Question finally asked after many years of engine service on my car: Why is there a rubber oil return pipe on the outside of the right cilinder bank beneath the coil distributor. The left bank has not this rubber pipe. Why is it designed this way? Can't figure it out. Maybe there is a logical answer. Thanks.
Its the crankcase breather pipe I think. Vents into the head then the head(s) vent into the oil/air separator via the crossover pipe on the top.
No, this hose dumps into the sump from the rear head at the exhaust cam bore. Why one head and not the other? Probably the wicked acceleration of the 308 made the oil all slosh to the back of the engine and it needed a way to get back to the sump. Yeah, I don't know either. Image Unavailable, Please Login
I think we are both right. There is no other vent on the crankcase/sump so this must form a vent but is also an oil drain, ie oil down, vapour up. The only other "hole" in the sump is the pipe which connects the bottom of the oil/air sep but I believe this extends below the oil level in the sump so is a drain rather than a vent.
Because the tube on top of the engine, running between the two camcovers, connects the three "crankcase vapor" areas all together (i.e., crankcase -to- 1-4 head -to- 5-8 head also connects the crankcase -to- 5-8 head). They just needed a way to connect all three areas into a common volume (it doesn't need a direct connection between every two areas).
Thanks for the reactions. Appreciate! Ok, so the horizontal ventpipe running between the camcovers connects the sump and both camspaces. However, I don't understand why the chamber on which the rubber drainbackhose is connected is dead ended. There is no bore visible. It is a blind space. The only thing visible is the outher end of the exhaust cam on 1-4. So it could only be draining the oil squeezed from the outher cam bearing. I will post a picture tomorrow.
Took another close look and youre right Steve, no pic needed because there is indeed a hole connecting the right bank camspace to the rubber "oil" return pipe. This means its main function is not to return oil, but to vent/connect the cam areas to the sump. Thanks for solving this little mystery for me!
