Author Topic: M42 race engine (Read 59683 times)

dsm2002 · « **on:** April 14, 2009, 09:28:26 AM »

I am thinking about building a BMW M42 for track and race engine. I have a 318i shitter, an M42 engine and a set of E36 M3 throttle bodies picked up cheap. It is mainly just for a bit of fun. It'll take a bit of time to do this and I'll update this thread as I go.

The spec that I am considering is:

87 x 81 bore/stroke
34mm inlet valves, 31.5mm exhaust
Catcams 290�/275�
Shim under bucket cam followers (Eurospec)
Compression ratio: 11.5:1
head porting
4 into 1 headers
E36 M3 ITBs
Type of flywheel: initially lightened steel (later aluminium)
Max intended revs: 8500
Power to start from: 5000�

I had a fella run these specs into a engine program to estimate possible power from this proposed engine and to advise on final choices such as cams etc. Here are some indicative power and torque curves. Whether or not these figures would be realised depends on a number of variables, no the least being the porting potential.

e30guydownunder · « **Reply #1 on:** April 14, 2009, 06:26:27 PM »

sounds interesting

i'll be staying tuned into this one for sure. Let me know when you are getting the cams posted out might wanna combine on shipping.

Is this horsepower predictor on the internet or elsewhere?

nuvolarossa · « **Reply #2 on:** April 15, 2009, 02:24:21 AM »

I know that software

if you really want it you can buy it.
In your list I would say HEAVY head porting and maniacal attention to its flow... that software is VERY influenced by head flow

the funny thing is that I done a similar analysis two weeks ago with same throttle bodies and same cams

If you watch catcams website there are for every cam all the details needed for the calculator.
I will stay tuned too

want to see those lifters working

Boyracer · « **Reply #3 on:** April 15, 2009, 06:06:58 AM »

Good plan! :cool:

Dont forget that you need aftermarket forged pistons and most propably con rods too which add to expense. And I would think valve springs need to be changed too.

dsm2002 · « **Reply #4 on:** April 15, 2009, 09:12:12 AM »

Quote from: e30guydownunder;70079

sounds interesting i'll be staying tuned into this one for sure. Let me know when you are getting the cams posted out might wanna combine on shipping.

Is this horsepower predictor on the internet or elsewhere?

I understand it is a proprietry software package not available as freeware or non the internet.

Quote from: nuvolarossa;70118

I know that software if you really want it you can buy it.
In your list I would say HEAVY head porting and maniacal attention to its flow... that software is VERY influenced by head flow
the funny thing is that I done a similar analysis two weeks ago with same throttle bodies and same cams
If you watch catcams website there are for every cam all the details needed for the calculator.
I will stay tuned too want to see those lifters working

The port diameters used in the calcs was a inlet port average diameter of 1.7" and exhaust 1.59". No idea yet if that is possible. I had a look at the ports for the first time tonight and seem quite small.:rolleyes: Anyway it'd be good to see what I can get.

Quote from: Boyracer;70123

Good plan! :cool:

Dont forget that you need aftermarket forged pistons and most propably con rods too which add to expense. And I would think valve springs need to be changed too.

I'll be looking at forged pistons and conrods a little later. For the valve springs, I an considering MM beehive springs. Currently researching this.

I have also ordered Supertech +1mm single groove inlet and exhausts valves.

dsm2002 · « **Reply #5 on:** April 15, 2009, 09:17:27 AM »

I had been considering N62 inlet valves which are 100.04mm in length - 6.28mm less than std M42 inlet valves (106.32mm).

Now the recommended Catcam solid lifter for the M42 is CC005 which has the following specs. [Dbilas parts no. 80.500.008 for BMW 318is / VW / Audi 8V / 16V has basically the same specs as the Catcams.]

CC005 Follower specs
External dia.   34.97mm
Internal dia.   33.0mm
External ht   26.3mm
Internal ht   14.7mm
Stud dia.   6.9mm [Dbilas 8mm]

There is another Catcams follower the CC068 which is a similar dimensions more or less, which is 5.30mm longer centre post.

CC068 Follower specs
External dia.   34.97mm
Internal dia.   32.9mm
External ht   30.0mm
Internal ht   20.0mm
Stud dia.   7.0mm

Excluding the under bucket shim, the net height of the M42 valve and CC005 solid lifter is 106.32 + 14.7 = 121.02mm and the net height of the N62B valve and CC068 solid lifter is 120.04mm (100.04mm + 20.0mm). Nearly 1mm difference, which could be taken up with different lash caps.

