My M42 engine rebuild

[wazzu70]

This content was taken from another site (e30tech) so if you want to read all the details you can search for it there. I figured the info would be more useful here.

As it arrived:


Early tear down:

 
WTF?

 

 

 
 
Getting help from the nephew:

 

 

 

 
 
M20 out:

 

 
 
M42 and M20 flywheel comparison:

 

 
 
Out with the old, preparing for the new:

[wazzu70]

[wazzu70]

Top deck:


Thrust bearing surface as viewed from the rear of the engine:


Thrust bearing surface as viewed from the front of the engine:


Thrust surface on the crank:


Crank itself (much lighter than the M20 one!):


Head:

[wazzu70]

Testing bearing clearances on the crank with plastigage:






Dropping pistons in to check connecting rod bearing clearances:








FWIW I hit the tops of the pistons with a bench grinder with a wire brush wheel to clean them up. I didnt touch the sides. Still using the original rings. Should be good enough for my plans for the time being.

[wazzu70]

These are the updated parts to upgrade the oil pressure relief. Thanks to Peerless for letting me know about this.


Part numbers are as follows:
Control Valve    11141247393
Spring             11411706809
Spacer Bushing 11141247397
Lock Ring         07119934625

Timing set.






Engine stands are so handy...




Before putting the oil pan on I put a very thin later of RTV black around the mating surfaces (both sides). This is because the oil pan gasket helps seal the oil sump in the pan to the front timing chain case. Not my favorite feature of this engine... Also, I used loctite blue on the bolts that hold the oil pan on to the front cover on the inside of the pan. These have been known to vibrate loose and this was a preventative measure.

Also, I replaced a lot of the external fasteners with socket head cap screws. I just like those better

COP kit:

[wazzu70]

Broke the engine in on the track Well, I drove it around town a few times first to make sure all was running well.







Car did incredibly well and is very well balanced. Only issue is its gutless If I was keeping the M42 atmo I would add cams and a 4.27 or steeper rear end for sure. I never even used 5th on the track. Max speed I got was somewhere slightly north of 100mph. Low power and aero of a brick do not help I'm sure

[wazzu70]

Some pictures from the dyno:





Dyno chart:



Dyno videos:
http://www.youtube.com/watch?v=oKq8Rkzj8-k
http://www.youtube.com/watch?v=Pq-S0PxWaAk

Cam swap (Delta 272deg):









Assembly lube on all the surfaces:




Cams in:

[wazzu70]

Now I am wiring up the VEMS standalone. Car is a bit of a mess right now:







Looking much better now...but no current pictures

[MLM]

Nice work. Looking forward to the re dyno on the new cams

[wazzu70]

I redynod on the new cams with poor results. http://m42club.com/forums/showthread.php?t=14016

I will dyno again once the car has been properly tuned.

[bmwman91]

Interesting. Did you get rid of the COP conversion, or is the BMW placard just on the valve cover to keep junk out of the plug holes?

126RWHP with a chip sounds about right. I dyno'ed my first 318iS back in 2003 with just a Conforti chip (and cheesy CAI + super sprint exhaust) and the dynojet said I laid down 131RWHP. My second one, with the same mods in 2006, put down 121RWHP. Once you get the engine management sorted out and tuned, I bet those cams will give a nice bump in the high end.

How are you going about the VEMS installation? Did you find a Motronic harness adapter, or are you going balls-to-the-wall and chopping it up?

[carnurd]

I dyno'd my car last year on stock bottom end with VAC 279/276cams and SS valves 2.5" exhaust(precautionary) and a WAR Chip(PITA to tune with the factory AFM), numbers were 142rwhp and about 128lb-ft at 2400lb elevation 90+deg ambient on a dynojet. So at sea level I'm probably making north of 150rwhp.

[wazzu70]

Interesting. Did you get rid of the COP conversion, or is the BMW placard just on the valve cover to keep junk out of the plug holes?

126RWHP with a chip sounds about right. I dyno'ed my first 318iS back in 2003 with just a Conforti chip (and cheesy CAI + super sprint exhaust) and the dynojet said I laid down 131RWHP. My second one, with the same mods in 2006, put down 121RWHP. Once you get the engine management sorted out and tuned, I bet those cams will give a nice bump in the high end.

How are you going about the VEMS installation? Did you find a Motronic harness adapter, or are you going balls-to-the-wall and chopping it up?

Good questions. I actually took the COP plugs off because I thought they were a PITA to get on and off. Im switching back to wires and an M44 coil pack located on the firewall somewhere. Honestly, I just really liked the look of the little spark plug cover and I couldn't fit it with the COP. Yeah, lame reason, but for some reason I really like the look of the motor with the cover. M44 coil is like the M42 individual coils all in one pack so its smaller and easier to fit, also much less wiring and an idiot proof round plug.

I may regret my decision later and revert back to the COP style coils. I'm keeping all the stuff so I can revert back if I need to

I started with a Motroinc harness adapter made by a friend, but then I decided I did not like having the "extra" harness in there as its another failure point. It also made it difficult to mount the ECU in the OE place due to another harness coming off the old harness. Then I decided to wire the inject sequential, add knock control, ECT and I decided just making a new loom would be easier. I chopped the Motronic connector off and used the wires from the OE engine harness where I could.

Lots of "unnecesary" work, but I hate electrical gremlins and I thought this would be a nice way to get a clean looking install...and one thats easier to troubleshoot. Over time I have learned the cleaner your engine is and the more organized everything is...the easier it is to troubleshoot and the less problems will go unnoticed among all the clutter.

I dyno'd my car last year on stock bottom end with VAC 279/276cams and SS valves 2.5" exhaust(precautionary) and a WAR Chip(PITA to tune with the factory AFM), numbers were 142rwhp and about 128lb-ft at 2400lb elevation 90+deg ambient on a dynojet. So at sea level I'm probably making north of 150rwhp.

Awesome results! I really think cams and a retune are the keys to unlocking power in these motors as your results show.

[carnurd]

Awesome results! I really think cams and a retune are the keys to unlocking power in these motors as your results show.

I think the tune probably would make the biggest difference.  My tuner is a AEM/COBB/Haltech Pro-Tuner, we talked about and we both came to the conclusion ITB's and some head porting would really free up these engines.  

Cam's definitely make a huge difference though as the car is much happier 4-7.5k now.  Likes to live up high and my peak torque is actually up at 6k RPM.

[wazzu70]

I think the tune probably would make the biggest difference.  My tuner is a AEM/COBB/Haltech Pro-Tuner, we talked about and we both came to the conclusion ITB's and some head porting would really free up these engines.  

Cam's definitely make a huge difference though as the car is much happier 4-7.5k now.  Likes to live up high and my peak torque is actually up at 6k RPM.

Do you happen to have a copy of the dyno sheet? I would love to see it!

ITBs....no way to go wrong there. Especially with better cams!