Project: BMW E21
Discussion
e21Mark said:
What ballpark re budget?
Unless you really want originality, I would go with a 316 and convert it to 323 spec yourself. Buy a 320/6 and the conversion is easier still, as you'll already have the six cylinder subframe and fuel tank sender.
Ideally backwards of £5,000, would prefer a genuine 323 however mind is definitely open to a project! Is there much you can do to the standard 2.3 to liberate any extra power?Unless you really want originality, I would go with a 316 and convert it to 323 spec yourself. Buy a 320/6 and the conversion is easier still, as you'll already have the six cylinder subframe and fuel tank sender.
Chunkychucky said:
e21Mark said:
What ballpark re budget?
Unless you really want originality, I would go with a 316 and convert it to 323 spec yourself. Buy a 320/6 and the conversion is easier still, as you'll already have the six cylinder subframe and fuel tank sender.
Ideally backwards of £5,000, would prefer a genuine 323 however mind is definitely open to a project! Is there much you can do to the standard 2.3 to liberate any extra power?Unless you really want originality, I would go with a 316 and convert it to 323 spec yourself. Buy a 320/6 and the conversion is easier still, as you'll already have the six cylinder subframe and fuel tank sender.
http://www.bmwe21.net/forum/viewtopic.php?f=5&...
e21Mark said:
You could spend around £400 on a Schrick cam, have some head flow work and a six branch, you could probably get around 160 brake? An e30 325 engine makes 170 for about £250. An m52/2.8 can get you 240 brake, but obviously costs a bit more and means a brake upgrade would be wise. I do know a 323 with Recaros, LSD, Alpina rims etc but it'll need some welding for the next MOT. It's £3250 ono, which given the spec, makes it a potentially good base for restoring.
http://www.bmwe21.net/forum/viewtopic.php?f=5&...
Thanks for that info Mark, I think 160bhp on skinny rubber will be ample for the spirited road use I have planned, plus getting to keep the original lump would be a bonus from an originality point of view. I like the (Alpina?) front air dam on that car, looks nice! Duly bookmarked for future referencehttp://www.bmwe21.net/forum/viewtopic.php?f=5&...
More wiring done today.
Battery terminal all connected up:
Tidied up the wires, they'll be wrapped in proper loom tape once I know everything is running.
The spliced loom plugged in too. I fear I've made the new bit too long, as there's a fair bit of wire hanging down when it's plugged in.
Got the fuel pump wired in on a spare fuse in the fuse box, so it's all proper and correct. Need to wire it to the actual pump still though.
Left to do:
Reverse light switch.
Tachometer.
Ignition coil fitted and wired up.
Oil Pressure Switch.
Few plugs left to sort etc.
ECU mounted and plugged in.
Then anything that's left outstanding.
Battery terminal all connected up:
Tidied up the wires, they'll be wrapped in proper loom tape once I know everything is running.
The spliced loom plugged in too. I fear I've made the new bit too long, as there's a fair bit of wire hanging down when it's plugged in.
Got the fuel pump wired in on a spare fuse in the fuse box, so it's all proper and correct. Need to wire it to the actual pump still though.
Left to do:
Reverse light switch.
Tachometer.
Ignition coil fitted and wired up.
Oil Pressure Switch.
Few plugs left to sort etc.
ECU mounted and plugged in.
Then anything that's left outstanding.
Not got any pictorial updates at the moment but progress has been great recently.
Most of the wiring is done, need to do the fuel pump still, got a few questions that need answering but I'm getting there.
Airbox is on, with brackets made. Expansion bottle is fitted, brackets made. Radiator is fitted. Ignition coil is fitted. Wiring loom is in place, and just needs a cut making in the firewall for the ECU to be mounted. Oil pressure switch is wired in. Exhaust downpipes are fitted.
Need to order some bits ready for some work on Friday, hopefully will be turning it over soon.
Most of the wiring is done, need to do the fuel pump still, got a few questions that need answering but I'm getting there.
