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After about 9 months since I bought the money pit it finally runs. This is the one some of you may remember me talking about welding up the pistons, well I did it and it is working so far. This is the DJXC engine.
 Question, on the engine, at the bottom of the oil filter housing, there is a small copper line that goes down to a small housing that says visco on it. I know it has something to do with a viscosity meter. Does this thing really need to be there? Does it serve any purpose other than providing a reading for the meter? Right now I have a oil pressure gauge that is reading of the top of the oil filter housing.
 I also installed a electric water pump on this thing because the old one was really messed up.

Randy

It isn't needed at all, mine was blanked off when I got my BD, I have since re-fitted it to keep it original.  I think they were more important when these tractors came out as the quality of oil was so variable and it gave a guide as to weather or not the oil you had was ok for the engine.  I think the guage is only an oil pressure gauge with a different face, but I'm not sure of the sort of pressure it runs at as its the pressure caused by the resistance to the oil flow. Sam

Another question, does anyone know what the compression ratio of the diesel engine is? Would advancing or retarding pump timing help any with starting? It will not start on it's own unless it has some heat in it.
Randy

The compression ratio for the DJXC as used in the OC 12 was 15.5 to 1.  Lots for things can cause low compression. If the engine has sat for a long time some of the rings may be seized in their groves. also rings loose their tension over the years and don't seal like they should.  The valves may also need gringing, also grinding the valves lowers them in the seats and this lower the compression ratio too.  If the seats need a lot of gringing then inserts should be installed to keep the valve height at spec.

Randy, these engines are hard starting by nature. Unless the engine is warm, you will probably need a little ether. Some even come with an ether system that uses pellets that you put in a canister and push down on a plunger, thus piecing the pellet and releasing the ether.

When you use ether, make sure the engine is cranking over good and you have smoke, meaning you have fuel going in, then give it a little spray of ether into the air cleaner. Don't stop cranking. You don't want the ether accumulating in the air cleaner or in the cylinders. It should fire right up with just a little squirt.

Blake

It has a fitting in the air intake right above the flange where it bolts to the head. It has what looks like a real small jet in it. The line to it is missing, and the fitting plugged. I am thinking about hooking up a ether bottle to it like I have seen on some trucks. It does start ok after it has some heat in it.
 What oil will work the best in the transmission and diff. in this tractor? I filled it with a 30w motor oil just to run it a little and flush it out. I would like to use a oil that will give the best steering performance.
Randy

I would not hook up any kind of ether system - too much chance of a valve sticking and not shutting off. Just use a spray can of ether.

The transmission takes 50 wt non-detergent.

The ether can I got with my military truck looks to be a commercial job. When you push a button, it rotates a plug to allow a precise load of ether to be loaded. Then when you release the button, that precise load is delivered to the engine. It isn't a simple valve, and if it sticks, it just doesn't work. My BDH also hates to start in the moderately cold weather.  Jim

First of all, did you know when those crawlers were new a blow torch was supplied as a starting aid. Second of all if you had the head off and ground valves you made the condition worse. Times and technoligy has changed. The distance the valve head is located from the face of deck of the head is critical to starting conditions, That tollerance is normally ,020. One valve job and that tollerance goes out the window. Installing valve seats is the way to correct that dimension. Of course all new valves are another answer but they are hard to come by. Startind speed also affect starting so does the fuel you are using.

I know there are new Delco starters with solenoids to pull the pinion gear in that will fit on these engines. I bet if you put a 24 volt starter on one, it would spin faster and start better.

I have 2 12v truck batterys on mine and it tourns over much better than when I had just one. I also fitted a thermo start to the inlet manifold, which hasn't failed to help it start yet. Sam

Hercules lists in their book the correct tolerances for grinding valves in the diesel engines. Grinding of the valves will not effect compression enough to be noticeable. I have cletrac tractors here on the farm that I have ground the valves on that have been running for up to 11 years since the regind with no problems running or starting. Injection pump timming, ring seal , and valve seal is the key to good starting engines

Does anyone know what cranking compression should be for the diesel engine?
Randy

Boy I would really need to do some digging to find it for the Hercules. The older Oliver wheel tractors also have a 15.5 to 1 ratio. The book specifies 300 psi mimimum. I will also will tell you a good guideline and then came from the Cockshutt service manager when we got into the Buda engines said 350 is what you need for decent starting. Newer technoligy has about made the 350 mandatory. I do know if you set the recession correctly you can pick up to 40-60 psi of compression. I have proven it to an Oliver dealer. I would like to talk to you more on this article send me a U2U. John

Can't directly answer your question, but the viscometer needs the full pressure line, plus it needs to dump oil back into the discharge side, so that line could be eitiher one. You shouldn't need the viscometer to run the dozer, though. Pretty cool gizmo, though.  Jim