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AceAndrew

M20 Triple weber build x2

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^ Thank you

1. BMW 2002 Front Subframe reassembly (Street Performance oriented)

Written by myself, Andrew Adams, with much help and teaching from Jeremy. This is intended to go up on our expanding Ireland Engineering Tech Section to help answer some of the questions we get asked regularly.

BIG DISCLAIMER: I am not responsible for your screw-ups.

GENERAL TIP:**Never fully torque down a bolt intended to hold a pivoting bushing into place until after the full weight of the car is applied.**(This is generally why you’ll see someone stress out and say their car is sitting like a 4x4 after going through their suspension)

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Starting with a blank powdercoated front subframe makes things nice.**The first thing I did was press in the Idler Arm Bushings (this would be a pain to do later on), the powder-coater was kind enough to mask off the holes so the new bushings were pressed in with relative ease. With the bushings in I slid the idler arm through and reused the cap washer/ castle-nut.

frontsubframe1.jpg

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From there I went straight for the radius rods. I used the IE urethane front bushing kit which included the radius rod bushings as well as the inner and outer control arm bushings. Grease-up the backside half of the bushing put the zinc coated concave washer in place along with the radius rod end and push into place ( if you leave the rod out, it won't fit later). Pushed in the front portion w/washer.

frontsubframe2.jpg

**Note, the earlier cars used drilled arms, castelated nuts, and cotter pins to keep everything in place. Later cars simply used lock nuts ( radius rod nuts are 14mmx1.5mm). I used locknuts where-ever possible since there a lot easier to deal with.

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The seam welded and powdercoated control arms were the next to have their bushings put in. The thinner-ended bushings went on the outside hole and the thicker were pressed into the inside .

controlarm.jpg

Earlier control arms did not have the bent “I” forming edges and are obviously not as strong.

frontsubframe9.jpg

The sway bar end links were put on next. Used the jam nut to tighten the bushing but made sure to leave the heim-joint loose (for easier instal later).

controlarmassemb-1.jpg

Next I pushed the large bolt through the subframe and the bolt sleeve, out the other side the 'shorty' bolt sleeve was slide on along with one of the bushing washers. With another concave washer slide on the back if the radius rod, it was time to slide the control arm on. With the other side washers in place I cinched on the 2 lock nuts. (don't mind the sway bar, got a little ahead of myself.)

frontsubframe8.jpg

Sway bar

The bmw 2002 Ireland Engineering 22mm front sway bar (full name, to help google searchers) routes underneath the subframe rather than the stock (and other aftermarket bars) which route up and over the subframe tips. The maths show that it acts as strong as if it were a 25mm bar routed through the stock location. The billet mounts for the pivot bushing utilize 2 of the 3 holes which attach the subframe to the chassis frame rail. I've chosen the 'drop-center' bar which will clear the oil pan for this M20 swap. The important part of the installation will be when I attach the end links to the bar (next write up). See above picture

steering box

After loosely attaching the passenger side motor mount and keeper (NOTE that I've done this wrong, whenever possible put the bolt facing downward and the nut on bottom, so just in case the bottom backs out you'll still have the bolt in place)

frontsubframe6.jpg

it was time to attach the steering box. The steering arm bolts got a little bit of red lock tight and were completely torqued down.

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The center track rod was then put in place (made sure to soak the rubber bushings in oil, as per the factory manual) and the ends bolted on loosely.

IMG_3327.jpg

All done for now! Next up is the actual installation!

frontcomplete2.jpg

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Looks like everything is coming along great! Quick question, roughly how long do you figure an average diy'er would spend rebuilding front and rear subframes. As in if you got all your bushings, parts, etc. laid out and ready to go?

Please take tons of video's of this thing running. The only video I've seen of a triple weber m20 is that e30 that you posted earlier. Good luck!

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Lumbergh --- I'd give yourself a full day for bench assembly and then a day each for the front/rear install.

BMW 2002 Front Subframe installation.

Going to breeze over this a bit.

To drop the front subframe I unattached the steering colum from the box (unbolted the four bolts inside the cabin where the steering column attaches to the fire wall and the steering coupler in the engine bay, couple good yanks on the steering wheel and it's separated.), unbolted the engine mounts, the strut mount hats, ground wire, and some other bits.

IMG_3341.jpg

With the car off the ground we wheeled in the cherry picker to hold the engine in place. We unbolted the 6 bolts which attach the subframe to the frame rails and out cam the old subframe, complete with strut assemblies.

frontsubframe13.jpg

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Slid in the new subframe assembly and started to raise it up on a jack. The billet pieces used for the IE sway bar utilize the forward two subframe-to-framerail holes, so they are held on pretty tight. It was tricky to line up the subframe holes (and the motor mounts) but it worked after some grunting and repositioning of the jack.

IMG_3357.jpg

frontsubframe14.jpg

We were reusing the upper spring perches (making sure they weren't mushroomed) so the upper assembly had to come apart. Most common reason people will get ticking in the corners or going over bumps with their newly refurbished suspension is because they do NOT leave enough space between the upper spring perch and the strut bearing, These need to be completely isolated from each other because as the strut bearing is bolted to the body shell and remains stationary, the upper spring perch twists as you twist the steering wheel. If you do not have enough spacing between two plates (washers) then they will bind with eachother resulting in the clunking/banging. This also holds true for adjustable camber plates.

frontsubframe13d.jpg

frontsubframe13e.jpg

The fixed camber plates go between the strut bearing and the body shell, it relocated the upper spring perch in-board. The plate and perch didn't want to cooperate very well and so a bench vice was needed to press them together.

