Dealing with an Oil-burning TR6

Date: Thu, 07 May 1998 12:59:17 -0700
From: Brian Kemp
Subject: re:TR-6 Oil burner

[...]

Just finished a rebuild on my 72 TR6. Before I got 150-200 miles per quart of oil. Lifting the accelerator pedal on the freeway at 70+ mph produced a very noticeable cloud of smoke (engine braking - oil sucked down the valve guides). My compression numbers were about 130 dry, 160 wet. The engine had 126,000 miles on the believed original piston rings. The previous owner claimed a valve job 15,000 miles ago. I was also a victim of low oil pressure, but the car performed very well, able to accelerate from 80 mph in O/D in a noticeable manner.

I removed/dissembled the engine and painted the engine compartment. I took the head to a local auto machine shop to get a seat replaced and be checked out. The valve guides and one valve were worn and needed to be replaced. I had new bronze guides put in.

The pistons seemed glazed. I honed and measured them and was suprised that they were still well within tolerances. I replaced the piston rings, all bearings, and seals and put the now clean and freshly painted engine back in the car.

I have 450 miles on the engine and have only used 1/3 a quart of oil. That included about 20 minutes of track time at Buttonwillow raceway during the VARA/Moss event last weekend (used a full quart on the track last year). There is no hint of smoke during engine braking and my hand in front of the exhaust no longer gets covered with black spots. I can even tell my oil pressure gauge is working with the engine at warm idle.

My engine ran very rich when I got the car (10-12 mpg). I think I saw somewhere that this can glaze the cylinders and allow gas to dilute the oil, allowing it to burn off faster. Try a wet compression test and see if the numbers go up much. If so, suspect rings.

To test the valves, try some heavy engine braking. If you get smoke your valve guides may not have been replaced or you valves may be worn. There are others tests for the valves/guides, but this is an easy one.

Hopefully this will give you more information to improve your car. I know many people that would be happy to get 500+ miles per quart of oil in their Triumphs. You may just decide a quart of oil every so often is worth living with.

Brian Kemp

72 TR6