valve spring retainer clearance
Posted: Wed Feb 21, 2007 1:24 am
I am currently assembling my twin spark head with custom valves, custom guides, performance springs, and 11.6 mm lift cams.
Before my final assembly I have checked the spring retainer to valve guide clearance at 11.6mm valve lift.
The exhaust retainer to guide clearance is 2.5mm (no valve seals) OK.
The inlet retainer to vlave guide seal is 0.5mm NOT OK. There is 4.4 mm clearance without the seal.
I cannot shorten the inlet guide any further. My only option is to machine some material from the bottom of the retainer, or assemble the valve train without valve stem seals.
Considering the alfa engines cam followers act as an umbrella to oil and there are many engines out there that don't use valve stem seals I feel this should not be a problem.
What do engine builders do when alfa heads are fitted with 13mm lift cams?
What is the recommended minimum valve retainer to guide/seal clearance?
Thanks,
Dom.
Before my final assembly I have checked the spring retainer to valve guide clearance at 11.6mm valve lift.
The exhaust retainer to guide clearance is 2.5mm (no valve seals) OK.
The inlet retainer to vlave guide seal is 0.5mm NOT OK. There is 4.4 mm clearance without the seal.
I cannot shorten the inlet guide any further. My only option is to machine some material from the bottom of the retainer, or assemble the valve train without valve stem seals.
Considering the alfa engines cam followers act as an umbrella to oil and there are many engines out there that don't use valve stem seals I feel this should not be a problem.
What do engine builders do when alfa heads are fitted with 13mm lift cams?
What is the recommended minimum valve retainer to guide/seal clearance?
Thanks,
Dom.