Airbox is on, with brackets made. Expansion bottle is fitted, brackets made. Radiator is fitted. Ignition coil is fitted. Wiring loom is in place, and just needs a cut making in the firewall for the ECU to be mounted. Oil pressure switch is wired in. Exhaust downpipes are fitted.
Need to order some bits ready for some work on Friday, hopefully will be turning it over soon.
Got a load of work done today, lots of jobs that needed doing.
Radiator mounted:
Coolant bottle mounted:
[url=https://flic.kr/p/n1hqxw]
Airbox mounted, just need some jubilee clips for the rubber boot:
The loom leading to the ECU needs to pass through the firewall somewhere. I've decided to house the ECU in the space under the scuttle panel. It'll be stored in a waterproof case to protect it from moisture. So the I cut a notch in the firewall in front of the heater fans:
Then with the modified scuttle panel fitted:
E30 coil is mounted in the OEM E21 position:
The standard E30 oil lines don't fit on the E21, so I cut them and I will fit rubber oil hoses between the hard ends:
Fitted on the car:
Oil cooler fitted on the car, sat in front of the radiator, I'm hoping the space between the cooler and the radiator will be sufficient to allow for the electric rad fan.
Also got the adapter fitted for the radiator fan temperature switch, put it in the top hose so as to get the correct temperature reading. For some reason the top house mounting point is in such a place that there is no way that it could be done in one single bit of hose, so it has to bend away from the 'stat housing and then back around. As a note, that hideous blue anodized adapter will be painted black. I can't stand for colours like that!
Engine bay is looking very full now. I've got a few bits on order, including the somewhat vital part that is the ignition coil main wire to the distributor. On back order from BMW, so I can only hope that it turns up soon.
I'm "hoping" to start it over Easter weekend, but it all depends if the parts I need arrive in time. Fingers crossed.
Radiator mounted:
Coolant bottle mounted:
[url=https://flic.kr/p/n1hqxw]
Airbox mounted, just need some jubilee clips for the rubber boot:
The loom leading to the ECU needs to pass through the firewall somewhere. I've decided to house the ECU in the space under the scuttle panel. It'll be stored in a waterproof case to protect it from moisture. So the I cut a notch in the firewall in front of the heater fans:
Then with the modified scuttle panel fitted:
E30 coil is mounted in the OEM E21 position:
The standard E30 oil lines don't fit on the E21, so I cut them and I will fit rubber oil hoses between the hard ends:
Fitted on the car:
Oil cooler fitted on the car, sat in front of the radiator, I'm hoping the space between the cooler and the radiator will be sufficient to allow for the electric rad fan.
Also got the adapter fitted for the radiator fan temperature switch, put it in the top hose so as to get the correct temperature reading. For some reason the top house mounting point is in such a place that there is no way that it could be done in one single bit of hose, so it has to bend away from the 'stat housing and then back around. As a note, that hideous blue anodized adapter will be painted black. I can't stand for colours like that!
Engine bay is looking very full now. I've got a few bits on order, including the somewhat vital part that is the ignition coil main wire to the distributor. On back order from BMW, so I can only hope that it turns up soon.
I'm "hoping" to start it over Easter weekend, but it all depends if the parts I need arrive in time. Fingers crossed.
So today was the first attempted start of the M20. Key word being "attempted".
First off, there was no starter motor, turned out I'd missed a ground strap, and the switched live on the SM had come undone, so that was fixed, but the SM tried to crank as soon as I connected the battery, that was because the switched live and permanent live (from the battery) were too close, and were arcing across. Some insulation tape and relocation of the wires sorted that.
With the engine now cranking, it was time to check the fuel pump, which seemed to be okay (apart from me forgetting to fit the fuse that I had wired in!).
So the engine was getting fuel and crank, but at this point we identified that there was no spark. The coil was getting the required 12v, and the resistance between post 1 (-) and 15 (+) was the correct 0.5 OHMs, the king post was the correct 5000 OHMs, and the coil to dizzy lead was the correct 2000 OHMs, so all seemed fine there.
