Tech Forum : unofficial M42/S42 thread

Posted Thursday, Aug 18th 7:53am [Edit] [Quote] [IMS] [View car]

Post nr. 469

I know almost nothing about these engines- teach me!!

I want to know what kind of displacement and power is reasonable to expect from these little engines. Of course...reliability would be nice too!

Sorry to sound like such a noob, I just didn't want to see this subject die so quickly.

jamie

Posted Thursday, Aug 18th 9:36am [Edit] [Quote] [IMS] [View car]

Post nr. 401

I'm glad someone brought this topic back up! I've been wandering down the M42 road for awhile, I think I've decided against the M10 (unless I got ahold of an m12 head) The only thing I dont like is that I cant punch it out to 2.3l like I was thinking about on the m10. But the head design is so much better, that I'm not concerned about it. All I have to now if find either a turbo manifold or some 13.5:1 pistons

Oh does anyone know what the CC for the combustion chamber is?

Posted Thursday, Aug 18th 2:50pm [Edit] [Quote] [IMS] [View car]

Post nr. 893

It might pay off if one does some preliminary research first, I'm sure there's plenty of facts on those engines to be found around the internet.

Everyone is welcome to discuss the quality and the property of these engines in the tech forum, but seeing as the last topic pretty much derailed I have my reservations

By all means, do not refrain from contributing to this thread. But remember that everybody is entitled to his own opinion, and any opinion is as good as any other.

I've never personally driven an M42, but I know the E30 318is equipped with them fetch handsome prices by now.. Wasn't the M42 BMW's first non-M engine to feature 4 valves per cylinder?

Posted Thursday, Aug 18th 4:33pm [Edit] [Quote] [IMS] [View car]

Post nr. 471

are they definately the same bore centers and head design as the M50 engines?

If so it should be possible to build a 200 hp M42 that is very reliable, even naturally aspirated.

jamie

Posted Thursday, Aug 18th 4:39pm [Edit] [Quote] [IMS] [View car]

Post nr. 870

imaradiostar wrote:

Jamie I can tell you that there was a e30 M42 turbo at the bav auto show. It was black and fast.
A turbo like what Nic is building would be fun.
The m42 engine is available for cheap too, so that
makes it fun and doable.

Personally I am using the 2.8 liter stroker, and then maybe a turbo.

later,
J

Posted Thursday, Aug 18th 4:39pm [Edit] [Quote] [IMS] [View car]

Post nr. 720

I thought about this for about a month. The recommendation was to modify the block slightly to accept an E30 M3 crank and change the pistons to VW pistons.

Yes.....that M42 had technology that appeared in later model engines.

Posted Thursday, Aug 18th 9:10pm [Edit] [Quote] [IMS] [View car]

Post nr. 402

modify an m42 to accept an s14 crank? that would be ALOT of modifying, since the S14 uses an M10 block which has 100mm bore spacing, and the m42 uses 91mm bore spacing

But yeah, its just a 4cyl M50

Posted Thursday, Aug 18th 10:11pm [Edit] [Quote] [IMS] [View car]

Post nr. 472

do s52 solid lifter buckets fit?

what is available in the way of camshafts?

would modified euro S52 ITB's fit?

How about pistons? Would 86.4 mm M3 pistons work?

Is the 1.8 or 1.9 crank a better option?

(yes, I have M42 and M44 parts laying around at work...heheheh)

jamie

Posted Friday, Aug 19th 12:03am [Edit] [Quote] [IMS] [View car]

Post nr. 403

I'm not sure if S52 ITB's would work, I'll have to compare intake manifold gaskets. and the S54 buckets do fit. I looked on the ETK and the S50 AND S52 use hydraulic lifters, the S54 however has solid lifters

You should be able to bore it out that far, since the bore spacing is the same, the only conerns, is the compression height is slightly different

US S50 Piston Specs..

