Re: broken top compression ring

Posted by Rusty O\'Toole On 2013/10/15 23:52:48

Heavy duty or detergent oil was on the market by 1947. Multigrade introduced in 1951.

10W30 was the default choice in all garages and dealerships in the fifties, sixties, and seventies. We kept single weight for those who insisted on it, and non detergent bulk oil for the cheap skates with oil burning clunkers but every oil change was 10W30 unless the customer said otherwise.

Chances are any post war car has used nothing but 10W30 since it became available.

If the car had hydraulic valve lifters the maker most likely insisted on heavy duty oil if you did not want to void the warranty.

I don't know why the rings broke up but this seems to be a common fault in old long stroke inline engines. You can reuse the pistons if the cylinders are within wear specs.Check the top ring for wear or damage. The ring groove can be cut oversize and a shim put in if necessary. Pistons can be knurled oversize if they are a little loose.

This is known as a ring and valve job and was a common overhaul procedure when your car was new.