This is a quick guide that I learned from Neil Porter owner of Porter racing http://www.porterracing.com
The formula ford that I own has a Hewland LD 200 gearbox. This is a fairly common gearbox used in many makes and models of formula ford race cars over the years. Changing the gear ratio’s is a fairly easy task. Based upon the lack of any decent HowTo articles I have found on the internet (read:zero) I thought I would put one together based upon the instruction I received from Porter Racing. It seems like everyone who is familiar with these cars takes this task for granted. If you race a lot, you will be doing this between each race if your next event is at a different track. With autocrossing I only expect to be changing gears until I find the ratios that suite my driving style. Once I get that perfect set, I’ll just put this task aside until I start doing track days and put the car on the track where it belongs.
- 10mm wrench & socket 1/8″ drive
- 11mm wrench & socket 1/8″ drive
- 13mm wrench & socket 1/8″ drive
- <socket for pinion nuts> 1-1/4″ socket or wrench
- oil pan
- allen wrench for gear linkage (SAE or metric depending on car/model)
optional (but recommended)
- gear change pan – I bought one of these gear change pans from Pegasus (link) and I find the tray useful, but not that helpful.
- dummy shaft – the most important tool to make the job painless. This tools lets you slide the gears onto the pinion shaft easily with few issues to worry about.
Get the car raised onto a secure work platform, anywhere it won’t be moved. I recently found a used brenner lift and stand off of Apexspeed.com and that was a very good purchase. It has really made working on the car easy compared to my old setup, working on the short stands with a low profile jack.
- The gear case is a zero tolerance piece. this means no gasket material should be required. Remove any that you find before re-installing. When you inspect the bearing carrier and end cover inspect the mating surfaces of the pieces for damage. On the photos you can view a white/black stripe on the mating surfaces. This is a Teflon gasket, similar to plumbers tape. this should be the only seal the case needs to keep the fluids in. If you develop leaks, then you should try to replace the Teflon gasket first before attempting to use silicon. If you use silicon, apply a very small amount, only the minimum needed to seal the case. DO NOT use RTV gasket material. Not even a little bit. This will adhere to the teflon gasket and lift it from the gear case. New gaskets are readily available from Taylor-race, but unless you have spares, this can be a hassle to deal with at the last minute. The Hewland Part # VG2019 and you can find it online for around $3
- If you do not have a dummy shaft, I pity you. When installing and removing the bearing carrier, you will need to cradle the upper gear set, with one hand while removing the bearing carrier with the other. It’s so much easier with the dummy shaft. You also need to be careful with the bearing for the pinion shaft in this case. It has the tendency to twist and can cause problems when installing the gear set.
- Do not reuse the cotter pins on the nuts. Always use new cotter pins. The layshaft and pinion nuts are supposed to be torqued to 115lbs. Here is a tip. Once you get the holes lined up when the nut is tight, it will be almost exactly 115lbs of torque.