1990 325is Progression // M20B25 Rebuild

[jeenyus]

your other red e30 was top notch. what wheels are those? VOLK?

[plmichal]

Ordered a few new shiny parts with plenty more on the way. A Bimmerheads rebuilt "Touring" cylinder head, a set of .020" oversize pistons, and damn near every single drivetrain gasket, bushing, bearing, etc, needed for a full refresh. I'll post a photo of everything together once it gets here.




In the meantime I tore down the M20 and have it ready for a machine shop. Heading to one in the morning, they seem to specialize in JDM AWD 4-cylinders but look like the most pro guys in the area. Anyway, I cleaned it up a bit. The amount of grease and gunk was staggering. I blew apart oil pump and found some damage / pitting on the teeth. I'm replacing nearly every component of the oil pump because buying parts, cleaning, and assembling it myself is half the price of a new one. Both intermediate shaft bearings are toast and new ones will have to be machined in place. Before & after a quick wash, hopefully the machine shop can clean it better. I'm going to be painting the block gold in homage to my last red E30.





Oil pump gear and intermediate shaft bearings. This M20 really needed a full rebuild even though it ran great.






Picked up a factory remanufactured 3.46 LSD from an E28. Swapped the diff cover and output shafts to fit the E30. I thought about it and a couple reasons for using a taller diff are...
1. I'm driving on the highway for long periods of time
2. I'd like to turbo the M20 after it's been rebuilt and has proven itself road worthy

[plmichal]

I came across a bottom end that had ARP mains and rod bolts. Pulled them for my motor.



Dropped off the bottom end and associated parts with Emerald Coast Motorsports in Fort Walton Beach, FL. They were on the only machine shop/ engine builder in the area that seemed capable of doing a proper rebuild.The owner took the time to discuss what I was looking for and showed me around the shop. In addition to the machine work and assembly of the block, they'll resurface and shave the flywheel, clean the oil pan, intake manifold, valve cover, etc. They include a build sheet with each rebuild including ring gaps, bearing clearances, etc.


And here we go...



I was happy to hear my crank and journals were in good shape and to order standard sized main and rod bearings. I think I'll buy Kolbenschmidt brand? OEM BMW bearing prices are astronomical.

[plmichal]

Wow... it's been exactly 1 year and 1 day since I updated this thread. This is probably the slowest build thread on the planet as not much has happened since then. Thread title should be "1990 325is Painfully Slow Progression". I bought an S52 drivetrain with plans to drop that in. But the M20 was the original plan and my heart is telling me to continue with the M20 rebuild. It's time to be decisive and get this thing on the road by years end 2020. If I don't have a video posted of it running by Dec 31st, I will... (reserved for doing something stupid).

[gnmzl]

Good things take time, but sell the S52 and finish the m20. Way classier and suitable for this car.

[plmichal]

Bottom end has been assembled.We will rebuild the original head. Plan is to mate headers to E36 M3 midsection and muffler. Found some Style 10's locally.