24V Cosworth into Mk4 Cortina

[roundozo]

Hi All!

I am in great need of some help, advice and guidance. Here goes...................

I have a MK4 Cortina currently running a 2.8 V6 out of a Capri. Unfortunately the engine needs a rebuild as I think the crank has warped causing all sorts of issues. The 2.8 currently has a webber 38 on it and to be honest its rather thirsty on fuel as you can imagine. She still runs but I don’t really trust it very much anymore and as I use it as my daily I can’t risk it and the fuel costs are rather high. So to rectify this I’ve bought.............a 24V cossy engine.

The 24v 2.9 V6 is a BOB but comes with all the bits necessary to fit to my Cortina (I think). In my purchase is;

24v 2.9 V6 with 2.8 flywheel and clutch
ECU
Wiring loom
Fuel Pump
Fuel lines
Manifold
Sierra fuel tank (with swirl pot ect)

I will need to get a rad that will cool the engine and will fit but I don’t think that would be a problem. My list of things to do is as follows;

Put battery in the boot
Cut the heater matrix box back a bit so the engine fits in
Modify the fuel tank (either get the sierra tank in or take all the bits out and put in the Cortina tank)
I was then just going to connect to the type 9 I have and the driveshaft and diff already in the car.

The area I need help in is the gearbox and drive shaft. I have been told varying things about what gearbox to use etc. I have a type 9 in there at the moment and was originally told this will be ok on the cosworth engine. Since then I have also been told this will shred it to pieces. I was told to look for an XR4I gearbox to use on the cosworth engine but they are also type 9’s so what’s the difference if any? I have also been told that my current drive shaft (with the rubber bit) will break when used with the cossy engine and would need to change this too. The rear diff on the car is a 2.3 and now I don’t know if this will be ok under the cossy power.

If anyone has done this conversion I would really like some advice and guidance and how you went about your build. Or if you haven’t but know how I would also appreciate your advice

Sorry for the massive message but I’m now not sure what to do regarding transmission.

Thanks in anticipation of your answers!!


George.

[popuptoaster]

2.8 granny rad will go straight in and cool it no bother, the inlet/outlet are in the right place for the 24v as well.

Some people seem to be able to make the type 9 last ok, but i fitted an MT75 with mine, its lighter and stronger, but requires more faffing about to get one and get it in.

Heres my old one.

retrorides.proboards.com/index.cgi?board=readersrides&action=display&thread=36179

[IDY]

I looked into this some years ago as I was thinking of converting my old XR4x4.

IIRC the Type9 is right on the limit of its torque tolerances with the 24v Cosworth, it might last fine or it may die rapidly, difficult to say as so much depends on your driving style, condition of the box in the first place, which automotive gods you have annoyed this week

[roundozo]

The MT75 you fitted, was that a manual or auto? I cant find many manuals out there and most seem to be from transits. i presume that putting the MT75 in i'll need to mod the driveshaft like you did?

cheers for the help though.

[roundozo]

HAHA, unfortunately i tend to annoy most automotive gods, my car history isn't great.

[roundozo]

Something like this rad then?

cgi.ebay.co.uk/FORD-SCORPIO-GRANADA-2-8-RADIATOR-85-87-/110649175104?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item19c3346c40

[IDY]

Apr 1, 2011 14:33:00 GMT roundozo said:

The MT75 you fitted, was that a manual or auto? I cant find many manuals out there and most seem to be from transits.

It is manual, came in 4pot and v6, RWD and 4x4 versions. Unfortunately Ford did not officially sell any V6 RWD cars fitted with it in the UK market so you need to import one, make one or buy one that someone made earlier.

IIRC making one involves using the front casing and internals from a V6 4x4 box and the rear casing and tail shaft from a 4pot RWD box - needs the use of a big press so not an easy DIY project

[roundozo]

hummm. Think i may have found one in Manchester on Ebay;

cgi.ebay.co.uk/FORD-MT-75-GEAR-BOX-99P-START-NO-RESERVE-/320678032071?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4aa9e672c7

[popuptoaster]

Apr 1, 2011 14:36:58 GMT roundozo said:

Something like this rad then?

cgi.ebay.co.uk/FORD-SCORPIO-GRANADA-2-8-RADIATOR-85-87-/110649175104?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item19c3346c40

No, mk2 granny, not Scorpio shape they are to wide.

As said above the MT75 needs to be a V6 rwd one, they pop up on German ebay fairly regular or there are companies here that will do the work, if you have to pay to much for one though you might as well beef up a type 9, lots of things you can do to make them stronger.

