My M20 swap

[Poon]

I mostly post up on a local BMW forum, but I wanted to make sure that I posted the content over here so you guys could enjoy. I'm just copying it over so some of it may sound silly and out of context, but you'll get the idea.

Well bad news bears today. I've had some issues getting the car running since I put the new carb on. I always new the car had low compression (could easily turn it over by grabbing the alternator belt/fan belt and turning by hand). I knew the rings/compression was weak, and I think when the new carb flooded the cylinders it was the final straw. Washing down what little seal the rings had.

Anyways, a compression test showed a pretty unhealthy 60-90psi across all 4.

Pulled the head off and found really bad grooves/scoring in the cylinder walls. Also found a really small crack in the head.

Unfortunately my "spare" M10 cylinder head also has a small crack in the cylinder head. I wonder if it's common? The car didn't over heat or anything, I don't actually believe the crack was doing anything. The rings are definitely fucked though.

At this stage I'm on the fence about what to do. I have everything to put together an M20B25, including all accessories, engine harness, clutch ect.

I will need a getrag 245 transmission with an M20 bell housing. So far I have a 4speed and 5speed dog leg as available options.

Then again, I may see if I can have the M10 rebuilt. The bottom end can probably get honed or bored out with new pistons and rings, but the crack in the cylinder head has me worried.

Oh yeah, I also pulled the cylinder head off and all accessories in less than an hour. The fastest I have ever done that, but I can't say that I wasn't driven by anger or emotions, haha. It was a pretty intense hour.

So much to think about at the moment. Either way the rest of the engine is coming out tomorrow.

[Poon]

I have another valve cover that will be going on that will get powdered coated the same time I do the intake manifold and thermostat housing.

Anyways, small update for today.

C101 connector is mounted and wired in. Everything is just but connected and heat shrunk for now. I will clean everything up, delete what is unnecessary and go back and solder and heat shrink all connections once the car is running and everything checks out.

Also had to relocate the battery to the trunk which now sits in my rear strut brace/battery tray. I used an E30 power cable and junction block to try and make things feel OEM

Colin helped me big time running the high pressure fuel line. I also bought a flaring tool to put a nice little mini flare so the fuel line seals properly.

Tool in action

Engine mounting brackets finally showed up today so I bolted them on. I used a modified E30 rubber mount for the left side.

Right side

Pete (Helga) gave me a hand lining up the engine and putting it in. Took a little wiggling but there was pretty minimal fuss

Way tighter in the front than I thought it would be.

Going to have to do some adjustments

Also had to tack on the bracket for the lower transmission platform mount. 2002s don't have a rear platform to chassis mount like E21s and E30s (and all later BMWs). They mount independently to the tranny, so I had to weld the bracket to my E21 323i tranny

That's it for now. Will post up more later.

Hopefully I can figure out which radiator I am using. Everything up until now has been for a rough mock up.

[Poon]

Updates when I say updates biznitch.

Anyways, I spent all of Good Friday working on my '53 pickup with my dad. Saturday I chose to dedicated to Minty. Woke up at 6:30AM , dropped the GF off at work and went straight to the shop to work.

Had 86mm removed from my drive shaft to accommodate a new engine position (M20 as far back as I possibly can have it. About 1cm from the firewall), as well as mated to the new E21 323i transmission. New U-joins, CSB, Guibo, and I also had to shorten both the shift platform , shifter selector rod, and shift platform support beam to accommodate a longer transmission while keeping the shifter level in the original hole in the tranny tunnel.

New gaskets and exhaust nuts. Unfortunately the M20 headers I had would not fit both in the front and rear. They hit the frame rail, firewall as well as Idler arm. Ended up using stock M20 manifolds with a shot of VHT header paint. The Cast Iron finish came out nicer than I thought it would

Most of the powder coated bits are on

Colin was parting out an E30 so I was lucky to have the chance to snip off a couple OEM pieces like the cooling reservoir mounting tabs. Trying to keep it as OEM as possible.

