AJS & Matchless Owners Club

I am experiencing a drip from the front oil pump cover even with the engine off. The screws are hard to reach with a screw driver, particularly the nearer ones. Any tips, tricks , that might help me? Is it likely to be the cover plate at fault?

Thanks

Paul

Hi Paul, there are a few possibilities but initially don't be tempted to overtighten the screws or to only tighten those you can reach (what is making it difficult to reach them?). the plates can deteriorate over time like carburettor bodies can but is not a common occurrence, could the oil be coming from the rocker feed and trickling down (this is also difficult to get a spanner on and turn), sometimes the original machining of the crankcase gasket face is not as smooth as you might wish for (put a good gasket goo on a new gasket but keep the rocker feed clear) , the screws may have worked loose (tighten) or the gasket shrunk (renew)

I had a similar persistent problem with this on a 16MS I finished recently. I tried flattening the cover plate using wet and dry on a surface plate, thicker gaskets, thinner gaskets etc. I finally discovered a weak thread in the upper inside screw. hole. When nipping it up to the point where it felt as tight as the others (admittedly not very tight) I left it overnight for the goo to set. Starting the engine resurrected the leak every time. It was only when I started to dismantle it for the final time I noticed that the aforementioned screw was no longer tight. The threads in the crankcase were so borderline as to allow the screw to be forced out with the oil pressure behind the plate. I eventually cured it by tapping the holes a little deeper (BA thread) with a plug tap and making new screws about 3mm longer than the originals and of the largest diameter that the split die would allow.. That cured it. The holes are blind ended so there was no risk of tapping into the oilways beyond.

Steve

Thanks for the replies.
I think my problem with the screws is finding a screw driver which fits correctly. I am now going to replace the screws use a new gasket and a sealing compound. Hopefully all will be well.

regards

Paul

Paul350 wrote: ↑Sun Apr 18, 2021 5:22 pm I think my problem with the screws is finding a screw driver which fits correctly.

Hi

A couple of suggestions:
Regards Mick