Anyway, I started looking at sensors and the possibility of the ECU not providing spark. CPS at the front of the engine was fine, but I noticed that the gearbox that came with the engine had two sensors in the bell housing. One is a speed sensor (irrelevant to me) and the other is a CPS reference sensor (or so I believe) The gearbox that is on my engine is an E21 gearbox and is required as it has the necessary provision for the mechanical speedo drive. That E21 gearbox does not have a provision for the CPS reference sensor, which means the ECU isn't getting a signal that it thinks it should be, and thus is not providing me with a spark.
So my options are:
- Run the E30 gearbox and use a GPS speedo drive + other mods.
- Keep the E21 gearbox and upgrade my Motronic 1.0 to a Motronic 1.3.
I'll probably be doing the latter because the gearbox swap requires the engine to come back out, and also means bodging the speedo. The Motronic 1.3 swap would be better because the M1.3 doesn't require the CPS reference signal, it uses a single sensor on the crank at the front of the engine. There is a cost issue with the swap though, as I'd need a fair few bits, but it's still probably the best option for me.
I also noticed that my ICV seemed to be on permanently, suggesting it was somehow on a permanent live. I'll see if that is still the case when I swap over to M1.3 and if so, address it then.
So in all, it seems my work/mods are fine, and the car would have started today had I known about the CPS ref sensor, but these things happen I guess.
Off to eBay I go to cost it up...
First off, there was no starter motor, turned out I'd missed a ground strap, and the switched live on the SM had come undone, so that was fixed, but the SM tried to crank as soon as I connected the battery, that was because the switched live and permanent live (from the battery) were too close, and were arcing across. Some insulation tape and relocation of the wires sorted that.
With the engine now cranking, it was time to check the fuel pump, which seemed to be okay (apart from me forgetting to fit the fuse that I had wired in!).
So the engine was getting fuel and crank, but at this point we identified that there was no spark. The coil was getting the required 12v, and the resistance between post 1 (-) and 15 (+) was the correct 0.5 OHMs, the king post was the correct 5000 OHMs, and the coil to dizzy lead was the correct 2000 OHMs, so all seemed fine there.
Anyway, I started looking at sensors and the possibility of the ECU not providing spark. CPS at the front of the engine was fine, but I noticed that the gearbox that came with the engine had two sensors in the bell housing. One is a speed sensor (irrelevant to me) and the other is a CPS reference sensor (or so I believe) The gearbox that is on my engine is an E21 gearbox and is required as it has the necessary provision for the mechanical speedo drive. That E21 gearbox does not have a provision for the CPS reference sensor, which means the ECU isn't getting a signal that it thinks it should be, and thus is not providing me with a spark.
So my options are:
- Run the E30 gearbox and use a GPS speedo drive + other mods.
- Keep the E21 gearbox and upgrade my Motronic 1.0 to a Motronic 1.3.
I'll probably be doing the latter because the gearbox swap requires the engine to come back out, and also means bodging the speedo. The Motronic 1.3 swap would be better because the M1.3 doesn't require the CPS reference signal, it uses a single sensor on the crank at the front of the engine. There is a cost issue with the swap though, as I'd need a fair few bits, but it's still probably the best option for me.
I also noticed that my ICV seemed to be on permanently, suggesting it was somehow on a permanent live. I'll see if that is still the case when I swap over to M1.3 and if so, address it then.
So in all, it seems my work/mods are fine, and the car would have started today had I known about the CPS ref sensor, but these things happen I guess.
Off to eBay I go to cost it up...
So, I bought a new rad the other day, as the previous one was both the incorrect rad, and it also leaked.
Got it fitted today, just need the coolant hoses to arrive and I'll get it setup.
Then this weekend, I need to cut my splices out for the injector loom and resolder on the C191 plug which allows me to plug the injector wiring in via the OEM plug. This plug is a known water/dirt trap, but I want to get things as OEM as possible so I can eliminate anything that might be causing this misfiring.
Got it fitted today, just need the coolant hoses to arrive and I'll get it setup.
