > Engine > Page 2

[745turbo]

A while ago I tried to buy h-beam rods for M30 from IE, but somehow they didn't bother to answer me on e-mails. Also, they list only larger exhaust valves, don't see 48mm intake.
Anyway, will try again with them.

JV

[Ken H.]

http://www.ferrea.com

[cgraff]

A while ago I tried to buy h-beam rods for M30 from IE, but somehow they didn't bother to answer me on e-mails. Also, they list only larger exhaust valves, don't see 48mm intake.
Anyway, will try again with them.

JV

In short, 48mm intake valves are very tough to fit, although doable. The problem is you'll need custom machined valve seats, and to machine the head to fit them as well. The amount of material left on the stock 47mm valve seats is probably enough to do 47.5mm, but not any bigger.

I've had this discussion with Top End which does a lot of M10s and M30s. They also said that with bigger valves you'll want to check your cam duration and lift to make sure you have clearance during the overlap phase.

Again, doable, but difficult. 47/39 (intake/exhaust) is probably the easiest to with minimal effort (see: 80/20 rule). Stock valve seats, custom (inexpensive though) stainless steel valves, and so on.

-Chris

[Jimmie G]

Topend performance seems to be a good source for the exhaust valves they have a very good price also.

Jimmie