Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: Richard48Y on Monday,April 07, 2025, 08:36:52 PM
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Putting in real effort to get the roller cross-flow rockers done.
The roller samples are not being so easy to measure accurately.
I also measured originals as well as I could.
I thought I had read that stock are 1.5 ratio but mine seem closer to 1.6 and 1.645.
No luck with web search.
So does anyone here know the real numbers?
As it turns out the different ratios require so little difference in locating the push-rod end that I only have to make one basic part.
The push rod location can be altered to yield the desired ratio.
I seem to recall there was interest in higher ratio than stock.
For myself I plan to use stock ratio as I already have the hairy CAT cam.
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It may be easier to set up a measurement rig with two dial indicators in place of the pushrod and valve stem if verifying the ratio is all you're after.
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I think I got the long side very close.
The other end can be calculated.
My original cross-flow rockers do not appear to be 1.5 ratio.
More like 1.6 and 1.64
Knowing the factory spec would help to confirm the drawing I am working with.
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Rocker ratio is an approximation/average as it changes through its travel. The easiest way to find out the ratio is to use two dial gauges and compare tital camshaft lift with actual total valve movement.