Lotus Elan

1971 Elan Sprint DHC update

PostPost by: tract0rman49 » Sun May 04, 2014 8:02 pm

Hi All

A while since I last posted.

My Sprint has been rather off colour for a while. Decided to grasp the nettle and buy a brand new set of Spanish Weber 40 DCOES as had been suggested that my originals would not adjust to allow a slow idle anymore.

So pulled the old carbs off a few weeks ago and shock horror on removing the GRP outer airbox shell it was full of nasty white creamy grunge from the crankcase breather end.

Dipping the oil the same creamy white liquid on the dipstick........immediately began to suspect a head gasket issue. Removing the radiator cap the level was low so began stripping to remove the head. When stripped could see no obvious point of any leakage. Cleaned head up and lapped head face with 800 Wet and dry paper on a flat steel block. Same with cylinder block top face. Cleaned - checked valve clearances (adjusting 2 that were slightly out of tolerance). Built everything up carefully, timed cams and with a new oil filter and fresh oil in the sump cranked the engine without plugs to achieve oil pressure (25 lbs pressure at cranking speed). Fitted new carbs cam cover and exhaust manifold etc. Checked all hoses tight and started it up. It fired up straight away and was idling well from the first. advanced ignition a little to the strobe setting. Left it running to warm up and noticed a water leak from the heater control valve that fits below the thermostat housing in the cylinder head casting. This probably was responsible for the water level loss in the first place and so the head gasket problem!!!!

After most of today spent fine tuning carbs and timing etc finally went out on a proper test! Wow....what a difference. BTW I should point out that I had my new carbs jetted as per Elan Sprint specification but fitted with 32 mm chokes instead of original 33 mm. My reasoning being that the black hole in the power delivery on sprints between 2000 - 2500 would be improved with the smaller chokes even if it does lose me a little ultimate top end power. Well its fantastic....the low to mid range torque is way up and power delivery is really smooth. Basically the car is so much nicer to drive. Maybe something other Sprint owners may want to consider.
Michael Farmer, Kenilworth, Warwickshire
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PostPost by: trw99 » Sun May 04, 2014 10:34 pm

Good outcome Michael.

You might like to spend a half day reading through what Keith Frank has been trailing over at Sidedraught Central. Do a search on here for his name.

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