Thread: Injection pump modification question

Originally Posted by Dougal

A stock pump can be adjusted to deliver approx 140cc/1000 shots of diesel.
The 250hp that John (Bush65) is expecting from 180cc is a conservative figure which I suspect is due to John (rightfully) picking a level of tune with very safe EGT levels for reliabilty in remote locations.
If you so wished his engine/turbo/pump combination may be able to put out closer to 300hp.

The 140cc will deliver in excess of 200hp and 700Nm. You need to provide around 25psi of efficient boost and good intercooling to use this 140cc maximum fuel.
250hp may be acheivable if everything is done perfectly.

Have a read of this thread: http://www.aulro.com/afvb/isuzu-land...rediction.html

Yes, 250HP was me being conservative.

We know that 70 cc per 1000 strokes achieves 121 HP at 3000 rpm from a 1989 model 4BD1T, so if double the quantity of fuel (140 cc per 1000 st) can be burnt as efficiently then the HP would double to 242 HP. In practice the efficiency won't be the same and because the extra fuel rate is achieved by extending the injection duration, the combustion pressure will be less than double.

We might expect 10% less than this, i.e. 0.9 x 121 HP x 140 cc / 70 cc = 218 HP, so 200 HP (17% less) should be easy from 140 cc per 100 st, and enough air to burn it properly.

Originally Posted by Adrian18

Its ok ancient mariner all good
Bush65" the full load screw on the outside of the governor" you refer to is that an internal part or external . Is it commonly refered to as the fuel screw on the outside of the pump a cam operated by a piece of thread m6 rod with loc nut.

Yes. It is the adjustment for the fuel rate at full load. The torque cam and the full load stop screw together limit how far the control rack can travel when your put your right foot flat to the floor.

This is pretty much the first adjustment point after the idling adjustments (6 possible idling adjustments), when the pump is calibrated (there being about 16 possible adjustment points with our 'RLD' governors). The control rack limiter (at timing gear end of pump) is the 16th and last adjustment.

If the screw has the original cylindrical steel tapper proof cover on it, then the pump has probably never been touched. When a shop sets the pump up, they will use wire and a lead seal so they can tell if the screw is tampered with when out of their sight.

The torque cam is inside the governor. What you called a cam is not a cam - even though it has a curve shape on one side, nothing runs on that curve.

The torque cam is rotated by a link and spring from the tension lever, which in turn is pushed by the fly weights as engine speed increases. The profile of the torque cam gives fine control over the fuel rate as pump speed increases.