With the subframe in and the struts now ready we slid in the strut assemblies and bolted the tops to the body and the bottom to the control arm.

The sway bar end links were next. To properly set the end links while the car is up it's best to disconnect the heim-joint from the rest of the link (snug the link down on the control arm) and jack up the the drooping control arm up simulating the arms position while on the ground (this way the bar will have NO pre-loaded stress when driving). The heim-joint and link will line up, simply attach and tighten down.

frontsubframe15.jpg

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Brake setup.

The hardlines on the strut were stripped before we touched them, so we had to bend up some new ones. Didn't have much time to spend making them look pretty, but they work. The inner hardlines were luckily not stripped, used the IE stainless flex lines to finish the connections.

frontsubframe18.jpg

Caliper and rotor in place. Make sure the caliper is centered over the rotor, I have had to use different size shims along the caliper bolt (tolerances were not always consistent with the Volvo calipers).

frontsubframe19.jpg

Reattached the steering column (couple of good shoves from inside the car) after swapping over the grounding wire on the steering coupler setup.

After attaching the tie rods to the steering arms and remounting the wheels, we did a manual alignment (old fashioned tape measure and string) and I headed on home with a much nicer behaving suspension.

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Awesome write-up!! Can't wait to see more of the progress

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Thanks Tito,

Things have been moving along slowly. Here's how the workbench sits right now, you can see the diff is pulled apart waiting for the limited slip pumpkin ..... I'll be running an E21 open case with a E36 318 pumpkin, will hopefully have full write up before the month is out.

IMG_3632.gif

Just piecing other small bits together including a new thermostat housing assembly. Didn't want to run the corroded heap that was on there. Made a new thermostat kit on the website since we get some calls for them. ( http://www.iemotorsport.com/bmw/E30-cooling/M20ThKT.html )

Old Vs. New

IMG_3627.jpg

Components

final2.jpg

Starting to assemble valvetrain components. including IE 272 cam, and IE HD rockers w/ new hardware, SS IE valves (standard size).

IMG_3629.gif

Some lighter H-beam rods.

IMG_3479.jpg

with ARP 2000's

IMG_3481.jpg

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I'm eagerly anticipating the LSD swap post. Please make it as detailed as possible. I picked up a 4.10 small case LSD that I'm planning to swap into my long neck diff in my 1800Ti.

Nice work!

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Glad to see some progress! I forget if you mentioned it earlier, but what crank/pistons are you planning to use?

Every time I see this thread it makes me want to throw away my megasquirt parts and just buy some webers, that thing is going to sound soooo mean. Keep up the good work!

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Here's how the workbench sits right now, you can see the diff is pulled apart waiting for the limited slip pumpkin ..... I'll be running an E21 open case with a E36 318 pumpkin, will hopefully have full write up before the month is out.

What ratio are you going for(?), I know manual 318s are 3.45. I assume the "pumpkin" you're referring to is the LSD pack. Aaron's car is boat loads of fun with the stock 3.64, traction is a problem when ever I want it to be :)

Can't wait for the write up, please go into great detail about setting the lash. I'd like to put a 4.1 in my volvo, but everyone tries to scare people away from ratio swaps b/c of the bearing pre-load.

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I'll try and do as detailed a conversion as possible. Very fortunate to have Rob of Precision Gearing acting as consultant.

tinkwithanr- After going over it, I'll probably end up using a set of new Mahle 89.5mm 8.8:1 "i" pistons. UNLESS I can somehow find a set of the early euro "i" 9.7:1 pistons in half-over, if you come across a set please let me know. You've got me confused with what engine you're planning on, saw something involving a larger motor?

Manimal - Yes with the 3.64 (your description reaffirms that decision). One benefit is that that was the ratio in the open E21 diff to start with, so it's already shimmed to size. Correctly measuring the shim sizing (side covers and pinion) with a ratio is something I probably won't cover. You've got an email.

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89.5mm pistons in an m20!? lol, I'm guessing you mean 84.5 (0.5 overbore)? I'll let you know if I see any HC euro pistons, but I've only seen one set for sale ever, so I'm probably not the best source. Either way, looking forward to more progess.

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Ha, long day yesterday I guess. For the pistons, I've learned the more eyes looking, the better.

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Thanks Tito,

Things have been moving along slowly. Here's how the workbench sits right now, you can see the diff is pulled apart waiting for the limited slip pumpkin ..... I'll be running an E21 open case with a E36 318 pumpkin, will hopefully have full write up before the month is out.

IMG_3632.gif

I am very interested in doing this, as i have an E36 LSD laying around at the shop. Are you going to put the whole E36 pumpkin in the e21 casing? or just the actually limited slip component?

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I am very interested in doing this, as i have an E36 LSD laying around at the shop. Are you going to put the whole E36 pumpkin in the e21 casing? or just the actually limited slip component?

It's been a bit slow going, but I will have a pretty lengthy write-up soon. I'm sorry for the delay.

Bullet points....

-Differences in the E21,E30,E36 LSD units

-Bearings pre-load (and how to compensate for ratio changes)

-Yes, the E36ti (168mm) diff will fit in an E21 open case, WITHOUT modification to either the case or the pumpkin. (little trick).

Here's a small pic preview

E21 pumpkin guts as compared to E36ti Pumpkin guts.

IMG_3833.jpg

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looks great andrew!

care to elaborate on how to fit the e30 strut housings to the 2002? how are they modified? you using e30 brakes as well, or the 2002 with some sort of hub/bearing adaptation?

thanks!

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