So as per Rob_Reilly’s pic, why is the hole for the center main bearing plugged in some models?? Sounds like it is quite important!
Simon
I see Realm Engineering has an Xk kit for £1950.00 sterling .A Toyota Supra Conversion.
Morris
Thanks Morris…interesting. No experience of the Supra box, but a good price for full kit…
Cheers.
Simon
Your 150 engine dates to mid June 1959 ,from a RHD DHC possibly.
V-7047 = S-827419 Rhd Dhc
V-7051 = S-827407 Rhd Dhc
Simon check the thread,
“5 speed conversion driven man”
Mostly EType but I have posted re 120 and Mustang box.
Peter B
The oil pump puts out more oil than the bearings can use, so there is a bypass valve which opens and lets excess oil flow back to the sump.
On earlier engines in 120, 140 and Mark VII, this was through that extra hole in the block, so the bypassed oil dumped onto the top of the oil in the sump. The pickup was also floating on the top, and is sometimes called a pancake pickup.
On the 150 and later models they decided to dump this oil through the hose shown in Morris’s picture into the bottom of the sump. The pickup also runs down to the bottom, as shown in Ian’s picture. Perhaps the idea was better circulation of the oil.
My concern was that you should not use a 120 or 140 or Mark VII filter head on your 150 block because you would have no passage for the excess oil to be dumped.
The other small hole in my picture, blanked by a screw in yours, is where the block is drilled through to the main bearing. The six brass plugs along the side are drillings for the other six main bearings. The oil gallery drilled front to rear connects all these to the large center hole in both our pictures.
Rob I think it`s worth stating the difference between the pressure relief valve and the
bypass valve. The bypass valve function is to allow oil at reduced pressure to be delivered
when and if the oil filter element is blocked, I stand to be corrected but i recall that the small
hole is used for this delivery of oil depending on the type of filter head used…
Peter B.
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Thanks all for the fantastic info and advice. I already feel like I’m now a bit of an expert on XK engine oil systems 
The engine and gearbox are now ready to come out which should be done by the weekend. I seem to have found a good project car - almost zero rust with no evidence of any major accident damage. There are a few interesting things about this car - it has been fitted with 150 discs all round. The 150 engine seems to have been ‘thrown’ back into the car (probably to make it more saleable??) but appears to be a rebuilt unit that has never been started. Will be interesting to see closer when I strip it down.
All in all, very happy with my new toy 
Will post some more pics at the weekend.
Cheers
Simon.
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Worth noting that on some models the hole is blocked by the gasket or the model specific oil filter assembly, so you may see some with the hole but no plug.
I remember seeing this on the BHCC site and noticing that about the brakes too and wondering how the rear disc brake hardware interfaces with the axle assembly. Also, is this the one with the exhaust piping – or what is left of it – taking the form of a twin exhaust with the piping running on both sides of the driveshaft? Let us know what else you find. Always fun to play car archaeologist.
Here is the flow pattern in the XK120 and early Mark VII filter head.
There is a small relief valve inside which permits oil to flow up from outside the filter element to the center chamber and thus to the oil gallery and bearings in the event of the filter being clogged.
The large adjustable brass relief valve on the outside front opens when the pump is putting out more than the bearings can take, and the excess dumps back into the sump.
Here is the 140 and late Mark VII head.
But I think we have established that Simon needs a head from a 150 or the equivalent saloon.
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Rob, thanks for the extra info, appreciated. I’m going to keep my eyes out for an original 150 (or later) assembly.
Hi Christopher, yes, you are correct, that is the one I bought!
Here are some initial pics of the brakes as found:
Also, a new(ish) fuel tank that somehow got over the wall 
Cheers
Simon.
Simon
You have the newer[although they don’t look it] quick change pad calipers,which were introduced mid Nov 1958.
recommend you sleeve them with stainless liners and SS pistons. The originals were alloy pistons and welded themselves to the mild steel caliper.
Looks like one of Jorge Cervera’s fuel tanks.