Lotus Elan

Racing High Lift Valve Springs

PostPost by: rgh0 » Sat Mar 05, 2016 10:30 pm

You cant really set up the valves and springs until you know what cam and cam base circle you are going to use. I doubt your set up will work with long valves and 3 mm shims under the springs as i know of no spring set that will work with that sort of shim and a high lift cam except perhaps the QED Q55 springs which are a very unusual design compared to most.

regards
Rohan
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PostPost by: nmauduit » Sun Mar 06, 2016 10:28 am

Yes, that amount of shims struck me as odd, but that is the way the head came back from B..... in the UK, where seats and guides were fitted some years ago. My goal is to fit .43 or .44 lift with about 280? duration cams. There are a few options I've seen (and possibly special request grinds), though I don't have a set just like that in hand yet. I need to get the head line bored for accurate checking of the clearances, and I leave it a little more time to get the cams so that all can be done in one pass at the machine shop.

regarding the Q55 springs, I've looked at the spring rates (added at the bottom of your calculation sheet) and they appear more than twice lower than any other: they look rather small unless I missed something...

spring load ranges from Rohan.xls
spring rates
(12 KiB) Downloaded 194 times
S4SE 36/8198
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PostPost by: rgh0 » Sun Mar 06, 2016 11:02 am

Yes the QED Q55 spring is a very low rate spring. As far as i can see it is basically designed for a high lift QED 420 cam to be fitted into an otherwise standard head and bottom end with a 6500 rpm rev limit. Gives you great power and a still tractable engine with very limited modifications

cheers
Rohan
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PostPost by: elangtv2000 » Sun Mar 06, 2016 5:07 pm

Hi Rohan,
Tony Ingram has some really nice springs he's developed. I am not sure of their specs, but you could get in touch with him and see if they are what you are close to what you are trying to achieve.
Cheers,
Greg Tatarian
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PostPost by: rgh0 » Sun Mar 06, 2016 6:29 pm

Hi Greg

This was an old post from many years ago that was recently revived. I decided not to go ahead and produce my own valve springs as I could not justify the expense. I have use Tony Ingrams springs and Titanium retainers for my race engines and they are great.

cheers
Rohan
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