No, I see what you mean but that’s not a stain I think it’s just that way the light from my torch is hitting it.
Split the case again, and have a good look (the practice will do you good ) Clutching at straws here, but you have got the case sealing o-rings at the base of the big case studs (see pic)? Missing one of the tiny (3mm?) core plugs behind the flywheel?
I’ve definitely got the o rings on the big studs- I’ve also got 6 new ones in the gasket set that I should probably fit. Not sure about the core plug as the bracket on my engine stand obscures a lot of the block. Can you remember which half of the case the core plug is on?
There are two teeny-weeny ones on either side that blank off the oilways to the tappets. Only about 3mm big. Down and to the left of the cam plug from memory. Unlikely they’re responsible, but were’re running out of ideas
Is that the end of a scrape ?.. and it looks like the gap between case halves widens towards the plug
Ha! Well spotted, funnily enough I did notice what looks like a gap in the photo but it wasn’t that apparent when looking at the engine- it might be an illusion, also never really noticed the black mark but it does look like the end of a scrape and that would definitely explain the leak I will give it a thorough going over when I get the case split again
So I have an update. Stripped everything down again and there were some stubborn deposits around the area of the leak- possibly original sealant not cleaned off properly….. anyway got everything cleaned up and had a proper look around the area. There appears to be a tiny crack in the case (second photo): I decided if it is a crack- it’s narrow enough that the sealant will stop it leaking, also, if what I cleaned off was the issue then the crack wasn’t the cause anyway…. I went ahead and re-sealed and assembled, filled with oil and crossed my fingers. No leaks yet (3-4 hours since I did it). I also noticed this: Difficult to see but it is what appears to be a very fine line of sealant that corresponds with the position of the crack. I’ll leave it to sit as it is and hopefully it remains leak-free, early indications are good so fingers crossed…..
Fingers crossed. Best to brush the sealant across the full width of the case edge, but I’d doubt it matters much.
Yea I covered the full width of the mating surface, there’s squeeze-out all the way round the outside joins and I shone a torch inside the case and there appears to be the same on the inside.
So today I got the rebuilt engine refitted to the bus, hopefully I’ll get back to it tomorrow and get it running ……
It’s running! Everything went according to plan, no sign of oil yet but I’m keeping a close eye on it…… unfortunately my paranoia has now shifted to worrying that I didn’t condition the new cam followers properly. I did the ‘run for 20 minutes at 2000 rpm’ thing and it starts now and ticks over fine, takes the throttle perfectly….. when and how will I know if I’ve not done it correctly?
Did you put any cam lube on them before firing up (not that it matters now)? Just enjoy, and see what’s happening to your tappet gap next time you adjust them.
