BSA M20 Engine - engine case halves have a gasket?
Disassembled my BSA M20 engine, inspecting all of the parts for cleaning and reassembly. Do the two engine case halves have a gasket in between them? When disassembled there was not one and I do not see a listing on the main page here that lists engine case gaskets. Was there a cork or cardboard gasket or sealant between the two engine cases so that oil would not leak?
Thanks!
Re: BSA M20 Engine - engine case halves have a gasket?
There is no gasket between the crankcase halves. It is important to avoid any leaks that both machined surfaces are clean and free of any burrs etc so that they mate up perfectly. I always put a smear of gasket sealant around the faces and never had any leaks. If the surfaces aren't perfect an old trick is to put a cotton thread around as well as sealant which crushes and helps seal once the cases are tightened up.
Re: BSA M20 Engine - engine case halves have a gasket?
Kim NALDER
There is no gasket between the crankcase halves. It is important to avoid any leaks that both machined surfaces are clean and free of any burrs etc so that they mate up perfectly. I always put a smear of gasket sealant around the faces and never had any leaks. If the surfaces aren't perfect an old trick is to put a cotton thread around as well as sealant which crushes and helps seal once the cases are tightened up.
Silk thread not cotton.
Silk is softer & more compliant.
And by silk thread you but some sewing silk, must be natural not synthetic which are plastic.
You then unwind the 3 to 5 strands that are wound together to make the thread and that is what you use.
You hold it on the case with a thin wipe of petrolium grease.
