M42b18 stroker + turbo junkyard/redneck/cheapskate build

[JuliusE30]

Hello guys, been folowing this forum for a while, and decided to finally make my first post.
So i have 1988 e30 318i coupe with no engine and e36 m42b18 engine at my disposal, so i figured why not putting them together.
After reading some post in this forum i decided to make a stroker out of it, and while im breaking all engine apart for rebuild why not putting a snail on it too? Im i right?
So the deal is i have a friend who works in the junkyard, so i get all the parts allmost for free. I got the m47d20 crank, m40b18 rods and pistons set , m54b30 conrods set , m52b28 pistons set for like 30 american greenies and +20 money thingies for 6 speed zf gearbox.
I dont have a turbo yet, because i have no idea what kind of turbo i need, but its not a problem cus there is plenty to choose from
So the idea is to mix and match oem parts to get drivable "something" as cheap as possible. This build is for shits and giggles, if it explodes - no biggie, but it would be nice if it stay for a while.

I just started my build and i already dickered some things that i need some help , and by the way this is my first engine build so take it easy, ok?

1 thing i disassembled the motor like 2 years ago, then life happened and then i lost all my pictures that i took during the butchery, and i can remember how to put  the main bearing caps back in order, s/n are diferent on each of them, googled - nothing. Help some one!!!!

2 thing i didnt dickered but the question would be which conrod is stronger m40b18 or m54b30? Got both m40 looks beefier, but looks might be deceiving.

Writing from my phone so when im back at home ill put some pictures, and fill you in in tge details what im after for.

Take care, Julius.

[Warsteiner]

Hey JuliusE30,

This is a tough one.....as I've said over the years to many people, Do your math. Then do your math again.

It doesn't matter what looks "beefier", it's what will actually fit into your math equations to make it work.

You need to plan out the whole build before you get any more parts. Especially if you plan on doing a turbo.

Do some reading. There is lots of info on this forum and others. There is no "one magical solution" to your project. You can make lots of things work you just need to do the math to make sure they'll fit properly.

Maybe someone who did a turbo will chime in and give you a starting point for a good "recipe"

Good luck with your build. Keep us posted on your progress.

Cheers,
~Ralph

[Warsteiner]

JuliusE30,

Here is an example of the stock M42 set up.

Desired Compression Height = Block height - (Stroke/2) - rod length
Desired Compression Height =*   ** * * **212mm - (81mm/2) - ((140mm[Honda rod]-.15mm{protruding out of block}))

212-40.5-139.85= 31.65

31.65mm is your stock compression height.

For a turbo you will probably have the piston recessed into the block a bit. So what compression will you be running? Well that all depends on the pistons, rods, head gasket and the crank. Are you shaving the block?

There are a lot of calculations.

Cheers,
~Ralph

[JuliusE30]

Hello , been busy, had to do a lot of body work on my friends cars, so i had no time for this project and my garage doors was frozen solid for almost 2 weeks ( but managed to break in today  )

So back on the project

I spend quite some time looking for information on the internet, but every  time i came across this topic there was lots of mixed information and decided to measure it myself. So today i had couple spare hours and i measured volume of combustion chambers and they were quite close to each other so i wont make any changes.

https://ibb.co/N2CX5Tp

the most important discovery i made was piston dish volume, i found  diferent measurements on the this forum , but mine was 10 cc , i measureded 3 times.

https://ibb.co/b2CB84N

next thing i compared stock conrods of m42b18, m40b18 and m54b30* . m40b18 and m54b30* are the same length 135 mm and m42b18 is 140mm

in this picture m40 conrod is on top and under it is m42 conrod

https://ibb.co/M9R7X9H

closer (top m40 below m42 )

https://ibb.co/jDbXMgS

i also droped in m47d20 crankshaft , m40b18 conrods and m42b18 piston into the engine just to check how it looks and all asembly is aprox 1.3 mm below the deck.

With all this information  i typed the digits to calculator and i ended up with this.

https://ibb.co/WPXnsk4

My plan is runing on low boost 0.6-0.8 bar on pump gas, here where i live E95 and E98 is in every gas station, 20 min away i can get E85 ( it would be better if i could run without E85, less modification needed) so maybe can somebody fill me in if this kind of fuel is good for this compression ratio ?

I'm also planing put o-rings and stock gasket any thoughtson this ?
Also modified m44 oil pump to eliminate chain sprocket ( i have spare m43 oil pump that im going to cut and weld CPS bracket to m44 oil pump) any tips on that ?


Edit : i cant post pictures so this post looks quite strange and also * marked my mistakes from before
Edit 2 : hope this helps

[JuliusE30]

Can somebody help me with how to post pictures?  my post would make much more sense

[bmwman91]

Upload the pictures onto a hosting service, or something like Google Drive. You can then link them in your post. If you click the Reply button at the bottom, rather than use the quick reply box, you'll get the full editor. Paste the URL text into the post, select it, and click the Insert Image button at the left of the editor options. That will insert the image tags around the URL, and it should display in your post.

[JuliusE30]

Still couldnt post pictures , so just added links to them, hope now all makes sense, please take a look and corect me if im anywhere wrong

Julius.

[JuliusE30]

Hi, I ran into ANOTHER problem, i cant find where to buy m42b18 (M44B19) main bearings its out of stock and the store have no idea when they gonna be available again, so i was wondering is there any other options that i could drop in without any machining ? maybe M47D20, does they fit  ? Maybe somekind of bearings with 360 oil groove and full thrust bearing ? maybe M47D20, does they fit  ? M50BXX  ?

i know there is king racing option, but in my country they are realy expensive.

 I'm always trying to use search before asking ,but didnt came up with anything in particular, it would be nice to have a pinned post on this kind a information that is confirmed and tested.

Well back to the drawing board i guess....

[JuliusE30]

Sorry , been busy, and been collecting more parts, received ARP head studs ( had to buy m50 ones, because m42 set wasnt available), still waiting on COMPLETE gasket kit ( top and bottom end) , main bearings, and conrod bearings, new BMW OEM rod bolts, should be here this week fingers crossed.

Also made a CPS adaptor for M44 oil pump, still waiting to be 3D printed so i can check if its in correct location and if not make some changes.
https://ibb.co/sWkTTFm
Also planing on 3D printing an exhaust manifold fabrication kit so when i assemble the engine i could start to design turbo manifold as soon as possible. planing on 42.4mm diameter 2mm wall thichnes 304 stainless steel, do you think its enough ?

I was looking for bearing clearances and only success was for main bearings (0.02mm - 0.058mm), maybe somebody knows what clearance should be on the con rods ?
Piston ring gaps ? stock NA and for turbo application ?
Thanks in advance.

[JuliusE30]

Hello, i know its been a while, but as usual life happened, and i had some other stuff to do, but i finished to repaint and assemble the engine, everything went better than expected (fingers crossed every thing gonna be fine), ill post pictures right below.

[JuliusE30]

Made camshaft aligment using a carpenters square straight edge 😀
https://ibb.co/0ttYdzb

Replaced chain, chain tensioner, some of the slides, did the timing.
https://ibb.co/hV8022r

Al new gaskets
https://ibb.co/b6X0WRD

"All" finished
https://ibb.co/LQ05xtT