Engine Instrument Notes...

Tacho Cable Route

Anybody mentioned how they route the tacho cable through to the rear cockpit ? I put a gearbox on the tacho (from Aircraft Spruce) and there's so much backlash in the thing it locked up and tore the end off the custom length cable I had made.

Keith Matcham

Combined Oil Temperature

Oil Pressure Gauge, Mechanical Operation We have wanted one of these for some time, but all the ones we came across were either too expensive, or not very attractive, or the capillary tube was too short. However a motor racing friend recommended Racetech instruments available from Raceparts UK Ltd of Wallingford. We subsequently obtained a gauge from them which has a 0 to 100 psi oil pressure range and 40 to 140 C oil temperature range. The gauge is 52 mm/2 inch diameter and has plain white printing and needles with a black face and bezel (the Racetech name also appears discreetly in green). It is available with either a 7, 9 or 12 foot capillary tube. The oil pressure sense pipe can be any length as it can be separated from the gauge. You can chose either Smiths type or Aeroquip fittings for the pressure side connections. We chose the later with an Aeroquip 1/8 inch BSP fitting to 1/8 inch NPT adapter to fit the engine port, plus stainless steel sheathed Aeroquip tubing. We are very pleased with it and it fits our Continental's oil screen housing fitting perfectly. The only slight down side is that the capillary bulb is fitted with a 3/8 inch BSP gland nut which is fairly bulky. This requires a 7/8 inch diameter hole (approx.) to allow it to pass through the various panels between the dashboard and the engine. The capillary tube itself is only 3/16 inch outside diameter. Raceparts supplied us with a 3/8 inch BSP to 5/8 inch -18 UNF adapter to allow the gland nut to fit our engine. Raceparts telephone number is 01491 822000 and their web site address is www.raceparts.co.uk (the gauges can be viewed on-line, but the images don't do them justice). Raceparts Ltd also do a good catalogue with many other potentially useful parts.

Chris and Fran