Wanted: A87 Head

An open chamber U67 will give an L16 a 7.72 compression.... very unlikely the pinging is caused by this. Even a closed chamber A87 is only 8.4. I would look for the real reason for the pinging...

Timing too advanced. Simple enough to check

Excessive carbon build up. Maybe choke on too much (short trips) or carburetor flooding?

Over heating. Water low, thermostat stuck, rad plugged with scale

Wrong heat range or make of plugs. Should be NGK plugs, never anything else.

Too low an octane gas. Try another brand.

What Mike said!  The higher the compression using a peanut/closed chamber head, the higher possibility of pinging, but all of the above should be checked first!

TJ

I have a spare L-16 head on my shelf looking for a new home..I'll have to check the designator on the head to see if it's a "U" type or an "A" type head. Is that stamped into the casting or is it molded into into it? Not familiar with where the designator would be located on the head. Thanks..Head is good, can't remember if it's a bare head or complete..I'll let you know...