A Little Smoke

[rickandlee]

We have a rebuilt 1975 A4 that runs great. Starts every time, new gas tank filters, recent oil change. Installed a Moyer thermostat,(raw water cooled) been running with a bypass valve only, and installed electronic ignition today. The sea trial went well, temps came up to about 160° ( never more than 110° before) and temp held at different power levels.

Problem: I went to WOT to check temps which is well above hull speed and started getting a little blue smoke from the exhaust. No smoke or smell at normal operating throttle. Any ideas where the extra oil in the cylinders may be coming from at WOT? Thanks.

[joe_db]

Rings and/or valve seats. If it isn't a lot I wouldn't worry about it other than to check the oil and make sure it doesn't get low.
You can always do a MMO treatment to free up sticky rings too.

[lat 64]

Smoke under high load can be:

• Blowby of combustion gasses from high pressures in combustion chamber--worn compression rings.(this smoke will show up in crankcase vent)
  
• Oil smoke from valve guides--worn valve guides.
  
• Oil smoke from combustion chamber out exhaust pipe--worn oil-control rings.

[ndutton]

Are you using any fuel additives?