M20 noob observations-love/hate relationship

[Nohawkscott]

For anyone still interested here, after pulling the eta head and seeing this… I’m having a local machine shop/engine builder (Ray Engine) in Tyler Tx build me a short block using the best block out of the two that I have (with 2mm or so removed from the deck) the 885 head that’s been tested and rebuilt (only needed seals), the m20b25 pistons w/ fresh rings and the eta rods. I guess I’m still going to have to use a standalone pnp if I can’t find a known good b25 AFM I guess.

im not sure how this eta ran with the exhaust valves slapping the pistons but obviously the PO had the cam timing a bit retarded

This is more work than I wanted to do but having a well built 2.7 stroker will be cool. I just hope the eta crank and b25 pistons are usable

[Nohawkscott]

PRO3 has allowed the 'Digital AFM' conversion from Panzer Performance.
If the 'as close to stock as possible and yet reliable' mood hits you...

fwiw,
t

This is cool. I had no idea about Panzer Performance. If I had a m20b25 AFM to send as a core, I would seriously consider this. But after some instagram messages with Jake at Classic Daily I think I’m going to go with his turkey and cheese pnp setup. This will give me the flexibility to go with a turbo down the road if I chose to go that direction. I’m just waiting to hear from the machine shop whether my new/used 885 head is going to be good.

As far as my original misfire issue with the eta, I believe I found the cause during my disassembly. Keep in mind I’ve smoke tested the hell out of this thing and never saw any leaks around the intake flanges but sure enough there were 3 nuts that were very loose. One of them on cylinder 1 was hand tight. I have no idea how my testing didn’t show leaks here? I feel like and idiot for not actually checking these but live and learn…

[TobyB]

PRO3 has allowed the 'Digital AFM' conversion from Panzer Performance.
If the 'as close to stock as possible and yet reliable' mood hits you...

fwiw,
t

[82eye]

Hmm, millers website looks like they are still willing to take my money??

that's a big part of the problem. what you get won't work and you'll be on your own to try and figure it out with zero support. any random google will bring up pages of angry e30 owners.

So the classic daily stuff is working well?

they have support among the board members. there are no large companies doing a maf conversion. keep that in mind. companies like sssquid disappear fast when the market changes. classic daily is no different.

[Nohawkscott]

Hmm, millers website looks like they are still willing to take my money??

So the classic daily stuff is working well?

[82eye]

I’ve decided to do the 885 head and harness swap on the eta block. I got the m20b25 engine and harness/dme but the seller didn’t have the AFM. Is the Miller MAF conversion not a good idea in yalls opinion for the NA 885 head/eta bottom end combo? I was about to buy the Miller PSIK…

miller maf has been dead for a few yrs now. you can't pay people to use them and they never work.

we were talking about this in another thread. there is an ms based plug and play that folk are going to if they want maf, or they are building and tuning an ms kit themselves. that's about it, maybe a couple other aftermarket options requiring dyno tuning etc for big money.

have a look here

https://www.r3vlimited.com/board/forum/general-forums/general-discussion/10145664-what-s-up-with-sssquid

[Nohawkscott]

I’ve decided to do the 885 head and harness swap on the eta block. I got the m20b25 engine and harness/dme but the seller didn’t have the AFM. Is the Miller MAF conversion not a good idea in yalls opinion for the NA 885 head/eta bottom end combo? I was about to buy the Miller PSIK…

[82eye]

Good plan with just using the m20b25 while maybe building the b27 up as a turbo at my leisure. But the eta has a 260 already, pretty sure of that.

you'll have to take apart both engines and mix and match to build the stroker or turbo. going that direction takes the car off the road and leaves it engineless until you complete the build.

you'll need the engine mgmt off the i car to run the stroker, and the i car trans is gonna be the better choice to use. the diff from i will be a better choice as well until you re-gear. the e car is pretty much the bottom end only.

