Does anybody know of a way of getting the square headed bolt out without having to lift the block?
I thought about trying to cut the head down and replacing it with an Allen Cap head. I have alot of oil pumping out of the bolt at the moment so I guess the fibre washer has disintergrated.

Hello Stuart
Common problem,
I tried to hacksaw through the head of the bolt, but without success eventually I had to strip the engine.
What i did then was to fit the cam bush,then drill and tap both the case and bush to 5/16 BSW.
An Allan set screw, a fibre washer and a little bearing lock did the trick. That was six years ago and I've never had a problem since!
Regards
John

Stuart,

get a very sharp, small, chisel and knock the corners off the square bolt, you should then be able to rotate it and remove it, replace with a similarly modified bolt or Allen bolt as reccomended by others.

Good luck

Ruairidh

Not too sure about Ruairidh's idea as access is a problem. Another worry that I would have is the fragility of the crankcase. The top surface is very thin, not much more that 1/8" in places and being cast aluminium would be easy to break

I can understand your concerns Brian, however I have successfully removed the bolt in this way in a dozen engines over the years (hence why I modify all the bolts I use in rebuilds now).

You do need a very sharp chisel and you only need to remove a very small amount from each corner (it is mild steel and comes away quite easily), to gain enough clearance to allow the bolt to turn. If you don't want to do this then you must remove the block, the choice is yours...

Cheers

Ruairidh

I can just about get in there with a junior hacksaw, so if I cut it part the way through then chisel it.
Can any body remember the length of the bolt, i.e will it come out past the dynamo housing. The engine is an early coil engine.

The bolt is only 1/2" long and, usually, will just come out to the side, it's only threaded part of the way and then turns into a locating pin for the camshaft bush.

Good luck.

Cheers

R

Its out Now just need to make another out of an Allen Cap head.
I cut through 3 sides with a hacksaw blade and that allowed it to undo like a normal bolt.
Thanks for the advise Ruairidh and all.

Stuart

Be carefull.....

When you replace the bolt bear in mind that the threads may be worn in the crankcase, which is why lots of people including myself tap a new thread right through into the bush. Worn threads can contribute towards the leak! You cannot really tap the thread into the bush without stripping the engine, so it is much more of a pain in the ar**.
The square bolt you take out will have a locating dowel section on the end that locates the bush. If you just replace it without stripping the engine and tapping through a new thread ,your new bolt will need to locate the bush as well because the bush has an oil feed hole that must remain aligned. Your bolt really should be turned down to match what you remove. Of course when tapping right through this is all taken care of automatically, but it is much more involved!

Have fun

Steve

Steve, the threads appear fine the Allen Bolt has been turned down to match the original bolt and it tightened up just fine. I put it in with a load of instant gasket to add to the sealing effect of a copper washer I used instead of a fibre one. So fingers crossed it all works. I'll be carring plenty of oil on the Exmoor Trial just in case.

Steve,

the answer to tapping the bush in situ problem is a simple one.
Start the thread with a No2 tap, then cut the end off with an angle grinder, you can then use the modified tap to cut a full thread right down to the bush if you are carefull. Ive done this twice now and the modified tap is kept in a special drawer for the very purpose.