28-12-2020, 12:04 PM
Tom I think the appropriate answer depends somewhat on your engine set-up.
A more usual way to restrict the flow is to thread a brass plug into the oil hole in the bush, Loctite it in then re-drill to a smaller size.
On a pressure fed engine running at say 30 - 50 psi 3/32" dia gives sufficient supply.
On my engine I have no seals on the front cam bush and it runs dependably. However mine is a 3-bearing engine with oil feed to the big ends from the centre main bearing. Those who pressure feed from the front sometimes have difficulty getting enough oil to number 4 big end and this may be a reason to seal your cam bushes against leakage. Certainly worth thinking about if using a standard pump and you have high rpm ambitions. Just don't forget your timing gears need some oil.
A more usual way to restrict the flow is to thread a brass plug into the oil hole in the bush, Loctite it in then re-drill to a smaller size.
On a pressure fed engine running at say 30 - 50 psi 3/32" dia gives sufficient supply.
On my engine I have no seals on the front cam bush and it runs dependably. However mine is a 3-bearing engine with oil feed to the big ends from the centre main bearing. Those who pressure feed from the front sometimes have difficulty getting enough oil to number 4 big end and this may be a reason to seal your cam bushes against leakage. Certainly worth thinking about if using a standard pump and you have high rpm ambitions. Just don't forget your timing gears need some oil.