HOW TO FIT A TYPE 9 GEARBOX INTO AN MT75/ZETEC CHASSIS
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My car (2000cc Zetec SEiW) has been an ongoing project since I built it in 1997/98. It has seen many changes including engine modifications to take it to 210bhp. Cooling system alterations with Raceline water rail and an electric water pump. It has been on a diet loosing about 50-60kg so now it was time for a close ratio gearbox to see if I could get it to accelerate better.
I started taking to people about a suitable replacement for my MT75 gearbox that I fitted to the car when I built it. An email to Quaife confirmed my worst fear that there are no closer ratios for this gearbox. This was now going to mean that a different gearbox would have to be fitted if I wanted to go on down this route. As my car is used for the road only I did not want a straight cut gearbox as I have been in cars with straight cut boxes and the noise is very wearing on the road. I priced up the Quaife semi helical gearbox and discounted this one on price so I looked at BGH Geartech and disused my needs with Brian and he recommended a 2.8 sporting close box code number E7. This seemed a good deal cheaper and would be up to my present and future needs even taking into account of engine upgradeituse.
I ordered the gearbox and then started to get the other parts together. I found a second hand alloy bell housing from the WSCC boardroom this weighed in at 3.5ish kg so a lot lighter than the cast iron one it replaced. This was an RS2000 until and would need modifying to make it fit the MT75 tunnel, as the bell housing is a lot wider then the MT75 unit. The type 9 is the gearbox on the right in the photo.
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A gearbox mount (P/n 32340001 @ £8.47 +vat)
A prop shaft type T5 to sierra (P/n 3211013 @ £127.05 +vat)
Ordered from
Rs2000 clutch release arm (Part number1438283 x1 £17.29 +vat),
Clutch release bearing (P/n 6124260 x1 @ £21.68 + vat)
Gear oil (1045737 x2 @ £8.55 +vat each)
Clutch leaver pivot (P/n 6022530 @ £0.77 + vat)
Anti rattle bush (P/n 1553790 @ £0.17 + vat)
Ordered from Ford
The first thing to do was to get the engine and gearbox out of the car so that we could see how much would have to come off the new bell housing. Once the engine/gearbox had been removed I could measure the tunnel and mark out the bell housing for cutting. This had to be done to both sides of the bell housing as the RS2000 unit has two cut outs for the starter motor. Some careful measuring had to be done as the clutch release arm sits inside the off side starter hole and this would need clearance so that the leaver could operate without fouling the tunnel or bell housing. So a lot of trial fits of the bell housing would be needed. If you take off too much of the bell housing on the o/s then the clutch release arm will need to be shortened making more work and a stiffer clutch so be warned. The cutting was best done by hand so out came the hacksaw and remove the excess bell housing.
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When I was happy that I had got the dimensions correct and cut to size it was time to send the bell housing off to an engineering shop to be welded up as I am not keen on the idea of running a bell housing with large holes down each side. This was ready for me to collect the following day and cost £25 to have done.
The next job was to shorten the Type 9 gearlever. The standard one is to long all I did for this was to cut the gearlever on the top side of the vibration damper, hold the vibration damper in the vice and drive the bottom part of the lever through with a hammer and punch. This then will leave a nice short gearlever. All that is required then is to thread what is left which will take a 10mm thread. As the lever is so short fitting a quick shift is not necessary as the throw on the lever is very short and nice and positive.
Next job make an adaptor plate for the clutch cable. As I am fitting an RS2000 bell housing there is no place for the cable, as it would have been fitted to a mount in the Escort. I had a peace of 2mm thick stainless steel sheet kicking around at work so this seemed like the perfect thing for the job. A template had to be made to get the bolthole spacing, cable hole and shape of the plate. This was then transferred to the stainless steel sheet cut out and drilled. Next a tube to give the cable some support was welded to the inside of the plate, which can be seen in the photo.
It was now time to bolt everything together and slide the engine and gearbox into place this was not too bad as the gearbox is about the same overall size as the MT75. Once the engine was resting on its engine mounts I could see that the gearlever was about 20mm further forward than it was on the MT75 gearbox so a little enlarging of the hole in the tunnel and the gearlever could now select all gears and still came through the same gearlever gaiter in the carpet. This is one thing that I was concerned about before fitting the gearbox. I had been told that I would need a gearlever extension, as the gearlever was much further forward on the type 9 all of which was not true. In real terms 4th gear on the type 9 is about the same place as neutral on the MT75. The gearbox now connected to the new prop shaft was centralised. The new gearbox mount was almost in the same place as the MT75 mount but the holes are closer together so this mean that the holes had to be slotted I did this with a die grinder. It could have been done with a file but the die grinder is much quicker. I fitted the bolts to the mount dropped them through the chassis and fitted a repair washer to the under side of the chassis to cover the slotted holes. These are then welded to the chassis so that the gearbox will always go back into the same position and restore the chassis strength.
It is was now time to bolt all the bits back to the engine fill it with coolant fill the gearbox with oil and road test the car. My first impression was how long 1st gear was before with the MT75 gearbox at redline (7500rpm) the car would do about 30mph now with the BGH gearbox it would pull 45mph engine revs dropped to 4600rpm for the next gear change instead of 4000rpm. Dropping the engine right into the power band the car now pulled hard to 73mph red line. As we are on the queen’s highway that’s where it had to stop and to work out the rest the calculator had to come out.
1st gear MT75 31mph BHG 45mph
2nd gear MT75 58mph BHG 73mph
3rd gear MT75 90mph BHG 95mph
4th gear MT75 120 BGH 120mph
5th gear MT75 146 BGH 146mph
BGH do a choice of 2, 1st gear ratios and 4, 5th gear ratios. I opted for the longest 1st gear and a standard 5th gear. The shortest 5th gear would gear my car down to 135 at redline in 5th but as my car is used for the road making 5th a close ratio was not required. All in all would I do it again yes the car is quicker through the gears and I get far less wheel spin when accelerating away from a standing start. The car will now take full throttle once moving in first and it will sit down and just go. It has taken about 10 hours to do and no great technical skills required apart from the alloy bell housing welding which a welding specialist could do.
If anybody would
like to talk to me about this conversion you will find my phone number in
the area organiser section, as I am the AO for