BMW M42 engine swap into Manta?

52354 Views 131 Replies 37 Participants Last post by cadence, 13 d ago

cadence

Discussion Starter · Jun 22, 2009

Has anyone looked into using a bmw M42 4 cylinder engine?

I am buying a parts car for body and interior panels for my 91 318is and it has a working, complete, m42 with getrag 240/5sp transmission. I know that the opel getrag will bolt in using parts from OGTS. i was wondering how different the mouting points and/or output shaft are for the bmw getrag 240. Its front sump so i will have to start measuring to see if the motor will even fit. but i thought i would put this out there first.

it makes 140hp/130ftlbs torque crank for that amount of power with a modern direct fire ignition and fuel injection for basically free. i think it would be a better candidate than dumping loads of money in the stock motor for comparable power.

1 - 20 of 132 Posts

RallyBob

· #2 · Jun 22, 2009

I would think it would be a very tight fit. It's angled over as installed in a BMW, and as well it's quite a bit wider with the manifolds and twin cam head.

If you straightened up the block so it was upright, you'd have a few more issues...it would end up being significantly taller, the manifolds would have to be modified/reconfigured, and the oil pan and pickup would also have to be modified to avoid oil starvation.

I've built a few headers for these engines and they're not easy to work on!

jtb

· #3 · Jun 22, 2009

Ha! This is a coincidence. My brother just sent me an ad from a guy in our little town who is selling an M42 engine and trans, and my brother was thinking about swapping it into the GT. On the plus side, M42s are light, and the intake and exhaust are on the same sides as the opel, but I haven't even seen it yet so I can't say whether it would fit or not. I think RallyBob raises some valid points, but any swap is going to have its challenges! The question is are you ready for this much of a challenge!?

Good luck if you decide to proceed!

jtb

BMWonly

· #4 · Jun 22, 2009 (Edited)

jtb said:
On the plus side, M42s are light, and the intake and exhaust are on the same sides as the opel, but I haven't even seen it yet so I can't say whether it would fit or not.
jtb

The M42 (like most BMW engines) is a crossflow motor, with the exhaust manifold on the same side as the Opel's, but the intake is on the other side.

It is a pretty tall motor, even in a 3 series the engine had to be tilted. The intake runners sit very high. It would be an excellent motor for a GT, though, if you can make it fit.

Dieter

jtb

· #5 · Jun 22, 2009

BMWonly said:
The M42 (like most BMW engines) is a crossflow motor, with the exhaust manifold on the same side as the Opel's, but the intake is on the other side.

Whoops! You're right, of course. I've never actually had an opel engine, that's my excuse.

baz

· #6 · Jun 22, 2009

i had the 2800 six pot in my GT for a while so i dont see why the 4 would be a hard swop

gear box is the hard part to get in

cadence

Discussion Starter · #7 · Jun 22, 2009 (Edited)

http://i112.photobucket.com/albums/n200/petebee/DSC01262.jpg

http://i112.photobucket.com/albums/n200/petebee/DSC01263.jpg

http://i112.photobucket.com/albums/n200/petebee/DSC01264.jpg

here is what it looks like. These aren't my pictures just a representation

I will be measuring tomorrow i have the manta and the 318is parked right next to each other out at my dads house.
the big plus for me and this swap is that i will have a running and driving 318is to crib off of while doing this swap

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ManBearPig

· #8 · Oct 12, 2009

cadence said:
http://i112.photobucket.com/albums/n200/petebee/DSC01262.jpg

http://i112.photobucket.com/albums/n200/petebee/DSC01263.jpg

http://i112.photobucket.com/albums/n200/petebee/DSC01264.jpg

here is what it looks like. These aren't my pictures just a representation

I will be measuring tomorrow i have the manta and the 318is parked right next to each other out at my dads house.
the big plus for me and this swap is that i will have a running and driving 318is to crib off of while doing this swap

did you ever get to measure?

cadence

Discussion Starter · #9 · Oct 23, 2009 (Edited)

ManBearPig said:
did you ever get to measure?

finally got the car so i am able to measure it.

its kinda hard to get spot on measurements with it in the car but this is what i came up with

from highest point on motor to the bottom of the oil pan it is
28.5"

from one motor mount location to the other it is
25.5"

from the back of the engine to the edge of the front pulley it is
22.5"

these are rounded to the nearest half.

here are some pictures of the engine bays. i tried to match the height and location on each.

I was able to get the bmw for free because it was about to get towed by the city. it has quite a bit of body damage and the front suspension is shot in every way but it runs good. other than the strut towers the engine bay size is very similar.

I also got a set of bmw ellipsoid headlights i am going to try to retro fit.
http://i6.photobucket.com/albums/y202/CruceE1Rubicon/IMG_0465.jpg

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2

blancojp (R.I.P.)

