This Underdrive Oil Pump Gear has a larger overall diameter to lower the very high oil pressures these engines reach and allows more oil to be in the pan where it should be to protect the engine.
- Fits All 4G63 & 4G64 Blocks for DSM & Evo 1 - 9
- Must have balance shaft delete
- Oil pump front cover requires light modification - can be done in car
- Gear Retards Cam timing about 2 deg please Adjust Accordingly
Q- Timing belt?
A- Same as stock. Just reset the idler on the tensioner. requires minor trimming of the pump and cover to fit. Not big deal for the engines these are made for!
Q- How much does it drop oil pressure?
A- 1100 rpm idle is 20 psi, the pump doesn't exceed 90 psi even with rolled bearings (deleted shaft). Cars that have a balance shaft delete but retain the shaft will be in the 80psi range which fits the old 10psi per 1000rpm rule even better.
A- Reduced load on the oil pump which means reduced failures of both pump and engine.