The camshaft retaining bolt on my Special has worked loose allowing oil to leak when running. The bolt is an original square head - presumably designed so that it cannot totally unwind, being trapped between the block and the fan housing. Of course this means that you cannot undo (or do up) the thing without lifting the block and that is something I am loathe to do as it is sitting nice and oil tight on the crankcase. I see on my Ruby that the bolt has been changed for a regular hex head. I reckon to saw off the corners of the square bolt and replace it with a hex head liberally treated with Loctite. Does the assembled company have a view on whether or not this is an OK thing to do???

Others might think differently, Nick, but yes, that's the way to go. The bolt isn't fully threaded the bottom portion having no thread and acting as a locating 'peg' so you will have to make you new bolt to match - not difficult.

When you fit your new bolt, put a turn or two of PTFE tape around the thread and seat it on a good fitting fibre washer with a slight smear of silicone on each face. You should have no further problems - always assuming the thread in the crankcase is in good condition!!

STEVE

Nick,

the bolt on my engine has been fashioned from a 'cap head' bolt, The advntage of the allan key fitting is that it can be nipped if neccassary without removing the dynamo housing.

Nick,

I have had success with the Allen key bolts Hedd mentions above and would reccomend them also.

Good luck,

cheers

R

Whilst rebuilding the engine, I tapped through the crankase and the bush whilst in situ with a new thread. I now have a cap head screw fully threaded into both crankase and bush, well loctited and the top surface of the crankase well lapped flat it doesnt appear to leak, although just about everything else does . You wont really be able to do this in your situation becasue you need to clean and de burr the bush afterwards, but I think its worth doing at engine rebuild time .

Steve.

p.s make sure the bolt isnt so long it touches the cam!

Is it just me, or are fibre washers not what thet were? I rather favour using a Dowty washer under the camshaft locating bolt nowadays.

Regards, Stuart

Thanks to you all for the advice. A session with hacksaw and chisel (gently!)to remove the corners of the square head resulted in the bolt being extractable - to find a very worn copper washer underneath. Still a good thread in the case so I decided not to go the PTFE/silicon route and it has gone back in with fibre washer and loctite. I also took the precaution of cutting a slot in the top so that it can be tweaked with a screwdriver if necessary.

The slots in bolts around that area are a good idea, I have put them on all the dynamo and fan housing bolts in that area to make life easier doing the bolts up, bar rthe final tweek.

Sandy