service sticker on 803a

[smokem joe]

This had a bunch of other work done, poorly, but it was done. No new engine though. They painted it up real nice to make it look brand new though! It has oil pressure issues. I think I will flush with ATF first and see what that does before I open it up.

I bought the unit out of Lochborne, but it had come from Albany without ever seeing use. Where it was for 6 years in between who knows.

 

[smokem joe]

You might see some from over here soon. A bunch of Gen sets, maybe 30-40 and about that many trucks and trailers were being loaded up in Grafenwoir for shipment to the states.

Problem is where they are selling them out of is to far away to be practical to look at them first, as well as the insane prices they seem to bring now.

 

[smokem joe]

Ok, I ran with tranny fluid for half an hour. Oil pressure dropped right to where LOP shutdown was about to occur. I drained the fluid and it was dirty for sure. Put oil back in and have no improvement in oil pressure. Under load it runs at 20psi which is under spec. I am using Mobil 1 5-40 synthetic oil. Paperwork inside shows it was load tested as part of the rebuild for 2 hours and had 25psi after 2 hours. So either the guy doing the load test lied on paperwork or something is different. So is the oil that the military uses thicker? I have heard Mobil 1 runs on the thin side of the spec. Should I try another oil or just tear into the engine at this point? If it held 22 or 23 I'd be ok with that, but dropping under 20 is not good.

 

[Zed254]

2nd black page is the Lubrication Order. It calls for OE-HDO-15/40 or OE/HDO-30 when ambient is above freezing.

https://www.steelsoldiers.com/showthread.php?175591-MEP-803A-All-the-TM-s-you-need

 

[jamawieb]

I would agree with 15w-40 and no synthetic.

 

[smokem joe]

I realize the spec oil is 15w-40. But that is still a 40 weight oil when warm. Most synthetic is 5w-40 and just helps it get the oil moving in the cold easier. However either oil should still be 40 weight once warmed up. How did the military oil hold 25psi and the Mobil 1 drop 6 or 7 psi off of that? Warm weight should be the same viscosity. I tried some John Deer break in oil in it at first when I thought the engine was pretty new. I had to shut it off and drain it out within a half hour due to LOP shutdown. That's a 30 weight oil when warm.

Jamawieb just curious why you don't recommend synthetic? I run it in all my gas and diesel engines. I've torn into engines with 200k miles on them that were spotless inside with Mobil 1.

Considering trying some 15w50 I have here to see if that builds pressure. If not I guess it's time to open the side cover up and see whats on the pickup screen and relief valve.

 

[Zed254]

True that if you are really letting it get up to operating temperature for an hour or so. However, on a short run if the oil is on the cool side the weight of your oil will be 10 - 20 instead of 30 - 40. I would change the oil and see how it runs. My 803 is on the low side of the pressure specification, too. It will sometimes dip below 25 psi, but these gauges have ball-field accuracy. On mine, the longer it runs the lower the pressure reading on the gauges. It will start around 40 psi and after an hour or so start dropping. 2 hours into a hard run it will be 25psi.

 

[smokem joe]

I can run it 2 to 3 hours before oil pressure gets to low with 40 weight oil in it. Paperwork shows they load banked it for 3 hours and had 25psi. If I could get 25psi I'd be ok with it. This one starts out around 40-45psi and drops pretty quick from there. Once it drops under 20 I shut it down. All readings are done with a mechanical gauge. I know the stock gauges are only close enough for hand grenades. Once I remove the 10k load the pressure recovers some, just to around 21 though. That is still under spec. From what research I've done there is a range of viscosity to be in to qualify as 40w oil. I'm wondering if the military stuff falls to the thick side of that and the Mobil 1 is at the other extreme.

 

[smokem joe]

Ok, I checked the oil this morning and it was looking pretty thin. Guessing it still had some tranny fluid mixed in thinning it down. Changed it one more time and put 10K on it for 3 hours. It didn't drop any lower than 25psi so I'm going to call this a success!

 

[csheath]

My unit gets a tad under 20 PSI when hot but doesn't shut off or go below. I am thinking one day I might try shimming the relief valve but I imagine it will eventually need new bearings. I have 15W40 Motorcraft diesel oil in it right now.

Edit: Ran it 3-1/2 hours this morning and it settled in around 23 PSIG. Must have been a hot day when it went below 20. Like everyone else I would like to see it higher but have seen several posts that indicate my results are fairly common.

 

[smokem joe]

If I was keeping it I wouldn't have worried about it so much. This one was a sold unit so I wanted to make it as right as I could.