Re: Any ideas what this piston is off?

Haven't seen something as high compression in years - wouldn't do well on Morrison's cheapest petrol!

500cc Manx 30M Norton?

Don't know price but maybe 100 quid and much more if it had the gudgeon pin and rings.

Les

http://racingnorton.co.uk/epages/4c675e64-813f-4c0a-8926-87a680c962a0.sf/en_GB/?ObjectPath=/Shops/4c675e64-813f-4c0a-8926-87a680c962a0/Products/%220397%20A11/160%22

http://www.racingvincent.co.uk/14%20Norton%20Site/N4%20Norton%20Cammy%20Photos/Cammy%20Nortons/Manx%20Norton%20Pistons%201.JPG

Les

Have you measured the piston? I am wondering if it is 79.0mm + .020" or perhaps 79.6mm std (that would be Manx). There are probably stanpings on the piston crown, also maker's name and part number.

Another revealing feature would be the width between gudgeon-pin bosses: 1.2" means International; 1.0" means Manx

Comparing your photo to the two photos of high comp pistons, it is higher crown than both the current offerings. So perhaps around 10:1 compression

Paul

Previously carl_sanders wrote:

Anyone any ideas what Norton this piston is off, what type it is and how much its worth?

Its brand new (looks like old stock), never been fitted and is 79 +20"

If the piston is a Hepolite one, I can give you the exactly model where it fits.

I need only the number cast inside the piston.

Hans in Chile.

Hi Carl,

Your piston looks to be a pre-war Hepoliteracing Inter piston. The compression on this is approximately 12.5 to 1 andis designedfor alcohol fuel. You may not find any markings inside as these pistons are made from forged aluminium and are machined inside, whereas most standard pistons are sand cast. Post-war the bore size was increased to 79.62mm which is about5 thou bigger than 79mm + 020 thou. The value would be dependant on a particular owner's use of their machine, i.e. racing/sprinting etc. Regards, Richard.