Help me identify this oil leak

[ThomasTe]

I removed both heat exchangers from my car, since I want to install telescope oil return tubes to cure a known oil leak. But it seems like I got other leaks, too. Dried off the engine, and left it overnight. This is what it looks like the day after. Looks like oil seeps down the back of the cam housing:



Any idea where this oil is leaking from? Anyone had a similar oil dripping pattern?

I have just had my original upper valve covers machined, since they were badly warped. But could the removal of material from them have left them too weak to seal properly? I have used new silicone valve cover gaskets (from real gaskets), new and proper nuts and washers. I have not torqued them down hard, but maybe a tiny bit more than factory specs.

I guess it could also be the valve rocker shafts leaking. Maybe RSR seals should be installed?

Any help is appreciated. Thanks!

[edmayo]

Looks like the normal leak that develops between the cam housing and the head surface. How long has the engine been together?

[ThomasTe]

Thanks guys!

Yes, valve covers look bone-dry when you view them from the side of the engine. But I guess the top ones could leak from the vertical edges at the rocker areas. Would a leak in this area not run down the back of the cam housing?

Cam housing/head surface is definately a good bid. Engine has had an unknown top end job more than 20 years ago. Before my time of ownership. I guess any cure for this type of leak would involve removal of the cam housing?

So, it does not look like a rocker shaft leak to you?

Thanks for the link. Those rsr seals are quite a bit cheaper than the factory ones.

[Flat Six, inc.]

Could be a rocker shaft leak...

[ThomasTe]

Well, I think I definately have rocker shaft leaks.

Since I have not yet drained the oil or removed the valve covers, I performed this very simple initial test, which I just want to pass on to anyone suspecting leaking rocker shafts:

I simply removed a spark plug wire, stuck my finger in, and could easily feel oil in there as well as tell that a rocker shaft was on its way out of its bore. Not loose, just about 0.5 cm out of the bore.

I plan to install rsr seals without dropping the engine. Next question is: how do I tell whether a rocker shaft is re-useable? Should it be absolutely unscratched, when carefully cleaned? Or should I just order new ones straight away? Or is it best to reuse the old ones, since each one will match the rocker they have fitted? I don´t plan to recondition the rockers.
And what about the shaft bolts, nuts and bushings? Can they be reused, if they look ok?

Thanks in advance.