If you get the ports increased over a certain point then you have to get larger valves anyways right?
How long till you think you get work done on yer engine sssgtr?
2 to 4 months dude, most likely december january.
Will start getting quotes after exams in mid november.
Need to buy an air compressor and die grinder etc etc. first before i can start porting the heads.
- Match porting everything on the intake side.
- 1-3mm oversize valves
- 3 angle valve job
- undecided on cam, depends on cost for re-grind
- slightly stiffer valve springs
- roller rockers; perhaps solid lifters if i can get 'em
- redo exhaust in 2.5" mandrel (so i can still go turbo if i can afford it in jan-feb)
Larger valves just allow greater volume of flow into the combustion chamber; as the throat of the intake port is approx. 85% of the valve diameter, the throat can be enlarged (but not by too much).
I'll be aiming for hopefully 20% better low lift flow, as i'm not always screaming around at 6000rpm.
My main aim with the porting is to clean up all roughness from casting marks, and to maintain a high velocity through the port to help cylinder filling.
This is the same cylinder head but from a US 240SX.