86.4mm Bore
31mm Compression Height
Wrist Pin 22x56

Euro S50
85.4mm Bore
32.3mm Compression Height
Wrist Pin 21x59

M42
84mm Bore
31.65mm Comression Height
Wrist Pin 22x54

M44
85mm Bore
30.4mm Compression Height
Wrist Pin 22x54

it looks like US S50 pistons would be the easiest to use. With an 86.4mm bore your cylinders are going to be 4.6mm apart, but that should be fine, the S50's do it, and the M42/M44 are cast iron. Now if you could achieve the same stroke as the S50, you could achieve a displacment of 2133cc

I've got a few of them lying around also.....In fact I have an M42 head ontop of my toolbox Next to the halfway built M10turbo

Posted Friday, Aug 19th 3:02am [Edit] [Quote] [IMS] [View car]

Post nr. 721

Yes....it has been done before. An E30 M3 crank works with a little bit of machining and modifying.

Posted Friday, Aug 19th 3:09am [Edit] [Quote] [IMS] [View car]

Post nr. 473

obviously this isn't the place for it but I wish BMW made a more current 16v head with M10 type bore centers- it's make for a cheaper high performance 4 cylinder!

Here's what I've come up with so far:
US S50 pistons, M42 crank, 1900cc's displacement
US S50 pistons, M44 crank, 1958cc's displacement

Someone in the other thread said something about the M42 crank being forged and the M44 crank being cast- if this is the case the extra 58cc's of displacement aren't worth it.

With the correct cams, fuel injection and careful balancing this would be a very high-revving engine.

jamie

Posted Friday, Aug 19th 3:22am [Edit] [Quote] [IMS] [View car]

Post nr. 393

Mayanarch- I'd like to see a link or something on that info regarding the M3 cranks- as has already been pointed out- the m42 is related to the M20/ M50 motor and as such the bore centres are 8mm different- the crank would require extensive modifications because the blocks are physically a different size/ construction- the M3 crank can be fitted to the M10 block as has been already discussed- I'd say it's not really worth the effort- ie. with the mods involved youd probably be better off getting your own custom 1 off crank being made from a billet.... not real viable.

Posted Friday, Aug 19th 5:02am [Edit] [Quote] [IMS] [View car]

Post nr. 280

Hi

Hartge done a 2.2 conversion for the m42,I wonder if the 4ly desiel crank would give the extra throw to get the displacement up.

Currenty I have a m12 block and I just picked up a s14 head so Im building up a 2.0l 16v m10 on mech throttle bodies with a dry sump, a as I think my race car is going towards a gruppe 2 type thing. But i do think the m42 is a good motor if you search there is a couple 200bhp motors out there it has a forged rank and oil squirters for the pitons lots of nice touches.

Jason

Posted Friday, Aug 19th 9:02am [Edit] [Quote] [IMS] [View car]

Post nr. 404

oh I never thought about the diesel crank.....I'm gonna find out more about that!

Posted Friday, Aug 19th 10:45am [Edit] [Quote] [IMS] [View car]

Post nr. 475

bmw_m_320i wrote:

oh I never thought about the diesel crank.....I'm gonna find out more about that!

I believe it's only 82.5 mm stroke, though I could be wrong. Google has been wrong before.

jamie

Posted Friday, Aug 19th 4:30pm [Edit] [Quote] [IMS] [View car]

Post nr. 546

Jason_323i wrote:

Hi

Hartge done a 2.2 conversion for the m42,I wonder if the 4ly desiel crank would give the extra throw to get the displacement up.
Jason

The Hartge setup is a billet crank, custom from hartge, and a shim that fits between the main caps and the block. Very exspencive

Posted Friday, Aug 19th 4:59pm [Edit] [Quote] [IMS] [View car]

Post nr. 871

M42powered wrote:

Jason_323i wrote:

Hi

Hartge done a 2.2 conversion for the m42,I wonder if the 4ly desiel crank would give the extra throw to get the displacement up.
Jason

The Hartge setup is a billet crank, custom from hartge, and a shim that fits between the main caps and the block. Very exspencive

Hartge has done a variety of stroker engines, and these sometimes have there own custom Hartge crank. If what Nic is saying is correct, and I think it is, the billet crank would probably go for a least 1k, if you could get it from Hartge,
and I am not sure about their other stuff needed to stroke the m42. Maybe Hartge has custom pistons, as well, so it would be very expensive, but a real performer.

