Lotus Elan

Camshaft identification

PostPost by: pburgess000 » Thu Jul 04, 2019 12:11 pm

Just about to replace the head and I realised the camshaft sprockets have vernier adjustment with no marks to align with the cylinder head.

So I guess I need identify the cams first, in order to get the timing angles. Can anyone help me here please?

Pics of both attached.

Thanks!

Peter

camshaft-1.jpg and

camshaft-2.jpg and
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PostPost by: avro » Thu Jul 04, 2019 5:13 pm

Hello Peter

The camshafts you have are a pair of KC D144. These are a Kent Cams profile equivalent to the QED 420 profile.
They are a fast opening high lift cam with relatively low duration and are considered by many engine builders experienced with the Lotus Twin Cam as one of the best fast road profiles available. With Sprint size valves, some good porting and the correct jetting I would expect to see 145-150 BHP and still have an engine that remains very tractable in traffic.

The recommended tappet clearance is .004” - .006” Inlet / .007” - .009” Exhaust.

Setting the cam timing using the full lift method :- Inlet 100 degrees ATDC and Exhaust 106 degrees BTDC.

Setting the cam timing using the lift at TDC method :- Inlet .155” / Exhaust .122”

Nick
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PostPost by: pburgess000 » Fri Jul 05, 2019 9:07 am

Nick,

Everything I could hope to ask for in one succinct response.

Thanks so much. Now I need to put the head back on and get the cam timings right.

Certainly the engine seems both tractable and powerful. Those power figures were confirmed on a rolling road some years ago, which at the time I thought unlikely. Maybe they were right after all.

Best wishes

Peter
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