Now I understand that the N62 valve has a 5,97mm stem which is undercut to 5,03 mm. Great!

Cost for me put an end to this course of action.

References:
(1) Catcams.be
(2) Boyracer's quest for NA 280 hp
(3) Cecotto's stroker
(4) other various sources

dsm2002 · « **Reply #6 on:** April 15, 2009, 09:20:28 AM »

Finally, I am led to believe this is a M42 in Gerhard Landl's 318iS in the vid (see link).

Gerhard Landl BMW 318is

Anyone know more about this car?

Boyracer · « **Reply #7 on:** April 15, 2009, 09:45:29 AM »

Quote from: dsm2002;70138

I had been considering N62 inlet valves which are 100.04mm in length - 6.28mm less than std M42 inlet valves (106.32mm).

Now the recommended Catcam solid lifter for the M42 is CC005 which has the following specs. [Dbilas parts no. 80.500.008 for BMW 318is / VW / Audi 8V / 16V has basically the same specs as the Catcams.]

CC005 Follower specs
External dia.   34.97mm
Internal dia.   33.0mm
External ht   26.3mm
Internal ht   14.7mm
Stud dia.   6.9mm [Dbilas 8mm]

There is another Catcams follower the CC068 which is a similar dimensions more or less, which is 5.30mm longer centre post.

CC068 Follower specs
External dia.   34.97mm
Internal dia.   32.9mm
External ht   30.0mm
Internal ht   20.0mm
Stud dia.   7.0mm

Excluding the under bucket shim, the net height of the M42 valve and CC005 solid lifter is 106.32 + 14.7 = 121.02mm and the net height of the N62B valve and CC068 solid lifter is 120.04mm (100.04mm + 20.0mm). Nearly 1mm difference, which could be taken up with different lash caps.

Now I understand that the N62 valve has a 5,97mm stem which is undercut to 5,03 mm. Great!

Cost for me put an end to this course of action.

References:
(1) Catcams.be
(2) Boyracer's quest for NA 280 hp
(3) Cecotto's stroker
(4) other various sources

A problem you will run in is that if valve stem is 6 mm shorter, also valve spring must be 6 mm shorter because upper spring retainer (?) is attached to end of the valve stem which would be shorter than OEM.

You either have to be content with very little valve lift (maybe 5 mm) and very high seat pressure because spring are always atleast half way compressed or you need to machine springs 6 mm deeper to cylinder head, which I think might weaken the construction and maybe puncture a cooland gallery :eek:

Also, I studied the OEM M42 valves I have (I suspect N62 is same design) and they are 2 piece design, valve stem and the plate bit are made separately and they have been friction welded together. It can be a problem on very high RPM use, no fun when stem and plate separate and drop to cylinder

Plus, considering intake/exhaust seat insert outer diameter (you should have atleast 1 mm larger seat OD than valve OD to have sufficient strength), 34 / 31.5 mm are about as large as you can go with stock seat inserts based on my measurements. N62 intake valves are too large.

So I think I will just buy 34/31.5 mm Supertech valves for around 300�. They are same lenghts as OEM so no problem fitting then, they have waisted stems so they flow well plus they are dished design so they are light but at slight cost to compression ratio. And of course they are one piece design so they can take more RPM's than OEM valves.

This is a good thread!

kowalski · « **Reply #8 on:** April 15, 2009, 10:03:04 AM »

Quote from: dsm2002;70139

Finally, I am led to believe this is a M42 in Gerhard Landl's 318iS in the vid (see link).

Gerhard Landl BMW 318is

Anyone know more about this car?

never seen that before, looks quick though

RouteZeroDesign · « **Reply #9 on:** April 15, 2009, 12:34:51 PM »

"Desire to turbocharge........getting weaker...."

Excellent Thread, i really hope that you succeed, and pave the way for future m42/44 barn stormers!

nuvolarossa · « **Reply #10 on:** April 15, 2009, 01:19:38 PM »

dsm2002, you measured the intake's and exhaust's port length in the head? I would like to know as I don't have a spare head here

just to see if my simulations are close enough!

thank you and good luck!

dsm2002 · « **Reply #11 on:** April 15, 2009, 09:30:43 PM »

The figure used for the length of head ports from middle of the valve to the head face was an estimate of 85mm. It was the best I could do at the time.

