HarryD

Hi,

I decided to clean my engine to localize the source of the ever spreading oil slick in my garage. Orginally I thought it was one of the Cam tower lines and an Oil return tube but after 50 miles of driving my vcleaned engine, both are dry. On close examinination it look like the leaks are from the valve covers and the line along the main case halves.

I figure I can just tighen them up a bit but before I get overly worked up, I need to know what "a bit" means. I am exremely paranoid that I will strip the holes in my alloy case and that is not a fun thing.

All advice is appreciated.

Thanks,

Chris Bennet

Oil Leaks, The Quest..

The torque value for the cam covers is only 8 Nm (7.4ft/lbs). Unless they are looser than that, tightening them up will tend to warp the came covers - not fix the leak. I'd remove the cover, check that it is perfectly flat using a decent straight edge and reinstall with new gaskets torqued to the proper value.

J richard

The perimeter case bolts are torqued to 16-18 ft/lbs. The type of sealant used on the crankcase surfaces is a hardening type which is usually unaffected by re tightening the case bolts.

Other areas to check however, a mis-aligned or loose rocker shaft can look like a leaky valve cover or cam housing, and a leaking thermostat o ring or leaking oil temp sender can let oil down over the top of the case looking looking for all intensive purposes like a leaking center seam.

good luck, getting a dry 911 motor is a challenge but worth it when the drive is clean!

HarryD

Thanks for the advice so far. When I lookd again today, I also noticed that there are seeps from the Cam Chain covers. I cleaned to top side of the sheet metal and note no leaks on the top however, so I think my thermosat and temp and pressure sendors are ok.

I know this may be a hopeless task and I'll just keep putting new oil diapers under the car but I thought only the Brits had a patent on engines that did not hold oil and wouldn't share their secrets with the other auto makers!

Happy Sunday!!

Paul Brewer

I believe (I could be wrong) that the '73 has magnesium exhaust valve covers, which tend to warp and leak. The fix is the "turbo" valve covers which are heavily reinforced.

Rick Lee

I second the motion to not overtighten the valve covers. That causes leaks -- does not fix them. I have a small leak at my lower left cam cover and will fix it eventually. But it's not too important. I think there are differing opinions out there as to proper torque specs. But you should definitely not over over-torque anything.

CamB

You should try changing the valve and chain cover gaskets because they are pretty cheap. Torque requirements for each of these is low, so overtightening is not a good idea. New nuts and crush washers are also a good idea. A kit with the gaskets, nuts and washers is available for the valve covers.

If you have the original valve covers they are probably warped - the "Turbo" covers most cars have been upgraded to have a 930.xxxxxxxxxx part number. They should be ok. Either way it is worthwhile checking them with a straight edge.

A little known fact about adjusting your valves (ahich you COULD do while you are there) is that it takes so long because there are 34 freakin' nuts to undo and do back up. The chain covers are no better and you do also have to remove the rear engine sheet metal and your muffler. It is a good chance to check the condition of your chains and chain ramps too.

Cam