Lotus Elan

0,44 / 11,2mm lift cams - any comments

PostPost by: el-saturn » Thu Feb 28, 2019 6:32 pm

just got the above cams - any new internals needed (springs, lighter valves, some titanium bits?? comments very welcome sandy
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PostPost by: rgh0 » Thu Feb 28, 2019 7:01 pm

You will need new springs and longer valves and thin followers to fit the higher lift cam. Exactly which combination of available parts is best depends on the base circle the cams have been ground on and exactly where the valves seats are cut in the head and how deep the spring pockets were originally machined versus the cam centre line. Titanium retainers come with some of the spring packs available but are not really needed but nice to have if building a 9000 rpm engine. Selecting the right parts so you get the right valve seat load and cam nose load is critical especially for engine life in a road car.

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PostPost by: elated » Thu Feb 28, 2019 7:04 pm

So no great consequential expense nor complication
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PostPost by: el-saturn » Thu Feb 28, 2019 7:29 pm

the measurements as follows: 25,5 / 36,7 and the present have a 10,8 lift and springs accordingly as ncik told me !! sandy
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PostPost by: rgh0 » Fri Mar 01, 2019 11:24 pm

el-saturn wrote:the measurements as follows: 25,5 / 36,7 and the present have a 10,8 lift and springs accordingly as ncik told me !! sandy


if you have a 10.8 mm lift cam already fitted then the current valve and spring set up may be ok to just drop the new cam in. As a minimum you need to check the springs are at least 1 mm off binding at the new full lift of 11.2 mm.

The nose load will go up but the extra 0.4 mm lift will typically only add around 5 to 7 kg in cam nose load.If you have details of the spring pack installed and take some measurements to confirm installed spring height you should be able to calculate whether it will be OK or not without removing the head and pulling the valves to measure everything up.

If by Nick you mean Nick Stagg and he did the build he should be able to tell you if the higher lift cam will work. What is the duration of the new cam versus the old as you want it to be below 290 degrees for road use.

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PostPost by: el-saturn » Sat Mar 02, 2019 8:58 am

......................thats exactly what nick said. next will be getting a mini camera to look into the chamber: actual valve clearance due to longer valves??!! the new cam lobes are pretty "pointy" (quick crossover/duration?) sandy -- the extra power will be added after MOT in march, if conceivable!?
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