Thread: Finally on the Road

Originally Posted by rijidij

Glenn, you might have seen my thread here regarding shortening the waste gate pushrod........http://www.aulro.com/afvb/isuzu-land...ost-level.html

Cheers, Murray

After my last post I went hunting and found your thread, after the exhaust is done I will put some time aside to mod our wastegate rod as you have.

Glenn

Originally Posted by The Mutt

Before I forget if A is the fuel adjust, what is B and C for?




Glenn

Yes that's the wastegate arm. Shortening it increases boost.

Items B and C are main shafts for the governor, you don't need (or want) to be adjusting those.

The canister of the waste gate actuator has a spring that pulls that rod to hold the flap valve (waste gate) in the turbine housing closed.

Also in the canister is a diaphragm so boost pressure can appose the spring and open the flap valve - as the flap valve starts to open, some exhaust gas can bypass the turbine.

Shortening the rod will increase the spring pre-load on the waste gate and the boost pressure will have to increase before it starts to open.

The screw shown within circle 'A' is the maximum fuel adjustment screw - winding the screw out (away from the cam) increases the amount of fuel. Only make small adjustments (say 1/4 turn) each time then test drive warmed up at full load (good hill) - ensure EGT does not get too high, and no excessive black smoke.

If high egt or smoke, you have too much fuel, or too little air - increased boost pressure can increase air and reduce egt and smoke.

Underneath the screw cap shown within circle 'B' are the adjustments for the governor shaft and the guide screw.

Underneath the screw cap shown within circle 'C' is the adjustment for the idling spring.

As Dougal advised, don't touch either adjustment at 'B' or 'C'.

You may want to increase the idling speed (if not already) above factory rpm. This will improve the torsional vibrations at idling - the vibrations that lead to gearbox failure. Use the screw on top of the governor (just above circle 'B' in your pic) to adjust the idle speed (no need for you to touch the adjustment of the idling spring).

The tamper proof shrouds have been removed from you fuel screw and max speed screws (alongside the idle speed screw), indicating these have been adjusted from stock settings - if done by a diesel shop they would normally wire the screws and fit a seal on the wire.