Then this weekend, I need to cut my splices out for the injector loom and resolder on the C191 plug which allows me to plug the injector wiring in via the OEM plug. This plug is a known water/dirt trap, but I want to get things as OEM as possible so I can eliminate anything that might be causing this misfiring.
It's been too long since an update, been very busy with the car and a new job.
It's a bit of a mixed bag at the moment. The engine runs very smoothly, no lumpiness or misfiring any more, but unfortunately it's revving very high, and I'm not talking a little bit high, it sounds like it's 3k+ and slowly climbing.
This high idle could be cause by the lack of back pressure, as there is not a complete exhaust at the moment, something I'm in the process of sorting. After a chat with Jord, we think it might be injector related, as I had the injectors doing this after the engine stalled:
http://www.youtube.com/watch?v=ICz-c3I0zaA&...
So I did some reading and it turns out that there were some very early, high impedance injectors, mainly Jetronic. The later cars all had low impedance injectors. The readings for the two types of injectors are as follows:
HI: 14.5 Ohms - 17.5 Ohms
LI: 2.5 Ohms - 3.0 Ohms
I tested the resistance of mine tonight, circa 16.0 Ohms. So it might well be that mine are somehow the wrong ones. The part numbers do vary it would seem, so I'm going to try a set of later ones, and see if the resistance is different, and if so, swap them, if not, back to the drawing board.
I have a very helpful breaker from E30Zone who is helping me no end with spare parts, and trying to find the issue.
ICV might well be at fault, but I'm not convinced it could cause such a high idle. The important thing to remember is the idle is smooth, not lumpy at all, suggesting it's not an air leak, as I believe a massive air leak would cause crappy running.
We tried blocking various things up to see what does what, and the only way to bring the idle down was the block the ICV, and open the hole in the rubber boot between the AFM and the TB that the ICV was in. When we did that, the engine idle dropped, ran rough, then died.
Had a look at the AFM tonight, and it seems spanking new inside, all clean and looked fine. Same story with the Throttle Position Sensor, which was perfect inside, no gunk or crap which is commonly found in there.
Next step is sort the exhaust so I have adequate back pressure. Then go from there.
It's a bit of a mixed bag at the moment. The engine runs very smoothly, no lumpiness or misfiring any more, but unfortunately it's revving very high, and I'm not talking a little bit high, it sounds like it's 3k+ and slowly climbing.
This high idle could be cause by the lack of back pressure, as there is not a complete exhaust at the moment, something I'm in the process of sorting. After a chat with Jord, we think it might be injector related, as I had the injectors doing this after the engine stalled:
http://www.youtube.com/watch?v=ICz-c3I0zaA&...
So I did some reading and it turns out that there were some very early, high impedance injectors, mainly Jetronic. The later cars all had low impedance injectors. The readings for the two types of injectors are as follows:
HI: 14.5 Ohms - 17.5 Ohms
LI: 2.5 Ohms - 3.0 Ohms
I tested the resistance of mine tonight, circa 16.0 Ohms. So it might well be that mine are somehow the wrong ones. The part numbers do vary it would seem, so I'm going to try a set of later ones, and see if the resistance is different, and if so, swap them, if not, back to the drawing board.
I have a very helpful breaker from E30Zone who is helping me no end with spare parts, and trying to find the issue.
ICV might well be at fault, but I'm not convinced it could cause such a high idle. The important thing to remember is the idle is smooth, not lumpy at all, suggesting it's not an air leak, as I believe a massive air leak would cause crappy running.
We tried blocking various things up to see what does what, and the only way to bring the idle down was the block the ICV, and open the hole in the rubber boot between the AFM and the TB that the ICV was in. When we did that, the engine idle dropped, ran rough, then died.
Had a look at the AFM tonight, and it seems spanking new inside, all clean and looked fine. Same story with the Throttle Position Sensor, which was perfect inside, no gunk or crap which is commonly found in there.
Next step is sort the exhaust so I have adequate back pressure. Then go from there.
So, the high idle is sorted! 
