Author Topic: Is my m42 e30 or e36? (Read 3813 times)

mcibmw533 · « **on:** February 15, 2012, 02:29:19 AM »

I know this is a newb question (fitting for a first post right), but I've spent the last couple hours searching and haven't found a definitive answer on my own.

I recently purchased a '91 318is and the PO said that it had an m42 swapped from a '96 318ti. From the info I've found so far, that means it should be an m44 then, right? Also, based on all the photos I've seen, it looks like my intake suggests it's an e30 m42.

Can somebody please tell me what I have, please see photos at the link below (I can't seem to get these to upload), or where I can look to see numbers to find out the specifics on this motor? I want to do all the typical maintenance items as well as some other stuff and don't want to buy the wrong parts.

http://i3.photobucket.com/albums/y53/mcibmw533/100_0434.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/100_0432.jpg

Thanks,

Micah

d.hitchcock · « **Reply #1 on:** February 15, 2012, 07:55:22 AM »

It looks exactly like the M42 in my car, fwiw.

DesktopDave · « **Reply #2 on:** February 15, 2012, 08:02:14 AM »

Definitely looks like an original M42 to me, but the PO might have swapped the intake manifold onto the newer motor. There were no M42s made in '96 AFAIK. OBDII was required that year; BMW used the M44 to meet those standards. I'm thinking you have a later model M42 with e30 manifolds, coils and (maybe) the v-belt accessory drive. Can you take a picture of the belt drive?

It's actually a bit difficult to tell if it's an M42 or M44. They look very similar. The M44 used a rear crank position sensor, MAF instead of an AFM, the later DISA intake manifold, as well as the serpentine belt setup. Another difference is the presence of two knock sensors on the head under the intake.

mcibmw533 · « **Reply #3 on:** February 15, 2012, 11:20:59 AM »

Thanks for the input so far, I'll grab some photos of the belt drive today and upload them tonight.

-Micah

DesktopDave · « **Reply #4 on:** February 15, 2012, 12:55:10 PM »

The upload is disabled or broken...I paste Photobucket thumbnail links into posts.

mcibmw533 · « **Reply #5 on:** February 16, 2012, 01:14:31 PM »

I've attached the links to some photos I took this morning. They're not the best, but hopefully they give you enough to get a better idea of what it is. And that's not fluid or coolant running under the motor in some of the pics, it's rain water on the asphalt below (it's raining here this morning).

http://i3.photobucket.com/albums/y53/mcibmw533/100_0821.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/100_0823.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/100_0824.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/100_0826.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/100_0836.jpg

Thanks,

Micah

DesktopDave · « **Reply #6 on:** February 16, 2012, 06:41:42 PM »

Looks exactly like my e30's early motor (except mine's missing two of those belts...) Later ones have two large flat serpentine belts instead of the three v-belts like ours do.

There might be a casting date on the head or block to check out.

mcibmw533 · « **Reply #7 on:** February 16, 2012, 11:46:04 PM »

Alright, well that simplifies things when it comes to ordering parts. Thanks for clarifying that for me. I'll crawl under and try to see some numbers.

Thanks again.

DesktopDave · « **Reply #8 on:** February 17, 2012, 08:08:15 AM »

You could be absolutely sure if it's an M42 by pulling the cam cover off. The M42 cam directly actuates the valves with bucket tappets. The M44 uses finger followers instead, sometimes called rocker arms.

mcibmw533 · « **Reply #9 on:** February 23, 2012, 10:27:18 PM »

I greatly appreciate all the assistance so far, hopefully this will be the last of my questions regarding this issue. I just want to be sure I get the right information so I don't order a bunch of wrong parts.

I pulled my valve cover (err, "cylinder head cover" per Bentley) this afternoon and shot some photos (see links below). I'm guessing it's the bucket tappets of the m42? I don't see the rocker arms that I've seen in the American iron I've seen before. I was able to see a date stamp of "94" on the tray piece in the head, that the cam sits in (not sure what it's actually called), if that makes any difference.

Also, I noticed that not all of the bolts around the perimeter (13, I think) are the same. Some have only a short length of threads, then they mushroom out to help retain the gasket - looks factory. Others (4, I think) are threaded all the way to the head and have a piece of wire going along next to the bolt shaft, separate from the bolt, but partially wrapping it. It looks like this would damage the threads, but I didn't notice any scarring of the bolt threads. Is this some sort of hack mechanic fix for stripped threads in the head of the motor, or making up for lost bolts? I've attached a photo of the wire that remains on the engine side for reference.

Also, if anybody sees anything else that looks suspect in any of the pics, please let me know. I have a big list of parts I plan on ordering from Pelican (or similar) soon and want to try to get everything in one shot so I don't have to wait on a couple parts in the mail.

http://i3.photobucket.com/albums/y53/mcibmw533/IMG_2618.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/IMG_2620.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/IMG_2624.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/IMG_2627.jpg
http://i3.photobucket.com/albums/y53/mcibmw533/IMG_2629.jpg

Thanks,

Micah

DesktopDave · « **Reply #10 on:** February 24, 2012, 07:10:02 AM »

That's definitely an M42. The M44 wasn't produced until late '95. In our M42 the cam lobe slaps the valve buckets directly. Helps to save reciprocating mass & allows the motor to rev faster. The M44 has a rocker arm under the cam that's called a "finger follower." Both are hydraulically adjusted. Rocker arms setups like a domestic smallblock are only used when you have to convert an up motion (pushrods) to a down motion (overhead valves).

The "wires" you see on the bolts are the stripped alu threads from the bolt holes in the head. Those little bolts need very little torque to hold the gasket in place. Everyone over-tightens them. There are only two ways to fix it if the bolts won't hold...first, get some heli-coil inserts for those size bolts, then drill & tap & screw the inserts in. That will permanently fix the problem.

I've never seen this done, but another potential solution is to remove the bolts and install studs like the older BMW motors. You'd need short matching studs, locking compound & acorn nuts to hold that all on. I'd head to a salvage yard for that..find an old 735i & strip the fasteners out of the head...I haven't seen anyone do that though, the heli-coils are cheap & easy.

mcibmw533 · « **Reply #11 on:** February 24, 2012, 03:21:23 PM »

Thanks now I can get all my parts ordered up and it looks like I'll be adding an order from McMaster Carr to the list as well. :cool:

Thanks for all the insight.