Replace engine oil pump?

[Blue-canoe]

Engine swap in progress. The old #141 had a bad injector and cracked #8 piston. Pulled it out, and found a low mileage #506. (105,000miles) I've already swapped a bunch of hardly used parts and installed a lot of new ones on to it. My question is should I replace the engine oil pump while the block is still out?

 

[FellowTraveler]

If I remember right the 98 & 99 506 had piston cooling jets 99 & newer are smaller than the 98 and the oil pump was a higher capacity unit.

Since it's out it wouldn't hurt anything but your wallet.

 

[ak diesel driver]

IIRC the high volume oil pump started in 97.

 

[Blue-canoe]

If I remember right the 98 & 99 506 had piston cooling jets 99 & newer are smaller than the 98 and the oil pump was a higher capacity unit.

Since it's out it wouldn't hurt anything but your wallet.

Mines out of a '98 and I'm sure it has the HO oil pump because it has 1/2" oil ports, just put Leroy's hoses on this afternoon. Is the pump difficult to change? Has anyone ever done it?

 

[THEFERMANATOR]

ALL 506 blocks came stock with the high volume pump for the piston squirters. Starting around 99 GM put smaller squirters in, but not enough so to really notice a difference in oil pressure. As to changing it, it's your call.

 

[WarWagon]

Oil pumps are generally replaced when you rebuild the engine or they have a known problem. You can dissemble yours and check it if you need the peace of mind. The military manual here in the reference section has info on how to check the oil pump.

I would worry about things that wear out more often like the timing chain, piston rings, and especially the Harmonic Damper. Rings on IDI engines can quickly fail from getting too hot without any wear on them or other engine parts. Did you see the engine run at all to know what the blowby and oil pressure is like on it? Signs like oil build up around the intake is a good clue. Low oil pressure you should look at cam bearings.

I like to drop gapless rings in, replace the stretched out by 30K miles timing chain, and a fresh set of injectors (80-100K life max) from a reputable source. As they have timing gear kits from Leroy Diesel I would, if the budget allows, skip another weak chain that can't take the IP load very long without stretching. ARP head studs sealed with blue Locktight go in every 6.2/6.5 I want to keep.

105K miles is NOT low mileage for a 6.5/6.2 engine! That is just over the 100K warranty GM had to give out to sell the 6.5 and GM replaced quite a few in warranty. Just saying check the wear items mentioned as those or cracks give you trouble with near zero wear elsewhere unless oil changes were neglected.

IMO it's a good idea to pull the heads off while the engine is out and easy to get at and see what you really got. Check heads for cracks, new gaskets, and give it a good chance to go awhile without leaks.

 

[Blue-canoe]

Oil pumps are generally replaced when you rebuild the engine or they have a known problem. You can dissemble yours and check it if you need the peace of mind. The military manual here in the reference section has info on how to check the oil pump.

I would worry about things that wear out more often like the timing chain, piston rings, and especially the Harmonic Damper. Rings on IDI engines can quickly fail from getting too hot without any wear on them or other engine parts. Did you see the engine run at all to know what the blowby and oil pressure is like on it? Signs like oil build up around the intake is a good clue. Low oil pressure you should look at cam bearings.

I like to drop gapless rings in, replace the stretched out by 30K miles timing chain, and a fresh set of injectors (80-100K life max) from a reputable source. As they have timing gear kits from Leroy Diesel I would, if the budget allows, skip another weak chain that can't take the IP load very long without stretching. ARP head studs sealed with blue Locktight go in every 6.2/6.5 I want to keep.

105K miles is NOT low mileage for a 6.5/6.2 engine! That is just over the 100K warranty GM had to give out to sell the 6.5 and GM replaced quite a few in warranty. Just saying check the wear items mentioned as those or cracks give you trouble with near zero wear elsewhere unless oil changes were neglected.

IMO it's a good idea to pull the heads off while the engine is out and easy to get at and see what you really got. Check heads for cracks, new gaskets, and give it a good chance to go awhile without leaks.

Where to start...
I don't have a lot of money into this. But I trust that the mileage is honest. I'm not going to tear into the heads yet. Maybe after I put it back in and it runs.