It was the simplest, and most obvious thing it could have possibly been! I actually felt pretty stupid once I noticed it!
Anyway, I'll explain myself:
So I looked at the realOEM drawings for the brake booster vacuum hoses and followed them. Anyway the rubber boot I bought from BMW had an outlet on the right, which matched the drawings, so I hooked it up as per the drawing.
I've illustrated it below:
14168432057_35605a7a70_o by Eddie the Kid, on Flickr
Blue line is air passing up the boot to the throttle body.
Purple is throttle body.
Red is air passing up the boot and through the ICV.
Yellow is air passing up the boot, through the brake booster hoses, and in behind the throttle body.
So obviously air was getting in, unmetered, causing the idle to shoot up. Such a simple mistake to make, but at least I've found it.
As a note, the injectors are spot on, and the various other sensors seem okay, although I want to do some more electrical tests.
Anyway, with the idle now at an acceptable level, we noticed that when the throttle was opened, there was some hesitation and slight misfiring, certainly didn't sound good. So we took the spark plugs out, and they looked like this:
Untitled by Eddie the Kid, on Flickr
So yeah, pretty disgusting, so I've already ordered some replacements in the form of some NGK's, which are recommended.
Hopefully that will get things sorted.
It was the simplest, and most obvious thing it could have possibly been! I actually felt pretty stupid once I noticed it!
Anyway, I'll explain myself:
So I looked at the realOEM drawings for the brake booster vacuum hoses and followed them. Anyway the rubber boot I bought from BMW had an outlet on the right, which matched the drawings, so I hooked it up as per the drawing.
I've illustrated it below:
14168432057_35605a7a70_o by Eddie the Kid, on FlickrBlue line is air passing up the boot to the throttle body.
Purple is throttle body.
Red is air passing up the boot and through the ICV.
Yellow is air passing up the boot, through the brake booster hoses, and in behind the throttle body.
So obviously air was getting in, unmetered, causing the idle to shoot up. Such a simple mistake to make, but at least I've found it.
As a note, the injectors are spot on, and the various other sensors seem okay, although I want to do some more electrical tests.
Anyway, with the idle now at an acceptable level, we noticed that when the throttle was opened, there was some hesitation and slight misfiring, certainly didn't sound good. So we took the spark plugs out, and they looked like this:
Untitled by Eddie the Kid, on FlickrSo yeah, pretty disgusting, so I've already ordered some replacements in the form of some NGK's, which are recommended.
Hopefully that will get things sorted.
Edited by eddiethekid on Thursday 5th June 23:42
New spark plugs arrived today, so got them fitted, old on the left, new NGK's on the right:
Slightly different fitting on the connector, but it seems to be fine. Idles well and revs up as it should.
Slight issue with the idle dropping lower than normal when I drop the throttle all the way off. Idle drops down and coughs a touch, then comes back to normal idle. I'm sure I've read about this somewhere before, so it should hopefully be a straightforward fix.
Also went up to Topgear in Stockport to collect my new Y-pipe. This will collect the gases from the two 1.5" downpipes into one 2" pipe that will head off to the backbox.
Plenty to be cracking on with over the next few days and this weekend.
Slightly different fitting on the connector, but it seems to be fine. Idles well and revs up as it should.
Slight issue with the idle dropping lower than normal when I drop the throttle all the way off. Idle drops down and coughs a touch, then comes back to normal idle. I'm sure I've read about this somewhere before, so it should hopefully be a straightforward fix.
Also went up to Topgear in Stockport to collect my new Y-pipe. This will collect the gases from the two 1.5" downpipes into one 2" pipe that will head off to the backbox.
Plenty to be cracking on with over the next few days and this weekend.
Right, the exhaust is on now. It's blowing slightly, but it's on. Firstly, it sounds immense! Such a lovely noise, it's maybe a bit louder than I would like, but I'll run with it for now.
Firstly, cooling system. I need to get it bled properly. Problem is, I don't have any bleed screws or anything so I'll have to bleed it through the expansion tank, something I'm not massively familiar with so I need to figure that out.