Test fitting my fabbed upper radiator support. It fits and works for now, but may have to come up with something else when I get an aluminum radiator made.

Got most of the wiring tidied up. Decided go with a 12'' fan kit from Ireland engineering. Glad I didn't get the 14'' kit as it would not have fit. Also decided to hard wire it to a switch rather than use the thermo-switch to control fan operation. I'd rather be in control all the time. The electric fan combined with the lower temp (70degree) thermostat should keep things nice and cool. Sexy face Colin!

The stock throttle pedal uses a throttle rod style system that was not going to work with the M20 throttle body. Ended up buying a Lokar cable from Mopac in Langley and fabricating cable stops/mounts to keep the original pedal box in tact.

Colin came over and helped me bleed the brakes, and after fabbing an AFM mounting bracket we fired it up and bled the cooling system. Bled quickly and easily, but was loud without any exhaust on it.

Here is a video of us bleeding the cooling system. Car is running open heads

I drove it around the parking lot and did a couple burn outs. The willingness to spin the wheels surprised me and take off with the 3.91 mated to the M20 in a 2200lb car is a lot more than I expected!

Anyways, today I permitted it and drove it over to the exhaust shop down the street open headers. First time I have driven the thing on the street in over 2 years. It was brief , but beautiful. Can't wait to give this thing a proper shake down once the exhaust is made.

The exhaust I'm having made is 1 3/4'' down pipes, Y'd to a 2 1/2 all the way back. No cat, no resonator and an 18'' Magnaflow. Should be a nice muscly tone but not too obnoxious.

Also got the hood fitted Monday morning. Took 3 hrs. I will never take a 2002 hood off ever again.

Over all I have learned a huge amount doing this engine swap. I have learned a lot about my capabilities, and what is required in terms of fabrication and problem solving.

What I thought was a well documented swap had me solving almost all of the problems on my own. There are a handful of 2002 guys on forums who have done M20 swaps and they don't post regularly so its hard to get simple answers such as "what did you do for _________?". I plan on writing a comprehensive DIY and taking many detailed photographs of the car once I get it back and the exhaust is wrapped up.

Very excited to have my car back. Still can't believe I drove it this weekend, and am stoked that it's ready for me to enjoy for the entire upcoming summer.

[dasfrogger]

Excited to see how this goes! I'm not too far behind you

[Poon]

How close is your conversion?

If you have any questions I'd be more than happy to help if I can.

[morfiya]

Just wanted to say you just gave Me a BIG booster shot.i also have been of the road for to years,doing the m20 swap, im running needs paint,and mmsome tweaking, thanks for the motivation!!

[morfiya]

Just wanted to say you just gave Me a BIG booster shot.i also have been of the road for to years,doing the m20 swap, im running needs paint,and mmsome tweaking, thanks for the motivation!!

[AceAndrew]

Looks great! Have enjoyed seeing your progress.

If you have some more shots/info on the selector rod and plate, I'd love to see them. I'll be doing the E21 style mount with the rubber bushing dropping down from the tranny tunnel.

[dasfrogger]

Got the motor and 323 transmission pretty much ready but im a ways off from install. Going to have the body mounted on a rotisserie this weekend, mediablasted with in the next two weeks. then fab, paint, and final assembly.




I'll be sure to stay in touch, your car looks great!

[Deutschman]

Very good looking m20 swap! Cheers!

[Poon]

Thanks for the kind words guys. Car has been driving great.

Need to do the heater box before I put the interior back in.

AceAndrew, I don't have any pictures right now but I'll snap some pics of the shift linkage next time the car is up on the rack. One thing to note is that I removed 86mm from the shift platform, which is exactly the same length I removed from the driveshaft. Since I kept the '02 shift platform and shortened the stock driveshaft, both required the same amount of shortening/modification. Your length may differ depending on your final engine position, but the shift platform/driveshaft relation should remain the same.