I have since taken off the inlet and exhaust manifolds and will be taking the head off in the near future so I can measure it.

These are the base figures used for the calcs:

Bore: 87mm (87mm = 1926cc)
Stroke: 81mm
Type of piston: Short skirt
Compression ratio: 11.5:1

Diameter of the valves:
Inlet: 34mm or 35mm inlet (stock 33mm inlet)
Exhaust: 31.5mm or 32mm (30.5mm exhaust)

Length of head ports from middle of the valve to the head face: 85mm (estimate)

Inlet & exhaust port average diameters. 40.5mm average
(M42 inlet ports W51.48 x H28.17 mm x R14.85 mm). The S42 runs just over 42mm inlet ports

Type of inlet manifold: ITBs
Diameter: 50mm
Lengths: 115mm
Trumpet length: ?

Extractors: 4-2-1 (paired 1&4 and 3&2)
Primaries:
cyl 1 300mm (approx)
cyl 2 220mm (approx)
cyl 3 160mm (approx)
cyl 4 160mm (approx)
Collector length: 450mm (approx)
Diameter: 1.75mm OD

Cams: Catcams.be
Cam option 1 Inlet Exhaust
duration 290� 275�
duration [1.0mm+cl] 252� 243�
valve lift 12.00mm 11.50mm
cam lift peak angle: 106� 106�
timing: 20/52� 48/15�
lift at TDC 3.75mm 3.20mm
Shim under bucket

Cams:
Cam option 2 Inlet Exhaust
duration [0.1mm+cl] 298� 290�
duration [1.0mm+cl] 260� 252�
valve lift 12.50mm 12.00mm
cam lift peak angle: 106� 106�
timing [1.0mm+cl] 24/56� 52/20�
lift at TDC [cl=0] 4.30mm 3.70mm
Shim under bucket

Cams:
Cam option 3 Inlet Exhaust
duration [0.1mm+cl] 307� 298�
duration [1.0mm+cl] 268� 260�
valve lift [cl=0] 13.00mm 12.50mm
cam lift peak angle: 104� 104�
timing [1.0mm+cl] 30/58� 54/26�
lift at TDC [cl=0] 5.10mm 4.50mm
Shim under bucket

Adjust lobe centres?: Yes

Type of flywheel: initially lightened steel (later aluminium)
Max intended revs: 8500
Power to start from: 5000�
Conrod length: 140mm (145 aftermarket rods may be available)

Note: the rhd exhaust manifold is different the lhd one. For my sort of engine the rhd one is rubbish:

dsm2002 · « **Reply #12 on:** April 15, 2009, 09:42:26 PM »

Quote from: Boyracer;70142

A problem you will run in is that if valve stem is 6 mm shorter, also valve spring must be 6 mm shorter because upper spring retainer (?) is attached to end of the valve stem which would be shorter than OEM.

Yep. I had thinking about this and, were I to go this way, was planning to buy one valve and play around with valve springs to see what sort of lift was possible. In the end the cheaper option seemed to be Supertech and it seemed to be more straight forward.

dsm2002 · « **Reply #13 on:** June 30, 2009, 04:40:13 AM »

UPDATE: Firstly, I had a phone call from a fabricator mate saying he has finished mounting the M3 throttle bodies onto the M42. I'll pick them up Saturday. Pics later.

I also have a engineer lined up to work the head once the TBs are fitted.

I am also slowly accumulating parts. So far, I have:

Eurospec mechanical lifters
+1mm Supertech inlet & exhaust valves & collets (single groove)
Metric Mechanic 6mm valve guides
Metric Mechanic head bolts
11129063333 Head gasket set
11111727595 Bottom end set
11111735525 Main cap bolts
11111717939 Freeze plugs, 36mm
11311247160 Timing chain
11211247338 Sprocket
11311721887 Sprocket
11311247470 Guide rail
11311721419 Guide
11311727569 Deflection wheel
11311727342 Chain tensioner
11311721641 Slide rail
11141714611 Oil pump rotor

I also have new Bilsteins, Kings Springs, 318iS 20mm/14.5mm sway bars, AKG bushes, camber/toe plates, E46/Z3 RSMs

dsm2002 · « **Reply #14 on:** July 05, 2009, 12:16:49 AM »

Pics, as promised. The fabricator welded some tabs on and drilled new holes for the studs.