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Cat 3116 Diesel Engine Tools and Adjustments

Cat 3116 Diesel Engine

During the late 1990s Caterpillar designed and developed the 3116. It only had a one exhaust valve and one intake valve configuration which was a weak spot. Especially with the exhaust valves. In our fleet it was usually #5 exhaust valve that would fail ( in other words break in two). The valve would fail at the base of the valve stem and make a big mess.

Unfortunately the head would get pulverized requiring a remanufactured replacement. The piston would need replacing and the cylinder would also have to be repaired. That’s where it got expensive. Since this engine was a dry cylinder design (non-removable) the engine had to be removed and stripped down for repair.

There was a repair sleeve available so the bore would have to be machined and the sleeve pressed in by a machine shop. The down time was long and the block had to have a jig installed so the boring would not damage or warp the block.

This repair was very costly and along with the repairs the tune-ups were fussy as well. The bottom ends on these engines were bullet proof. The head components were the achilles heel of these models. Note: I talk in the past tense because CAT does not build these engines anymore. In fact they are right out of the highway truck engine business. I heard they are teaming up with Navistar? Who knew??

Tools and Adjustments – A Quick Over View

With adjustments came the tools required to do a proper tune up. The 3116 uses a unit injector with a fuel rack / governor controlled fuel system. The rack adjustment comes first since it’s the first part that goes on the head after the fuel injectors are installed.

As you saw in the video the dial indicator that comes in the tune up kit has an extension arm that rests against the rack on each injector. The #1 injector is factory set so it is checked for proper position and once that setting is done the other injector racks are checked for the correct travel.

When they are all adjusted within the proper parameters the next step is injection timing. The engine has to be positioned properly for this adjustment. The valves can be adjusted at the same time with two revolutions of the engine.

The full fuel needs to be checked as well. It is the maximum travel allowed on the governor so the engine RPMs don’t go over the factory specs. This part of reassembly is time consuming but once the adjustments are done correctly these engines ran very well and they used all of the 250 HP they came with.

Fuel Shutdown Solenoid

You saw the first slide of this video which was the fuel solenoid. It had failed on us a few times mainly because when you hit the ignition and start button it stays energized with a hold in and pull in coil. So the heat is constant within these solenoids when the engine is running. They are threaded in to the governor housing and you can get them out without the Cat tool but you need to exercise care.

I hope this post enlightened you regarding Cat 3116 diesel engines. We had a lot of experience with them over a 15 year period.