which model/yr of 80's M30 engines had big valves

[dwa1971]

I know that certain year m30 engines in the 80's 3.5s had small valves and others had larger ones. I would appreciate it if someone could let me know which is which. Thank you

dwa1971

[bimmerphile73]

1987-1992 E32 7 Series
1988-1993 E34 5 Series
1988, 1989 E24 6 Series

Those are all U.S. model years, build dates can be different. For example E32 model year 1987 production began in August, 1986. Model year 1988 6 Series production began in June, 1987. In addition to bigger valves, these engines have higher compression ratio, resulting in 208 hp in the U.S models. Most, except for the very early 7 Series and the 6 Series engines, require an adapter for the right engine mount.

These engines can be identified by the toothed harmonic balancer and the intake manifold being braced underneath instead of being braced to the valve cover.

[dwa1971]

Is it worth it to go to one of these vs. the smaller valve 3.5s for ease of install to the e9? thanks

[bimmerphile73]

You can get an adapter from Carl Nelson's shop, La Jolla Independent, 800 466-8184. It's a custom built item, so it'll take a bit of lead time.

If you're going with the Motronic, the engine is better since you won't need the motronic bell housing, since the sensors are on the front of the engine. If you're going with carbs, the engine is better because it breathes better than the M30B34 engine.

[dwa1971]

Thanks, yes I know Carl well and he knows my credit card well. I plan to go the carb route as I hate electronics and such and prefer old school. I have been planning this for some time and will most likely do it this winter after I find the right engine.

[dwa1971]

What sort of 5 sp do you suggest as I have heard everything from an early 533 tranny to just leaving the 4 spd which I hate. I appreciate your thoughts.

dwa1971

[bimmerphile73]

First, the 265/5 is the "dogleg" 5 speed which has a 1:1 final ratio. You don't want that one unless you're planning to do the Pike's Peak Hill Climb. And according to Carl, it's a POS. The 265/6 was in various early '80s 5, 6, and 7 Series, as well as the 1985 5, 6 and few 7 series and also the E30 M3. The 1985 transmissions require the addition of the speedo gears, since those cars had electronic speedometers.

Don't bother with the Getrag 260 series, the early ones (pre 1985) suffered from poor layshaft lubrication, the later (post 1985) ones aren't much better. The reason BMW went back to the 265 in 1985 was that the 260 wasn't hacking the program. The 260s have an integrated bellhousing and the 265s have separate bellhousings.

The 262 4 speed is a great transmission, but if you want a 5 speed, the engine swap is the obvious time to do it. Carl can fix you up. His children will appreciate the college educations we are all providing for them.

[PORCHE505]

The only change in the m30 valves is for the b35, as mentioned. The thing is that it only grew 1mm. Every other m30 head has 46/38 valves. Nothing to get excited about there. Pistons can be used to bring up compression, so all the b35 really has is displacement. Its not as special as everyone thinks it it.

[PORCHE505]

The 262 is the CR if I remember correctly. The 265/5 is an overdrive trans with the detachable bellhousing. Its actually a very goos trans.

[bimmerphile73]

...perhaps by the Metric Mechanic site which incorrectly indicates the sport transmission as a 262 on one of their pages. However, their other pages correctly refer to the sport and the overdrive collectively as 265s. Yes, the 265/6 OD is a great transmission. I'll take the experts' opinions that the dogleg is not.

The link shows the designations in a format that's a bit easier to read than MM's site.

The G262 is a direct drive 4 speed.

[bimmerphile73]

And the difference between 182 hp and 208 hp is inconsequential. That could have been easily accomplished with just an increase in displacement and compression ratio? I'm guessing not, otherwise BMW would not have invested all that time and money changing the valves (and the head, and the intake manifold) in the first place.

But I'm no fluid dynamics engineer, maybe someone has a flow analysis that can show why they wasted all that effort.

[PORCHE505]

That, the 264 degree cam, the higher compression pistons and motronic 1.1 would be more than enough to do it. Or do you honestly think it was a 1mm larger intake valve instead of more modern fuel injection, a hotter cam and higher compression?

[PORCHE505]

I have seen a lot more saying otherwise than that one website. I'll have to go look at some bellhousings some time to confirm this.

[bimmerphile73]

I knew you were going to bring that up.

No, if you will read my post carefully, I asked if you thought that just an increase in compression ratio and displacement would be sufficient to raise the power that much. By implication, they do have an effect. Motronic 1.1 has some nice driveablity improvements, such as controlling cold starting from the ECU rather than using a cold start injector, but that doesn't increase power. Try putting Motronic 1.1 on a B34 engine. Will it produce any more power? No, 1.1 doesn't cause the extra power and torque, its mapping allows the B35 engine to take advantage of the increased compression ratio and cam duration. Motronic 1.1 has greater spark advance, which is needed to take advantage of the higher compression ratio, which in turn requires premium fuel. But you can do those things using carbs and a distributor, as well. 1.1 just does it in a very elegant manner. As I mentioned in the very first post, the bigger valves allow the engine to breathe better. The bigger valves let even more air in during that longer duration intake cycle. Maybe 1 mm doesn't seem like much but evidently it's enough. Again, tell me why BMW would bother if all the other changes were enough.

[bimmerphile73]

RealOEM emulates BMW's ETK data. BMW probably has the information more correct than some unofficial source.

[528ita]

Thats only another 13.4 cubic millimeters. The motronic 1.1 and 264 cam compliment each other for the extra power. I dont think another 13.4 cubic millimeters of valve opening is going to blow anyone away. Its the cam and matching EFI.

[528ita]

Dont tell me about official BMW data. And I still dont buy it.

[Velocewest]

262 is the 4 speed. 265/6 is the OD 5 speed. 265/5 is the sport 5 speed (dogleg).

And not to be insulting, but saying you work at a dealer isn't much of an endorsement -- I school the guys at my local dealer about older BMW info all the time. Crap, some of them think the only 530's and 745's BMW ever built are current cars.

Tony

[Velocewest]

All the castings have 262 part numbers.

Tony

[bimmerphile73]