[kid2002]

Wow. Very cool build. Love the paint and the simple paint scheme of your M20. Thanks for taking and sharing all the photos. Like others have said, this is very inspiring and i'm sure it's a kick in the pants to drive. I plan to do the same except with a G260 (E30) transmission.

[Thorbjorn]

I am in the planning and collection parts phase of an M20 swap, so I would like your input on:

• I was wondering how the radiator is holding up with the heat of the M20? You are using the E21 323i radiator mentioned in the 6into2 guide. I have seen more and more forum members use the 83-85 VW Golf/Jetta/Scirocco mk2 radiator (the AirCondition model is recommended as it is the largest) VW Part # 191121253G.
   
• Chris swapped his E21 323i radiator for the VW one (http://www.bmw2002faq.com/topic/67840-71-2002-m20-conversion/page-3), as the E21 radiator had a hard time keeping things cool. Note: Chris lives in Australia.
   
• How did you solve the limited space between the engine and the radiator? Did you move the radiator further forward, or did you shorten some of the bolt/pulleys on the engine
   
• Which clutch/flywheel/pressure plate/through out bearing did you use?
   
• Would you by any chance remember the length of the Lokar throttle cable you used?
   
• Are you running with an oil cooler? If so, where is it located, and which model? I guess the E30 oil cooler will not fit, at it is wide and narrow (4 by 4 or something).

Edited October 9, 2014 by Thorbjorn

[Poon]

Sorry I havn't replied earlier, I have not been on the forum much since getting the swap running.

1)The radiator is holding up well with the temperatures, although I do notice when It's over 30degrees and I'm on the hwy at high speeds (over 4000rpms) the temp will sit slightly above half. Normally sits at 1/3 with the 70 degree thermostat.
2)I moved the rad as far forward as possible, and shortened the main crank bolt as well as the 4 waterpump pulley bolts have been shaved (unfortunately not doing this earlier cost me a radiator). My throttle bracket also sits in a position with my new strut bar that stops engine from traveling forward under severe braking.
You can see this here


3)  I used an E30 325is clutch,flywheel, and pressure plate. I cannot remember which bearing I used, I believe it was e21 323i.
4) I cannot remember cable length, but if you buy the longer cable you can shorten it to required length
5) Currently the car has no oil cooler, although I would like to add one, space is very limited. I have a Kamei airdam which would allow my to run an E30 cooler, but I'm on the fence about mounting it.

 

[Poon]

So far, the only hiccup I have had since finishing the swap has been eating one radiator.

Since the getting the swap running I have added a secondary fuse panel to help clean up a bit of the wiring, and make adding accessories (such as Nitrous ) easier to install


My valve cover gasket also started leaking prematurely so I decided to change to a chrome cover a friend gave me


Nitrous solenoids hooked up


Bottle mounted in the trunk


I'm currently running a 35shot of Nitrous with the wet system (injects fuel and nitrous oxide), and even though it's a small shot it is very noticeable. The kit that I purchased comes with jets for a 35,50 and 75 shot and I may or may not up to the 50, but I'm very happy with the 35 for now.

Also the 4spd 323i tranny and 3.91 rear end is not the greatest combo. I do a lot of hwy driving (work is 35 kilometers each way)  and I'm always over 4000rpm. I purchased a 3.64lsd which I have yet to put in, but if I were to do it again I would have used a 5spd from a m42/m44 car and figured out the speedo pickup (there were no 5spd 323i trannys available at the time I was looking). I will most likely do a 5spd down the road (don't want to use the 260 as I am not interested in cutting the tranny tunnel at this time) but it will happen when I build another M20 for it (have a longblock on a stand with hopes of an Ireland 3.1 stroker).

So far the car has been an absolute blast to drive and I am just enjoying the hell out of it. I have still yet to put carpet or a stereo in (too many distractions with my other cars!) but it will happen with time. I bought a nice set of JBL speakers which have very simple looking covers which will not look out of place on the rear parcel shelf.

The car's insurance expires end of this month (rain season is here) so I'm driving it pretty much every day I can until then.