2.8L M20 9.8:1 stroker build: my 323i reincarnated

[betz]

Your engine build sounds very similar to the spec of mine,

M52 crank, early higher CR 325i pistons, M20B20 rods, 885 head, schrick 272 cam, M50 injectors, Porsche 944 S2 FPR, AEM fuel pump, big bore throttle body and a BTB 6 branch manifold. CR is 11.3:1, had to get the valve reliefs machined so the wasn't valve to piston contact to get that CR.

It was live mapped a couple of weeks ago, still running Bosch M1.3 and made 202bhp. I was hoping for more, but it's so fun to drive, revs quickly and pulls well throughout the rev range, with a nice kick when the cam comes alive. The remapping has made a big difference.

The main trouble I had was getting enough fuel in, the original Bosch pump just wasn't up to it, especially after upping the fuel pressure. I also have to run it on 97.

My head is standard, but I've heard good gains can be had from those 3 angled valve seats, wish I'd got the head fettled a bit before it was all bolted together.

Also, I don't run an oil cooler. Modern oils are so much better, but then I do live in the UK, so our temps aren't as high.

Dang, that CR is crazy high. I have to go to a race track to get octane higher than 91.
Have you considered moving to a standalone EMS?

Probably not going to run an oil cooler to start. Trying to keep it simple since it's my first build. Speaking of which, what oil should I run? Would 5W-30 be to thin even on a basically new motor?

[betz]

It looks like you have the stamped timing sprocket, not the cast one. The stamped steel sprockets are a known failure item and it should have been replaced. My timing belt came off but didn't brake but the timing belt sprocket got destroyed, see attached photo. It's now in three pieces. This caused the 4 rocker arms to brake off.

Oh shit. Thanks for the heads up. Is the timing sprocket that attaches to the cam also prone to failure? I'm assuming the one that goes at the end of the crank is okay, it looks super beefy.

I will def be buying a new IMS sprocket, at $35 its a no brainer.

[TC Baur MD]

It looks like you have the stamped timing sprocket, not the cast one. The stamped steel sprockets are a known failure item and it should have been replaced. My timing belt came off but didn't brake but the timing belt sprocket got destroyed, see attached photo. It's now in three pieces. This caused the 4 rocker arms to brake off.

https://www.r3vlimited.com/board/attachment.php?attachmentid=60512&d=1348451647

[Kedge]

Your engine build sounds very similar to the spec of mine,

M52 crank, early higher CR 325i pistons, M20B20 rods, 885 head, schrick 272 cam, M50 injectors, Porsche 944 S2 FPR, AEM fuel pump, big bore throttle body and a BTB 6 branch manifold. CR is 11.3:1, had to get the valve reliefs machined so the wasn't valve to piston contact to get that CR.

It was live mapped a couple of weeks ago, still running Bosch M1.3 and made 202bhp. I was hoping for more, but it's so fun to drive, revs quickly and pulls well throughout the rev range, with a nice kick when the cam comes alive. The remapping has made a big difference.

The main trouble I had was getting enough fuel in, the original Bosch pump just wasn't up to it, especially after upping the fuel pressure. I also have to run it on 97.

My head is standard, but I've heard good gains can be had from those 3 angled valve seats, wish I'd got the head fettled a bit before it was all bolted together.

Also, I don't run an oil cooler. Modern oils are so much better, but then I do live in the UK, so our temps aren't as high.

[betz]

Graduated to the garage :)

[betz]

Rear main seal


Oil pan



Sprockets harmonic balancer etc

[betz]

keep an eye on temps so add a gauge if you dont have one. many say the stock one has minimal cooling capacity

Would you recommend one of these to plug in a temperature sender?

http://www.ebay.com/itm/Oil-Filter-Sandwich-Plate-For-BMW-E30-E36-M20-Audi-VW-TT-A4-/120646379190

[digger]

Also never considered an oil cooler. Should I?

keep an eye on temps so add a gauge if you dont have one. many say the stock one has minimal cooling capacity

[sert57]

2.85 using s50us crank and a thicker MLS HG. oem pistons and eta rods, and a little bit of block grinding...
MY CR ended up being 9.7:1, so a really similar setup.
I have a bimmerheads 272, IE longtubes, and M52 pink tops, but thats about it for the rest of the mods. mines a solid street motor.

Oil cooler wouldn't hurt. I know etas didn't have them but the i models did. I've got one laying around if you're interested.
Ive never seen actual numerical data for oil temperatures with and without though, so you may be fine. Also not sure how hard they are to retrofit to an early model.

[betz]

So that mystery hole that sits next to the bitch tube and goes into the oil pan.

I may have figured it out. I didn't those mad Germans could come up with anything so clever.

It's the dipstick.

[betz]

Sounds really similar to what I just finished building. If it helps at all I LOVE mine, really wakes the car up. Excited to see your results!

Not running an oil cooler with it?

Fun is the goal :) I'm excited its finally coming together

2.9, did you use custom pistons?

Also never considered an oil cooler. Should I?

[sert57]

Sounds really similar to what I just finished building. If it helps at all I LOVE mine, really wakes the car up. Excited to see your results!

Not running an oil cooler with it?

[wworm]

For our cars they basically just need to pass the sniffer test. That is, get the right C02s and 02s and HCs and whatnot. An overly agressive cam is an easy way to fail. But if I've got a good catalytic converter, and a mild cam I'll probably be good for smog. There is some leeway to the allowed limits.



The timing of the engine will be critical, but as long as everything is dialed in I should be okay.

Good to know. Really looking forward to this.


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[betz]

Still waiting on the valves, package was delayed. Meanwhile I bolted on some accessories to the block, nothing too major.
There's a hole pointing down towards the oil pan on the intake side next to the bitch tube, looks like a plug should go in there. Can't find what went in there in my boxes of stuff though, so idk. Another problem for future me.

[betz]

Would like to hear more about these plans. Wouldn't running such an aggressive non-stock setup be a surefire way to fail smog? Not trying to sound like a smart ass, generally curious as a California native who wants to build an engine.

For our cars they basically just need to pass the sniffer test. That is, get the right C02s and 02s and HCs and whatnot. An overly agressive cam is an easy way to fail. But if I've got a good catalytic converter, and a mild cam I'll probably be good for smog. There is some leeway to the allowed limits.

The timing of the engine will be critical, but as long as everything is dialed in I should be okay.