Fellow Einzlinder Enthusiasts
I am very happy to see that all at Edersee had a great time and I look forward to joining you one year soon.
My 1955 R25/3 is now on the road and thanks to all on this site for encouragement and material help - it has been much appreciated.
I have now done nearly 200 miles and on the overrun or closing throttle the engine does not sound as you would expect with a banging sound not apparent under power. I wondered if it is a partially sticking exhaust valve being closed abruptly. I had trouble with the inlet valve which seized before the guide clearance was opened up a fraction. The engineering company who did the work thought the exhaust guide clearance was fine. The exhaust pipe seal to the head is good so it is not a backfire.
On to the point of this post. As you can see from the photos an oil stain is being produced directly above the hollow exhaust valve tappet adjuster on the underside of the cover. I have completely rebuilt the engine and was as careful as possible to clean out all oil ways including the holes through the pushrods. I left a solvent soaking in the hidden oil ways in the head and blew through with compressed air several times. Oil is getting up to the rockers, which were also dismantled and cleaned, with more oil appearing at the inlet than the exhaust. The exhaust tappet clearance has opened up both times I have checked since I have had the machine running.
Where is this oil stain coming from? I don't think it is from the same feed as to the rockers. It is likely coming up through the cam follower, through the hollow push rod and tappet clearance adjuster. But everything was cleaned out throughly before assembly and I don't like to think I have missed something vital. I had hoped it would clear after I had run the engine for a while.
Your thoughts would be welcome.