Can anyone assist with identifying the exhaust tappet of an m20 engine please? I have read details on this forum about chrome plating and a thicker pad.
My issue is I have a what we think is a replacement NOS exhaust tappet, the thickness where it is ground perpendicular to the running face seems the same as the inlet. The inlet one i have I can only describe as more triangular ( so looks thicker overall which is what is confusing), and the exhaust one flatter overall and I can't seem to detect a chrome plating finish.
I am not familiar with BSA engines so want to be sure I am fitting the right one in the right place. I am sure I am over thinking it and should just go ahead and fit them!
Have searched for hours trying to find a decent picture which tells the story better!
The foot of the exhaust cam follower that contacts the cam is treated on its face in the sidevalve engines only and in all wartime and post war engines of the type....Personally I think the treatment is hard chrome plating as Stellite cam followers generally have a pad of stellite brazed to the face.
However, that's an academic point and which ever finish it is it has a 'whiteish' colour compared to the untreated inlet follower.. If you hold both together you should clearly see the colour difference between the two...If you can't then you have either two inlets or two exhausts and the problem then is to identify what you have...Post the result after you have made a comparison....Ian
Yes I was talking about the followers, that's my bad description, apologies.
As I have one original inlet follower which wasn't badly worn it has been difficult to compare the faces.
From the links that Mark has posted, my NOS exhaust looks more like his inlet ones in that the "foot" overall looks slimmer in thickness (from radius to foot) and partially ground near the radius. The confusing part is my inlet one looks more like Marks exhaust one!
When looking at the foot of my NOS one it does look shiny and ground on the foot face. It arrived covered in grease and paper.
I guess I will have to purchase another from a different source and fit both New ones, even if it does mean potentially fitting 2 exhaust ones!
To wrap this up, I sourced an exhaust one from Russell Motors while placing an order for some other parts, looks more like the pictures i have seen, thicker foot and overall deeper than the original inlet one i have. I will use the other NOS one on the inlet side, although it doesnt quite look as thick as the existing inlet one I have, I am sure it will do just fine.
