e21Restoration

The late Pete McHenry, respected BMW engine guru, supplied a two liter crankshaft from an early M10 to increase the stroke to 90mm and he installed 91mm bore forged pistons, bringing the displacement to 2146cc (up from the stock 1766cc). He also rebored the throttle body, increasing it from 48 to 56mm and I added a larger 80mm air flow meter from an early 2.0 liter 320i (replacing the original 60mm). I have replaced or rebuilt all of the components of the K-Jetronic fuel injection system with new parts to improve reliability.

 

 

 

 

 

 

 

 

 

 

     The cylinder head was completely reworked by Leo Goff at Memphis Motor Works, adding a Schrick 284 degree camshaft and Schrick dual core springs along with all new seals. This Stage Two upgrade includes mild porting and polishing.

    Almost all of the engine components are new. The exceptions are the crankshaft and connecting rods, but all of the reciprocating and rotational mass parts were weight equalized and balanced as a unit by Fryar’s Performance Engines in Asheville. I welded in an oil pan baffle to keep the oil pump well supplied during hard cornering.

    I made a replica of Metric Mechanic’s “curved finger” water pump by machining a block of aluminum that smoothes out the flow of water through the pump’s 90 degree turn. By coupling that with a new Behr radiator,  a 71 degrees Celsius thermostat, a smaller pulley, and an e30 viscous damped fan clutch, I’m expecting big improvements over the marginal stock cooling system.

    I had originally planned to use the stock sized 215mm clutch with my lightened OEM steel flywheel. When I found a used, excellent condition 228mm JB Racing aluminum flywheel, all of that changed. I sent the flywheel to JBR for reconditioning and rebalancing and got the upgraded 228mm Sachs “Sport Clutch” from Bavarian Autosport.  

 

 

 

 

 

 

 

 

 

 

 

 

     The single largest investment in this project has been the new Metric Mechanic Sport OD, close-ratio, 5-speed transmission. The Getrag 240 that came in the car from the factory had oddly spaced ratios that aren’t well suited to most american driving situations. First gear was way too low, second was pretty useful, but the rest were too far apart. Jim Rowe at Metric Mechanic redesigned a hybrid of the Getrag 245 and 260 transmissions, that evens out the discrepancies and still provides an economical overdrive gear. The Getrag 240 was also infamous for it’s troublesome aluminum shift forks and weaker synchronizers.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    I’ve approached the suspension improvements to the car with pretty much the same philosophy I had for upgrading the engine. I want a car that is fun to drive, but easy to live with.  I've preferred to stay with period correct modifications for the most part, but I’ve been willing to incorporate improvements from later years when it makes sense. An example is the substitution of e30 calipers for the rear disc brakes. These have a slightly larger pad area than the e21 323i, but more importantly, replacement parts will be readily available for the more popular e30.

     In 2014, I joined some fellow enthusiasts from the e21 board on Bimmerforums.com in a group buy of quick-steering racks from Kiley-Clinton in the UK. It reduces the number of lock-to-lock turns from 4 to 2.5 and replaces the plastic bushing with one machined from bronze with a modified slipper pad. It"s still a manual rack, so it requires a bit more effort, but there is much less steering wheel movement.