So in your opinion there is no benefit to using something like megasquirt or the classic daily system on anything other than a turbo setup? I’d really like to delete the AFM.

for most things NA i'd stick with the motronic and a good chip. you'll have zero choice but to go to a standalone if you ditch the afm for maf. no one does a maf conversion for NA motronic any longer.

research well, a lot of the maf conversions are a mess even with a standalone. the good news is there is a lot of experience with standalones, turbos, and mafs around, so you should be able to draw on a ton of information.

[Nohawkscott]

I would personally prep the b25 to swap in WITH the getrag 260 and get your eta running right... I have read the 260 is a better transmission than the ones eta's came with (240 I think?). Then you'd have a fresh, running engine and all the time in the world to build it for a turbo if you are in fact ready/equipped to do that.

Check that your throttle switch is working correctly too and that your plug wires are in spec. On a different car I once had a plug wire intermittency that caused booming backfires when the ignition lit after skipping a cycle or two.

Good plan with just using the m20b25 while maybe building the b27 up as a turbo at my leisure. But the eta has a 260 already, pretty sure of that.

New plug wires (NGK) and TPS was taken apart and cleaned. Then reinstalled, adjusted and it’s testing good.

[Nohawkscott]

i came from vw as well.
what do you need another platform doing the same thing as the vw for? just asking. the goals here seem awfully undefined. if you don't know what you want you're not likely to get it.

This is a great point. I did not consider the redundancy of owning 2 turbo’d cars. And yes, most of my car goals are always awfully undefined which is what leads to the snowball effect.




e30 motronics are the dirt simplest of engine mgmt systems. they use a total of 3 sensors. 4 in the e car but one is redundant. even if you turbo that will be the entire number of inputs.

So in your opinion there is no benefit to using something like megasquirt or the classic daily system on anything other than a turbo setup? I’d really like to delete the AFM.




i'm not sure what i'm missing here ... not sure adding complexity and a pile of work and cash to fix something simple is the best path. i would fix the e first so you have a reliable car while you plan the next move.

Starting to agree with keeping it NA..


i'm running normally aspirated and lightly modded. my original plan was engine swap or turbo, i'm really grateful i did neither. i'll never find another e30 here and am happy i didn't ruin it chasing power.

This makes a lot sense. I’m fortunate to have found a one owner car with no rust and no previous accident damage. It makes sense not to do too much to it.

Thanks for the insight and rationale!

[McGyver]

Why did you swap out all the ignition components? Were the old ones bad? I've seen cheap parts wreak havoc (like using a cheap coolant temp sensor).

I've had a set of plug wires fail on one or two plugs and cause big problems. I've also had crazy issues caused by a bad coolant temp sensor (only buy Bosch).

Unless you replace the failed component with the head swap, you'll still have the misfire issue after the swap. Why not focus on getting the car to run right?

I think newer scanners can do everything the old school ones do, but getting something like a Baum Tools CS2000 Data Scanner can really help with troubleshooting Motronic 1.3. They pop up on ebay often, just make sure you get the plug-in cartridge for our year BMW.

[It's Soda Not Pop]

I would personally prep the b25 to swap in WITH the getrag 260 and get your eta running right... I have read the 260 is a better transmission than the ones eta's came with (240 I think?). Then you'd have a fresh, running engine and all the time in the world to build it for a turbo if you are in fact ready/equipped to do that.

Check that your throttle switch is working correctly too and that your plug wires are in spec. On a different car I once had a plug wire intermittency that caused booming backfires when the ignition lit after skipping a cycle or two.

https://www.e30zone.net/e30wiki/index.php/Drivetrain

[88Sedan]

I would personally prep the b25 to swap in WITH the getrag 260 and get your eta running right... I have read the 260 is a better transmission than the ones eta's came with (240 I think?). Then you'd have a fresh, running engine and all the time in the world to build it for a turbo if you are in fact ready/equipped to do that.

Check that your throttle switch is working correctly too and that your plug wires are in spec. On a different car I once had a plug wire intermittency that caused booming backfires when the ignition lit after skipping a cycle or two.

