MG Car Repair: white smoke, head gasket leak, valve stem seals

Question
i am fixing up a 68 B and on occasion it will blow out fumes of white smoke when reved up...but not always..the car has only been driven rarely in the last 5 years that i know of..before that i have not clue how long it sat....could this be valve seals???...thanks..daniel

Answer
Hi Daniel,
It depends on weather it is white or pail blue smoke. Blue smoke is oil burning and white smoke is antifreeze or brake fluid.

If it is blue smoke (oil) and is valve guides (MGs don't have a conventional valve stem seals). They do however have a small rubber "O" ring just under the valve stem keepers to keep puddled oil in the area between the keeper halves from running down the valve stem. The symptom is usually blue smoke out the exhaust on first start up and then goes away as you drive.

Blue smoke out the exhaust on hard acceleration (as viewed from behind the car) is rings. A dry and a wet compression test will confirm this.

White smoke out the exhaust is either brake fluid (if the car has a brake booster) or antifreeze, usually from a head gasket leak.

Howard