M3 EX (EXperiment) Engine Project Complete Spec
Complete Engine build spec, start reading from the bottom...
05/31/2008 Update:
Finally, Engine build is now complete. Final spec is as follows
Displacement: 2.3L
Compression ratio: 11.07:1
RPM limit: 9500
Connecting rods: Arrow
Connecting rod weight: 546gr.
Connecting rod bolts: ARP2000
Crankshaft: Original, blueprinted
Crankshaft bearings: Dry film coated Calico bearings, stock size
ARP Main studs
Pistons: Wiseco Grp A copy. Moly coated skirt and dome ceramic coated.
Piston diameter: 93.6312mm (1st BMW factory oversize)
Piston weight: 394gr.
Piston rings: Total seal
Piston Material: Forged aluminium 2618
Piston - cylinder clearance: 0.076mm
Piston pin weight: 89gr.
Top ring: 1.2mm, stainless
2nd ring: 1.5mm, cast
Oil Ring, chrome
Honing process: 80 grid 2 thou, 150 grid 1 thou, 280 grid to size, plateau brush 400 grid 3-4 strokes
Head gasket: Cometic MLS
Head gasket thickness: 1.29mm
Quench: 1.0033mm
Oil Pump: EVO3
Head:
Camshafts: Schrick 284 exhaust/292 intake
Camshaft sprockets: CT Motorsports adjustable
Valve Springs: Schrick
Cat cams cc0010 Shim under buckets
7mm shim diameter
Valves. Schrick, Nimonic Exhaust valves. 38mm intake valves
Head porting: Intake ports only. Flow good for 320hp.
Throttle body: 50mm
Cambox sealant: Wurth green flange sealant
Injection: Sequential
Injectors: Siemens Deka 3102 575cc/min
Ignition: Sequential, direct ignition
05/20/2008 Update:
It's alive! Engine started at first try without any strange noises, so all good at that front. But there are problems as well: Airbox is hitting the brake booster and has to be modified. Everything else looks fine.
05/18/2008 Update:
Accurate Engines
Address: 723 9th Ave # A. Kirkland, WA 98033
Telephone: (425) 822-4776
After disappointing experiences with Autosport Seattle, I had to find another. I visited Accurate Engines before going to Autosport but I selected Autosport since they had the torque plate. Big mistake as you already know. I got the torque plate from VAC Motorsports and went to see Mike with the same paper as I went to see Autosport Seattle, with detailed explanations what I would like to get done. Went that thru with Mike and we were able to come to an agreement what the price would be. He said the engine would be ready week later. 2 days before the deadline, I got a call from Mike saying that one of the ARP2000 connecting rod bolts won't stop stretching. Next day we got the replacement and engine was finished the same day. Went to pick up the engine and everything was done plus some things I didn't request, like painting the block. Mike also helped with valve adjustment, he was wiling to work during the evenings to help out.
Highly recommended and Mike will always go the extra mile to help you out. Ask for Mike Kolbet and tell he was recommended by Esa.
Engine is now back in engine bay and been finalizing the last details before starting it. Engine didn't crank first and had to remove the starter and open it. One white plastic protector had broken and I removed it. Installed it back and now engine started to turn just fine. Cranked the engine until oil pressure came up. Good news. Also fixed both front ABS sensors, installed the heat shields.
05/10/2008 Update:
Engine is now complete, Rotella T 15w-40 engine oil is in. Clutch is going in tomorrow and back to engine bay. Intake will not be complete yet since I'm missing the intake bellows.
05/09/2008 Update:
Valves are now adjusted. Intake valves are between 0.25 - 0.279 and exhaust 0.279 - 0.3mm. Here is a picture of the valve bucket and shims. Shims are 7mm shims sitting at the top of the valves below the buckets.
Next dilemma is what oil to use? Some say you need to have a oil with a lot of ZDDP (Anti-wear agent), some say you need to use dino oil, some say it is ok to use synthetic etc... I'm a fan of Mobil1, so I'm going to start with regular Mobil1 and then change to synthetic later.