Someone should email Hartge and check to see what the details on their kit are - hp, torque, etc, - price of the kit, and if its still available.

Lots of stuff for their M20 strokers are NLA

later,
J

Posted Friday, Aug 19th 5:49pm [Edit] [Quote] [IMS] [View car]

Post nr. 547

JJG323 wrote:

M42powered wrote:

Jason_323i wrote:

Hi

Hartge done a 2.2 conversion for the m42,I wonder if the 4ly desiel crank would give the extra throw to get the displacement up.
Jason

The Hartge setup is a billet crank, custom from hartge, and a shim that fits between the main caps and the block. Very exspencive

The kit is NLA as I talked to Dazz motorsports in California that is the US distributor for Hartge. The crank is probably the cheapest part of the kit. From my understanding it is a full set of internals from bearings to rings. The shim is the most exspencive part as it moves the center axis of the crank down to keep the piston from hitting valves and the deck of the head. Not sure how this works for the flywheel and transmission, but I didn't ask for too many details after they told me the kit retailed back in the mid 90's for close to 15 grand. It included new chip for the added displacement and of course and hartge valve cover and intake manifold. Supposedly the kit didn't sell too well.

One thing to remember when trying to stroke the M42 is that the compression ratio is a little high 9.5:1 and finding a crank that fits will be a little difficult. Hartge had to do some tricky stuff to get it to work, so finding a drop in probably isn't all that easy. Plus the M42 crank is forged the M44 is not, so forget about trying to get the extra tenth of a liter that the M44 has, in my opinion it's not worth it to pass over a 8 counterweight forged crank to a 4 counterweight unforged crank just for a tenth of a liter. The M42 also has oil squirters to cool the tops of the piston crowns (boost), and hydraulic lifters are nice as long as you aren't trying to spin it to 10,000 rpm. Chaning shims is a bitch and not my idea of fun, even if there are only 16 of them instead of 24 on a six. Good motor and plenty reliable. Even after my motor swap all I've ever done is change the fluids.

Posted Friday, Aug 19th 6:28pm [Edit] [Quote] [IMS] [View car]

Post nr. 872

M42powered wrote:

15K! No wonder why it did not sell.

Thats a lot of mola for a stroker. You can get the 3.0 liter Metric Mechanic engine with e36 m crank, and still take a trip out to Vegas for that price..
So ok the hartge kit is out. So what crank can you use in the m42 to effectively stroke it. I never have heard off the s14 crank working in it.
What engine does the diesel crank come out off?

Nic or anyone, is there anything that can work, maybe even in the BMW, or VW world. I know the autotech sells forged cranks for there 2.0 stroker engines, but I am not sure if they are even close to working in the M42. We sould be able to find something given all the BMW engines out there ever made, plus even VW or Audi engines.

any ideas??

later,
J

Posted Friday, Aug 19th 7:31pm [Edit] [Quote] [IMS] [View car]

Post nr. 897

I don't think there are many cross-brand cranks that swap right in BMW engines... These things are designed with a precision within a hundred of a millimeter, if not more on recent engines.

Anyway, I'm always thinking in terms of a six, maybe there is more to be found among the diversity of four-bangers out there.. Running a crank from another brand is a shot in the dark, but if it fits it might actually work.

Posted Friday, Aug 19th 11:17pm [Edit] [Quote] [IMS] [View car]

Post nr. 477

I think the real beauty of the thing here is to use custom forged (ie lightweight) 86ish mm pistons and take advantage of the inherant strengths of the M42 engine- it has a forged fully counterweighted crank. Make sure everything is balanced carefully, perhaps do a mild clean up of the ports in the cylinder head and you'll have a very over-square BMW engine. The M42 supposedly flows very well on its own so it would probably be more than sufficient for our applications.

