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Lotus Europa Forums => Garage => Topic started by: TurboFource on Monday,July 04, 2022, 12:28:45 PM

Title: Initial valve adjustment
Post by: TurboFource on Monday,July 04, 2022, 12:28:45 PM

Is it ok to the initial valve lash adjustment for a Twin Cam on the bench?

Then of course following up after it has been started and ran a couple hundred miles?

Title: Re: Initial valve adjustment
Post by: 4129R on Monday,July 04, 2022, 01:20:03 PM

I don't understand your question.

Are you talking about the tightness of the timing chain, or the tappet gap between the cam and the cam bucket?

Title: Re: Initial valve adjustment
Post by: TurboFource on Monday,July 04, 2022, 01:21:35 PM

Valve lash

Title: Re: Initial valve adjustment
Post by: 4129R on Monday,July 04, 2022, 01:45:13 PM

Quote from: TurboFource on Monday,July 04, 2022, 01:21:35 PM

Valve lash

Valve lash is the available clearance (or gap) between the rocker arm and the tip of the valve stem when the lifter for that valve is sitting on the base circle of the cam lobe (when the valve is intended to be fully closed).

In the UK I have always known that as tappet clearance or valve clearance, i.e. the gap between the cam lobe and the cam bucket.

If you don't get the gap right before starting the engine IMHO you risk burning out the valves seats, the valves hitting the pistons, and all sorts of expensive nasties.

Title: Re: Initial valve adjustment
Post by: jbcollier on Monday,July 04, 2022, 02:46:51 PM

Bench setting the valve clearances is best practice.  If the seats and valves are cut correctly and concentrically, it won't change.

That said, BE CAREFUL.  Because you are only moving one cam at a time, it possible for the valves to hit and bend.  I would fit and adjust one cam at a time to avoid the issue.

Title: Re: Initial valve adjustment
Post by: TurboFource on Monday,July 04, 2022, 02:58:19 PM

Thanks JB! Thought this would be easier done before installing the head!