E30 M20B29 Project

[E30kid 27]

Better late than never, but here's a foray into the next major step in my E30 I began last week - the drivetrain!

This has been on the cards for a few years, but I finally settled on what I want to do with my 300,000km M20B25 and work has begun, have slowly been sourcing parts for it over the last year or so. 

The juicy bits are basically a 2.8 M52 crank to build a stroker from the original b25, coupled with custom pistons further pushing to a 2.9L displacement, with RHD ITBs, hotter cam and Link Fury to be the brains of the thing. Loads of other bits along the way naturally!

Last week I managed to hire a couple of bros to pull the engine, win win because I got free labour and they got to learn cars without the pain and expense of projects themselves.

During the week I tore down the engine to get it ready to take it down to the engine shop for boring. Good to see that the weld on the head from the infamous M20 crack two years ago held strong with all looking in order. Remarkable how little wear in the bottom end bearings on a 300km motor! Local engineering shop completed my crank spacer too so the b28 crank should drop straight in now.

Todays agenda was removing the rear subframe, as to clean it up/blast/paint and re-bush as I sourced new Powerflex bushes to go in. Tomorrow I'll take stock of exactly what I need to prep and take for sand/vapour blasting and paint prep and tidy the engine bay up and remove the brake master/booster in lieu of the replacements currently in freight.

 

 

 

[Harper 615]

Curious what you think of the RHD itbs when you get them. I'm not far off ordering a set for my M44/42 in my E36 318is.

[E30kid 27]

40 minutes ago, Harper said:

Curious what you think of the RHD itbs when you get them. I'm not far off ordering a set for my M44/42 in my E36 318is.

Managed to score them second hand but not actually run earlier in the year, they certainly look the part and seem pretty well made. I've seen the odd set in the wild at this point so doesn't seem to be anything surprising.

[E30kid 27]

Small progress, subframe completely stripped and just awaiting being sent for stripping/powdercoating. 

Fitted first of the rear braided brake lines, and continued cleaning - need to find a good degreaser/cleaner for the wheel wells/bay! My springs are purple again at least though.

More interestingly, pulled my cluster and changed the econometer face to a oil temperature gauge, and my tacho to a 8k redline face from a M3.

From what I can read, the econometer is a result from the SI board processor calculating fuel usage by an equation of fuel injector duty and Vehicle speed input. By removing the input pin for Vehicle speed, and soldering the two pins together so they receive the same input, I should be able to program the ECU to run the gauge accordingly

Fuel rail adapter turned up so I can remote mount a regulator, and Corrado rotors ordered through EBC so hopefully over the next week my RX7 calipers and new master arrive so I can get started on the front brakes.

[Neil McCauley 483]

Another trick to get the M3 tacho to read correctly is to use a 6 cylinder coding plug from another M engine, in my case I used an M635csi coding plug which slots straight in.

Edit: this was using the genuine 4 cylinder 8k tacho and making it read correctly for the 6 cylinder engine, so if yours is just an 8k face then you might need to use your method. 

Edited Monday at 03:44 AM by Neil McCauley

[E30kid 27]

28 minutes ago, Neil McCauley said:

Another trick to get the M3 tacho to read correctly is to use a 6 cylinder coding plug from another M engine, in my case I used an M635csi coding plug which slots straight in. 

Interesting, hopefully I should just be able to setup the ECU to output accordingly but I'll remember this.