pictures for neverfear

I guess the message I posted last night didn't actually post, I apologize for that. Anyway here are the pics I got.




This is the port block that is installed in the engine block.




On the left is the oil pump rotor installed in the idler gear(the rotor and idler gear are sold/serviced as one unit. The rotor does slide a little in the gear, but does not really come out.) On the right is the stator; spring, retainer, and e-clip; and the pump cover.





Rotor/gear and stator installed.



Cover installed on the pump(I did not install the spring/retainer/e-clip for the pic). It's a little hard to see, but there is a significant gap between the cover and the inside of the gear. I believe this is because of the off-center hole in the cover; the cover would catch on the inside of the gear and try to "follow" it around. So a large gap is left, and the cover is held centered by a roll pin(in the timing cover) in the hole on the right. We determined that the pump cover alone couldn't possible seal the pump effectively, that led us to suspect the timing cover. So I packed that gap with grease, and our trial run had oil pressure real quick.




This is the bore in the timing cover that the front end of the oil pump/timing gear fits into(arrow is roll pin to hold pump cover). The bore appears to provide a little support to the gear, as well as to effectively seal the pump. We believe under normal conditions the remainder of this bore should be full of oil, and slight clearance between pump/gear and cover would hold oil in and keep air out. This is the point where I measured the bore and the gear to check for clearance. If my memory is correct, the engine here had between .001"-.002" clearance, while the other engine had between .005"-.006", with slight signs of wear. We were pressed for time, so instead of ordering a new timing cover, we built up the gear to get .001"-.002" clearance, as the bore in the cover was still fairly smooth yet. Probably better to get a new cover, but the repair did work, and it's still running fine.




If you're going to try to repair it yourself, it's not a real bad job, so here's some tips. You will have to remove the front pulley, and the injector lines, then before you remove the injector pump, the fuel shut-off solenoid has to be removed from this hole.





Loosen the injector pump bolts evenly, and you can start to pull it out, then you will have to remove this cotter pin and pull the linkage off before it comes all the way out. Don't loose the shim/s!




Linkage from the timing cover.



So, my personal opinion is that the fit of a steel pump/gear into an aluminum cover providing a seal for an oil pump, may be a weak point here as the aluminum of course will wear easier. I wonder if maybe a steel or cast iron bushing embedded in the cover might have solved the problem? If you have any other questions, let me know. I may even have some torque specs if you need them. Good luck!

Thanks for taking the time to post this. When you say you "built up the gear" are you talking shim somehow or weld and grind? Please excuse my ignorance as this the first time seeing any type of setup like this.
So to just replace everything the parts list would be cover,gaskets and all associated seals with the front timing cover? Depending on inspection of course,no other hard parts?

To build up the gear we used a technique called spray welding, the same thing used to build up a badly worn journal on a crankshaft, seal surfaces etc. We built up the O.D. to fit into the timing cover with a couple thousandths clearance. Would have been better to replace the cover though. As for the parts, what we had been doing at the shop was to replace the port block, pump/gear, and pump cover (before we knew about the timing cover issue), but I myself question now whether those parts were a problem, or if it was all in the timing cover. The fact that your running oil pressure (and the running oil pressure on our project) being near/within spec would seem to say that the pump itself is probably not worn out. If it was my machine I’d probably just replace the timing cover and see what happens. So your list would be the timing cover/gasket, and a new front crank seal if you think it needs it. To replace the port block would require special tools, and if you replaced that or the pump/gear and rotor, you’d have to check the endplay of the gear and shim to spec if it needs it. On the timing cover, I doubt that a new one would come with any of the governor/linkage parts installed, so be careful when swapping them from your old one, I don’t know if anything could be screwed up there or not. Also, I forgot to mention, when installing the timing cover, getting the roll pin in the pump bore to line up with it’s mating hole in the pump cover can be a challenge, be careful and don’t pull the cover in with the bolts. BTW, today a customer brought in one of these engines that had knocked out a rod bearing. Strange though that it was #1 rod, usually it would be the back one, as it’s the last one to get oil so the first to loose it to. He has to bring the head in yet so I told him to bring his timing cover and pump along and we’ll take a look at it. I’ll post here what we find.

Just a thought....what do you think about using an oil accumulator as a temporary or even permanent fix as long as the engine carries descent oil pressure while running?

I had never heard of such a thing, I had to google that one. Not sure what to say, it might work, but I have no idea what they cost, where they hook up, or many other specifics about them.