M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: ronan on December 09, 2014, 12:29:36 AM
-
Hello so I have been lurking for a while now reading all these great posts about motor builds and boom there goes my engine so I guess I will make one of my own! A little intro of me and my car. My name is Josh and I have owned my e30 318is for almost 2 years. Replaced upgraded everything but the motor.
So here is what I have so far. Lost the bottom end on my m42. Happen to have a spare m44(which I thought was a m42 until I removed the valve cover, came with a transmission I needed). As of today I am the prood owner of 6 s50 pistons and rods.
I know I will have to skim the pistons to make them work and I will post up some of my math later to make sure I am doing it right. My question is is it better to skim a little off the pistons and use gsr rods(I think that will work but not sure how to handle the 21mm wrist pin size please advise) or use the m44 rods and skim more of the pistons.
I almost forgot to say I am planning on using the m44 bottom end with the m42 head. I plan to send my cams off to get reground to 250/250(like Ralph's) I think that will be perfect since this is my daily. I almost had my hands on s52 cam trays and lifters this weekend also but they got away. But I will keep searching.
Any ways I am going to try and do the best build I can on a very tight budget and any and all advice is greatly appreciated.
Thanks
Josh
-
Ronan,
The small end on the rod is easily handled. You just have it re-bushed and honed to 22mm with the new bushing to fit the S50 pin. Done!
If you don't change the crank then I see no need to use the GSR rods but they could run you in $300-$400 range. Shaving the piston, cutting reliefs and re-bushing the small end on the rod is minimal. Just talk to your machine shop that will do the work. If you're not going with the M47 crank then just change your pistons with minimal modifications and call it a day.
You definitely have to do your math!!
Here is an old post of mine I found with the math done for you. Just double check it and make sure I did it right!
M3 pistons are all S50 in the Mahle catalog. But you need to refer to them as US or Euro.
Euro wrist pins are 21mm. US are 22mm.
86.0mm S50B30 US compression height 32.8mm
86.4mm S52B32 US compression height 31.0mm
S52 is based off the M52
86.0mm S50B30 Euro compression height 31.6mm
86.4mm S50B32 Euro compression height 32.3mm
No matter what, all need to be decked and pocketed for the valves as well as dished for desired compression.
I think the M44 head gasket will allow for the 86.4mm piston.
Desired Compression Height = Block height - (Stroke/2) - rod length -piston protrusion out of block
Using stock rods and M44 crank:
DCH= 212-(83.5/2) - 140 -.15
DCH= 212-(41.75)-140-.15
DCH=30.1mm
So you can use any piston of your choice as long as you make the CH 30.1mm So if you go with the US 3.2L 31mm/CH 86.4mm piston you only need to shave off .9mm, then dish it and cut the pockets for the valves. Simple!
Just to give you an idea....for my stroker I used 3.0L US pistons and 138mm rods. I spoke with TEP racing when I was considering going with JE pistons and they said that even a 28.15mm CH was ok. NOW that is with a custom piston and stock rods at 140mm on a M47 crank. It all depends on how much meat you have at the top of the piston.
Compression Height of Stock S50 Piston is 32.8mm with Honda 1.8L VTEC B18C (GSR) 138mm rod
Desired Compression Height = Block height - (Stroke/2) - rod length
Desired Compression Height =212mm - (88mm/2) - ((138mm[Honda rod] - .15mm{protruding out of block}))
Desired Compression Height =212mm - 44mm - 137.85mm
Desired Compression Height =*30.15mm
The DCH is a desirable height.
30.15mm = 212mm - (88mm/2) - 138mm -.15mm*
This tells you that your target compression height is 30.15mm and we have enough meat to shave off 2.65mm from the 32.8mm :-P
Rod needs small end bushing to be drilled to fit 22mm S50 pin.
Again.....do all your math first and then buy your parts. Or use what you have and make it work. BUT I would never deck the head to make up any kind of distance when you have so many other variables such as the HG and pistons and rods. Just my .02
Cheers,
~Ralph
-
Ralph,
Thanks so much for the help. I have read your post 20 times over the past 2 days haha.
