Ever since performing my Zetec engine swap I had felt that the gearbox was letting the new engine down. Having been originally designed for the Sierra XR4x4 I guess it had to be able to cope with those pesky people who tow caravans, up hill, at 10mph. Therefore 1st and second gears are particularly low, and the gap between the gears doesn't drop the engine back to where it wants to be, but tends to cause it to bog down. This had the effect that I tended to rev much higher in 1st than I liked and it always felt like it was hard work pulling away.
I weighted up a few options, such as a semi-helical box from SPC, or perhaps a 6sp Caterham box, but in the end it was nearly always going to be a re-build by BGH (Brian Hill Geartech). After helping Jason with his engine change in the winter of 2003, I knew he was very pleased with his BGH box. I also knew that the price was especially good - around half the cost of any of the other options. The other benefit as far as I was concerned was that it remained a fully helical gear set, and so would remain relatively quiet in operation (I say relative - all things are relative in a se7en!)
After speaking with Brian, it seemed my main option was what they call the 'E7'. This would be a strip and re-build of my gearbox, replacing any worn parts as required and swapping 1st and 2nd for new ratios. I believe they also change one or more of the others in order to match a new main shaft - but I didn't ask too many questions in this respect - but I know 5th is now very slightly shorter than it was.
I was given the choice of 1st gear ratios, between 2.66 and 2.75, 2nd gear was to be 1.75 and then 3rd remained at 1.26, 4th at straight through (1:1) and then I was given a few choices of 5th, between 0.82 and 0.87. After a few calculations using my gearbox spreadsheet I decided that I would go for the longer of the two options for 1st, 2.66. With the low weight of the se7en I felt that the slightly longer 1st wouldn't be a problem on the road - Jason's experiences with his gearbox also backed this up as he went for the 2.66 option as well.
For 5th gear I decided to keep my standard ratio of 0.82. All of the other options were shorter which would have made 5th more accelerative but as I only tend to use 5th as a relaxed cruising gear I didn't see the point in making it shorter. The Zetec has bags of low down torque and easily coped before - with more torque coming via the injection and cam upgrade, it wouldn't be a problem.
The only other option I took up was to have a drain plug fitted. This is drilled and tapped holt in the bottom of the main case, towards the rear to allow you drain the oil without having to remove the gearbox from the car – as you would normally have to do. This added around £20 to the bill which is well worth it as I can perform regular oil changes as part of my services.
The first job was to pull the engine out of the car (yet again - I seem to have been doing this every year). Once again I enlisted the excellent service of Steve's hoist. This job was undertaken at the end of November.

Once the engine was out, the gearbox and bell housing was split and the gearbox was ready to be delivered for modification. I arranged this for early December and after posting a wanted advert on Blatchat managed to arrange collection of a F.I tank and pump as part of the same trip, which was a handy result.
While the gearbox was away I made use of my polishing machine (i.e. old washing machine motor with bench grinder polishing kit) to clean up the bell housing. While this was set up I gave the exhaust pipe a quick clean up also, so they were nice and shiny again – which lasts about 30 seconds once you start the engine!
Whilst the gearbox was being modified I made a start on my main project of the winter.
BGH’s workload was typically high on the run up to Christmas, with everyone wanting their gearboxes back in time for the break. My due date came and went and I began to wonder if I would get to get the engine back in the car over the few days off over Christmas. In the end my gearbox was rebuilt on the 22nd December which just left me with the question of collection. My work finishes at lunchtime on Christmas Eve, so I was hoping to make use of this – although the prospect of a drive around the M25 when everyone is finishing work wasn’t very appealing. Fortunately, as the workshop is located at the bottom of Brian’s garden, he suggested that I could travel down one evening. I went for this and made my way there on the 23rd, and enjoyed what I suspected were much quieter roads. It is this sort of service which I think sets apart those businesses that are willing to go that little bit further to offer excellent service – I’d happily recommend them to anyone. The other satisfying thing is that I didn’t come away feeling like I had been ripped off. Chris, who is working alongside Brian, told me that my gearbox was one of the cleanest they had recently worked on, and as a result, they could make use of more of the parts elsewhere. As a result my total bill was £470, plus the cost of my fuel of course. Compared to the £1400’ish cost of a semi-helical, or £2k+ for a 6sp, it makes this gearbox far more affordable, and one which I could justify whereas I could the others.

My boxing day was happily spent in my garage, bolting the gearbox back onto the shiny bell housing and then the engine. The whole lot was lifted up and dropped into the engine bay. I then bolted the various parts back on the engine and started on the major project of the winter - Fuel Injection

 
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