Crankcase, barrel, head jigsaw!

uktom77 · Post by **uktom77** » Mon Dec 26, 2011 10:15 pm

I have a '52 18s bottom end and have sourced a '54-'57 barrel (or at least that is what I'm told) am I right in presuming these will be ok together?

When searching for a head (presuming the above is ok) are my options limited? I am aware how naive this sounds but my knowledge is limited to say the least! Over to you.

wilko · Post by **wilko** » Mon Dec 26, 2011 10:33 pm

Pushrod tubes differ, later head finning extended down to top of barrel.

uktom77 · Post by **uktom77** » Mon Dec 26, 2011 10:40 pm

So by the sounds of it heads are/were interchangeable to a degree. Presuming a head is sourced then it's a case of getting the appropriate tubes to fit??

Don Madden · Post by **Don Madden** » Tue Dec 27, 2011 12:00 am

Up through 1955 barrels were drilled to match a feed hole on top of the crankcase. The oil feed has a checkvalve pressed in, which can be seen just at the surface, It is threaded to take a screw, (2BA?) for extraction. If a later barrel is fitted without a path for the oil, it will likely be forced throuth the joint. The oil to the cylinder must not be vital, as they deleted it for 1956. Theoretically the check valve can be removed but I was unable to one the engine I tried. The feed can be blocked off. Cheers, Don.

uktom77 · Post by **uktom77** » Tue Dec 27, 2011 4:25 pm

Thanks Don/Wilko, so it looks like I can use the barrel (with a little fiddling if needed).

....And when looking for a head, an earlier (closest to my '52) would have open fins reaching further up the head, ok.

Any thoughts on an earlier head sitting on a later barrel (other than authenticity)? Any obvious problems with this - fit/oilways/etc.

Thanks for the help so far, the fog is clearing a little.

itma · Post by **itma** » Tue Dec 27, 2011 4:36 pm

you need a barrel with a spigot and head to to suit.
matching pushrod tube for what ever years they are.

they all mix and match up to a point, some combinations just look silly though.Edited by - itma on 27 Dec 2011 5:28:59 PM

uktom77 · Post by **uktom77** » Tue Dec 27, 2011 4:44 pm

Hmmmm, I'm not going for complete authenticity (obviously) but I would like to think it'll look good when finished, so it does sound like there's a lot to this matching parts up lark. I had a look around at some bikes today (of the marque) and started to see differences that hadn't been apparent until you look closer. I know that sounds obvious but I am the 'untrained eye'.

I intend to take some good photo's of what I have and show them to the good folks at my next section meeting.

Thanks for the help.

wilko · Post by **wilko** » Tue Dec 27, 2011 11:24 pm

Don;t worry about the oilfeed to the barrel . there's so little pressure it won't cause a problem. Show your pictures here.