Lotus Elan

Valve Spring Seat Washer Question

PostPost by: hbferrariguy123 » Sat May 11, 2019 5:58 pm

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My Elan head has washers under the valve spring seats. There is no mention in the factory manuals calling for these flat washers. Were these included in the engine's past rebuild to increase the tension of the springs?
The washer I'm referring to is the flat large diameter one on the far left in the photo. Could this be a upgrade that people did tighten the springs for quicker valve reaction time? Should I leave them in place when re-assembling the engine? Thanks!
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PostPost by: rgh0 » Sat May 11, 2019 10:40 pm

Your engine has been modified with none standard valve springs. Potentially you have a high lift cam shaft and longer valves and other modifications. Potentially the spring pockets in the head may have been deepened. Are all the seat shims the same thickness as engine builders also use them to adjust the spring heights individually to be identical and compensate for small variations in valve spring pocket depth or valve seating height.

I think you need to do some careful measuring to figure out what you have before buying parts and rebuilding.

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PostPost by: promotor » Sat May 11, 2019 11:25 pm

That valve spring set-up looks to be an Iskenderian one - normally to give more room for higher lift cams with standard length valves and no machining to the valve seat pockets in the head.

I can't remember what the installed length of the springs should be but the shims / washers will be to set the spring at the right pre-load / length. Of the sets of Iskenderian springs I have seen they have all had washers like those with them.
Last edited by promotor on Sun May 12, 2019 7:16 am, edited 1 time in total.
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PostPost by: avro » Sun May 12, 2019 12:04 am

From your previous post l understand that this engine has stood unused since the 90s. As some of the valves would have been In a position of fully open or very close to fully open, the springs would have sat compressed for all those years. This would have undoubtedly weakened the springs so it is most important that a new set is fitted.
These Iskenderian springs would have originally come as a spring package that includes the retainers ,cotters and platforms but the springs can be purchased on their own.

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PostPost by: rgh0 » Sun May 12, 2019 12:13 am

promotor wrote:That valve spring set-up looks to be an Iskenderian one - normally to give more room for higher lift cams with standard length valves and no machining to the valve seat pockets in the head.

I can't remember what the installed length of the valves should be but the shims / washers will be to set the spring at the right pre-load / height. Of the sets of Iskenderian springs I have seen they have all had washers like those with them.


You hope the shims had been used to set the spring heights and thus loads correctly by the engine builder but I have seen it done wrong to often to have any confidence without doing the detailed measurements and calculations myself. I don't even trust the spring suppliers installed height recommendations as these can be well outside the ballpark for some builds. I measure the spring rate and then determine the required installed height for the needed seat and cam nose loads for the engine use and with the cam its using paying due regard to all the other clearance issues that also need to be satisfied.

In general when building a high lift cam engine you are struggling to get enough space for the valve spring to be in the right operating load range and all the other clearances right. Adding shims under the spring seat unless you're compensating for spring pocket depth variation ( in which case the shallowest pocket should have no shim) can mean something else is not right as your using up space you should not have in the first place. :lol:

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PostPost by: hbferrariguy123 » Sun May 12, 2019 7:30 pm

I haven't had the time to measure all the pieces/parts but I did find that the cams are a Kenny Harman grind, number KH/2. I was told the specs are .380 total lift and 274 duration. Also, the valves measure 1.526 intake and 1.326 exhaust. That's as far as I got today, being it's Mothers Day!
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