QUESTION.
After reading your article about rebuilding a cylinder head on a Lotus Esprit turbo HC engine with cracked cam followers, I would like to know if the light weight cam followers are an after market product or a genuine Lotus part?
J.G. - Perth, Western Australia
ANSWER.
The standard cam follower used in the Esprit turbo HC engine is the same component as used in the earlier Ford/Lotus twin cam engine.
The original cam follower (Lotus part number A026E0024) was made from chilled cast iron and is no longer available from Lotus.
This cam follower was made obsolete on 23rd August 1996 and was replaced by Lotus part number B920E0017Z.
This is a steel cam follower that was fitted to all production engines from the obsolete date onwards.
These same cam followers have been checked by Lotus Marques and found to be heat-treated to a hardness of 58 Rockwell C.
The replacement steel cam followers available from Lotus are very light weight and are of a very high quality.
They also have a unique swirl pattern on the top friction surface.
This pattern retains oil and also assists in breaking in the new cam lobe and new follower.
And as usual these components are priced accordingly.
However, there are high quality after-market cam followers available and they have various heat treatments and coatings.
It is wise to research and establish where these followers are manufactured and to establish what material and what heat treatment has been applied.
Lotus Marques has carried out extensive investigations in to cam followers and has submitted samples for electron-microscope analysis to fully understand quality issues.
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