Crankcase ventilation

Sump Pressure.

Harvey,
back in 1980 when I had a 'H' 2000tc,I had a sump crack along the bottom, I could not remember bottoming it out,I was young and did race it a little 'lot!!!' round our lanes :p .
I went to the scrap yard and got another sump,put it on and assumed that was that :( but,only a few miles later ,that one split as well,I got another,and that split ??? I was extreemly lucky not to blow the engine up !! I contacted a local p6 dealer and he suggested I clean all the breathers vents,as if they get blocked,sump pressure increases,and there was not enough room via the dip stick to relieve it quick enough on a long run.I found them all to be totally blocked with a sandy,oily crud!! :p . once done,another sump fitted,there were no more problems and there was a noticeably better running engine as well
 
Well, it's certainly something I've never come across, even on cars that the breathers were blocked solid, and I'll have to accept at face value what you say, Pilkie. However I remain sceptical that it was purely crankcase pressure that was high enough to crack the sump. I can feel an experiment coming on, anyone got a 4 cyl engine still running in a car that's available to sacrifice, lets get those breathers blocked up! As I said before, I would be very interested to see it.
 
I can feel an experiment coming on, anyone got a 4 cyl engine still running in a car that's available to sacrifice, lets get those breathers blocked up! As I said before, I would be very interested to see it......reading this gave me an idea, :p,...what if were to block all the breathers on Rufus and connect an airline to the front crankcase breather ???,...result,...oil everywhere and a popped chaincase plug
Click to expand...
 
That would be exactly what I would expect to see, and I doubt crankcase pressure would be anywhere near as high as an airline. I have seen cracked sumps but not caused by blocked breathers.
Sterling effort on your part Hermione149, hope you enjoy cleaning up all that oil!
 
One thing I do seem to recognize is a better running engine.
Mind you, I did clean out the crankcase ventilation filter and the flame trap first, when this high oil pressure occurred. But I seem to notice that my engine runs smoother and pulls stronger after having loosened that release valve.
This might be just a subjective impression, having more to do with my psychic relief than the actual oil pressure relief, of course :D
 
thanks Harvey your suggestion was an inspiration, :cool:, i actually got Rufus's engine running, he's been standing since 1990,had to change the fuel pump and carb because they were gummed up,had a misfire due to a sticking valve but thats now cured,changed the interior to some very nice black leather that i've been hiding in the loft, just got to overhaul the brakes and find someone to respray him,MOT and he's ready for the road.
 
UUmmmm,you know that sticking valve i had on Rufus,... i left him running this morning (like you do), while i was having my mid morning snack i heard this "clacking " noise coming from the garden, i rushed out switched him off but i think it was to late, i've done a compression test and got zero on number one,60 on 3, 125 on 1 and 4, i'm going to take the head off this weekend,...i just hope that the valve seat hasn't dropped out
 
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