Otherwise the engine is now alltogether, 50mm intake is in place, airbox adapter is ready. Missing are the intake hoses and airbox support.
04/20/2008 Update:
Head is in place and installed permanently. Having issues with valve clearances. Since some of the valves were cut too short, I have to use lash caps on exhaust side. I'm planning to install 0.85mm caps between the buckets and valves. I was able to find the caps from rdvalves.com
04/04/2008 Update:
Piston-Valve clearances were measured today. Results look like this, these are measured with stock timing:
| Crank Pos | Intake Piston-Valve clearance | Exhaust Piston-Valve clearance |
| -20 | 10.5 | 4.44 |
| -15 | 8.58 | 3.56 |
| -10 | 6.56 | 3.27 |
| -5 | 5.20 | 3.17 |
| 0 | 4.11 | 3.96 |
| 5 | 3.88 | 4.93 |
| 10 | 3.83 | 6.14 |
| 15 | 4.60 | 8.18 |
| 20 | 5.18 | 10.3 |
| Timing: 0 | Timing: 0 |
Quench is 1.08mm, which is very good.
Complete engine assembly instructions are in works.
03/08/2008 Update:
Autosport Seattle
Address: 2121 Westlake Avenue, Seattle, WA 98121
My disappointing experiences about local machine shops continue. It was agreed that my engine would be ready tomorrow and this was clearly written to the paper which was used by Autosport Seattle to give my quote for the work. Guess what: Work wasn’t even started as of today. Response was that it might be ready later next week. I decided that this company is not worth my money and trust.
I had my doubts about this since place it is full of unfinished work, but since this was the only place with torque plate I decided to take a risk.
Not recommended by me, you might have better luck. Good luck if you use them.
03/18/2008 Update: Short block is now almost complete and looks very nice. One problem though: One of the ARP2000 connecting rod bolts is faulty and doesn't stop stretching. New one is required. New engine shop has been doing great job, review about them will be available later.
| Stock head gasket thickness | 1.6 |
| Ex head gasket thickness | 1.2954 |
| Piston pop-up | 0.2921 |
| Quench Stock | 1.3081 |
| Quench Ex | 1.0033 |
03/05/2008 Update: Back to Torque plate hunt. Luckily Tony from VAC Motorsports was able to help and rent me one. Thanks Tony!
02/22/2008 Update: Since there was a huge difference in weights between cylinders,took each part and measured those individually to see where the difference was. Here are the results:
| Cylinder | Wrist pin | Piston | Rod w/o bearings | Total |
Diff to lightest |
|
Cyl 1 |
120 | 498 | 660 | 1278 | 1 |
| Cyl 2 | 120 | 498 | 659 | 1277 | 0 |
| Cyl 3 | 120 | 499 | 661 | 1280 | 3 |
| Cyl 4 | 120 | 500 | 663 | 1283 | 6 |
| Total | 5118 |
No wonder why S14 in known for it's vibrations!. 6 grams is a huge difference... New engine max difference between cylinders will be less than 1gram. Savings in piston, rod and wrist pin rotating mass in total is almost 4kg (989.6gr/cylinder). This together with lighter valve train should make it rev.
02/22/2008 Update: Engine block is now at machine shop and should be ready 03/04/2008.
02/21/2008 Update: Having trouble in locating a machine shop with torque plate! One reputable shop in Seattle area doesn't use one and they have done a lot f 4-cyl engines over the years. They said they don't need one and there is no difference in honing without it. For fun I asked about what king of roundness and taper they can quarantee if we hone it without the plate? Guess what, suddenly torque plate was needed...
I asked this also from Wiseco who provides the pistons. Keith said the last honing strokes should be done with 280 grid and don't do the 400 grid plateau hone. Totalseal, who provides the rings says only way is to hone with torque plate and they won't give any spec for honing without it.
Finally I was able to find one shop with it and hopefully we can come into terms and get the bring and honing done. Wil go and see the shop tomorrow, more to come..
