Fitting the 24v Cosworth engine into a 2.9 XR4X4

The Flywheel and clutch

The first thing you need to get done is to modify is the fly wheel, as although this should be balanced on the original engine it will not be balanced to the Cosworth engine.

At this point it would be a good idea to think about lightening the flywheel, you may or may not think this is necessary but the thing to remember is the flywheel was designed for use on the engine to smooth out the engine vibration and to collect kinetic energy (torque). By lightening it you might loose some smoothing effect but gain on acceleration slightly, but please take advice and don‘t go to far as it could be dangerous if too much strength is lost by this process. A good short cut here is to use the 2.8 flywheel. This is half the weight of the 2.9 flywheel,However some have found this does not work, the thiner flywheel means the clutch doesnt sit as far out. this is easy to mod, the mt75 box has a piviot for the reliese arm, remove it and weld a threaded rod to the back of it like this (note the sloted end for ajustments later)

Then drill out the hole in the belhousing where the piviot used to go, thread it with the same thread as the rod welded to the old piviot. screw the modded pivoit back in and fit a lock nut on the out side, as in the picture below.

many thanks to my good friend Jurgen, known to us petro; heads as cossiemk2 for the pictures above, cossiemk2,s web site www.cossiemk2.tk

i swapped my 2.9 flywheel for the 2.8 fly wheel and i can say i am pleased with the effects, it has made the engine more responsive and now revs up quicker, it also seems to pull harder through the gears.

a question i was asked in regards to the flywheel was "well if im using the 2.8 flywheel do i use the 2.8 starter motor? and will the type 9 fit the 2.9 24v engine? the answer to this is no! think of it this way, the starter motor is bolted to the gear box, so if your using the older type 9 gearbox then you will have to use the 2.8, 3 bolt starter motor for the type 9 gear box and if your using the MT75 then you need to use the two bolt 2.9 starter motor, by the way both flywheels have 138 teeth, yet the 2.8 starter has 1 tooth more than the 2.9 starter, this is down to the position it bolts to the gear box thats all. both gearbox's fit the 24v engine,they have the same bolt pattern as the 24v engine, so no problems there

The better clutch to use is a 1993 Escort Cosworth highbred clutch, it will fit straight on and the only visible difference is on the plate; it has more springs and stronger springs in the cover (Ford part number is 5029565).

27/4/2003 Just a foot note here,well i have been busy sorting out some issues with this cossy clutch and have now found some more answers!

firstly i have noticed that with this cossy clutch fitted, the gear box tends to rattle when on idle, this is due to the springs on the pressure plate, they load and unload constanly, this being due to them being made for a 4 cylinder engine and dont seem to cope with the v6 so well (v6 having more vibration), it is no problem machanicaly, but does cause this rattle.doh!

having tryed out a combination of the cossy friction plate in the 4b cover, the same applies (rattles) but the clutch will not hold the same torque, in fact it down grades it considerably (aprox 20%). this is due to the fact that the cossy cover has very strong springs(compared to 4b) and a harder compaound on the friction plate. in other words you end up with a less grippy friction plate and the same pressure plate to hold it,,,not good!

best option would be to use a cossy pressure plate with a 4b friction plate, this does not suffer the "rattle" in the gear box and also has the benifit of up-grading the torque that the clutch would hold by some 10 to 20%, this could be of a benifit and is due to the friction plate from the 4b being softer compound and more grippy and the cossy cover having stronger springs.

if thats not enough for you i have just finished fitting an alcon sprung 6 paddle clutch on my 24vxr4x4 and i have to say its very good, and i can say this is the best way to go if your looking bigger power incresses or just use for track days. it has less movment to operate it, it hooks up better yet is still very drivable in town traffic i would give it a 10 out of 10...... regards....... tony

28-0402003 just been asked a question that i feel i should answer," This alcon clutch, what is the acual book figure for it's torque rating?? Is it another Cossie 4x4 clutch kit or an uprated Cologne clutch?? see what i'm getting at does it rattle?and lastly.... how much?? "

its rated for cossy stage two(what ever that is???) it doesnt suffer the same problems with rattles at all. reason is this, on the cossy (ford)clutch the springs are quite loose and the tension is held by some "helper" springs (see the inner ring with 3 srings) in the centre, these set up the "load/unload " problem. the alcon sprung clutch altho its a cossy item does not have the "helper"springs the main springs are under tension all the time. thus no rattles.(no inner ringwith springs) just to add to what i said, the alcon is ideal for road use as far as i am concerned, the main diferance you will find is the travel needed to engage/disengage it, its about 1/3 of the normal travel, and its slightly heavyer under foot. very easy to get used to it in tragffic to. cost was around the £300 mark, worth it tho! if you would still need info/figures try asking them (trident racing supplies), phone 01327 857822 or e-mail on sales@tridentracing.co.uk (i wish i was on comishion!) regards tony

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