While not necessarily as efficient as a less over-square engine, this sucker should turn very high RPM with little trouble. I think a big shrick cam & HD valve springs, ITB's (even if you have to improvise and use motorcycle parts!) and megasquirt or some other stand-alone management system could make for a very high-revving engine that would probably make around 200 horsepower. Perhaps it would be a neat experiment to use VW knock-sensor ignition (where the heck would you put the distributor?) and CIS basic, just for the simplicity of it.

thoughts?

jamie

Posted Saturday, Aug 20th 12:01am [Edit] [Quote] [IMS] [View car]

Post nr. 548

many parts here... had long conversations with this guy. He wants to buy my exhaust manifold design for the turbo.

http://www.gttechnic.com/catalog.html

Posted Saturday, Aug 20th 2:37am [Edit] [Quote] [IMS] [View car]

Post nr. 1

There are several companies out there that can make a custom stroker crank for a "reasonable" price.

They weld the rod journals and turn them to the new stroke, very common in VW/Porsche type 4 aircooled racing and street engines.

Scat used to make M10 stroker cranks back in the day... I'm sure they could whip up a one-off, bullet proof but big $$$.

Once you figure out your stroke and bore you would likely need custom forged rods and pistons... then cams/intake/exhaust to match. Anything can be done with enough $$$. Anyone know where there is a fully loaded, unattended armored car sitting around???

ken

Posted Saturday, Aug 20th 2:45am [Edit] [Quote] [IMS] [View car]

Post nr. 405

imaradiostar wrote:

If you use an E36 M42, it already has knock sensors. The M44 I dont really like..at all in comparison to the M42. The M44 has the cast crank, AND uses stamped steel rocker arms, as well as all of the OBDII emissions compliance crap. The M42 is a much more solid engine

Posted Monday, Aug 22nd 8:14pm [Edit] [Quote] [IMS] [View car]

Post nr. 878

..Are Superchargers available for the m42?

I was reading that someone took an e36 m42, added a Dinan 45 supercharger - (This is from a Minicooper) and ran *8* psi. This person ran 100 octane gas and was competitive with e36 m3s..

Also I saw the posting of this link:
A killer turbo M42, which is looks like fun.

http://www.pure-pf.com/phpBB2/viewtopic.php?t=956
later,
J

Posted Monday, Aug 22nd 9:18pm [Edit] [Quote] [IMS] [View car]

Post nr. 549

For the M44 there is a Downing Atlantic Supercharger Kit. This kit does not fit on the M42 without exstencive changes to the intake manifold second set of runners.

Posted Monday, Aug 22nd 10:34pm [Edit] [Quote] [IMS] [View car]

Post nr. 479

I have a really strong urge to build on of these things all of the sudden!

jamie

Posted Tuesday, Aug 23rd 12:10am [Edit] [Quote] [IMS] [View car]

Post nr. 406

yeah me to! I've already started stripping a head down! Hey M42powered is the sump of your oilpan at the front or the rear of the engine? I've got several E36 oilpans with the rear sump, but no E30 ones with the sump in front. If I can get the engine far enough back I MIGHT be able to use an E36 pan.

Posted Tuesday, Aug 23rd 12:14am [Edit] [Quote] [IMS] [View car]

Post nr. 550

Mine is in front. E30 Style. If you can push the engine further back than me I would be impressed. I can barely service the idle control valve, and the intake manifold is about to touch the blower motor cover.

I can probably snag a few pics of the E30 sump in relation to the front subframe if you need it. I had to cut the support for the steering rack to make the upper pan wrap over it. My steering is fine before everyone jumps on me.

Posted Tuesday, Aug 23rd 12:29am [Edit] [Quote] [IMS] [View car]

Post nr. 407

I think if I push the engine back, and cut the doublewide section of the steering rack like you did, I could use an E36 oilpan. Also I've got a 6cyl subframe, and transmission, so I wont have to modify the 4cyl one as much as you did, and I should be able to keep the speedo!

