24V AWD Swap Knowledge Base

[LJ851]

Not in the front view projection.

The dynamics are not existing in only front view projection. I am tired of trying to explain this, you are wrong.

[The Dark Side of Will]

EDIT:

If you have a tie rod by itself... bolt down the inner end and move it through its range of motion. The tip will sweep out an arc and the rod itself will sweep out a plane.
Move the inner end a known distance perpendicular to that plane.
Lengthen the rod according to pythagorean theorem.
The tip of the longer rod can trace EXACTLY the same arc the shorter rod traced. However, the longer rod sweeps out a cone instead of a plane.

The same thing applies if the original rod swept out a wide angle cone and the longer rod sweeps out a narrow angle cone.

[nando]

don't be so defensive. he's trying to help.

anyway, the engine should be horizontal when installed in a car - which is how it was mocked up (sitting on the ground, oil pan flat basically). remember, I'm using a Gertag 260 - to use the original E30 ix mounts, I can't have the trans at some weird angle or 1.5" further back. :p

[The Dark Side of Will]

Yeah, but is that the attitude the crossmember has when it's bolted into the body?

Nisse did the same mockup and thought that it looked like it would fit... but it doesn't.

See edit above, also.

[The Dark Side of Will]

engine is still about 1/4-1/2" back than the M20 at this point, but that's probably doable without messing with the firewall:

what I'd really like is a bellhousing face to subframe measurement for the M20 ix to see how this relates to the stock engine placement.

here's all my mockup pics:
http://www.325ix.com/photos/index.ph...Engine_Mockup/

Thanks for the link to the album.

The E53 diff hits the rack also... would have thought the E53 would be much worse than the E34 setup.

It doesn't really matter where the bellhousing ends up. What matters is where the back of the cylinder head ends up.

It matters to you because you're trying to use the stock T-case & mount... but that's not what really determines where the engine fits.

I'd still like to do the crossmember, as I have a 332iX project with an S52 and 4HP22/24 waiting after my S62 install, and I'd like to be sure I can use the E53 6 cylinder sump.

EDIT: and with a teensie bit more thought, I see that I'm in the same boat as you in that I will need to keep the bellhousing face in the same location so that I can use the original T-case mount.

Of course all that's out the window with the V8 swap and frankendrivetrain.

[The Dark Side of Will]

what I'd really like is a bellhousing face to subframe measurement for the M20 ix to see how this relates to the stock engine placement.

15 5/8" from the bellhousing face to the REAR edge of the bottom surface of the crossmember (NOT the bumper) on a stock 325iX.

E30 pan:
Bellhousing face to axle centerline: 10 1/8"
Bellhousing face to front of sump: 14"

E53 V8 pan:
BH face to axle CL: 10 3/4"
BH face to front of sump: 14 5/8"

E53 I6 pan:
BH to axle CL: 11 1/4
BH to sump: 15

BH to CL of axle:
~11 3/8"
BH to front of sump:
15 1/4"

So if the stock E30 sump length is 14" and it's 15 5/8" to the edge of the crossmember, AND the E34 sump is 15 1/4" long, then the bumper/crossmember/steering rack/whatever's in the way will have to move forward 1 1/4" to maintain the same relationship to the front of the sump.

As the E34 has the longest sump, if I move the rack & bumper mount forward far enough to clear it, everything else will be gravy :D

So now I need to go snag a couple of pics of the bellhousing to cylinder head relationship on my dad's S52 and compare it to the M20 to see where the back of the 24V cylinder head will end up compared to the M20 cylinder head.

[nando]

Yeah, but is that the attitude the crossmember has when it's bolted into the body?

Nisse did the same mockup and thought that it looked like it would fit... but it doesn't.

See edit above, also.

Yes, the subframe sits flat in he car.

Nisse had it too far back to clear the firewall. Also, if you match the m20 bellhousing location, by extension the motor will clear too. :)

Thanks for the measurement, I'll check that vs my mockup and see how far off i am using he E46 rack.

[Nisse Järnet]

Basically... how far forward does the engine have to move in order to be out of the firewall? How far forward of where it sits now would you want it to be in a finished swap?

That's pretty much the only thing I need to know in order to figure out how far to move the rack.




Cool!



Wouldn't hurt... the M60 swap guys frequently do it... but wouldn't help anything either. Like Nando said, the pan would still hit the rack.

Its hard to say 100% now when i already banged the firewall hehe but i think at least 3cm, maybe 4 if your on rubber mounts.

[Nisse Järnet]

Yeah, but is that the attitude the crossmember has when it's bolted into the body?

Nisse did the same mockup and thought that it looked like it would fit... but it doesn't.

See edit above, also.

Before i threw out the M20 i measured the crank centerline in the front (hight/width) and the TC output flange centerline and now using those measurments to align the M50 engine/gearbox/TC.

I would like to lower the front of the engine ~1cm though, that would make things easier! Specially with the firewall clearence.

[The Dark Side of Will]

Great to hear you measured the crank position first
Is the center of the M50 crank higher than the M20's was?

Yes, the subframe sits flat in he car.

Nisse had it too far back to clear the firewall. Also, if you match the m20 bellhousing location, by extension the motor will clear too. :)

Thanks for the measurement, I'll check that vs my mockup and see how far off i am using he E46 rack.

On the M20, the bellhousing mounting face is basically flush with the back of the cylinder head, right? Is the same true of the 24V engines? In a typical RWD 24V swap, does the bellhousing face move forward?

[Nisse Järnet]

Great to hear you measured the crank position first
Is the center of the M50 crank higher than the M20's was?



On the M20, the bellhousing mounting face is basically flush with the back of the cylinder head, right? Is the same true of the 24V engines? In a typical RWD 24V swap, does the bellhousing face move forward?

Not sure, have to measure! But i think the pan is a little shallower over the rack on the M20. Will see if i can cut/weld/trim the M50 pan over the rack area!

On my RWD E30 M50 the bellhousing face is pretty much as it was with the M20, the head almost touches the firewall.

[nando]

Why would the crank centerline move? They're basically the same engine family. Heck, they made a getrag 260 that works on an m50 by just rotating the bellhousing a few degrees.

[nando]

On the M20, the bellhousing mounting face is basically flush with the back of the cylinder head, right? Is the same true of the 24V engines? In a typical RWD 24V swap, does the bellhousing face move forward?

M50 is basically an M20 with a different head, so yes.

[flyboyx]

chris, why do you say that the e46 rack would only need to be moved forward .5 inch? i guess its hard to tell in those photos, but apparently there is more clearance? honestly, i would say that if thats the case, it would probably be the best thing we have going at this point. assuming the geometry is acceptable of course.

[nando]

yes. the E30 rack severely conflicts with the E34 differential, the E46 rack doesn't.

I think it's also a question of which is worse - bump steer increase from moving the rack, or from changing the length of the rack? however the E46 xi rack has the advantage of being a lot quicker/more responsive than the E30 ix rack. And also if we can get tie rods that will work.