03-06-2020, 01:39 PM (This post was last modified: 03-06-2020, 01:43 PM by Hugh Sammons.)
I am dismantling and cleaning a three bearing engine crank case.
The big end bearings are as shown in the photograph. Why are they less wide than the connecting rod housing into which they fit?
Are they perhaps incorrect shells?
03-06-2020, 02:01 PM (This post was last modified: 03-06-2020, 02:03 PM by Chris KC.)
So that they clear the fillet radius on the end of the crankpin.
I have no idea how present supplies (ex-Reliant I think) compare with original Austin shells but they are generously sized compared with modern big ends.
Shells in modern cars appear incredibly meagre for the whopping and sustained cylinder pressures and rev capability. The fancy thin layered materials running on hardend shaft, with pressure lube, withsatnd in psi several times thick white metal.
HI ALL,
One of the reasons for bluing shell bearings when fitting is to make sure that there is full contact between the rod and shell to transfer heat other wise you are libel to melt the shell material at that point.
Where does the heat come from? Presumably the oil is heated as it cools the bore and piston. Without some form of cooling is there really enough friction in the big end bearing to create a problem with high temperatures?