Posted Tuesday, Aug 23rd 12:31am [Edit] [Quote] [IMS] [View car]

Post nr. 551

Assuming your tranny bolts up to the M42 block. Isn't it a M50 bolt pattern? The getrag 260-5 or whatever it is on the M42 is such a smooth shifting unit I don't know why you'd stick with the M20. Speedo's are overrated anyway

Posted Tuesday, Aug 23rd 12:43am [Edit] [Quote] [IMS] [View car]

Post nr. 408

the bolt pattern is the same between m20/m42/m50 engines. I like to see what 5th gear 6000rpms translates into!

Oh yeah, that also means I can use the older single piece flywheels, instead of the dual mass setup which weighs more.

Posted Tuesday, Aug 23rd 2:51am [Edit] [Quote] [IMS] [View car]

Post nr. 480

M42powered wrote:

I believe there may be a difference in the angle of the engine- 10 degrees IIRC.

jamie

Posted Tuesday, Aug 23rd 4:39am [Edit] [Quote] [IMS] [View car]

Post nr. 409

thats nothing a lil custom fabbing wont take care of!

Posted Tuesday, Aug 23rd 7:42am [Edit] [Quote] [IMS] [View car]

Post nr. 481

bmw_m_320i wrote:

thats nothing a lil custom fabbing wont take care of!

agreed. I worked through this when I was considering the M50 swap.

jamie

Posted Tuesday, Aug 23rd 6:31pm [Edit] [Quote] [IMS] [View car]

Post nr. 552

I should probably get a junk M42 head sometime soon. Anyone know of a cracked head or one that is warped in their area? I'll pay shipping, and a little extra for your time. I had one squared away in Seattle, but haven't had contact in a while.

Posted Tuesday, Aug 23rd 6:36pm [Edit] [Quote] [IMS] [View car]

Post nr. 482

I know of an m42 engine, trans, harness, etc near Murfreesboro- don't know of just a head; though I do have a cracked M44 sitting in the aluminum scrap bin here at work (as well as the leftovers from an m44 engine we bought for the cylinder head). Is there anything from that one you might need?

I wonder if the company that makes the BMP ITB's makes or could make an ITB set for this engine?

jamie

Posted Tuesday, Aug 23rd 7:10pm [Edit] [Quote] [IMS] [View car]

Post nr. 880

imaradiostar wrote:

I wonder if the company that makes the BMP ITB's makes or could make an ITB set for this engine?

jamie

I thought someone - posted - I think it was NIC BMP's manfuacturer of the ITB's. Its in germany, and I also thought they made one for the m20...

Anyone?

Posted Tuesday, Aug 23rd 7:15pm [Edit] [Quote] [IMS] [View car]

Post nr. 553

http://www.regal-shop.co.uk/asps/ShowDetails.asp?id=1892

Look familiar minus the red paint?

A side draft option for M10 E21's

http://www.regal-shop.co.uk/asps/ShowDetails.asp?id=1996

No pics on their main site:

http://www.dbilas-dynamic.de/index.htm

Posted Tuesday, Aug 23rd 10:33pm [Edit] [Quote] [IMS] [View car]

Post nr. 410

who makes a turbo manifold for the m42? I've got all these turbo parts lying around and I HAVE to use them!

Posted Tuesday, Aug 23rd 11:04pm [Edit] [Quote] [IMS] [View car]

Post nr. 554

Never seen one that was worth anything. Custom is the way I'm going.

Posted Tuesday, Aug 23rd 11:51pm [Edit] [Quote] [IMS] [View car]

Post nr. 411

where did you get the flanges? are you making an equal length type turbo header?

Posted Wednesday, Aug 24th 12:28am [Edit] [Quote] [IMS] [View car]

Post nr. 555

You can get the flange from stahl. I bought one, but I also have an extra exhaust header that I can cut up if I want. The big problem is squishing down the circular tubing to fit in the oval exhaust ports. I'm working on finding the right height metal block to use as a squish gauge so that each port is the same size. I will be making equal length single pipe header, thickwall stainless probably as the bender I have won't do thinwall, and thicker is better for holding in the heat.

My other option is:
I made a solid model of the exhaust flange, and extruded the ports out so that they flow nicely into a circular tube. That way I just have to weld them in one place. Plus I added threaded holes just like on the stock manifold for an EGT.

