Is your V12 engine Aston smoking on start-up? Has this issue worsened over time? You're not alone. This smoking issue is increasingly common and will likely affect all V12 engine Astons at some point.  But don't worry, we have a solution. Let's first delve into the problem.

Over time, the seals lose their ability to control the quantity of oil that runs down the valve stems.

This 'smoking' is a regular occurrence in many engines, but why does the V12 engine, with this issue, smoke so badly on start-up and overrun?

2 main reasons:  Traditionally, valve guides have a steep angle approaching the valve stem; when the oil is washed onto the stem, the sharp angle (this can be seen on the bronze valve guide in the images) allows the oil to run off the guide and away from the stem, thus reducing oil passes into the inlet and exhaust ports.  The valve guide in the V12 engines has a taper at the top; this taper is tapered towards the valve stem. When the stem seals start to fail, these recesses fill with oil, allowing the oil to run down the valve stems/guides into the inlet or exhaust track and ultimately burn, either as part of the combustion process or "burning off" in the exhaust system.

The second reason is the number of valves, 48, 48 opportunities to allow a few droplets of oil into the combustion process.

Our solution involves a meticulous process. We measure each valve guide bore and valve stems. If they are within tolerance, which is usually the case, we can simply replace the valve stem oil seals with high-quality Viton seals. However, for worn valves and guides, we have developed a method and the necessary tooling to safely extract the worn valve guides and install new ones. We can then precisely cut the valve seats to the original specification, ensuring a thorough and effective solution.

Contact us today to kick the smoking habit!