Sq 4 Valve Timing

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Sq 4 Valve Timing

Postby KevinDennis » Fri Dec 04, 2020 12:20 am

Hi to all, working on a ‘53 Sq 4 engine all my Valve timing settings are around 15 degrees out.
My inlet Valve was opening 10 degrees AFTER TDC with holes on cam sprocket and mark on timing pinion aligned (factory is 25 BTCD) so I moved the cam sprocket by one tooth.
Inlet is now opening about 10 BTCD, engine came with a new (probably refurbished) cam shaft.
I could move the crank pinion one tooth but would still be out by 10 degrees.
Does anybody have figures for their own machines??

Holder of a Golden Anorak
Holder of a Golden Anorak
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Re: Sq 4 Valve Timing

Postby nevhunter » Fri Dec 04, 2020 12:43 am

I'd suggest you plot the entire 4 figures and see how that looks. Normally this is done with a considerable valve clearance to get clear of the ramps
Naturally that makes the figures look tame, but it's more accurate .Nev

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Re: Sq 4 Valve Timing

Postby ryszard.pisula » Fri Dec 04, 2020 6:02 pm

Hi Kevin

If you are still having problems with your timing, please give me a ring on 01279 413705, and I will be happy to run through the solution.

Kind regards


Holder of a Silver Anorak
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Re: Sq 4 Valve Timing

Postby roger.fellows » Fri Dec 04, 2020 7:50 pm

Grandmothers and eggs, etc.

Have you taken into account that the cranks rotate in opposite directions - i.e, before can be after?

There should be keyways in the crankshaft sprocket which would enable finer adjustment.

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