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Terroth

Another basic Engine swap ? Thread

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Sorry to bother all the bimmerheads with such a basic question but I'm a little bit confused after much research on R3v, Bimmersport/Forums and E30Zone, and i'm looking for a bit of clarification (spoon feeding)

I'm looking to do the simple m20b20 to m20b25 swap, easy enough right, plug and play. However the E30Zone wiki has me a bit confused on my parts list.

Assuming My car is m20b20 1989 FL and the donor is M20B25 1989 FL too, is my parts list correct as follows

Full Engine -

ECU

Injectors

Intake Manifold

Throttle Body

AFM

Exhaust

I'm assuming my Getrag 240 and 4.1.1 Diff will work perfectly fine with the B25 swap, although might be a bit high revv happy?

Next part confuses me

I'm assuming that from the list I wont need the following

Engine Mounts

Cooling system

Gearbox Mounts

Loom

Alternator

Starter motor / flywheel

Cheers guys

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You're right,

Cooling system and engine mounts can be swapped straight over as far as I know. Consider replacing the mounts with new ones while you're there, much easier while you're already in the process and they don't cost much.

As far as the gearbox, if it's the same box I can't see why the mount would be any different so should be fine.

Not sure about the other items, and having never done the swap myself I may be wrong with what I've said above but having researched M20s a lot they're almost identical externally.

Maybe someone who knows for sure will see it and correct me or add to what I've said.

Good luck, consider this a 'bump'

Edit: Here's an idea, find the VIN of a 89' 320i and an 89' 325i. Go on realoem.com and compare the part numbers for the parts you've mentioned. If they are the same for each vehicle then you can be certain they're the same

Edited by Kepes

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You have the right bits, it is all just plug and play.

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Possibly will need a B25 loom over the B20, in part due to oil sensor location etc, but other than that should be all the same.

May also need to modify the exhaust and/or put a 325i exhaust on, 320i have single pipe 325i dual, cant remember the differences in the headers between the two but from memory are different, however mounting to the head is the same, so you could put the 320i headers on the 325i engine and then run the 320i exhuast. not the correct way to do the swap though.

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Possibly will need a B25 loom over the B20, in part due to oil sensor location etc, but other than that should be all the same.

May also need to modify the exhaust and/or put a 325i exhaust on, 320i have single pipe 325i dual, cant remember the differences in the headers between the two but from memory are different, however mounting to the head is the same, so you could put the 320i headers on the 325i engine and then run the 320i exhuast. not the correct way to do the swap though.

Cheers all for the replies, hadn't checked this topic as I thought there wasn't any.

I am part way through the swap, and have successfully pulled out my old engine without too many issues so far. Fairly proud as i had previously not done much more than basic maintenance.

As for the loom, I have both the current 320i Loom in my car as well as a 325i Loom that i got when i purchased the engine. I have checked over these two and they both appear to be exactly the same.

As for the headers / Exhaust, my current headers and the ones i received with the 325i Engine also appear exactly the same, are you certain the downpipes are different? As i have a dual pipe leading down to the mid section muffler ( or cat, not too sure at this point ) followed by a custom 2.5" exhaust through to the back, so I dont think i will have any breathing issues.

Obviously i've ran into a few hitches along the way, the exhaust headers wouldn't unbolt from the downpipe so I had to just manouver them out of the way when removing the engine, wasn't nearly as big of a hassle as I had imagined, but now that there is more space it may be easier to do so, with the steering in the way its a right pain to get a good angle.

One of the engine mounts ripped completely out, the threaded rod + plate that is connected to the rubber mount just ripped out completely on one side with a little shake once the hoist was hooked up. Must of been deteriorated to crumbly weetbix before the removal.

Some of the hoses had deteriorated as well, and broke off.

I am about to order in some replacement parts, if anyone has some recommendations as to what i could add to the order that'd be primo.

So far i am just ordering

New shifter bushings etc

New P/S / Alternator belts

Cambelt, Waterpump kit

New Engine mounts

Clutch kit

New Flex disk

New Exhaust manifold studs / nuts

Oil / Air filters

Spark Plugs

Any other refresh parts i should get while I am at it?

Edited by Terroth

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Fuel filter and distributor rotor and cap? Check the latter two for wear anyway.

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Fuel filter and distributor rotor and cap? Check the latter two for wear anyway.

Distributor rotor and cap appear to be fine.

Fuel filter is the filter that is behind / near the rear suspension correct?

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yes back of the car just forward of rear wheel, both simple enough to do after the swap, though highly recommend replacing the fuel filter at the same time

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Cheers Andy, I think I will save that for another payday, at the moment the bill is coming up quite large. I am going to use Pelican Parts and pray to god that nothing goes wrong regarding shipping.