As for everything else, I have a long list of parts that have been replaced with new or hardly used like:
HB & CP
Oil cooler & lines
Injectors & GP's
Crank & rear seals
Feed the beast & RBF
... there's more, can't remember it all

It sounds like the oil pump is something that doesn't normally fail, maybe I won't do it. Just thought it would be easier while it's out.

 

[Blue-canoe]

105K miles is NOT low mileage for a 6.5/6.2 engine! That is just over the 100K warranty GM had to give out to sell the 6.5 and GM replaced quite a few in warranty. Just saying check the wear items mentioned as those or cracks give you trouble with near zero wear elsewhere unless oil changes were neglected.

This engine was the best option for me, considering up here there isn't a lot of options. $5500 for a rebuilt? No thanks. Ted's or optimizer? Exchange, gst, duty & shipping will cost a fortune. My old #141 was tortured, overheated, starved of fuel, and had ridiculous EGTs, and still lasted 250k miles. What brought it down was a bad injector, lack of preventative maintenance. My bad.

I'm not terribly worried about the #506, if it lasts another 5 or 6 years I'll be happy. Got a spare #599 with 120k miles in storage

 

[WarWagon]

This engine was the best option for me, considering up here there isn't a lot of options. $5500 for a rebuilt? No thanks. Ted's or optimizer? Exchange, gst, duty & shipping will cost a fortune. My old #141 was tortured, overheated, starved of fuel, and had ridiculous EGTs, and still lasted 250k miles. What brought it down was a bad injector, lack of preventative maintenance. My bad.

I'm not terribly worried about the #506, if it lasts another 5 or 6 years I'll be happy. Got a spare #599 with 120k miles in storage

I'll save you the heartburn over the busted EGT myth The Place spits out like a religion. (No doubt I have a well earned special hot spot reserved for me in 6.5 Hell.) EGT's on this engine let you know how hard the engine is working and where the turbo blanket starts to burn. The A Team Turbo can take 1550 sustained EGT's pulling a trailer for miles up an extreme grade and this was on a 6.2 bottom end without the benefit of the coated 6.5 pistons. The Turbo blanket was black on the underside from this sort of thing. The paint on the floorpan over the downpipe where the passenger feet are was turned brown on the topside from exhaust heat. Of course ECT was under control while nearly pegging the EGT gauge and keeping ECT under control is CRITICAL for these engines.

You advance the timing and EGT's go down, turbo lags, and more heat is kept in the engine. Retard the timing and EGT goes up, less turbo lag, less power at a point, and less heat in the engine. So YMMV with any changed condition. Just note I like timing advance to the edge of glow plug erosion when I say the 6.2/6.5 EGT myth is BUSTED. This includes with the more difficult to keep ECT in check GM3 turbo I ran extremely hard towing the grades on the Mongolian Rim ignoring the 1440+ EGT's. IMO below 7% is an anthill as we get 18% grades around here making it literally uphill both ways. Did I mention how much I hate the useless fuel wasting GMx turbo's?

The stretched timing chain is a easy job vs. the suggested ring refresh. I don't bother to pull the crankshaft when deglazing the cylinders specifically to reduce the possibility of main cracks or making the cracks even worse. The amount of blowby from 30K mile surplus military engines I get made me regret not doing rings before dropping an engine in especially since I had to pull an engine back out due to FOD and found out what zero blowby is like after 8 NOS slugs, gapless rings, and used heads were dropped in/on. Budget at the time I dropped the surplus engine in didn't even allow for blue locktight let alone new rings: so the ARP head studs got Red Locktight I had on hand for the block side.

 

[Will L.]

While its out read the manual Warwagon posted the link for and check your oil pump. If is a little labor, easy job, and will set you back pocket change for gaskets. Then if it is out of tolerance you can buy a new melling. And you'll know your oilpan gasket wint leak then. I always use permatex the right stuff, and it never failed me.
I would put my money on a 141 before a 506 anyday. I cant count how many 6.5s never hit the 100k mark, so dont assume 105 means it has a ton more to go. It is all if the p.o. never let the temps break the 220 mark, and kept clean oil and air in it.

Fingers crossed, let us know.