Posted Wednesday, Aug 24th 12:31am [Edit] [Quote] [IMS] [View car]

Post nr. 412

it would be easiest to start with a stock manfold and cut the flanges off where the ovalized section of tubing is still there to work with. would save a step in the process...just ruins a perfectly good header....but sometimes one has to make sacrifices!

Posted Wednesday, Aug 24th 12:53am [Edit] [Quote] [IMS] [View car]

Post nr. 556

bmw_m_320i wrote:

Would be the easiest, but not stainless steel.

Posted Wednesday, Aug 24th 1:10am [Edit] [Quote] [IMS] [View car]

Post nr. 413

good point....

How close are you to completing one? would you be willing to make more than one?

Posted Wednesday, Aug 24th 1:28am [Edit] [Quote] [IMS] [View car]

Post nr. 557

I have yet to cut metal. I'm focusing more on my block at the moment. Probably won't be welding for another month or so. I am making 2 already, one for me and one for Todd in Colorado. I'll keep everyone posted. It won't be cheap depending on how I go about putting it together. Also, the turbo flange will be up to you, I am not in charge of placing the turbo for Todd, he is doing that himself.

I'm thinking if there is a market I might make a jig from the first one to make a few more for those interested parties.

Posted Wednesday, Aug 24th 1:50am [Edit] [Quote] [IMS] [View car]

Post nr. 414

what type of turbo are you going to run? and what are you doing to your block?

Posted Wednesday, Aug 24th 2:18am [Edit] [Quote] [IMS] [View car]

Post nr. 558

The block is getting machined, and I will take all the flashings out of the it to reduce windage. It's a stock rebuild basically with custom pistons and polished beams on the connecting rods, etc. etc.

GT2871R

Posted Wednesday, Aug 24th 3:10am [Edit] [Quote] [IMS] [View car]

Post nr. 415

what CR are you aiming for?

Posted Wednesday, Aug 24th 9:21am [Edit] [Quote] [IMS] [View car]

Post nr. 559

it's calculated at 8.5:1

Posted Wednesday, Aug 24th 3:23pm [Edit] [Quote] [IMS] [View car]

Post nr. 729

Here is the email of a guy that converts the M10 block to accept E30 M3 cranks: EDK40@aol.com

Keep in mind that this is NOT an endorsement, since I never actually did business with the guy.

I only entertained this avenue for about a month, and then commited to the M20. If I recall, both Ray and Ken knew something about this conversion. It needed Porsche or VW pistons.

ERIC SAID:

M10 with a S14 stroke crank,and big bore for a 2.3.

The M10 if yo u use Weber 45's will make 180 plus HP and 180 ft lb of torque. I have cranks in stock. Cam is either a 292 or 304 Schrick depending upon your intended use.

Details easier to discuss on th e phone, bu t Ill tell you th e engine less induction is a $4200 project. Core to be negotiated.

I do hav e one opportunity for a less expensive version , same stroke, bu t a 2.2 with a 90 mm bore. I own the pistons for it,,so I can make a great $$ deal, to be discussed. Will still be 180 hp.

Pistons usually JE custom, then machined by me.

Power peak will be in th e 5600 rpm area, and torque peak down just under 3000 rpm. Redline stays stock at 6400 , and its all you need , as I sai d I drove with a similar engine for a few years, Its awesome.
Cranks are used, magnafluxed and polished . Rods get magnafluxed too. As I work full time at a race engine shop, doing exotic and historic engines, I hav e full facilities at my hand. Been doing these M10s etc for 23 years now . MY head porting is worth 16 to 18% flow increases, and is needed to get the potential , especially with the bigger engine.

Posted Wednesday, Aug 24th 5:40pm [Edit] [Quote] [IMS] [View car]

Post nr. 483

I appreciate the M10/S14 info but let's try to keep this thread M42/M44-centric. The M10 is an incredible engine but we're try to focus on what can be done with this lower displacement engine as it seems to be highly tunable.

jamie

Posted Wednesday, Aug 24th 6:46pm [Edit] [Quote] [IMS] [View car]

Post nr. 730

sorry. Got confused. Brain fart.