So I ran through some examples of the formula and I think you need to add the .15 not subtract it.
For example a m42 engine: 212+.15-140-(81/2)=31.65mm. Which as far as I can tell is the correct CH value.
Since I am using an m44 bottom end, I think this is the equation: 212+.15-140-(83.5/2) =30.4mm ch value.
Does that make since?
As for the compression I was thinking of going with 10.8-11:1 ratio. How did you determine the pocket size on the piston? I have some ideas but any advice is greatly appreciated.
Thanks again
Josh
-
Hey Josh,
Anytime your piston protrudes out of the block it is a (-) negative number for deck clearance. When I built my motor my deck height was 212". For all I know that block could have been decked but I measured and had another shop measure to make sure of the math. You can definitely measure your block to see it that is a valid number and this is why I always encourage people to do their math before buying any parts to make sure it will all work. It then involves the quench zone, which depends on the HG you'll be running. But Yes.. I see what you're saying about the math and the CH. Not sure how Mahle includes their quench or deck clearance along with the HG.
I'm assuming BMW was running maximum quench on the M42 to get the most power from the best air/fuel mixture burn which in turn leads to better fuel efficiency and less timing needed so any chance of detonation is reduced. They did a pretty darn good job!
10:8-11:1 is a good place to be for a street motor on a budget build. You could go much higher but you'd have to offset with cams and then the street motor is kinda out the window so to speak.
I went with stock pocket size from the M42 piston at the proper angle since I wasn't going with any radical cams and wanted to limit the amount of material that needed to be taken off my S50 piston. The main reason I went with those pistons is because they are cast not forged. Forged will slap around the cylinder until they heat up hence the reason they need more bore clearance than a stock cast piston which is very quiet.
Hope that helps you....Go measure your block and let us know what you find. Also see if the M44 piston sticks out of the block at TDC.
Cheers,
~Ralph
-
Thanks! I will try and measure it this weekend and see what I come up with.
Josh
-
I have started thé samedi build ans warsteiner gave me the infos you have above, will jeep on été on y ou huile as mine is stop as i have on money tout put info ah thé moment
-
OK sorry the holidays got in the way. So my dad picked up the s50 pistons for me but he didnt look at them very well. They are all dinged up so they are trash. I am having trouble finding a place that can get the mahle s50 pistons. Where have you guys been getting them from? Or if you have some spares laying around let me know ;). At this point I am leaning toward just getting my m42 head reworked with the 6 mm valve out of my m44 head and bolting it up to the m44 block and calling it a day. I contacted the place that Ralph had his cams ground at and they want 650 now so I think that is out. I will keep you updated as I make progress.
Ralph do you have some pictures of your head porting? I will be doing this and have a pretty good idea of what to do but would love some guidance?
I have talked with Markd about a chip and I think I have a plan for that but it will be a bit more than I thought at first but I am sure it will be well worth the extra effort and money.
Thanks
Ronan
-
OK so I am considering maxsil pistons. Does anyone have experience with these? They are in the price range for my budget build for sure but I want to make sure they are decent pistons.
Thanks
Ronan
-
What is your opinion about Opel C20xe pistons?
-
Ok so I have ordered pistons(MaxSil) but of course on back order so another 3-4 weeks wait there. But while I wait I have turned my attention to the head. I have found a company to regrind my cams and I have got my hands on some M52 cam trays and lifters. Hopefully this week I will be able to get the exhaust cam tray welded on so I can machine the oil supply grooves. I pulled one valve out to see which valves were in my head.(Not sure what year the motor was in the car) Turns out I already have the 6mm valves!!!! Looking at the valve springs they are a single spring per valve but I don't know if they are beehive springs? Did the later M42 have beehive spring? Here are some pictures of the valve springs(installed). I also have a M44 head. Which springs would you install?
Thanks,
Ronan
-
Just keep the M42 head all intact. The M44 springs, even though they are beehive style, feel too light and I don't think they are strong enough for the buckets. An added bonus, my 6mm valve head has the lighter M50 type lighter buckets. Yours should too!
