The Journey of Linda and Friends - the M20b31 Lives

[AWDBOB]

Not to mention that you can also sell the M52 crank and get a decent chunk of your money back

That should be a pretty potent combo. My M52 with S52 cams and OBD1 manifold made 225whp

You're exactly right! Just sold my e36 so I'm going to strip the motor down next week and get it all off to the machine shop.

That's what I'm hoping this will make! Or somewhere in the ballpark. I really just want a fun, drivable car that I can have a blast putting some seat time in.

How much horsepower at the wheels are you expecting? Makes a lot of sense to do it your way like you said the s50 or s52s are all pretty high mileage and $1500 just to get the engine.

Yep, that's exactly why I went this route. I'd be happy with anywhere from 215-240whp, but I am not going to fight over a couple hp.

[AWDBOB]

Also, while on the subject, I learned a few things tonight.

M52 blocks and S52 blocks share the same deck height, meaning that the major difference (extra .2L) comes from the bore (84mm vs 86.4mm).

I have to hone my block anyway- talked to my machinist and there's no issue at all boring it to whatever S52 pistons I find, and S52 pistons seem to be fairly cheap.

So I'm just going to go the extra mile and make this thing an S52b32.

[AWDBOB]

And further calculations tell me that if I open up the bore to 87mm (adequate size for many aftermarket Pistons) it'll be a 3.3L. I like where this is going.

[st.petebiodiesel]

And further calculations tell me that if I open up the bore to 87mm (adequate size for many aftermarket Pistons) it'll be a 3.3L. I like where this is going.

I'm glad my thread has inspired you. I've been driving my M50B32 for 2 months now. It's super torquey even in an e36.
Just be aware that with the higher compression pistons you will need to utilize some Torco or any decent octane booster and colder spark plugs to eliminate pinging. 11:1 is about as high as you want to go with 93.



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[AWDBOB]

I'm glad my thread has inspired you. I've been driving my M50B32 for 2 months now. It's super torquey even in an e36.
Just be aware that with the higher compression pistons you will need to utilize some Torco or any decent octane booster and colder spark plugs to eliminate pinging. 11:1 is about as high as you want to go with 93.

Absolutely- I didn't know that the m52 and s52 blocks shared the same deck height and bore spacing or else I would've been planning this a long time ago!

My hope is to go 11.5:1 or somewhere around there.

I will likely go 87mm- considering these JE pistons, but can't find reviews on them.

https://www.ecstuning.com/b-je-pisto.../je297173~jep/

I'm also going to send my s52 cams/throttle body off to riot racing.

[Jaker]

I've been successfully running 11.5:1 compression on my S52 crank/84.5mm 3.0 build for close to 3 years now on 92 octane Chevron (up to 10% ethanol) and 94 octane Chevron (no ethanol). I've got more duration/lift with my Metric Mechanic Rally spec cams which leads to a bit less dynamic compression but it's all tuned on the OBD1 DME by Zack from 22RPD.com to the tune of 270whp/240ft-lbs. An 11.5:1 compression motor with an 87mm bore could actually run "slightly" more ignition advance than an 84.5mm bore motor, or be a little more on the "safe" side with the same timing. Bigger bore generally needs more advance because the flame front has further to travel for complete burn, so it has to start a "bit" sooner.

I recently tore the engine down (don't wanna talk about it, OK?) and there is absolutely no sign anywhere of detonation of any kind.

[st.petebiodiesel]

Absolutely- I didn't know that the m52 and s52 blocks shared the same deck height and bore spacing or else I would've been planning this a long time ago!



My hope is to go 11.5:1 or somewhere around there.



I will likely go 87mm- considering these JE pistons, but can't find reviews on them.



https://www.ecstuning.com/b-je-pisto.../je297173~jep/



I'm also going to send my s52 cams/throttle body off to riot racing.

Just be aware that is you go to 87mm you can't use the stock S52 head gasket. There are many companies that sell aftermarket head gaskets for 87mm bores in many different thicknesses (.070" thick is stock)


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[AWDBOB]

Just be aware that is you go to 87mm you can't use the stock S52 head gasket. There are many companies that sell aftermarket head gaskets for 87mm bores in many different thicknesses (.070" thick is stock)

Yeah, the only annoying part is that I can't seem to find an 87mm NON-MLS gasket.

I've used MLS before on FI applications but I see no reason to run one on a naturally aspirated car.

[AWDBOB]

Trying to get over the hurdles that have been halting progress. The parts piles are growing!






3.73LSD and a Z3 1.9 2.7 turn steering rack!






I got my new fuel lines in and have been working on getting the brake line kit fitment.

There is going to be a 90* at the proportioning valve soon to help that transition.

I'm hoping these lines don't make the pedal feel too mushy- but if they do I have the hard lines from the parts car I can throw on.

[paynemw]

Get after it man!

[AWDBOB]

Get after it man!

I'm trying man! All of the bs with the chassis is holding me up.

I spoke with a few folks about the effect of running braided brake line over hard line (after I spent $225 on that brake line kit) and they stressed how it will ultimately lead to an extremely mushy brake pedal.

So I am now waiting on copper/nickel brake line to come in so I can finally finish this tedious project and get the rear subframe back in the car and start on the front suspension.

I am also on my way to owning every garagistic product offered for the e30.

[AWDBOB]

Someone please tell me that it would be smart to just swap in the M52 and not build the bottom end. If I did that I could use the funds from selling the crank to get cams.

I just want to get this car done and DRIVE it. I don't care whether it makes 200whp or 240whp.

With good cams and bolt ons, will it REALLY be worth having 3.2L over 2.8L?

[e30austin]

I'll bite...

Take the M52 and slam it in, call it a party. If you really want more power, don't waste your money punching your existing engine out, just buy a lower miles S50/52 and be done with it.

As they say, "there's no replacement for displacement."

[oekundar]

Just read all 12 pages and looking forward to your progress. Just now getting into a Brilliant Red iS myself...and the 24v swap is calling me despite the other issues I know I need to tackle.

[AWDBOB]

I'll bite...

Take the M52 and slam it in, call it a party. If you really want more power, don't waste your money punching your existing engine out, just buy a lower miles S50/52 and be done with it.

As they say, "there's no replacement for displacement."

I like your thinking. I am a perfectionist at heart, but my limited time/funds for cars as of late (thanks, life) are forcing me to rethink the foundation of "build it to the tits the first time" mentality and rationalize a bit.

My whole goal for this car (see, first page) was to simply refresh the car and drive it, so I think the M52 will be more than fine to thrash on and have a good time in, and also, it will be set up for 24V so it would be as simple as buying a motor and dropping it in down the road.

Just read all 12 pages and looking forward to your progress. Just now getting into a Brilliant Red iS myself...and the 24v swap is calling me despite the other issues I know I need to tackle.

They're the best, although I'm not biased or anything.

24V is becoming so easy and affordable there's almost no reason to mess with the m20 if it needs anything other than general maintenance.