My XK120 has a scroll slinger on the rear of the crank with a very close fitting half cover, which pushes the oil back inside. If you have a large leak there, perhaps your scroll is full of crud and acting like a straight shaft, in which case you could drop the sump and the rear end half cover and clean out the grooves.
A small leak there like a few drops after a run is probably not worth worrying about, part of the charm of the car. You can’t really expect these cars to be leak free like modern cars.
I would not connect the front breather hose to manifold vacuum. You don’t want to suck oil away from other places like your distributor shaft.
I thought you were concerned about the smell, as the road draft hose ends in front of the pedals on LHD cars.
Vacuum assisted brake systems “contain” the vacuum soas not to interfere with the intake/carb system. They employ a check valve…that is why you would still have vacuum assisted braking(for a time) even if the engine stalls while driving. A PCV system is open, in the sense that vacuum dies immediately if the engine were to stop running.
The problem is that a carb/intake system not originally designed for that controlled vacuum leak would require a jetting change IF that leak was now present, especially at idle.
PCV valves do “float”, influenced by vacuum changes during different driving conditions, changing the amount of leak present at various times(operating conditions). That’s why they rattle when shaken.
I suspect that the scroll will be fairly clean (only very miles since it’s last rebuild and annual oil changes) but I will drop the sump to take look anyway - good advice thanks.
The problem is that a carb/intake system not originally designed for that controlled vacuum leak would require a jetting change IF that leak was now present, especially at idle.
Yep - understood, quite happy to re-jet if/as required.
PCV valves do “float”, influenced by vacuum changes during different driving conditions, changing the amount of leak present at various times(operating conditions). That’s why they rattle when shaken.
That’s one of the things that drew me to the ME Wagner valve - it effectively has two (adjustable) circuits - one for idle and one for running so it can be tuned to the specific installation. I ordered it last night and will drop updates on here as and when.
Now that’s interesting…full throttle will basically eliminate PCV due to the loss of vacuum, but cruise and idle do “activate” the system so adjusting your new toy for light-load conditions should be where you concentrate your efforts…I hope you have a way to analyze the exhaust gasses.
Keep in mind that, going by my 1965 3.8S, Jaguars post about 1964 did not have an open draft tube . Instead there was a different top timing chain adjustment cover which was marked as in compliance with California emissions requirements and this cover had a vertical cylindrical piece and a tube that lead to the intake plenum between the air filter assembly and the carbs. Don’t believe this was a typical PCV set up but it probably did create some vacuum in the crankcase. Other BMC cars of this vintage did have a PCV which was made by Smiths. This system fed the crankcase fumes into the intake manifold between the carb (s) and engine where there was more substantial vacuum. I have successfully retrofitted this system to older British cars like an MGTD and it does seem to reduce rear scroll (seal) leakage. Photo shows one on a Morris Minor with 1098cc engine circa 1967. They were common on Triumphs MGs and some Land Rovers. Many posters do not indicate their location so I am unsure if any have seen the Jaguar system used on US spec cars post 1964 IIRC. One photo shows this California system just behind the ceramic section of the ignition coil. The other photo shows the Smiths system as fitted to a Morris Minor.
So I’ve collected the parts for this project and have a small engine breather filter, various pipes and barbed fittings and the rather lovely adjustable PCV valve…
In trying to identify which of these fittings I could connect a vacuum to - I got soaked in coolant (that’ll be the WRONG plug then). Rather than continue the unrehearsed coolant drainage exercise, can I assume that the fitting on the far right (of the picture) is ‘inlet manifold’ (thus under vacuum).