02/14/2008 Update: Piston and connecting rod weights:
| Item | OEM | Ex | Notes |
| Piston | 498 | 394 | without wrist pins |
| Wrist pin | 120 | 91 | |
| Connecting rod | 659 | 546 | without bearings |
| Total | 1277gr | 1031gr |
Total weight saving: 246gr.
All pistons, rods and wrist pins are equal weight.
All parts are now in and finally I can take the block to machine shop!
Some piston details:
| Item | OEM | Ex | Notes |
| Dome depth | -1.4 | -0.76 | mm |
| Intake valve relief depth | -2.4 | -4.95 | mm |
| Piston Volume | 8 | 6 | cc |
| Wrist pin offsett | 0.9 | 0.75 | mm, towards intake |
02/11/2008 Update: Head is now back from Finland and looks pretty good. Nothing else has really happened after last update, still waiting for parts. Pistons came in today and look very good. One slight problem: Wrist pins are wrong, too heavy. 111gr vs 89 what they should have been. Arrow connecting rods should come in tomorrow with bearings and EVO3 oil pump. Block will go into machine shop this friday.
01/12/2008 Update: Since my intake system will be pretty different compared to stock M3 intake system, I need to figure out what intake runner lenght is the best for my setup. If Stock M3 torque peak is at 4750 rpm, it is tuned to 4th harmonic of the intake pulse. 2nd harmonic in stock setup is around 9000 rpm, so it is pretty much unusable. But due to my different setup, bigger throttle bodies, longer duration cams, I can take advantage of the second harmonic and boost also higher RPM's.
Comparison where intake pulse harmonics hit with 43.7cm intake runner lenght:
| Harmonic | 4 | 2 |
| Stock M3 | 4500 | 9000 |
| M3 EX | 4100 | 8200 |
By changing the lenght of the airhorn depending what the RPM is, I could move my torque peak quite easily.
If I move the runner 7cm, I can move the torque peak between 4000-4700 and 8000-9400. Ferrari engine below uses this approach and has smaller airhorns inside which extend out from the airhorn by extending the lenght of the runner. Need to go and copy that design.
01/11/2008 Update: Valvetrain is now ready, Weights compared to stock:
| Item | Stock | M3 EX | Diff | Notes |
|
Cam follower weight |
79gr. | 51gr. | 21gr. | Stock weight with 2.85mm lash cap |
| Lash cap weight | tbd | 0gr. | EX design doesn't use lash caps | |
| Spring pressure Closed | 30.6kg | 30.2kg | 0.4kg | |
| Spring pressure Open | 98.5kg | 86.2kg | ||
Valvetrain is adjusted for 9500 rpm redline.
01/05/2008 Update: First HP simulation done. Observation is that as expected due to agressive cams, torque and power at low rpms is low. Have to invent something to improve this. Maybe this could be fixed with adjustable air intake system like modern cars.
01/03/2008 Update: Final Cylinder bore and Piston spec
| Item | Value | Notes |
| Cylinder Bore | 93.6312mm | |
| Piston diameter | 93.555 | 1st Standard BMW Oversize |
| Wall-Piston diameter | 0.076mm | |
| Piston design | Risto Virtala Racing, Finland | |
| Piston Manufacturer | Wiseco | |
| Piston Material | 2618 Forged Aluminium | |
|
Piston wrist pin weight |
89gr. | |
| Coatings | Skirts and dome | |
| Piston rings | Total Seal 1st: 1.2mm, 2nd: 1.5mm, Oil: 3mm oil |
Head is now done and based on our calculations max power would be about 326hp provided everything else is perfect.
