Re: Solutions?

[Dick Roberts (Web admin)]

Posted by Derek Harnett on June 24, 2004 at 09:15:26:

In Reply to: Solutions? posted by Catherine (Wooden Spoon Bearer) on June 23, 2004 at 22:08:00:

I think it's a pretty good bet that the new cam spec has something to do with it - given the non-typical number of engine failures and high number of identical looking failures.

What was very unusual was that it's an inlet valve that was at the centre of things rather than an exhaust one, so the engines were not buzzed in the 'traditional' fashion. This is because the inlet valve opens as the piston draws away from the valves and so it's highly unusual for them to meet.

The two main theories I've heard relate to the inlet valve being dropped back into the head too quickly and the timing being altered such that one inlet opens too early and can be licked by the piston (as it completes the exhaust stroke). Both could lead to fatigue in the valve and the break in the valve stem that so many of us discovered.

Unfortunately the damage done isn't limited to just a piston and valve in my case. The amount of large bits of metal circulating mean that my heads are gone, barrels and pistons are gone, the crank cannot be trusted and the valve train is suspect too. Pretty much the only thing left is the crank case. So, a pretty expensive and frustrating failure :-(

The solutions will of course depend on the identification of the root cause of the problem - obviously there were one or two teams out there running with a different set up to the rest of us who didn't have problems so if we can get data from them that will help as well as looking at the failures.