'89 325i + m30 + 4hp22 build

[n3nyongmini]

OK before anyone asks, I'll lay it out here - I'm doing an AT swap because I haven't seen many others doing it, if at all. I am using the 4hp22 that I have at the moment; future plans may include a 4hp22EH swap.

If you want to discuss the pros and cons of MT vs. AT please do it somewhere else or PM me if you'd like.

I'll be more-or-less following FrankM e30's guide, but here are the big parts:

1989 325i automatic coupe with about 200k miles, very well maintained by the previous owner and his father (original owner from new). I've got the receipts back to the mid-90's or so. Just about all of the wearing parts have been replaced at least once.

A complete m30b35 out of a 1990 535i automatic with the harness cut just beyond the injector harness cover. I was told by the seller that this was in a car that was totalled in 1993 with 36k miles and has sat since then, mostly in the car, but out of the car for the last two years. The VIN he gave me checked out with AutoCheck (THANK YOU Mercury[BKM] !) with the same dates and mileage. There isn't a VIN sticker on the motor, but I haven't found evidence that the seller's story isn't true based on the condition of the engine and parts.

4hp22 from the 325i.

The car (with the m20 and 4hp22 on the hook):



The motor:

[n3nyongmini]

Plugs taken out, cylinders given some oil and motor turns over easily. Valve clearances checked and lobes greased:



New rear main seal - old seal showed no sign of seepage. Corrosion on block is from when the motor sat so long in Houston humidity.



OK here it is ready to go in:



Before I put it in I removed a few key pieces to maneuver easier; pull-ups and harmonic balancer, passenger side motor mount arm and AT dipstick/fill tube.

On the rearmost mounting position, mostly likely a 2-1/2, it put the AT about 15mm further back than where it was originally with the M20. After reattaching the original driveshaft with the 4-6mm preload, the CSB sits with the attaching bolts "on the other end" of the oblong holes. In all, I am very pleased with the fitment:



Currently wiring, using the M30 harness (which was cut off just as it exits the injector harness cover) and matching wire colors and using Mitchell diagrams:



The wires running off to the driver side (picture right) are the relays and M20 diagnostic connector, which I intend to use.

[uturn]

Looks great! What engine brackets are you going to use? Also I think the tranny from your 3 won't fit right. The bell housings are offset for the different motors.

[n3nyongmini]

Looks great! What engine brackets are you going to use? Also I think the tranny from your 3 won't fit right. The bell housings are offset for the different motors.

eBay brackets, Made in England.

You are correct on the bellhousing; I switched out the e30 4hp22 bellhousing for one off of an e34. The back of the m20 and m30 are different.

[CorvallisBMW]

I like the idea actually, the AT makes good use of the m30 torque. Would be a great DD.

Will the trans fit in the tunnel though? And what about driveshaft length?

[slammin.e28]

M20 and M30 4hp22s are also different with respect to the output shaft flange. So, if you space things properly, you could use your unmolested e30 driveshaft. BRILLIANT!

[n3nyongmini]

Will the trans fit in the tunnel though? And what about driveshaft length?

I believe some tunnel "clearancing" might need to be done at the tail end, and the driveshaft I have might need to be spliced with another half to work, but since I couldn't find any write-ups for this particular combination, it will be an "in situ" determination.

On the other hand, FrankM e30's write-up mentions that he replaced his driveshaft with a rebuilt unit of the same spec/length and was still able to fit the driveshaft properly in the "2.5" position he used.

I don't know if there is a length difference between the 260/5 and 260/6, but if there isn't I should be OK with the driveshaft I have since I'm not changing transmissions per se, just bellhousings. FWIW I re-used the torque converter and flex disc from the e30 and fit-up to the m30 was good, so I don't think the bellhousing swap will affect overall engine/AT length.

[Robotin]

i dont really understand the point of swapping an AT into a car. unless you had some kind of physical/mental disability.


but whatever. dope build. love m30e30s.

[slammin.e28]

I believe some tunnel "clearancing" might need to be done at the tail end, and the driveshaft I have might need to be spliced with another half to work, but since I couldn't find any write-ups for this particular combination, it will be an "in situ" determination.

On the other hand, FrankM e30's write-up mentions that he replaced his driveshaft with a rebuilt unit of the same spec/length and was still able to fit the driveshaft properly in the "2.5" position he used.

I don't know if there is a length difference between the 260/5 and 260/6, but if there isn't I should be OK with the driveshaft I have since I'm not changing transmissions per se, just bellhousings. FWIW I re-used the torque converter and flex disc from the e30 and fit-up to the m30 was good, so I don't think the bellhousing swap will affect overall engine/AT length.

It should be fine. Your car started as an auto, correct? You should only need to swap the bellhousing on the trans. Everything back should be the same. Otherwise, the M30 4hp22 tail shaft flange is different and requires A) swapping it for an M20 cars tailshaft, B) swapping the driveshaft for an M30 cars front section.

I know this because we tried swapping a bellhousing on a 4hp I had from an M30 to an M20 car (e28s) and everything fit except the M20 cars driveshaft to the trans output shaft.

[n3nyongmini]

It should be fine. Your car started as an auto, correct? You should only need to swap the bellhousing on the trans. Everything back should be the same. Otherwise, the M30 4hp22 tail shaft flange is different and requires A) swapping it for an M20 cars tailshaft, B) swapping the driveshaft for an M30 cars front section.

I know this because we tried swapping a bellhousing on a 4hp I had from an M30 to an M20 car (e28s) and everything fit except the M20 cars driveshaft to the trans output shaft.

That's what I found as well - the motor & trans are currently together on the floor waiting for install. Oh and also used bellhousing bolts from e34, as the sizes/lengths are different as well.

[slammin.e28]

Were you doing a high stall torque converter too? Todd at TCD has one that's pretty amazing for drag racing.

[n3nyongmini]

Were you doing a high stall torque converter too? Todd at TCD has one that's pretty amazing for drag racing.

One fight at a time, Padowan.

Sent from my DROID RAZR using Tapatalk 2

[Stanley Rockafella]

I like the idea actually, the AT makes good use of the m30 torque. Would be a great DD.

[Stanley Rockafella]

i dont really understand the point of swapping an AT into a car. unless you had some kind of physical/mental disability.

I LOL'd!

[navytapaul]

I'm curious about this as I was considering doing this swap also. Any progress?