Hitchcocks Forum

Hi Chaps

I've been working hard to get rid of various small oil leaks from Connie, my '59 Constellation. So far so good but I have one really puzzling one left...

It seems to be weeping copiously from somewhere between the inner P/Case and the crank-case just to the rear of the crank. Oil is seeping from there down the crankcase and also down the P/Case (I definitely know it's not coming from P/Case due to colour of oil!).

This seems to happen continuously - ie not just after a run so I conclude it's coming from the oil tank rather than somewhere it's pumped to during running.

I stripped and rebuilt this engine myself last year and have only done 300 miles since. If anything it seems to be getting worse...

Any thoughts before I start stripping the Primary side?

Thanks Stephen

Stephen, the bad news is I'm afraid you're going to have to strip it. This leak is very common and is almost always the crankshaft seal. The original design calls for a metal to metal joint (gasket cement only,) between the crankcase and the inner primary case but I have found making a paper gasket to cover this gap can help. The reason being that the case is only secured by 3 screws around the drive side main bearing and can distort as a result. Later versions (notably on the Interceptor) have additional fixings and are mostly better. But not always! The situation is complicated by there also being changes to the crankshaft seals over the years, some have sealed bearings specified and others have steel shims in a sandwich assembly which can be a sod to assemble. You don't say what your leak modifications are but if you don't provide a good size breather as part of the work you will pressurise other parts of the engine, the primary case being an essential part of the internal breathing chain.

REgards, Mark

Thanks Mark for your helpful reply (as always!)

I'd be disappointed if it's the crank to P/Case joint as I assembled it with a thin film of black Loctite silicone which has been also used to form an effective crankcase centre joint seal. Maybe it is that though and all will be revealed when I take the P/Case off!

Also it's a little odd that it continues to leak when standing for days, which made me wonder about the oil tank. When I bought the bike it had a HUGE leak from the bottom rear crankcase through-stud that was allowing oil from the tank to enter into the stud tunnel so I was wondering it this could also be the case for one of the other through-studs...?

I take your point about breathing, and I have done the recommended mods including the big through holes between crankcase, timing chest and oil tank and have a large bore breather pipe from the top of the oil tank.

Any additional thoughts most welcome!

Stephen

Stephen, I just checked on a Super Meteor (almost identical to the Connie) bottom end I have lying about (as you do,) and yes, there is a substantial stud that goes through the oil tank and emerges behind the primary case about level with the crank. That could be your problem. You'll still have to remove the primary case though. Good luck!

REgards, Mark

Thanks again Mark

Just stripped the primary off and have discovered the source of the oil leak - the inlet cam bush cover. When I rebuilt Connie I didn't have a gasket so I made one out of cardboard. I won't be doing that again - ha'peth of tar and all that!

Just going to order some gaskets from Mr H!

Thanks again for your ideas.

Stephen

PO51UHD, nothing wrong with making gaskets out of cardboard, as long as you use the right type of card board. Single ply.

Well in one way that's a relief as the stud through the oil tank would almost certainly be a pig to seal! I have kept a small roll of gasket paper for a few years now, I don't use it often but it's a life saver when you find this or that little gasket is missing from the set you put on the shelf ages ago. A set of Imperial wad punches completes the job. As Papa says, cardboard can work, a Kelloggs cornflake packet proved to be the only way I could stop a BSA A10 rocker oil feed weeping once!

REgards, Mark