hi need help with m20 just wondering if the bsa m20 has a sludge trap like in a bsa a65.i didnt think it had one. its just on the quote i got for a rebiuld.
thanks in advance.

Not a sludge trap as such (as on a Triumph twin for example)...However, there is a drilling through the crankpin that passes the supply of oil to the big end and sludge can build up inside the hole..

The hole is closed off by small blanking screws and it may well be that on a high mileage engine, or one with an unknown history, the screws were removed and the drilling was cleaned out...

That would infer that the engine has been properly overhauled as few people go to those lengths...Ian

email (option): ian@wright52.plus.com