M52 Conversion: Real World Costs

[Eddie.]

As above basically.

What are the real costs of the swap?

I've asked a couple of people and I have a vague idea, and of course if you went for custom everything, it could get silly expensive.

So, from those that have done it, or are doing it, what sort of expense are we talking?

[nas80]

you could do it for a couple of grand if you do all the labour. however, i warn you,, its a major job and if you think you can run standard brakes and suspension with this engine then you are wrong!

thats why its so expensive, because you have to upgrade the WHOLE CAR. I use all the best stuff and i would never cheap out on something like this. in fact upgrade all your chassis and brakes before thinking about more power that way you wont kill yourself.

at my work we have a poster up in our office.

good, fast and cheap you may choose any two..

If its good and cheap - wont be fast
if its good and fast - wont be cheap
if its fast and cheap - wont be good.

[Eddie.]

Yeah, 'the triangle' works for a lot of things.

I know there are other bits involved, as you say brakes, suspension ect, but the chassis itself is good for the power isn't it, or does it need bracing?

I presume the hardest part is getting it to run, as with most conversions? Wiring for example, does this need to be custom made?

From looking at threads on here, the custom parts needed are:

- Mounts
- Rad
- Exhaust
- Wiring(?)
- Prop

I presume the E36 gearbox fits in the transmission tunnel of the E21 okay?

[e21-Mark]

It's easier to just use a 320/323 m20 gearbox. I would recommend an uprated clutch though and you'll be wanting an m20 flywheel too.

You could probably get the e36 rad in there but the alloy one isn't too spiteful when it comes to cost. You can chop and re-weld the e36 inlet manifold (I may sell mine as I've opted for a six branch this time)

As Nas has said, your original brakes and suspension simply will not cope. An uprated kit from Spax would be ok though, so don't feel you simply must have coilovers. Even 323i brakes, when they're in good condition, are pretty poor. Put them in a car with e36 M3 performance and they're pretty much useless. They were never designed with that much performance in mind. I ran Wilwood 4 pots and a larger master cylinder, braided hoses etc and they still weren't great. I'm working on a solution now, as is Nas, but it's a fair bit of work.

A single silencer exhaust is also considerably cheaper than a twin 323 style.

It's not a cheap conversion but it's cheaper and more powerful than building a 2.7 or 2.8 m20. I spent a considerable amount on a 2.7 with Schrick camshaft etc but as soon as I drove Nas' m50 powered car I knew I wanted to swap. It was Nas who then converted my car to an m52/2.8, to which I did the m50 inlet swap to get 220bhp.

Doing the m52 conversion transformed my car and that's the main reason I opted to take the same route again this time. It's a cracking engine which sounds awesome and a few simple mods can give 240+ bhp. An added bonus is getting 40+mpg too!

[nas80]

well.. yeah its obv worth doing - when i first got mine running properly i couldnt believe the rediculous speed it was capable of lol.

Does the chassis handle it?

Considering the forces your putting through the car (twice as much as bmw intended!) the e21 handles it well. in fact it is pretty hilarious at how you can just smoke your tyres and fly out of junctions sideways. The chassis doesnt flex as such, but all the bushes including the prop center bearing / guibo and the main rear axle bushes and all the front bushes will expose thier weaknesses. Obviously get a strut brace.

Doing the swap

harder way

you can do it a couple of ways really. You can use the the engine and box from the e36 as is, but your diff ratio will be too high and you will need a custom speedo and prop, then you would have devise a way to lose the brake linkage. (this is the method I will be employing on my car) because i have a replacement e12 LSD diff / prop / speedo / brake system.

easier way

You can use the stock m20 5speed box and engine mounts and this allows you to keep your speedo, brake and diff. you will need a custom chopped and rewelded sump and pickup pipe, if you dont you will have about an inch or two of clearence. You could forget that sump modification and just do what fritzbitz does and run your car with the unmodified "suicide sump" and stick the god almighty sump guard there, but then your stuck with a really high ride height.

No matter which way you do it your going to need

Rad (you could cut the front panel out to fit the standard m52 rad?)
you dont NEED a custom exhaust, id hazard a guess you could cut the stock e36 one to bits and if you handy with a welder jerry rig something - not elegant enough for me though.
steering link - engine manifolds will sit too close and it catches.
e34 sump and pickup pipe.
and a load of sundries like pipes / switches / sensors / soldering stuff / paint / fluids etc etc (this stuff adds up pretty quick)
ecu needs hacking to get rid of the ABS nanny state rev limiter.

brakes, suspension, flywheel, clutch, then fuel pump + new fuel lines / cost of a flatbed truck t'exhaust place. it goes on you know - while you got the engine out you may as well paint the bay, while the suspension is off you paint all that stuff too.

