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I need to resurrect my 5 series after doing one complete restoration almost 20 years ago. My car is modded with late model brakes, 5-spd, limited slip, coilovers, 305 Shrick cam, 40mm DCOEs, lightened flywheel and rods, etc. Car was a daily driver/track car but I havent run it in several years.

I spent a few years restoring a Reynard Formula Continental that I have been driving for about six years now. But, I would like to get my bimmer running again and run some HPDEs around Texas.

I may need to pull the engine and freshen it up with some bearings and seals. But I also have a 3.3 block and a 3.5 block and head w/the large valves. I am wondering if I can install the 3.5 and use the Schrick cam and modify the intake manifold to run the DCOEs. When i looked at the 3.5 block it didnt look like it had the engine mount bosses in the same place as the 3.0. If this is the case, maybe I can build up the 3.3 with the 3.5 crank and head with the cam and carbs I have.

Anyway, older guy here needs to get his butt motivated and get some cars running again. I also have a '76 2002 I have owned since '78 and its modded to same level as the 530. And, then I also have a '91 850 that needs some attention.

Thanks,
JP



here is a very old pic of my 2002 soon after I repainted before I had installed grills. Just had to get it on course before last details were finished.

3.3 and 3.5 use the same crank, just a different bore, and yes it can be bored out to 3.5, but it's pretty thin. Yes you could use an early Schrick cam in a later engine as long as you aren't going to use Motronic, which if you're sticking with the carbs you wouldn't likely be. If you're talking a late 3.5 motor mounts are a complication but can be custom made. I believe there are adapters to use a late 3.5 in E28s, but I don't know about E12s.

Mike W. wrote:3.3 and 3.5 use the same crank, just a different bore, and yes it can be bored out to 3.5, but it's pretty thin. Yes you could use an early Schrick cam in a later engine as long as you aren't going to use Motronic, which if you're sticking with the carbs you wouldn't likely be. If you're talking a late 3.5 motor mounts are a complication but can be custom made. I believe there are adapters to use a late 3.5 in E28s, but I don't know about E12s.

Thanks for the help, Mike!

Is the bore spacing on the 3.3 and 3.5 the same? Seems like it would be both blocks use the same crank. What is the best source for parts now, like pistons?

jdp530 wrote:

Mike W. wrote:3.3 and 3.5 use the same crank, just a different bore, and yes it can be bored out to 3.5, but it's pretty thin. Yes you could use an early Schrick cam in a later engine as long as you aren't going to use Motronic, which if you're sticking with the carbs you wouldn't likely be. If you're talking a late 3.5 motor mounts are a complication but can be custom made. I believe there are adapters to use a late 3.5 in E28s, but I don't know about E12s.

Thanks for the help, Mike!

Is the bore spacing on the 3.3 and 3.5 the same? Seems like it would be both blocks use the same crank. What is the best source for parts now, like pistons?

Yes, bore spacing is the same on all M30s from the 2500 to the B35, 3.5. Pistons are tricky, a few factory ones are available but custom are becoming more competitive to cheaper. Several places do them, JE seems to be the one I've heard about the most, but no personal experience.