Rebuilding Questions. I was originally going to just replace the oil pump and the timing gears/chain and the bearings on the crank. Since I'm already half way into the motor, why not do more, lol. I'm going to pull the heads later on during the week and inspect everything. I want to put in a new cam, lifters, pushrods, rebuild the rocker arm assemblies etc. etc (rebuild of the heads/ upper end basically) Can I get away with doing the valves and or the pistons at a later date and time. I plan on using studs this go around for the heads as to make it easier to access again in the future to either pin or re sleeve with top hats. I was thinking pull the heads maybe replace the valves, throw the heads back on and go from there. Any advice on this rebuild? I'm trying to rebuild it in truck but we'll see how that pans out....................

 

If you want to install a new can then you will need to pull the engine. It’s not too much more work to pull it after all the disassembly you are talking about.

 

You actually do not have to pull the engine to replace the cam, but you do have to remove the radiator and move the air conditioning condenser out of the way..

Regarding the rest of it, what is your main objective? Most Disco motors I have had apart have almost no wear on the crank bearings, and unless there has been an oil pressure issue the rod bearings have minimal wear. Pistons typically are within factory specifications as well. Rings do usually fall outside factory wear specification. The crank bearings are difficult to replace in the truck but not impossible, rod bearings and rings are relatively easy to do in the truck. You can't replace the sleeves in the truck, now or later. Valves don't really wear out sub 350k, rocker shafts don't typically wear out either unless there was a oil pressure issue or oil changes were heavily neglected.

The one I just did had 150k on it and blown hg. Overall in good condition, rings needed replacing and I did the bearings and seals too since it was on the engine stand. Everything else checked good to factory specs.

 

Oil changes have been routine, always used Rotella 15W 40 with a good filter(not Fram). I was noticing that upon start up the oil pressure took a little bit longer to rise. I never checked it with a gauge though ( yeah yeah, I know lol). Then I was noticing that sometimes at idle while driving I could hear valve train "tapping sounds" from near the driver side valve cover. I though that it may have been an exhaust leak due to the fact of recently replacing the cats but I was wrong. Drove it to work, went to leave and no bueno. I started it, zero pressure, revved it just a little and valve train noise got super loud and I turned it off. Long story short, I pulled the oil pump, it cracked in 4 spots. It looks like the front cover is fine though, I'll be cleaning it and taking measurements later. I haven't checked clearances on the crank yet either, it's good to know that they're "bullet proof" though. I still need to pull the valve cover(s) too, I have yet to inspect in there. On the cylinder liners, my plan was to buy the tophats and then eventually take the block and heads to a machine shop. That is down the road though. I'll know more by end of day tomorrow, I just need the free time to get to wrench on it.

 

My guess is your pump initially cracked in one place, you saw and heard that drop in oil pressure, then it cracked in 4 places, that is when you got the zero pressure situation. I doubt you have any significant wear not associated with normal mileage.

 

That's what I'm thinking too. I checked everything when I did the Head Gasket Replacement 80k ago. I guess I should have done the oil pump, timing chain gears back then as well, oh well. Does anyone know off hand what the replacement part # is for the Oil Pressure Relief valve rebuild kit? I cannot find one online...... I definitely want to replace those bolts on the front plate....