Torque and Power

	D3400 Engine 3.750" bore X 5" stroke, 221 CuI.   25.8 BHP (19.2kW) Continuous Output Power   125ft/lb (169.4Nm) Torque @ 1050 RPM

Injector Specs.

• 1500 psi opening pressure, 0.007" lift and a 2A5750 nozzle

Pony Governor Belt

• Cat original - Premium XL-25-09905,   Dayco equivalent - 15380 (11A0965)

Diesel Valves

• Valves should protrude .093" below head face as part of maintaining correct compression

D2 Injection Pumps

The Rack (1) is actuated by the governor and turns the gear (2) at the bottom of the pump plunger.  The plunger is lifted by the pump's camshaft and at the top of the plunger is a helix cutout (3) which passes by the inlet port (5).  When the top of the plunger is below the inlet port, fuel is forced in above the plunger by the pressure of the fuel transfer pump.  As the plunger rises the inlet port is closed off, pressure rises and fuel is forced out of the pump, past the spring loaded valve (4).   As the plunger rises further, the helix cutout re-opens the inlet port and injection stops.  So... when under light load, the helix is in such a position that the effective stroke of the pump is very short before the inlet port re-opens.   Under heavy load, the governor moves the rack, which turns the plunger to give a longer stroke before the inlet port re-opens.

Injection Timing on a D2

Correct injection (ignition) timing is critical with all diesels just as for a petrol engine.  The following is a brief rundown of the procedure for setting the timing on a 3J D2.

The first step is to find the timing marks and get No.1 piston to Top Dead Centre on compression stroke.  On the right side of the tractor just below and to the rear of the oil filler, there is a cover plate secured by two 1/2 inch bolts which once removed, allows you to see the front of the diesel flywheel. Remove the plate and turn the diesel clockwise (viewed from the front of the tractor) with the pony motor flywheel until the "TC - 1&4" mark is directly in line with the indicator.  You have to make sure that if you are timing No 1 first that it's No1 cylinder that's on the compression stroke when you are coming up to the mark.  The easiest way is to remove the rocker cover and watch the valves as well or you can remove the injectors if you prefer.

Once you're on the mark and you know that it's No1 cylinder that's on TDC of the compression stroke, remove all the injector lines and place them somewhere clean.   Next, clean thoroughly around the injector pumps and then number them with a marker of some kind.  Take off the side plate of the pump housing and remove the rack by undoing the two 7/16 bolts that hold it in place. 

Next remove the bolts that hold the pumps onto the housing and one at a time, very carefully remove the pumps one at a time, while keeping the plungers in the pump bodies.   These's no need to remove the plunger and doing so increases the chances of foreign matter entry and worse - mixing up the pump plungers.  Put the pumps somewhere clean and safe out of the way.

Once you're at this stage you are ready to check the timing.  It is set by controlling the distance from the top of the pump housing once the pumps and plungers have been removed, to the top of the adjustable lifter in the pump housing as indicated by the vertical arrow.

The correct lifter setting for a D2 is  1.736" +/-.002".  

So.. Once the pumps are out, using a depth micrometer, measure down from the top face of the pump body to the top of the inner face of the lifter.  If it is not within an few thou of spec, loosen the lock nut and adjust it until it is correct.   One point - The lock nuts can be real buggers to get undone.  You can see in the above photo that I had to resort to some rough tactics to get mine loose but I figured that if all else failed I could just totally destroy the nuts and then replace them with new ones (high tensile of course).

Once you've done the timing for number one go back to the timing marks on the flywheel and move it round to the next cylinder to fire..  The firing order is 1-3-4-2.  Once the marks are lined up, use the same method for checking the next cylinder and so on with each of them.  Be as accurate as you can with your measurements and  take your time.

Once they're all done, carefully replace the pumps, making sure that the right pump goes in the right spot and that the mating surfaces are extremely clean.   Next it's time to replace the rack.  On each pump plunger there is a toothed gear and on one tooth there is a mark (see left arrow in photo).  The mark on each plunger has to line up with the corresponding mark on the rack so be careful to get this right as failure to do so could have catastrophic results for your engine.

That's it.  Replace the covers, prime the system and fire her up.   Incorrect timing can have the same symptoms on a diesel as with a petrol engine such as hard to start, backfiring, smoking etc etc so if you have checked everything else and your tractor still runs like a dog - have a look at the timing.