12/30/2007 Update: Weights of pistons, rings, wrist pins, connecting rods and bearings:
| Item | Weight (gr) | |||||||||
|
Piston 1 |
1336 | |||||||||
|
Piston 2 |
1329 | |||||||||
|
Piston 3 |
1333 | |||||||||
|
Piston 4 |
1331 |
12/29/2007 Update: Pistons and block are now measured.
|
Item |
BMW Spec |
Measured min - max (mm) |
max wear (mm) | |
|
Cyl 1 |
93.4 | 93.4127 - 93.44445 | 0.04445 | |
|
Cyl 2 |
93.4 | 93.4000 - 93.4508 | 0.0508 | |
|
Cyl 3 |
93.4 | 93.4127 - 93.4508 | 0.0508 | |
|
Cyl 4 |
93.4 | 93.4127 - 93.4381 | 0.0381 | |
|
Piston - wall clearance (mm) |
||||
|
Piston 1 |
93.355 | 93.3069 | 0.13755 | |
|
Piston 2 |
93.355 | 93.3069 | 0.1439 | Signs of overheating |
|
Piston 3 |
93.355 | 93.2942 | 0.1566 | |
|
Piston 4 |
93.355 | 93.3069 | 0.1312 |
So, pretty good for 153kmile car. Next oversize piston is size 93.555, so those will be ordered. With luck I could fit 93.405 "00" pistons, but due to "windows" I won't take the risk since I will be buying custom pistons. Piston - wall clearance needs to be bigger due to forged piston compared to stock cast pistons.
12/21/2007 Update: M3 Ex head is now ported and results are below. Measurements were done with the same pressure what Metric Mechanic used and MM values are from their brochure.
Remember that Flowbench is just a tool...
Some pictures of the timing chain guides. One of them was broken and one really worn.
Interesting picture of the HOME tooth. This explains some ignition timing issues I had. Tooth has obviously hit the sensor and is bent now. Will have to be replaced.
Pistons were original from the factory.
12/08/2007 Update: Stock valve springs were measured.
Valve cosed 30.6 kg
5 mm 52.4 #
7 mm 64.1 #
9 mm 75.7 #
10 mm 83.6 #
11 mm 91.1 #
12 mm 98.5 #
Schrick info will follow when parts are available. Head porting has been started.
11/25/2007 Update: Cylinder head is now removed and so far it looks everything is looking pretty good. Following was found:
- Timing chain guides must be replaced. Not a surprise.
- All valves are in perfect condition. None bent or damaged.
- All pistons are in good condition.
- Original oilpump is in perfect condition and reused. Middle plate will be changed
- Block not cracked anywhere.
- Reason to oil leak was found, it was the head gasket close to timing chain.
- Intake camshaft was pitted. Will be replaced anyway and this was known. Exhaust side is good.
Cylinder head will be shipped to Finland this week and work will start Saturday. Block will be taken to machine shop here. Block will be measured to see what oversize pistons I have to order.
My engine has about 150k and it is time to refresh it before the "Kablamo" is heard. So, during this winter it will be opened. Goal is the do the best possible (Durable, street and track drivable) engine with reasonable budget. Earlier I had a vote to decide what to do with my engine. Sorry Doug & Co who voted for 2.5L. I decided to stay in 2.3L for now, maybe 2.5L time will come some day. If it comes, I'll do it with proper Evo block instead of boring the one I have now. 2.3L should be quick enough to get me into trouble.
Spec for the engine is as follows:
Displacement: 2.3L
Compression ratio: 11:1
Use: 60% Street, rest autocross and track
Durability: Has to last app 50k before next refresh.
Connecting rods: Original, blueprinted
Crankshaft: Original, blueprinted
RPM limit: 9500
Pistons: Wiseco Grp A copy. Coated skirt and dome. Piston pin weight: 89gr.
EVO3 oil pump
Bearings: Coated Calico
Head:
- Camshafts: Schrick 284 exhaust/292 intake
- Valve Springs: Schrick
- Valves. Schrick, Nimonic Exhaust valves. 38mm intake valves
- Head gasket: Cometic MLS
- Head porting: Intake ports only. Flow good for 320hp.
- Throttle body: 50mm
Performance: app 270hp measured from crankshaft
Emissions: HC: <100
Fun will start maybe in end of November and head will be shipped to Finland for porting. Engine block will be done here in Seattle.