Their pricing, easy shopping and parts availability are quite nice, especially regarding rebuilding the shifter mechanism due to all its fidgety and small parts. Its like doing some clothes shopping online really haha.

I will definetely be replacing the fuel filter straight after I get the engine up and running again, as I am not sure how old it is (285K KM old potentially), due to the fact that this will be the third engine this car has seen (Previous owner having overheated the original engine and getting it replaced by a shop in Auckland).

Just noticed that a new fuel filter is only 17NZD from Pelican, into the stockpiled cart it goes

Edited by Terroth

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If manual check the condition of the pivot ball for the clutch fork.

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Although it is in the distant future at this point in time. I would like for this car to be legal as after putting so much money into it, it would be a shame if it was stolen or crashed without a cert, and Insurance would likely not pay out.

Sooooo, regarding certification, using OEM replacement parts is obviously fine. I've had a read of the engine conversion information available on the LVVTA website, as well as the Driveshaft Loop section, and am wondering. Given the stock power output - For safety sake we'll use the lowest output of the 2L engine and highest of the 2.5L, but more than likely between 120-130 for 2L and 160-170 for 2.5L, and the Driveshaft loop requirement section as of 2011 states that a driveshaft loop is required when there is a significant increase in power or torque, which is defined by "A significant increase in power or torque in a low volume vehicle is considered to be over 50% of the vehicle’s factory power output.".

That means that, even with the engine conversion, and having originally had a 320i in it, there is technically speaking not a "significant increase in power or torque" as

Original engine

50% 120HP = 60

50% of 164NM = 82

New engine power output

170HP

226NM

A 50% Increase would therefore have to be 180HP and 246NM of torque, meaning that driveshaft loops are not required as technically stated by the Driveshaft loop section of the LVVTA standards.

Or have i just completely misinterpreted this in hopes of saving a few extra $$ on installing these bloody things and they are required no matter the engine conversion?

Links to sections in question

LVVTA Driveshaft loop Requirement Classification http://www.lvvta.org.nz/documents/infosheets/LVVTA_Info_09-2011_Drive-shaft_Safety_Loop_Requirement_Clarification.pdf

Engine and Drivetrain Conversion section in question http://www.lvvta.org.nz/documents/standards/LVVTA_STD_Engine_&_Drive-train_Conversions.pdf

Any help regarding this legal side would be amazing, and if anyone has gone ahead and installed driveshaft loops, did you use universal trademe jobbies or get them custom made to suit?

Cheers again guys

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ANY engine conversion in a front engine/rear dive car, requires driveshaft hoops... EVEN if you use all factory parts and effectively make it the same as a factory built car.

2.5(8) A front-engine, rear-wheel drive low volume vehicle that has undergone an engine conversion, or has had its factory-fitted engine significantly modified, such that a significant increase in power or torque has resulted, must be fitted with an effective 360-degree front drive-shaft loop, mounted within 150 mm rearward of each front drive-shaft universal.

The guy certing it can tell you if you need one, before you go there - just call him and check.

Edited by Allanw

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Cheers Allan, must've just glazed over that part and hoped to high hell that I wouldn't have to get them, pity really, seeing as the bloody driveshafts are practically the same besides length.

Has anyone got experience using those trademe Universal driveshaft loops? Or is it best to just get them fabricated professionally?

150MM rearward of the drive shaft universal would mean that it would be mounted 150mm to the rear of the Center support bearing, or 150mm rear of where it meets the transmission?

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As Allan has shown you will need to fit drive shaft hoops (pita). The other reason I found out was the vin number for your car has certain info ie engine cc, auto, four door, wagon etc.When you change this the vin info is incorrect for this vehicle's current state and needs to be altered and logged with vtnz hence the cert and plate are required. Its to keep all the paper work in order paper war and you have to pay for it to keep it all legal. One of the many joys of modding a vehicle these days best of luck

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150MM rearward of the drive shaft universal would mean that it would be mounted 150mm to the rear of the Center support bearing, or 150mm rear of where it meets the transmission?

Mine were near as makes no difference 150mm either side of the CSB.

Having said that, everyones opinions on the law varies, and at the end of the day, there is only one person you need to satisfy and thats your certifier, so give him a call and ask him what hes expecting. Much cheaper to call him now, get them placed correctly first time, than rely on a forum of different opinion/experience and end up with an extra 4 or 8 holes in your floor. Your cert guy does not charge for the phone calls you give him during the process, and if anything will probably warm him to you for making sure you are getting it right first time, makes it cleaner sailing come time for the actual inspection.