[Rev. Dick Deluxe]

2.3 rear end will be fine. Don't the BOB's have immobilized issues though? I think you might need the complete wiring loom and the keys from the donor to make it work.

[popuptoaster]

if you have the ignition lock with the loom and stick the key in it somewhere up under the dash it should work, they run PATS so need the chip in the key to run.

You can use a BOA loom and ECU if your not using the autobox, but you need some way to work the VIS if you do that.

[roundozo]

Been speaking with a few people about this as it is the BOB engine and I don’t have the key or ignition lock but I do have the whole wiring loom etc. They reckon you can get it to work without but we shall see. I might need to buy a megasquirt ECU and then I can get around the immobiliser. Think I’m going to go for the MT75 box otherwise I’ll be back in the garage in no time it seems. Found a few MT75 RWD V6 box’s on ebay so they should be ok.

On another note I want to replace the rubber engine mounts with something a bit stronger. Does anyone know where I can get these as I can’t seem to find any? Also I’m going to replace the front shocks as they're on their way out anyhow but I’m looking for something a bit stiffer to take the extra weight of the engine. Any suggestions as I really don’t know where to start on this one.

Cheers

[popuptoaster]

you want stiffer springs to take the weight, and stiffer spring will mean uprated dampers to match, both are easily available.

I have seen car alarms with PATS bypass on them so they can run remote start, if your happy to spend the money though i'd go mega squirt just to give you more tuning options in the future.

never seen uprated engine mounts for cortinas, the 2.3 ones should be ok on it, never noticed any issues with mine, you could build new mounts to accept tubular urethane bushes if your worried.

Bit of box section with a tube welded across the end, push the bush into the tube and another bit of box with a C section on the end with holes for a bolt to go through the bush.

[sheffieldcortinacentre]

V8 land rover ones are stronger mounts

[racingdave]

sorry to divert the thread roundozo, but from your avatar i can see your reg ends "26T

wouldn't happen to be this car would it?

[roundozo]

No, but thats mighty close. They must have rolled off the production line not too far apart. mines even 526T but starts with "C". Used to be a 2.3 GL. Thats strange though as in your pic that car has two wing mirrors where as i only have a drivers side. hummm.

[popuptoaster]

passenger mirror was an option on most mk4's

[roundozo]

Ah, I see. Quite like having just one. Less things to get broken off!

Popuptoaster, sorry to keep on pestering you but you have been a great source of information for my cosworth project I’m about to start. With regards to the MT75 box, I’ve found a few on eBay that state they are a 5 speed RWD box. Now this, I my mind, is what I need as it’s an MT75, rear wheel drive, manul. But I am also dubious as some of them state they are from a 2.0 DOHC sierras. I am also dubious as I have been told they are quite hard to find but there seems to be a few on the bay. Here’s one I was looking at as it’s reasonably close to where I live;
cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=180648484862&ssPageName=STRK:MEWAX:IT
then theres this one
cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=160567943429&ssPageName=STRK:MEWAX:IT
and then there these?
cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=200594118591&ssPageName=STRK:MEWAX:IT

I just don’t want to buy the wrong one and don’t have any experience with them or a lot of money. I’m trying to do this as cheaply as possible but in the right way. Managed to get the engine, loom, ecu, tank, manifolds etc, etc all for £150 so the budget has a little room to breathe.

Thanks in advance.

[popuptoaster]

you don't want a DOHC rwd box, they only fit the 4 pot engine, the V6 4x4 mk2 Sierra used a MT75 that can be used along with a DOHC 4 pot box to build a V6 rwd gearbox, but its not really a home job. there were a few V6 manual granny scorpios but they are very rare so the boxes are correspondingly rare.

If you see a MT75 and its less than 300 quid, its VERY unlikely to be a V6 rwd gearbox.

There is no cheap way to get a strong manual gearbox to be honest, whatever car your building, to many people want them.

Question I asked myself was

"how often do i want to be laying under the car fitting a new gearbox instead of driving it?"

A healthy MT75 will easily cope with the 24v engine, while a type 9 will be over its torque limit, so you either wear it out and replace it, or beef it up first, either way it costs money.

spend more now, spend less (and less time off the road) later.

150 is a good price for all those bits, but thats gonna be the tiniest part, mine owed me 3 grand before it was painted and before the interior was finished.

[bortaf]

Pretty much everything has been coverd i think, i actually know mnore people with type 9s on 24Vs than MTs, some last, some don't as already said a lot depends on your driving style, don't give it death off the line in first and you'll be ok, one thing i would recomend is a quaif or similar top plate, they are a lot thicker/stronger and help stop the box twisting with the torque of the engine.