M30B33 pros and cons?

[SpecRaceM5]

I have acquired a M30B33 and am curious of it's specs compared to the other M30 options out there. All I know is it is smaller bore and pretty low compression. My long term plans are to turbo it. Are the heads on the different M30 variants different? Can one head be used with the M30 to make it better? If I were to change the rods and pistons would it make using the M30 worth wild? Basically looking for any way to use this motor short of purchasing another. Any info on the B33 would be greatly appreciated. I will post up casting numbers on both the block, manifold, and the head tomorrow when it is light out. They seemed a little confusing to me.

Cheers,

Brian

[SpecRaceM5]

Here are some pics I just snapped after putting it up on the stand. The manifold is stamped 3.2/3.5, the block is stamped 3.0/3.3, and the head is just stamped 3.5. The head also has an 83 casting year. Is this just a standard 3.3 out of a 633 or has it been messed with?

Cheers,

Brian

[gearheadE30]

What year car did it come out of? The 1984 cars had a hotter cam, higher compression, and a lightweight flywheel on them. Sorry, cant tell you about the block/head, but that is the right manifold.

[SpecRaceM5]

I believe it is from a 1984 633csi. From what I read, those motors have the same stroke as the 3.5 but different bore. Is this correct? If so, can it be bored out to 92mm or is the casting completely different leaving the water jackets as an issue?

[euroshark]

Same stroke as the b34 (86mm) but the bore is 89mm on the B32 instead of 92 on the B34. Yes, they can be bored but I wouldn't bother personally. Finding a B34 block will be cheaper probably. The block and head combo is correct, there was only one casting for all of the 3.0, 3.2, and 3.4 liter heads from the late '70s to the late '80s when the B35 replaced the B34.

GearheadE30 is almost correct - US Spec B32s up through 5/84 had a lightweight flywheel and hotter cam, but the compression was the same as the 3.4 at 8:1. the euro B32 had 10:1 compression just like the euro B34 and the power difference was about 18hp. US Spec B32s are rated at 1hp less than a US spec B34 and about 15 to 20ft/lbs less at the peak.

[SpecRaceM5]

Thanks for the info. So what I'm getting from this is that I might as well use this unless I want to go with an m30b35 from an e34 or e32. Is this correct? My plan is to add a turbo to it later. That being the case, is there any reason to change the pistons or rods, or should I just put on a metal head gasket and arp headstuds and call it a day?

Cheers,

Brian

[Danny]

Just a gasket and headstuds will give you 15psi easy.

[RickSloan]

Just a gasket and headstuds will give you 15psi easy.

this is very true, the b34 is good for 15 pounds on stock everything and is apparently very reliable at that. I would just replace the head gasket and the studs like danny said.

Will the b35 head work on this block and drop the compression like it does on the b34?

that would make it a dog now but would probably allow you to run 20lbs or so on stock internals

[SpecRaceM5]

Anyone have an idea of how much power and torque I would be looking at with 15psi?

[RickSloan]

look at good and tights threads, and be prepared to shit a brick with a huge smile on your face

[SpecRaceM5]

That's what I was hoping for. I didn't have any specific numbers in mind. Any where near those numbers will definitely suffice though.

Cheers,

Brian

[euroshark]

Todd at TCD told me to expect about as much power as a B34 at 9.5psi (around 280 I believe) and a bit less torque (maybe just less than 300). I am recalling this conversation from over a year ago but that's pretty much what stuck. We are only talking about 220cc after all! :)