When did M30 valves get bigger?

[permit]

Yeah, I have an '86 M30 head, just need to know if it's identical to '90 M30 heads. I'm planning a rebuild of it, but I heard that the valves got bigger at some point in time.

[Scott H]

46mm to 47mm on the E28 535.

They should all be 47mm from a E32 735

The M30B35 in an E34 535 uses 47mm intake


Yeah, I have an '86 M30 head, just need to know if it's identical to '90 M30 heads. I'm planning a rebuild of it, but I heard that the valves got bigger at some point in time.

[permit]

So it wouldn't really matter if I'm going to buy new valves anyways, right? The casting is all the same?

[Barry]

Jeremy,Awsome looking cars you have there..

Shogun,Does that mean that the small valve head also came with smaller intake ports??
Imo the std e34 47mm valve port is too big for an auto trans. car.
Has this topic been covered elsewhere??

[Bill R.]

m30 used in the e32 and e34, but since torque is improved over the old motor at an even lower rpm i would say that the larger port and manifold helps an auto trans car rather than hurting it.



Jeremy,Awsome looking cars you have there..

Shogun,Does that mean that the small valve head also came with smaller intake ports??
Imo the std e34 47mm valve port is too big for an auto trans. car.
Has this topic been covered elsewhere??

[Barry]

Bill,Was this accomplished through a revised cam profile??
My car is very sluggish down low,but hauls a*s higher up..

[Bill R.]

cam profiles from the e28 to the e34 m30's. I'm certain it was changed but i would be more likely to blame the sluggish response on the gear ratios available on the auto transmission and the differential. The later 535 autos had the higher stall speed converter and the different gear ratios and are much zippier down low than our early cars.



Bill,Was this accomplished through a revised cam profile??
My car is very sluggish down low,but hauls a*s higher up..

[Barry]

If it helps at all,Im doing 130km/h at 3100rpm-top gear.
I presume its fitted with the 3.6:1 ratio??

[Derek A.]

the later m30 also had a bump in compression if memory server. That is a help in low end torque. E28 was a lot lighter than the e34 is.