$0.02

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Mine were near as makes no difference 150mm either side of the CSB.

Having said that, everyones opinions on the law varies, and at the end of the day, there is only one person you need to satisfy and thats your certifier, so give him a call and ask him what hes expecting. Much cheaper to call him now, get them placed correctly first time, than rely on a forum of different opinion/experience and end up with an extra 4 or 8 holes in your floor. Your cert guy does not charge for the phone calls you give him during the process, and if anything will probably warm him to you for making sure you are getting it right first time, makes it cleaner sailing come time for the actual inspection.

$0.02

All very good points, it'll be something to think about when it comes closer to the time.

Cheers Andy

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One thing I do want to chime in about is that you want to pay close attention to where your engine looms came from/out of. Did your car have ABS or did the donor 325i have it? I mention this because only SOME looms have a power wire that goes through the C101 connector, that will cause a short if you have an ABS loom in a non ABS car. Which makes lots of burnt wires and smoke - ask me how I know. The good news is that this is super easy to check for (you can just peel back the rubber covering the C101 plugs and look) and also super easy to fix. As long as you know about it that is. More info here http://www.e30zone.net/e30zonewiki/index.php/C101

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I have a Non ABS loom in my car, which I know for certain due to some dodgy roads in Dunedin leading to some dodgy braking. I recall the previous owner advertising ABS delete lines, but I'm guessing if I have a non ABS look and an ABS engine going in I should have no issues?

Thanks for informing me mate, haven't put the new engine in yet as am waiting roughly 2 weeks for replacement parts.

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the drive shaft loops off trademe dont really work haha easy for the front loop near the gearbox but for the 2nd loop after the center bearing the only bits i used were the two "L" brackets the rest was custom.

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Cheers Jib, good to know so i don't go out and waste my money.

The M20 Flywheels are the same between the 2.5 and 2.0 correct? Both engines are motronic Facelift 1.3, just my current flywheel off the 2.0 looks to be in much better condition and the flywheel i recieved with the 2.5 appears to be a bit too light and missing a lot of mass on the engine side of the flywheel, only weighs in at 6.3kg's too according to the trusty bathroom scale.

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Cheers Jib, good to know so i don't go out and waste my money.

The M20 Flywheels are the same between the 2.5 and 2.0 correct? Both engines are motronic Facelift 1.3, just my current flywheel off the 2.0 looks to be in much better condition and the flywheel i recieved with the 2.5 appears to be a bit too light and missing a lot of mass on the engine side of the flywheel, only weighs in at 6.3kg's too according to the trusty bathroom scale.

Its either been machined for a 24v swap or it's an e21 m20 flywheel :)

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Its either been machined for a 24v swap or it's an e21 m20 flywheel :)

How would it handle as a M20B25 flywheel then, quite light / high revving?

If thats the case I'd rather go for my m20b20 one as it looks to have a lot more meat on it, and i'm already running a getrag 240 with a 4.1 diff so 1st and 2nd are going to be f**ken short as it is.

Plus the car is going to be daily'd, so I'd rather not have a super grabby clutch / flywheel setup that will suck dick during traffic

Edited by Terroth
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I have a Non ABS loom in my car, which I know for certain due to some dodgy roads in Dunedin leading to some dodgy braking. I recall the previous owner advertising ABS delete lines, but I'm guessing if I have a non ABS look and an ABS engine going in I should have no issues?

Thanks for informing me mate, haven't put the new engine in yet as am waiting roughly 2 weeks for replacement parts.

Good someone brought this up, i forgot about this.

If the body of your project has ABS, you need an ABS loom or add a wire.

If the body has NO ABS, you need a non-abs loom or DELETE the wire out the plug

Please confirm with the E30 wiki posted above, the wiki is correct, i will be a bit rusty.

Hope this clears it up

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I am not swapping over looms from the B25 as the m20 looms are apparently the same, so should have no issues there. Also the car is non abs so If I do have to swap over the looms I will just delete the ABS wire.

Cheers for the information.

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How would it handle as a M20B25 flywheel then, quite light / high revving?

If thats the case I'd rather go for my m20b20 one as it looks to have a lot more meat on it, and i'm already running a getrag 240 with a 4.1 diff so 1st and 2nd are going to be f**ken short as it is.

Plus the car is going to be daily'd, so I'd rather not have a super grabby clutch / flywheel setup that will suck dick during traffic

Ive driven my mates m20 with a factory lightened flywheel and it's pretty tame. He also had a autoclutch built clutch which IMO was also quite tame.

But then again I only have my car to compare to, and i kinda went full retard. lol

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