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MG MGA - Valve Clearance

I have a early 1800 head on a 1600 block. What is the correct valve clearance?
C M Harter

Should be the same. The big difference is your valves are larger.
JEFF BECKER

The 18 head has larger valves and larger volume combustion chamber, so it will have lower compression in stock form. If you shave the head to get back to original compression ratio you likely need to add eyebrows in the block to clear the valve heads. Valve clearance is always the same, unless you instlal a non-stock camshaft.
Barney Gaylord

Valve clearance should be .015 hot. Lossen #2 and #3 exhaust a bit more to .017. That's what I do on my early 18G engine (in a '64 B). Just drove it 8,500 miles this summer coast to coast, in extreme heat, with no issues. Took the Rockies in third and fourth gears!

The "book" specs have long been superceeded by "Confidential Factory Supliments", and experienced professionals in the field. hth

Paul

Paul Hanley

Barney is right - unless you are running a Mk 2 engine, in which case the valves and chamber are the same as the original one.

BTW - I wouldn't shave the head to regain lost compression (bad for valve geometry) I'd replace the pistons with 1622 versions (if your engine is currentl;y a 1588)
Bill Spohn

Thanks for your responses. I realized I need to give alittle more info which may affect the clearences. The bore is 30 over. Flat top pistons and a mild cam. The head was shaved .030. Compression 10:1
C M Harter

With flat top pistons you do not need to shave the head. If the cam has increased lift you may still need to add eyebrows in the block. No change to valve clearance unles it is specified by the cam supplier.
Barney Gaylord

This thread was discussed between 04/09/2005 and 05/09/2005

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