After a long day of “Where’s my Speed Six engine?” type calls, the last thing you want is to be standing at the bus stop waiting for a bus that was due 20 mins ago. Well I say that, but it’s actually not all that bad, especially when alternative transport arrives in the form of a 3 door Sierra Cosworth. Good old Blackpool Transport! Without their reliability, Back Home Performance may never have been born.
Dave was newish in the TVR Service Department. I didn’t really know much of him. I liked him though as he was the bloke who ordered me a chip barm cake occasionally, he filled in his job cards properly (massive brownie points in my book) and unlike most the other lads, he didn’t poke fun at me. Well not to my face anyway 😛 Until the bus stop I hadn’t a clue what he drove. Needless to say I was instantly impressed!
Dave bought ‘ELF’ for £7000 in 1996, just six weeks after he started work at TVR. The car was completely standard spec when he took delivery and on a rolling road test produced 218 bhp. This was still enough to make Dave question what he’d just traded his Mark I Escort in for. As he left the showroom the car was sideways after the first corner.
The first work to be carried out was changing the head gasket to a group A gasket and the chip was replaced with a stage 1 chip to produce 270bhp. Unfortunately, on a track day at Castle Combe, the engine bottom end went. The number 4 big end bearing picked up on the crank resulting in Dave needing to carry out a full engine rebuild.
Whilst rebuilding the engine, Dave overbored the engine block and replaced the original pistons with 4×4 pistons. This cured the pistonslap which all 2 wheel drive Cosworths suffer from. This then lowered the compression ratio which allowed it to run with higher boost. The valve guides were replaced, along with some of the valves. After a running-in period, the chip was replaced with the fitting of dark green injectors and a 3 bar map sensor. ‘ELF’ was getting quicker!
In between the regular track days, RS Owners Club meetings and events, Dave was kept busy making more and more improvements to the car.
Improvements & Upgrades
Over the following couple of years, Dave upgraded the stereo system, including base sub, 20cm rear speakers, uprated dash speakers, amplifier, head unit, 6 disc changer and graphic equalizer. Carbon fibre panels were custom-made by Trevor at TVR. The panels were used to fit the graphic equalizer, oil pressure gauge and boost gauge to the dash. The front light units and indicator lenses were replaced with new. Dave acquired a tatty looking replacement front bumper, which thanks to our friends in the TVR paint shop, was resprayed to look as good as new! RS500 front splitters were also fitted. Both of the Recaro front seats were replaced along with the dash top that had cracked.
Under the bonnet, Dave fitted a strut brace, to restrict the inner wing movement that occurs under load. An aluminium header tank replaced the original plastic tank which were known for cracking when old. An aluminium swirl pot was introduced to cut the hot spots that occur when the engine is hot along with silicone hoses to the cooling system and air intake. An RS 500 intercooler replaced the original intercooler.
All this cosmetic improvement was fine but the handling could be better. Koni adjustable shock absorbers with uprated and lowered springs were fitted. This added to the new AP 4 pot calipers, 325 mm front discs, new 4×4 rear discs, rear calipers and 17 inch wheels meant ‘Elf’ was looking and feeling mighty fine!
Time to hit the track and enjoy!
Engine rebuild Mark II
All was going quite well for a while, apart from the clutch was starting to slip a bit. Dave was on the way to work at TVR, possibly a little too enthusiastically, when the centre shaft in the turbo snapped. A huge cloud of oil smoke came out of the exhaust and there was suddenly no boost. With all the work required to repair the car, Dave thought that is was a good time to carry out some further upgrades to the Sierra.
Once the engine had been removed, the engine bay was re-painted. The cylinder head was removed to be replaced with a ported RS 500 cylinder head allowing for more air to enter the engine. The cams were also swapped for higher performance BD10 cams with vernier pulleys. The destroyed turbo was replaced with a hybrid T34 turbo. This was used because it has a larger intake housing for increased boost. The T34’s smaller exhaust housing also means less turbo-lag. The clutch was changed for a Borg&Beck heavy duty clutch. The flywheel was also replaced.
Time to say goodbye
Over the 6+ years of ownership it’s hard to say just how much money we spent on this Sierra 3dr Cosworth. Even before the second engine rebuild, Dave had stopped counting at £20,000. Was it worth it? Hell yes! The car had gone from producing 218bhp to 368bhp and a big improvement in torque! Dave says it was great fun owning & driving this car. He drove all over the country, meeting lots of different people and heads always turned wherever we went. I miss the dump valve sound effects and the spitting of flames from the exhaust. I don’t miss the polishing that happened as soon as we arrived at an event (and I only did this once).
We sold the car in 2003.
- Top Selling Cars of the 1980’s (roadsister00.com)
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