E30 320 to 325, whats required?

[c9in]

Hi all,

My first post on here and what a friendly place it seems I ve been in the Cossie world for a long time but not really messed about with my E30 runabout as its been bulletproof up until now.
Due to some enthusiastic driving the other day I managed to get a valve to bounce and in turn knacker one of the tops of my valves which is causing a horrible ticking noise as one of the rockers is not hitting the valve straight.

So rather than take the head off and mess about with swapping the valve I was wondering whats the crack with swapping the M20 2.0 engine in my E30 to a M20 2.5? The cars a 90 H plate 2dr manual, could my current gearbox be swapped over? ecu? etc.

I've seen people mention the E36 engine but remember its a runabout and needs to be a quick turn a round to complete the swap.

Any advise welcome

[calder]

from experience (although i swapped the other way)
drive train: gearbox, propshaft, diff, gearshift console/shifter (the bit the gearstick sits in), gear shift rod (the bit between the gear stick and the gear box), and the shock damper metal donut for the 325 that's not on the 320 and there's probably other stuff i've forgotten
Some people say that you *can* use the original propshaft but you'll be stretching/compressing it beyond its safe limits, the problem is that the 320 and 325 boxes are about an inch different in length hence all the above bits. IIRC the 320 box is shorter than the 325. Safer to get new bits all round. Gear stick won't sit central in its position unless you change the shifter and rod.

As an afterthought you might be better keeping the 320 box and drive train for the 325 engine. I looked at the ratios when i was changing the box and thought that the 320 ratios in 2nd and 3rd would be better for the 325 as well as the 320 due to the length of the 2nd and 3rd gears and where it drops you in the rev band in 4th. 4th is same 1:1 ratio on both boxes.
This was for track use not for every day driving and assumed gear change at 5800 - 6000 rpm. Ratios should be close enough that you won't see a difference in normal driving. i wasn't looking at the 325 engine specifically so this doesn't take account of the 325 power and torque curves.
conclusion: you don't really need to change the box and all the other stuff unless you want to get a sport box which i think are a bit rare and pricy.

Engine (obviously), ECU, throttle body (may already be on engine if complete), possibly engine bay wiring loom - these are not always compatible, AFM and there's bound to be more.

If ypu want them I have a 325 gearbox and 325 propshaft for sale if you're anywhere near Kent?

[hairypete]

hmm, not too sure about the gearbox's not workin, i did the conversion on mine almost 2 years ago now, still using the 2 litre prop, clutch and diff and only looking to swap the diff cause i want a drift slag LSD!
its been well and truly hammered since to be totally honest. not to discredit you calder, you may have had something i havnt come across or i might just have been damn lucky! the only trouble i have ever had is from a busted rocker or two, but i put that down to limiter bouncin! lol,

all you need is about 8 hours if your a halfway decent mechanic with a mate and a crane. provided you dont get anything daft happenin. just make sure you get the AFM, ECU (from the 2.5 cause a 2 litre one doesnt work very well!) , oil cooler and all the other ancillaries and it is just a straight swap. undo it, refitting is a reversal of removal. would recommend re tapping the manifolds and replacing all the studs and bolts on both sides cause its much easier when the head is out and makes it easier in the future. change the cambelt cause that pish easy with the lump out and clutch if you really want it to get picky. i personally just went for it! but then i am a bit of an impatient git when i get excited!

but all in all, dead easy job, bonnet off, undo everything, rad out, exhaust off, undo prop, let the box supports off and let the gear stick stuff off, crane and hoist it out, with someone standing on it if you leave the box attached!

at least thats how i remember it, strange, its all a bit fuzzy now! Lol, still, be doing a 2.7 turbo swap out in a couple of weeks, bit of a refresher!

all the best and hope it goes well if you decide to go for it! its so much fun if you do!!!!

http://media.putfile.com/rollin-burnout

[c9in]

Cheers for the input boys sounds like not to much effort is required then which I was hoping.

Another question where do you guys source your bits from, and what sort of money should be be about for half decent 2.5 complete with aux's? I see there is a fair bit for sale from peeps on here but I really dont fancy going all over the place. Local scrapyard has one but is an old D plate and it does not look in the best of condition. Anyone know anywhere Nothants / Leicester way I could have a look?

[Avner]

calder,
can you please eleborate (or post a link to your source) regarding the gearbox differances (especially what ratio does each gear have)?
I have a '85 320i gearbox in the car, and a '87 325 cab in the shed. I always assumed they are identical, at least internally (ratios), but now it turns out they are different.

Avner

[jmc330i]

You dont absolutely need the oil cooler.
If you get one with the 2.5, then use it. But if you cant get one, you just use the 320i setup - take the oil filter off the 320i and remove the threaded section that the filter screws on to (24mm deep socket IIRC) and fit it to the 2.5.

Thats how my 325i is running and its fine.

Oh and welcome BTW