[82eye]

That’s fair. I do realize it seems irrational but I’ve owned a few water cooled VWs with aftermarket turbo and ecu configurations. A turbo car can be reliable, fast and fun but I know it takes some dyno time to get it there. I currently have a mk7 golf r that’s chipped, tuned, big turbo, down pipe, injectors blah, blah and I trust that car to go cross country.

i came from vw as well.
what do you need another platform doing the same thing as the vw for? just asking. the goals here seem awfully undefined. if you don't know what you want you're not likely to get it.

I guess the thing with this ‘85 eta that I feel the least positive about is the ancient motronic management system. I think I have figured out how to troubleshoot this system for the most part but it seems that sensor failures are always right around the corner, which lead to excessively bad A/F mixtures, fouled plugs, ruined O2’s and tow trucks.

e30 motronics are the dirt simplest of engine mgmt systems. they use a total of 3 sensors. 4 in the e car but one is redundant. even if you turbo that will be the entire number of inputs.

I feel my current misfire is due to a bad AFM or the DME itself, or both. The AFM seems hard to test properly without specialized equipment and I hate just replacing parts. Plus there isn’t anyone around here that’s into these old BMW’s so swapping parts isn’t an option. The signal from the DME to coil is a bit concerning too. I don’t see my test light flickering like I think it’s supposed to when grounded to the primary side of the coil

i'm not sure what i'm missing here ... not sure adding complexity and a pile of work and cash to fix something simple is the best path. i would fix the e first so you have a reliable car while you plan the next move.

So am I right in thinking that this early version of Motronic sucks?

it is entirely of it's time. remember the majority of cars were still carbed when these were new.

It seems I have 4 options:

1: Keep replacing the parts needed on the eta

2: Add the i parts to the eta bottom end and maybe go the turbo route in the future, maybe just enjoy ~140hp

3: Go through the M20B25 engine I’m going to buy for 1200 bucks and install it.

4: Tear down both the eta and the i bottom ends and use the i pistons for a proper NA stroker build
This scope of work is something I have less experience at and I’d rather avoid.

Thanks for you feedback 82eye! Keep it coming, I’m fine with taking criticism on topics I’m not a pro on

you have all the options open with the engines available. turbo is only one path. the reliable aspect is what you are ultimately playing russian roulette with. that's simply standard when delving into turbos.

i'm running normally aspirated and lightly modded. my original plan was engine swap or turbo, i'm really grateful i did neither. i'll never find another e30 here and am happy i didn't ruin it chasing power.

[Nohawkscott]

That’s fair. I do realize it seems irrational but I’ve owned a few water cooled VWs with aftermarket turbo and ecu configurations. A turbo car can be reliable, fast and fun but I know it takes some dyno time to get it there. I currently have a mk7 golf r that’s chipped, tuned, big turbo, down pipe, injectors blah, blah and I trust that car to go cross country.

I guess the thing with this ‘85 eta that I feel the least positive about is the ancient motronic management system. I think I have figured out how to troubleshoot this system for the most part but it seems that sensor failures are always right around the corner, which lead to excessively bad A/F mixtures, fouled plugs, ruined O2’s and tow trucks.

I feel my current misfire is due to a bad AFM or the DME itself, or both. The AFM seems hard to test properly without specialized equipment and I hate just replacing parts. Plus there isn’t anyone around here that’s into these old BMW’s so swapping parts isn’t an option. The signal from the DME to coil is a bit concerning too. I don’t see my test light flickering like I think it’s supposed to when grounded to the primary side of the coil

So am I right in thinking that this early version of Motronic sucks?

It seems I have 4 options:

1: Keep replacing the parts needed on the eta

2: Add the i parts to the eta bottom end and maybe go the turbo route in the future, maybe just enjoy ~140hp

3: Go through the M20B25 engine I’m going to buy for 1200 bucks and install it.

4: Tear down both the eta and the i bottom ends and use the i pistons for a proper NA stroker build
This scope of work is something I have less experience at and I’d rather avoid.

Thanks for you feedback 82eye! Keep it coming, I’m fine with taking criticism on topics I’m not a pro on