Posted Wednesday, Aug 24th 9:37pm [Edit] [Quote] [IMS] [View car]

Post nr. 484

MayanArch wrote:

sorry. Got confused. Brain fart.

no prob dude. we're all guilty of the occasional brain fart!

jamie

Posted Thursday, Aug 25th 8:01pm [Edit] [Quote] [IMS] [View car]

Post nr. 485

so what about pistons- are you guys going to use custom units built to spec or try to adapt existing pistons to your application?

jamie

Posted Thursday, Aug 25th 8:06pm [Edit] [Quote] [IMS] [View car]

Post nr. 486

quick thought since I'm at work- perhaps dished M20 pistons could make a good low-comp turbo piston for this engine while preserving decent squish clearances.

jamie

Posted Thursday, Aug 25th 8:28pm [Edit] [Quote] [IMS] [View car]

Post nr. 561

M42powered wrote:

Posted Thursday, Aug 25th 11:25pm [Edit] [Quote] [IMS] [View car]

Post nr. 487

rrrright...I missed that. who is supplying the custom pistons?

jamie

Posted Thursday, Aug 25th 11:47pm [Edit] [Quote] [IMS] [View car]

Post nr. 562

anyone can do it. I choose CP based on my machinest recommendations. After they lost my order and had me sitting on my thumb for 3 months I finally got them. Nice units, it just tastes like they shit in my mouth, making me wait so long.

Another thing I thought of while thinking about my engine (and playing with the parts). Adjustable cam gears on exhaust and intake. 3 degrees on both, which adds up to a 6 degree dip if you want to reduce overlap (good for turbo).

Posted Friday, Aug 26th 1:13am [Edit] [Quote] [IMS] [View car]

Post nr. 418

I'm thinking to just get 4 86.4mm Dished M3 pistons

Posted Friday, Aug 26th 6:57pm [Edit] [Quote] [IMS] [View car]

Post nr. 488

bmw_m_320i wrote:

I'm thinking to just get 4 86.4mm Dished M3 pistons

would you take half a mm off of the top of the S50 pistons to correct the compression height?

jamie

Posted Friday, Aug 26th 7:29pm [Edit] [Quote] [IMS] [View car]

Post nr. 421

for a turbo yeah...for NA I would leave it if the vavles didnt hit

Posted Friday, Aug 26th 11:03pm [Edit] [Quote] [IMS] [View car]

Post nr. 563

bmw_m_320i wrote:

for a turbo yeah...for NA I would leave it if the vavles didnt hit

FYI, Stock M42 pistons are fly cut

Posted Friday, Aug 26th 11:15pm [Edit] [Quote] [IMS] [View car]

Post nr. 489

bmw_m_320i wrote:

for a turbo yeah...for NA I would leave it if the vavles didnt hit

I know there are differing opinions on this kind of thing but I wonder if careful trimming of the inside of the piston crown would be better for turbo applications- it would preserve the tight squish area at the outside while still lowering CR a bit for the turbo.

I suppose this would be very difficult to do with hand tools but surely a machine shop could do it in a way that would be identical on all four pistons.

Anyone know a good source for S50 pistons?

jamie

Posted Saturday, Aug 27th 5:39pm [Edit] [Quote] [IMS] [View car]

Post nr. 423

M42powered wrote:

Adjustable cam gears on exhaust and intake. 3 degrees on both, which adds up to a 6 degree dip if you want to reduce overlap (good for turbo).

The M42 already has adjustable cam gears

Posted Saturday, Aug 27th 8:14pm [Edit] [Quote] [IMS] [View car]

Post nr. 890

M42powered wrote:

Nic can you post a few pictures of the CP Pistons?
thanks
J

Posted Sunday, Aug 28th 3:54am [Edit] [Quote] [IMS] [View car]

Post nr. 564

bmw_m_320i wrote:

M42powered wrote:

Adjustable cam gears on exhaust and intake. 3 degrees on both, which adds up to a 6 degree dip if you want to reduce overlap (good for turbo).

