School Me on M30 Heads

[ClayW]

I’m picking up a solid 3 liter M30 bottom end for a slow build and I have zero knowledge of M30 heads. I assume that the design changed over three decades and several displacement sizes.

Ideally, I’d like something that would work with Motronic 1.3, but I’ve probably got some learning to do before then. (Would Motronic 1.3 even work with 3.0 liters? What should I do about a distributor, with or without 1.3?)

 

[adawil2002]

When Athena's original head was cracked at 2 exhaust valves. We went with a 1986 M30 head as it has drilled water jackets and 11mm of clearance at the exhaust valves. We also had a triple core radiator built and replaced the friction fan clutch with the updated viscous clutch. I run the original D-Jet.

 

[Gary Knox]

My 3.8+ liter M30 has an '80 head. Been on it since 1993, now into the third owner, no problems whatsoever. It is also a FI engine with Motronic.

The engine etc. was built by Jim Rowe, owner of the popular BMW performance shop called Metric Mechanic and opened in 1977 near KC Missouri. His bored and stroked M30 engines usually dyno'd at about 275 HP and about 290 Ft Lbs of torque. Here's a link to Metric Mechanic's current heads for the M30 engine: http://metricmechanic.com/engine-heads/

Gary

 

[Ohmess]

PM sent.

 

[sfdon]

Motronic 1.3 for the big six engine uses specific port shape, different intake valves, K cam, no cold start valve, larger combustion chamber.
On a usa m30 block you will have about 7.1 : 1 compression. Nobody does this combo because of that.
You will need to port match your intake to your intake ports on the head.
And install a turbo with 10 psi.

 

[Markos]

I’ve read this through and through a few times...

M30 Cylinder Head FAQ

 

[rsporsche]

i haven't heard any recent track record from MM in quite a while. they were a good shop back in the day between Rowe's engines + Blanton's trannies. anybody had any recent experience? as our getrag 5 speeds age, they might be one of the few groups that can / will still deal with them. 3000 bucks is still a big pill to swallow.

 

[Gary Knox]

Scott,

About 2 years ago I called MM with some questions regarding the engine in the car I'd bought. The office manager suggested I needed to talk with Jim Rowe. He willingly came on the line, and was very responsive to all the questions about what he'd done, the upgraded components used in the head, exhaust, etc.. Jim was very cordial, chatted for quite a while, and vividly remembered the car and the man who had the upgrade work done. He even flew to WI a few months after the car was delivered to the the owner/restoration client to do some additional tuning for the owner.

He has moved the operation to Richland MO (a bit south of Columbia MO) a few years back. His son is now actively involved in the business as well. They still promote quite a few BMW engine upgrades. Here's alink to the current staff. http://metricmechanic.com/staff/

Gary

 

[Honolulu]

Jim Rowe's ex-partner, Jim Blanton, IIRC opened: Blanton Transmissions, 1427 W 9th St, Kansas City, MO 64101
Though I only looked at the first page of results for "Blanton Transmissions", a quickie web search finds him on Facebook but not a website.

 

[m5bb]

If you're in to reading forum discussions by some informed knowledgeable people and some dumb asses you can find page after page on cylinder heads and their performance.
My E28.com is full of head discussion articles . You've got to be careful what you believe because this was a bunch of young guys searching for every ounce of power they could get out of an M30 motor. Many did not know what they were doing.
You won't like the info about MM. Know for their way overrated numbers for their rebuilds.

The trans guy Jim Blanton does not rebuild the 280 version of the Getrag trans (which I have in my 88 M5) because he can no longer get parts and there prohibitively expensive.


http://www.mye28.com/viewtopic.php?f=3&t=79678

http://www.mye28.com/viewtopic.php?t=87932

 

[ClayW]

Motronic 1.3 for the big six engine uses specific port shape, different intake valves, K cam, no cold start valve, larger combustion chamber.
On a usa m30 block you will have about 7.1 : 1 compression. Nobody does this combo because of that.
You will need to port match your intake to your intake ports on the head.
And install a turbo with 10 psi.

What I’m hearing here is, “Don’t bother trying to retrofit Motronic onto anything but a B34/B35 M30. Correct?

 

[sfdon]

Motronic is a wiring harness and its computer that has maps or tables....there are many different versions of Motronic 1.0, 1.1, 1.3 and on and on.
Each version has files of spark and fuel settings that are set at the factory for specific engines. Putting a Motronic version with files or tables designed for a larger engine with high compression into a car with a smaller engine or low compression is a fail.
Customizing the maps to fit a different engine can be done- for a lot of money......

 

[ClayW]

Motronic is a wiring harness and its computer that has maps or tables....there are many different versions of Motronic 1.0, 1.1, 1.3 and on and on.
Each version has files of spark and fuel settings that are set at the factory for specific engines. Putting a Motronic version with files or tables designed for a larger engine with high compression into a car with a smaller engine or low compression is a fail.
Customizing the maps to fit a different engine can be done- for a lot of money......

What's the compression ratio on my 3.0L bottom end? Wikipedia says 9.0:1. Aren't 3.5L engines the same compression ratio, just 500ccs bigger?

 

[Ohmess]

Clay -- here is a table with the various M30 engine compression ratios. https://motor-car.net/bmw-engine/item/16041-m30-engine

 

[sfdon]

you will now have 16% more fuel than you need in each cylinder. That will drop your hosepower, wash your cylinders and give you bad cold starts.

 

[Peter Coomaraswamy]

Motronic is a wiring harness and its computer that has maps or tables....there are many different versions of Motronic 1.0, 1.1, 1.3 and on and on.
Each version has files of spark and fuel settings that are set at the factory for specific engines. Putting a Motronic version with files or tables designed for a larger engine with high compression into a car with a smaller engine or low compression is a fail.
Customizing the maps to fit a different engine can be done- for a lot of money......

OK Don, then tell him to use Megasquirt instead of Motronic.

 

[ClayW]

you will now have 16% more fuel than you need in each cylinder. That will drop your hosepower, wash your cylinders and give you bad cold starts.

Wouldn’t the DME compensate based on the AFM and O2 sensors?

 

[sfdon]

No it won’t.
Go read up on why catalytic converters get ruined.
DME units don’t have unlimited abilities to richen or lean out an engine.

Engine exhaust is already quite hot, so when you add in a contaminant like unburned fuel, which can find its way into the exhaust system when your motor is running too rich, you compound the effect, as that fuel typically ends up burning inside the converter itself. This can damage or even melt the honeycomb structure that is required for the catalyst metals to do their job, leading to a blockage and restriction in exhaust flow. If your engine is misfiring or if you see a warning code for a bad oxygen sensor, it’s a good idea to take care of the problem before it can lead to catalytic converter failure.

 

[HB Chris]

What's the compression ratio on my 3.0L bottom end? Wikipedia says 9.0:1. Aren't 3.5L engines the same compression ratio, just 500ccs bigger?

US coupes have 8.0:1 compression, Europe got 9.0:1. The b35 is 9.0:1 and 207hp vs coupes at 170hp or so, the real difference is the torque.

 

[ClayW]

This is all fantastic information.

According to this table https://motor-car.net/bmw-engine/item/16041-m30-engine , the B30 had 9:1 compression in al three forms. All three have the same bore and stroke (89x80). Would a head or piston difference be the cause for differing compression ratios in Euro vs USA motors?

Side note: my block has flat top pistons, if any info can be gained from that. I also confirmed the bore and stroke. Strangely, the block has no serial numbers; just two Xs.