In the 1944 RAF parts list the in-and exhaust cam pinion spindles have the same part number:65-2422. But in my engine one of them is marked "IN"...
And yes, I nearly forgot that before pressing them in, I have to insert the tappet guides and tappets...

email (option): viaconsu [at] planet [dot] nl

Hans, I think that's for the elderly amongst us

John

email (option): john.kater@chello.nl

Hi Hans, there are three different types of cam spindles for these engines..
1)Drilled right through with the inner end of the hole blocked with solder.
The piece that fits into the casing is completely circular and they are not marked for location.
2)Not drilled right through and in other respects the same as above.
3)Not drilled through and marked 'in' and 'ex' respectively, with the circular piece that fits into the case also having a flat machined onto a section of the diameter.
The reason for type (3) is that BSA found the proximity of the cam spindles to the main bearing housing was sometimes leading to distortion of the bearing housing when the spindles were fitted, thus altering the fit of the bearing itself.
Machining a flat on each one to relieve pressure at this point resulted in them being 'handed' and they were therefore marked to indicate correct fitment....Ian

email (option): ian@wright52.plus.com

Thanks Ian, problem solved
I take it that the three types are interchangeable? The exhaust one is not marked but similar to no. 3
And while cleaning the tappets I forgot that they are different
So what's the difference? One is a couple of mm shorter and the head is a bit wider than the other; could the shorter be the exhaust one

email (option): viaconsu [at] planet [dot] nl

Hi Hans, If you look at the back of the cam spindles you will see the flat that is machined onto the spindle where it fits into the crankcases.. (not the flat on the shoulder that you line up with the tappet when fitting the spindles). This flat on the rear part of the spindle should face the bearing housing, so the inlet one faces one way and the exhaust the other. So the marked spindles are not interchangeable unless you choose to ignore this modification or, if you have the earlier spindles without the flats on them they are.
Regarding the tappets...On sidevalve engines only the exhaust tappet is hard chrome plated on the face...so they should be fitted in the correct location....Ian

email (option): ian@wright52.plus.com

email (option): viaconsu # planet dot nl

Hi Hans,
66-1493, Valve tappet in & ex (2) 1937-1960 JM19-B33 (Cam follower or lifter, CAUTION some, but not all, ex WM20 cam followers appear to be approx 1/16” longer in adjustment thread, if used in pre WW2 OHV motors valve clearance adjustment may be compromised by this excess length. The adjuster will screw right down, but extra length of tappet adjustment male thread prevents pushrod seating fully in hole of 66-1511 (OHV adjuster). Very painful to completely assemble motor, then discover that you cannot get valve clearance, the cylinder, timing cover, cams and cam spindles must be removed before the 66-1493 tappets can come out again. How do I know this?

I don't know why they lengthened them, but does not appear to matter for SV.

email (option): n.gentner@bigpond.com

email (option): viaconsu # planet dot nl

Hi Hans..The plated tappet can usually be identified by a slightly thicker head and the colour difference on the face between the plated and non plated surfaces. The non plated one has a more yellow coloured finish than the more white/silver coloured plated one. Also you can sometimes see the quite thick 'edge'of the plated layer around the rim of the foot of the tappet.
Of course you may not have the plated exhaust one in which case they may look identical...To further complicate things I have noticed there are small variations in the dimensions and machining styles of the tappet heads over a period of years (they were manufactured for at least 24 years). You will note I'm sure, that your two aren't identical in this respect....Ian

email (option): ian@wright52.plus.com

Hi Hans,

You should also read this thread:

http://pub37.bravenet.com/forum/static/show.php?usernum=3155626639&frmid=16&msgid=1203812&cmd=show

The most easy way for me is the see if the edge of the tappet has (hand-)grinding marks. It looks like the plated exhaust tappets are held against a grinding wheel by hand, maybe to remove a burr from the chrome build up on the edge from the plating process?? Also the plated one are brighter like Ian says but I can understand that difference is hard to see if the tappets have been used.

So, if you can find (irregular) grinding marks on one of the edges of the tappets, my guess it that that one is the exhaust.

Good luck, Michiel

email (option): m.wijbenga@hotmail.com

Thanks Ian and Michiel; I had a good look with a 10x loupe and on both there are circular grinding marks! So perhaps both exhaust tappets?
Is it ok to conclude that with the mileage we go on our bikes (Ian of course excluded ) it does not matter a sh*t which tappet we use....

email (option): viaconsu [at] planet [dot] nl

Hi Hans..I guess if you have two exhaust tappets it doesn't matter...or if the mileage is limited. However, if you want to ensure the well being of your engine for future users I suppose you must be quite sure you have the correct exhaust tappet....Ian

email (option): ian@wright52.plus.com