The M42 already has adjustable cam gears

Yeah, that's why I brought it up.

Posted Sunday, Aug 28th 3:56am [Edit] [Quote] [IMS] [View car]

Post nr. 565

JJG323 wrote:

Nic can you post a few pictures of the CP Pistons?
thanks
J

All in due time. I'll take pics when I get the whole shibang home for assembly... soon.

Posted Sunday, Aug 28th 4:16am [Edit] [Quote] [IMS] [View car]

Post nr. 425

oh ok, I wasnt sure if you were referring to an aftermarket kit

Posted Friday, Sep 9th 10:59pm [Edit] [Quote] [IMS] [View car]

Post nr. 432

M42powered wrote:

bmw_m_320i wrote:

M42powered wrote:

Adjustable cam gears on exhaust and intake. 3 degrees on both, which adds up to a 6 degree dip if you want to reduce overlap (good for turbo).

The M42 already has adjustable cam gears

Yeah, that's why I brought it up.

now how exactly does advancing the exhaust and retarding intake cam timing on a turbo? whats the theory on this? I'm not discrediting it....I simply dont understand the full dynamics of this...

Posted Saturday, Sep 10th 12:33am [Edit] [Quote] [IMS] [View car]

Post nr. 508

bmw_m_320i wrote:

M42powered wrote:

bmw_m_320i wrote:

M42powered wrote:

Adjustable cam gears on exhaust and intake. 3 degrees on both, which adds up to a 6 degree dip if you want to reduce overlap (good for turbo).

The M42 already has adjustable cam gears

Yeah, that's why I brought it up.

now how exactly does advancing the exhaust and retarding intake cam timing on a turbo? whats the theory on this? I'm not discrediting it....I simply dont understand the full dynamics of this...

on a forced induction engine excessive valve overlap allows compressed charges to sneak out the exhaust rather than being used in a contructive way. By reducing overlap you're reducing the chance of that happening. Forced induction cams are often a moderate duration assymetrical grind with this thought in mind.

jamie

Posted Saturday, Sep 10th 12:42am [Edit] [Quote] [IMS] [View car]

Post nr. 433

ahhh ok....

Posted Tuesday, Sep 13th 9:30pm [Edit] [Quote] [IMS] [View car]

Post nr. 1

One think that I havnt heard mentioned about doing the M42 swap: it uses the M42 fuel dizzy, right? Well, will the the e21 K-jet w/lamda run this motor? I wouldnt think so...so do you remove the brain box and the O2 sensor?

John

Posted Wednesday, Sep 14th 3:04am [Edit] [Quote] [IMS] [View car]

Post nr. 1

The m42 uses a completly different fuel injection-EFI=no fuel distributor. It would be a lot of work to try and get a m42 to run on CIS for less power and reliability.

ken

Posted Wednesday, Sep 14th 6:51pm [Edit] [Quote] [IMS] [View car]

Post nr. 567

yeah if you can acutally fab the motor mounts, and do all the other stuff wiring up the engine is a walk in the park compared to that.

Posted Thursday, Sep 15th 7:24pm [Edit] [Quote] [IMS] [View car]

Post nr. 434

yeah the m42 has a beautifully easy wiring harness to adapt to the e21....I'm actually thinking about using a complete e36 harness for the whole carm since I have to rewire the car anyways. the motor mounts should be easier to do if you use the m20 subframe.

the most challenging part will be the turbo exhaust manifold

Posted Friday, Sep 16th 5:48pm [Edit] [Quote] [IMS] [View car]

Post nr. 569

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4573426529

9:1 JE pistons for sale on ebay for the M44, should fit an M42 bore.

Posted Friday, Sep 16th 9:03pm [Edit] [Quote] [IMS] [View car]

Post nr. 437

you would have to rebore...the m44 is 1mm larger, but at least its not 1mm smaller

Posted Friday, Sep 16th 9:04pm [Edit] [Quote] [IMS] [View car]

Post nr. 570

Well given that they are probably oversized M44 pistons you'd probably have to go a touch over 1mm.