I'm worried (I like to worry) about the temperature of the coolant. The gauge is saying it's fine, but it's a 38 year old gauge and frankly I'm not sure I trust it. I need an aftermarket temperature gauge really, something I can fit and it can give me a readout in the car, and I'll just tuck the new gauge away somewhere nice and hidden. I'm open to suggestions for this though.
Next up, with the throttle open and the revs high, there's a fair bit of blue and black smoke, although mainly blue. So it's burning oil. I did a compression test and got the following:
Cyl 1: 148
Cyl 2: 142
Cyl 3: 152
Cyl 4: 155
Cyl 5: 148
Cyl 6: 162
So they seem "okay". That was on a warm engine, with the throttle closed, and all spark plugs removed. I've not done a wet test to compare, so I can't completely eliminate the piston rings. Might well be valve stem seals, it also might just be because it's not been used in a long time, and it just kicking old oil out, I don't know at the moment.
It's very close to being driveable though, when it is, I'll be taking it to an exhuast shop as it 100% needs something better making than my attempt.
Firstly, cooling system. I need to get it bled properly. Problem is, I don't have any bleed screws or anything so I'll have to bleed it through the expansion tank, something I'm not massively familiar with so I need to figure that out.
I'm worried (I like to worry) about the temperature of the coolant. The gauge is saying it's fine, but it's a 38 year old gauge and frankly I'm not sure I trust it. I need an aftermarket temperature gauge really, something I can fit and it can give me a readout in the car, and I'll just tuck the new gauge away somewhere nice and hidden. I'm open to suggestions for this though.
Next up, with the throttle open and the revs high, there's a fair bit of blue and black smoke, although mainly blue. So it's burning oil. I did a compression test and got the following:
Cyl 1: 148
Cyl 2: 142
Cyl 3: 152
Cyl 4: 155
Cyl 5: 148
Cyl 6: 162
So they seem "okay". That was on a warm engine, with the throttle closed, and all spark plugs removed. I've not done a wet test to compare, so I can't completely eliminate the piston rings. Might well be valve stem seals, it also might just be because it's not been used in a long time, and it just kicking old oil out, I don't know at the moment.
It's very close to being driveable though, when it is, I'll be taking it to an exhuast shop as it 100% needs something better making than my attempt.
Before you start worrying about bore wear etc, put a few hundred miles on the engine and give it an oil change. As you say, it hasn't run in ages, so will be wanting a little while to allow everything to bed in. M20 engines are lovely things and those readings seem fine for its age.
I wouldn't worry with the temperature gauge either, although a simple aftermarket one is simple enough to add. You could get the 3 gauge pod from an Audi or VW of the same era and put it in the centre console? I found them on eBay cheaply enough. You can use one of those infrared thermo tool things to check the rad temperature once up to speed.
Anyway, enjoy your first drive!
I wouldn't worry with the temperature gauge either, although a simple aftermarket one is simple enough to add. You could get the 3 gauge pod from an Audi or VW of the same era and put it in the centre console? I found them on eBay cheaply enough. You can use one of those infrared thermo tool things to check the rad temperature once up to speed.
Anyway, enjoy your first drive!
Before you start worrying about bore wear etc, put a few hundred miles on the engine and give it an oil change. As you say, it hasn't run in ages, so will be wanting a little while to allow everything to bed in. M20 engines are lovely things and those readings seem fine for its age.
I wouldn't worry with the temperature gauge either, although a simple aftermarket one is simple enough to add. You could get the 3 gauge pod from an Audi or VW of the same era and put it in the centre console? I found them on eBay cheaply enough. You can use one of those infrared thermo tool things to check the rad temperature once up to speed.
Anyway, enjoy your first drive!
I wouldn't worry with the temperature gauge either, although a simple aftermarket one is simple enough to add. You could get the 3 gauge pod from an Audi or VW of the same era and put it in the centre console? I found them on eBay cheaply enough. You can use one of those infrared thermo tool things to check the rad temperature once up to speed.
Anyway, enjoy your first drive!
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