ianellison

When my engine was out oil leaks were apparent from all the usually places. But the worst news was that the inner original metallic coating of the rocker covers had flaked off in places - some areas as big as a coin - and clearly this swarfe had got into the engine.

Because of this my garage recommended splitting the crank case to see the condition of the oil pump and crank. The crank was scored and one bearing nearly worn through - presumably due to the abrasve metal particles trapped in the engine. The crank has to ground -0.25mm with new oversize shells & bearings fitted. But they also say it is essential to replace the oil pump and oil cooler and flush out the oil system to ensure that the metal particles from the rocker covers are completely removed. This of course makes it a top & borttom rebulid and very expensive.

What I do not understand is why I haven't seen this problem with the original powder coating used on the inside of the rocker covers causing problems being highlighted in this forum? Or am I just very unlucky that it has happened to my car having done 103000 miles?

The garage say that had the bearing collapsed it would have thrown a rod through the crank case and would have been a much worse problem.

Your comments and experience welcome - as you can imagine I am truely p****d off big time!!

springer3

I did my valves last December, and did not notice any problem with the valve covers.

What puzzles me is how did the paint flakes get to the bearing? The oil travels through the main filter before it is distributed throughout the engine. I think the filter must have failed if abrasives large enough to cause harm reached the main bearings. Perhaps that is why this problem is not widely reported.

Geoffrey

Your valve covers on the early 964s are magnesium and the magnesium breaks down and breaks off the cover. The previous generation engine used aluminum valve covers and were not painted and the 993 uses plastic valve covers which do not share the same problem.

dutchcrunch

do not see the paint making it to the bearings. all oil from valve rockers migrate down the oil return tubes and gets picked up by the sump pump and sent thru the filter. that oil does not go or cannot get into the main oil pump intake. the oil intake is directly from the oil tank via the rubber hose and channeled thru the case to the pump. kind of odd. not to say the damage you report could not happen. i believe the damage you have is from something other.

dutchcrunch

unless like springer said the oil filter bypassed or failed.

cadence

Do you suggest aftermarket billet covers as preventative maintenance on all 964 engines? Do either the upper or lower covers tend to deteriorate sooner?

TR6

One other minor point. You don't necessarily have to buy a new oil cooler although it certainly wouldn't hurt. Both the oil cooler and the tank can be sent out to an aircraft certified vendor to be cleaned. They do this with aircraft oil coolers all the time (where the cost of failure is much higher than in a car). You should definitely count on a new oil pump though. I had a similar failure recently where a rod bearing delaminated and also scored the crank. Result, like yours, was a complete engine rebuild. I don't want to scare you, but it ain't cheap, as they say... On the plus side, its a chance to upgrade the engine as I did in my case.