Oil feed to tensioner

S14 and S15 engines fitted with Variable Cam Timing (VCT) have one very small external difference in the front timing case. When viewed from the front of the motor the top left mounting screw on the front timing cover is moved about 15mm to the left on engines fitted with VCT. Whilst this may seem like a very insignificant diference the reason is very important.

On VCT engines an extra oil way has been added to the engine block and the front timing cover bolt had to be moved to accomodate this change. The extra oil way feeds the timing chain tensioner

This extra oil way runs behind the water pump and down to the main oil gallery. Its so close to the front of the engine that the water pump recess in the block has been made smaller on VCT engines resulting in a different water pump as well.


Non VCT Engine "D"

Engine fitted with VCT "B"

Front Timing Case

Note the relocated mounting hole

Timing Case__non_VCT

Timing Case__VCT

Engine Block

(looking at front right corner)

Non VCT engine is missing the extra oil feed 

Tensioner oil_hole_non_VCT

Tensioner oil_hole_VCT

Cylinder Head

Extra oil hole that feeds the chain tensioner


SR20 cylinder_head_oil_hole

Water Pump Recess

On the VCT engine the water pump recess is not as deep to allow for the extra oil feed to pass behind the water pump

SR20 water_pump_housing_non_VCT

SR20 water_pump_housing_VCT

pdf-iconObvoisly there is also a very subtle difference in the head gaskets to accomodate the extra oil feed as can be seen by this document produced by Permaseal.