· #10 · Oct 23, 2009

cadence said:
Has anyone looked into using a bmw M42 4 cylinder engine?

I am buying a parts car for body and interior panels for my 91 318is and it has a working, complete, m42 with getrag 240/5sp transmission. I know that the opel getrag will bolt in using parts from OGTS. i was wondering how different the mouting points and/or output shaft are for the bmw getrag 240. Its front sump so i will have to start measuring to see if the motor will even fit. but i thought i would put this out there first.

it makes 140hp/130ftlbs torque crank for that amount of power with a modern direct fire ignition and fuel injection for basically free. i think it would be a better candidate than dumping loads of money in the stock motor for comparable power.

Not being Johnny Raincloud here but the oil pan will be a major issue. The sump will be right over the steering rack and crossbar on a Manta /Ascona.

cadence

Discussion Starter · #11 · Oct 23, 2009 (Edited)

blancojp said:
Not being Johnny Raincloud here but the oil pan will be a major issue. The sump will be right over the steering rack and crossbar on a Manta /Ascona.

E36 m42 Oil pans are rear sump if i had problems i was going to swap out with one of those.
i also have a slim civic radiator to give more space in front of the motor. and will be using an electric fan.

cadence

Discussion Starter · #12 · Nov 11, 2009 (Edited)

Well, started pulling the engine on the bmw. The wiring is very simple. All the engine wiring, ecu, alternator, and starter is in one harness with a single plug to connect the power grounds and ignition switch to.

Here is a crappy cell picture of the progress.

http://i123.photobucket.com/albums/o281/sidv66/SSPX0087.jpg

cadence

Discussion Starter · #13 · Nov 12, 2009

motor is out

http://i123.photobucket.com/albums/o281/sidv66/img1257990150022.jpg

http://i123.photobucket.com/albums/o281/sidv66/img1257990167173.jpg

cadence

Discussion Starter · #14 · Dec 2, 2009

Here is a picture of the self contained wiring harness. Power cable to battery from alt., ecu plug (long Skinny), and body plug (big Round). the body plug contains 15 wires more than half of which are for the instrument cluster, and diagnostics. I will need to wire in a couple grounds, start signal, switched power, constant power and fuel pump. The relays for starter, fuel pump, and ecu are already built in to the harness.

http://i123.photobucket.com/albums/o281/sidv66/DSCF0173.jpg

and just some random pictures of the motor
http://i123.photobucket.com/albums/o281/sidv66/DSCF0170.jpg

http://i123.photobucket.com/albums/o281/sidv66/DSCF0164.jpg

http://i123.photobucket.com/albums/o281/sidv66/DSCF0171.jpg

DennisGardiner

· #15 · Dec 3, 2009

Looks Good.

Have done a few different engine swaps in my day, while keep the EFI from that same engine.

My only advice to you is to get a BMW Factory service manual for this car/engine with a good wiring diagram.

Don't get a Chiltons (or the alike) they generally will not answer the hard questions that you will run into, like... "What the @!?#% does this wire do",
or "Why won't the @[email protected] engine run"

Been there,... Done that!!

cadence

Discussion Starter · #16 · Jan 19, 2010

progress is slow going. I am surprisingly busy this winter. I finally got around to removing the engine from the manta, and taking engine bay measurements. from the crossmember to the hood bmw = 20 1/2" manta = 20" much closer than i expected. the length of the transmissions and engines are almost identical. i was too tired to write anything down last night but i will get some good measurements and better pictures soon.

http://i123.photobucket.com/albums/o281/sidv66/Cars/img1263866002699.jpg

cadence

Discussion Starter · #17 · Jan 19, 2010

also i was wondeirng if anyone had any ideas on a drive shaft for this thing. the bmw uses a guibo rubber mount between the driveshaft and the trans and a center bearing with a slip yoke in the middle of the driveshaft.

http://www.pelicanparts.com/bmw/catalog/images/BMW_Tranny/E30_guibo.JPG
Replacing the driveshaft bearing - Bimmerforums - The Ultimate BMW Forum
http://bokchoys.com/differential/pictures/flex_disc_support_driveshaft.jpg

opelnut10

· #18 · Jan 19, 2010

BMW driveshaft

My suggestion is to leave the front of the driveshaft as it is to bolt up to the BMW transmission and make up the rear to the right measurment with a u-joint to bolt up to the Opel torque tube/propeller shaft, unless you are going to change out the rear end for something else.

cadence

Discussion Starter · #19 · Jan 19, 2010

that is what i had planned but was worried about the spring inside the transmission to hold the torque tube shaft in place on the driveshaft does that always need tension?

opelnut10

· #20 · Jan 19, 2010

BMW driveshaft

No, the spring only keeps the front yoke from going up on the output shaft too far, your rubber mount does the same thing and absorbs the movement of the rear end housing and cushions the connection to the rear of the transmission.

1 - 20 of 132 Posts