Hi all, I'm mid build on my '68 B44 but have noticed the oil feed/return pipes under the engine are different to standard, and look to be from a B50, with two separate pipes rather than both being fitted via a dedicated block with pipes for the two fluted upwards towards the tank. I'm presuming the new crankcases used for the rebuild are from a B50 as looking through the parts book the pipes look the same. However this means the oil feed pipe is at a right angle as the B50 was oil in frame. I can still get a pipe on it from the oil tank, but will have to loop it a little (being careful not to kink it and cause oil starvation) as per the pic attached (need to fit the pipe clips).
My question is do you think this will be okay? The oil is obviously gravity fed to the pump and my concern is if it will flow okay via this loop. Would welcome thoughts (would rather not strip and rebuild the engine if I can avoid it)
If your crankcases have barrel studs spaced to accept a B44 (or B40) barrel, that's what they are for. B50 has different stud spacings.
The post '71 type oil pipes on B44/B40 cases appeared on a mid '71 batch of spare crankcase for B40 military use, which changed back to the earlier oil pipe union design on later batches of spare B40 military cases - because they don't fit easily in a pre-oif set up. The only '71 produced B44 "spares" cases I've seen had the earlier type of oil pipe union. If the tacho drive isn't machined on your cases they were intended as spare B40 military cases. To answer your question, if you can connect pipes onto the pipe studs without them kicking, all well and good. May be worth considering copper pipes bent to fit with short lengths of rubber pipe to join them.
Thanks Rupert, this is so useful to know and v interesting to know BSA did this. The crank cases were are like new, and the tachodrive feed is machined into them - which means they are military B44 spare cases?
Great tip on the copper pipe, I've swapped the feed/return pipes around as the return is thicker and less prone to kinking but your suggestion on using curved copper pipe is a better longterm solution. Thanks so much!
+ for the rubber pipe. Remember my Norton 99 top feed copper pipe broke and fed oil to the rear tyre. Interesting broadsiding. At the time when petrol stations had rubber pipe and jubilee clips.
B44 "spares" cases with oif pipe connections is a new one on me, but I've ceased being surprised by the things BSA did towards the end! Usually at that time the casting date for the cases was stamped under the rear lug, might be nice to know when they were produced. They should also have the stud bosses for three oil pump mounting studs as per all '71 onward production, although the boss for the top stud wasn't always drilled and tapped on the spares cases.
Using copper oil pipes shouldn't put them at risk of vibration fracture if they are connected with short lengths of rubber pipe to isolate them.
You were absolutely right! I've found the dates and near the rear engine mounting - 12.7.71 and then each case seems to have 'o17s' stamped at the back (which shows they're matching at least).
On the front of the right crank there's what I think is the tacho drive hole, and then on the front left crank another threaded hole facing upwards, I'm not quite sure what that one is for yet. I'm not sure about the oil pump, would this be inside the crank cases? Would be useful to know if these are B40 or B44 crank cases (and what the differences are).
...couple more pics
That date matches the one on the B40 military "spares" cases I have with oif oil pipes so it looks like they are both from the same production batch. As i previously mentioned, later production of "spares" cases reverted to the pre-oif oil union so it looks like the mid-'71 batch with oif oil pipes was a production error - can't really have been intended for use in an oif frame due to the narrow rear lug.
Your tacho drive hole having been machined means they were specifically intended as civvy B44 cases, not B40 military, the nearest BSA got to producing an oif B44 engine!
The hole facing upwards on the front of the drive side crankcase is for a tool to be fitted to fix the crankshaft in the correct position for timing the spark. In normal use a hexagon headed threaded plug is fitted. That feature was introduced at the start of the 1969 production season.
That's really helpful - thanks so much, so I now know what they are and even the year thanks to your intel - much appreciated.
...don't suppose you know what size/part number that blanking nut is do you? Can't find it in the parts manual...
From memory without looking it up its a 21-.... number. I think I have a couple of new original ones left.
Pm me if interested
PM sent :D