Not True that was my first post to AccessNorton...as far as my olde knackered brain can remember anyway!!
Please try to remember that the lump is called an oil bath CHAIN case and the reason for it was to try to keep chain efficiency above 90% and if anyone quotes that chains are 98% efficient PLEASE qualify the statement with @IF EMPLOYED AS PER THE CHAIN MANUFACTURERS DESIGN MANUAL. Now go take off your bookshelf 'Speed and How to Obtain It' and on page 45 and I quote 'The oil bath clutch is frankly a compromise but for touring its faults are more than balanced by the condition of the primary chain over long mileages......' Please remember that the design life of a Renold chain is a MINIMUM of 15,000 hours or if run at say 2000rpm carrying a constant 5hp all day long with pump and sump lubrication 600,000 miles !!! Guess how totally incorrectly we employ chain!!
Also read on page 47 and I quote ' It is not always realised what a hard working component the primary chain is.It runs at very high linear speed and, though it comprises a series of plain bearing, it is usually given nothing like enough oil to either lubricate these bearings properly or to cool them. Under the best of conditions a chain is a most efficient form of transmission but even so it absorbs about 2 % of the power input in internal friction. The power lost is converted to heat . The wastage with an inadequately lubricated chain is considerably higher, so that several horse power may well be used purely in heating up the chain'.
Personally I can still remember the day I went to check primary chain tension with my finger on John Taylors G50 after a couple of into the 90s laps of the Isle of Man in Manx GP practice......the smell of burning flesh was something I thought I had left behind in the blacksmiths shop at Cromptom Parkinson during my 6 months it it during my apprenticeship!! Anyone want to guess why Mr Jack Williams(Father of Peter Williams) wrote in one of his early 1950s design notes books that for the 7r and Porcupine race bikes he had requested oil bath lubrication with the lower run of the chain immersed in oil wnen at rest. Management clearly beieived riders prefered lots of oil on the rear tyre to improve handling especially between a rock face and Manx dry stone wall!!
In my Renold chains folder I have a copy of a telegram sent to Renold in the 1930s by the National Physics Lab which states that the chain during the 6 hour test run was 98.4 to 98.7 % efficient. It was a 1 inch pitch chain running at very low linear speed carrying 25HP with a Renold sump and pump lubrication system. IE the chain was being employed as per the manufacturers design manual. People simply do not qualify statements these days. Some ..err... 'people' tell the World that the heat found within primary chain cases is all down to the alternator!!
Please don't anyone get me going on the missing Dommy and Commando camshaft oil bath that Mr Hopwood so very carefully designed into his original Dominator engine to ensure correct lubrication for the cam...which the ***** later at Norton/NVT totally forgot about resulting in premature cam failures. As for the stress raiser the pratts introduced inside the cranks during machining directly beneath and in line with the drive side big ends outer 90 thou radius that allows cranks to break very easily at that point please don't start me off!! Quotes from Mr Hopwoods' letters to me. 'The camshaft tunnel of the Dominator engine was designed to RETAIN as much oil as possible and in fact the lip was designed to run within 1/8 -3/32 of the flywheel rim to pick up oil from it'........To the sketch I sent him showing the crank stress raiser position...'It leaves something to be desired in technique!'.
No spell or grammer checks done.....blood pressure was down to 99 over 62 a few minutes ago. I need a beer but they aint allowed these days.