You also NEED an LSD - spinning one wheel all the time is the most rubbish thing ever.

Like i said you may think it costs a bit - but you have to think objectively - cos what you end up with is a tarmac shredding hooligan for the price of a reasonably priced diesel 4 door saloon..

[e21-Mark]

By the time my car is finished it'll have cost about £8k (it would have been £10 - 11k but I had most of the bits left from MIB) and I still think it's cheap for what you end up with.

[Eddie.]

Yeah, as engine swaps go, it seems to be on the cheaper side. Dropping any engine into any car is never going to cost a few hundred quid, I'm well aware of that.

It's something I think I would like at some point, I've watched pretty much every video of MIB, Mark, and it sounds sublime. It also appears to go like a rocket too!

I presume standard practise is to buy an E36 328 as a donor, or can you just buy the lump and start from there?

I'll probably do it over winter of this year, as I want to enjoy the car through the summer really, not have it off the road.

[e21-Mark]

I presume standard practise is to buy an E36 328 as a donor, or can you just buy the lump and start from there?

We got this cheap. Ex BMW demo car with known history and all for a couple of hundred quid.



Obviously you can throw loads of money at an engine swap. You don't have to but some folk think big price tags are impressive.

[problemchild75]

my car is around the 10k mark now and TBH its the smaller little bits that bump the price up and I had no intention of sinking anything like into it. ive a huge pile of bills for nuts, bolts, clips, bearings etc that im too scared to add up but I promise you you could buy another decent E21 for what they add up to. once you start you cant stop it WILL get expensive especially seeing that seem to you approach things in the do it right first time manner so far. I was told on this forum within days of buying my e21 that modifying them is expensive...............They were not wrong I wish I had listened

[arshad76]

I've been extremely tempted to do this conversion, except I'm not sure how long I'm going to keep my E21 in the future. I can't think of a better engine for performance, smoothness and fuel economy for an E21. Problem child's and Nas's are top notch conversions, Marks will be too.

If you're planning on keeping yours for a while Ed, I'd do the conversion tomorrow. I've already gone to the expense of a 325i conversion, but if yours is unmodified then I'd go for it. It would be the first series 1 car I've seen with the conversion too.

[Eddie.]

Nobody has done a series 1? You mean an early one, like mine?

Why have you told me that?!? Now I want it even more!

Hmmmm, I do have a do it right attitude, but then at the same time, I love nothing more than a bargain. Having said that, £10k (including the purchase of the car) for something that would give an M3 a run for its money (right?) is extremely good value.

[nas80]

if you need encouragement get someone to take you out in a 24v. start putting money aside cos you will want to do it.

i can help with supplying parts n tech support if you have the spanner juggling skills

[e21-Mark]

Having said that, £10k (including the purchase of the car) for something that would give an M3 a run for its money (right?) is extremely good value.

Plus an e21 looks way cooler and you wouldn't have to suffer that horrible Vadar interior!

[Eddie.]

if you need encouragement get someone to take you out in a 24v. start putting money aside cos you will want to do it.

i can help with supplying parts n tech support if you have the spanner juggling skills

Nice one

Certainly between me and some of my friends (one of which is very technical and spanner handy) I think I could do 90% of it at home. Obviously the custom sump and radiator I would have to send off for.

Having said that, £10k (including the purchase of the car) for something that would give an M3 a run for its money (right?) is extremely good value.

Plus an e21 looks way cooler and you wouldn't have to suffer that horrible Vadar interior!

Yeah, my mate has a Techno Violet E36 M3 Evo, it's a nice car, all things considered. The interior is woeful in comparison to my other mates E46 330ci though. (yes, we are a bunch of BMW whores).

As advised, I think I'll start putting money to one side each month, get a saved search on eBay for E36 328's and start collecting parts.

Sigh.

[TopCat]

One question I would like to ask the experts here iro engine conversions

And the solution might possible help with RHD brake setups.............

Why can't the engine be mounted vertically (like all Nissan's RB motors) in the engine bay -with a nice dry sump to eliminate the depth issues? Have seen an article with early BMWs fitted with a vertically mounted Nissan RB.

This would free up space alongside the engine for a proper brake unit and ancillaries?
just a thought.........