-
Well I waited 10 weeks and then canceled my order because they couldn't tell me when I would receive my pistons. So I am now going to us the m42 block instead of the m44. It is at the machine shop now getting bored to fit my used m44 pistons. Should have it back next week. They are pressure test my head for cracks and will deck it if it isnt flat. Once I get it back I will lap the valves and port match the intake to the gasket. I also aquired a single mass flywheel. Had it machined down to 16 lbs and had the m42 ring gear put on it. I have some m52 cam trays and lifters to fit but not sure I will get it done before I am ready to assemble. I have already welded up the exhaust tray but I haven't machined it yet and not sure I will be able too any time soon. I made this while disassembling my m42.
https://docs.google.com/file/d/0B45sfJYZtdxsbVRqZTdSblNNRTQ/edit?usp=docslist_api
More updates soon!
-
Hi
That video is very cool. Great actually!
No idea what you where doing though apart from teaching a little person how to play with a m42.
Nice work Rohan
-
So does the M52 have the 33mm cam trays and followers like the S50/52's?
-
Actually it references to a lot more than just M52.....
http://www.realoem.com/bmw/enUS/part?id=BG93-USA-12-1996-E36-BMW-M3&mg=11&sg=15&diagId=11_6081&q=11121436224
Cheers,
~Ralph
-
Interesting. I didn't know that. I thought the M50 had 35 and the s50/2 and now M52 had 33's. I never even considered it since everyone wanted a mint for S50/2 stuff. I'll add this to my list of upgrades.
-
Benz-tech yes it does have the 33mm lifters and does come any many other engines as Ralph pointed out. I just happened to get mine out of a m52.
-
Well I am finally making progress. I managed to get the cam trays machined and have start reassembling my engine.
Here are some pictures
https://drive.google.com/folderview?id=0B45sfJYZtdxsflduNU9US1lKbE1HXy1kelo1NmlrbHBUTllDUVBvV21NM1BZajgtaTUzVmc&usp=sharing
So one of the pistons was damaged at the machine shop. I removed the high spots and I am hoping that will not cause any further issues. I was hoping to finish it up this weekend but the front main seal they shipped is the wrong size. So next weekend it is.
Ronan
-
Nice work Ronan
That's a cool upgrade 33 mm lifters plus you have got the last m42 type of timing set up. 42 with no wheel but crank sensor.
Cheers Rohan
-
It's alive and drives great! Thanks for all of the help.
-
Hi Ronan
So what was the final set up?
86 mm 83.5 mm compression etc etc
Cheers Rohan
-
Ok here is the final build.
M44 stock internals
-85mm bore
-83.5 mm stroke
10:1 compression (probably slightly higher given the head was decked to insure it was flat)
M42 block bored to fit pistons
M42 head with 6mm valve
Sadly stock cams since the place I sent them to get ground told me they couldn't after assuring they could(Will try and get some stock cams later and try again)
S/M52 cam trays with 33mm lifters
M20 flywheel lightened to ~16 lbs. I just took all the meat off the back side up to the ring gear which was switched to the m42 ring gear.
COP's and an electric fan
Not installed yet but have a turner chip. Will install very soon just didn't want to add another variable if it didn't start.
Still have a few thinks I will do just haven't had time yet. One is making an oil catch can(have the materials), the other is putting pulse chambers on the intake manifold(Have a spare manifold to work with). Thinking about making them adjustable length since I don't have experience with them. If anyone does I would love some advice. I also thought about boring out my extra throttle body, but we shall see.
Ronan
-
Looking good! Is it on the road yet? Would like to know how it runs. I can't drive mine yet so I'm curious about yours.
-
Drives like a dream!! I have 3 tanks of gas through it and called it broke in after 2 tanks. Installed my Turner chip and wow! With all of the lighter parts it revs much faster and it pulls hard from 4k all the way to 7k and there is more low end torque for sure. I love it and considering I did it all for $1200 I am very pleased. My old motor was very tired looking back ha-ha.
Ronan