Spinning a motor w/o oil:

[speeder]

I think I know the answer but asking anyways. I have an engine sitting around that I want to compression test on the floor, most of the oil is drained from it. It is not literally dry inside but only has residual oil.

It's an older Powerstroke 7.3, how much oil would I have to put in in order for sump to suck some up and lube bearings while being turned over w starter? It WILL NOT be started, only spun w starter motor.

It holds something like 4 gallons installed. I'm also not sure yet what I have to block off to prevent spills/leaks, need to figure that out. I know that I could safely turn it over by hand as it is but it's going to need oil to spin a little faster.

Just enough to submerge the sump? What say? 😺😬

[speeder]

[dad911]

I'd do a leakdown test on a sitting engine.

[Hugh R]

I don't know the engine at all, but in the past with other engines that had sat for a long time, I introduced a cup or so of oil into the engine via' a fitting that came from the engine to an external oil cooler to flood the oil pump, that should give it enough lubrication to wet the main and rod bearings, I'd also squirt a little in each spark plug hole.

If you can turn it over by hand to see if everything clears, what additional benefit do you get by using the starter?

I hope you strap it down before doing this.

[speeder]

Originally Posted by dad911

I'd do a leakdown test on a sitting engine.

A Diesel engine can have 300+ lbs. of compression and be completely shot/needing rebuild. A leakdown test would tell me nothing that I need to know.

Originally Posted by Hugh R

I don't know the engine at all, but in the past with other engines that had sat for a long time, I introduced a cup or so of oil into the engine via' a fitting that came from the engine to an external oil cooler to flood the oil pump, that should give it enough lubrication to wet the main and rod bearings, I'd also squirt a little in each spark plug hole.

If you can turn it over by hand to see if everything clears, what additional benefit do you get by using the starter?

I hope you strap it down before doing this.

See above.

[island911]

Originally Posted by Hugh R

....

If you can turn it over by hand to see if everything clears, what additional benefit do you get by using the starter?

I hope you strap it down before doing this.

This.

Plus, if you crank it by hand you can feel the compression bumps. (and any that are pathetic)

edit. ah... Diesel. You'll need a long bar.

[Hugh R]

Like I said, I don't know the engine....diesel...., nevermind.

[fastfredracing]

Whatcha building Denis ?

[speeder]

I have a truck w a bad motor and I have this used motor that I bought up in Oregon, represented as "good", whatever that means to the guy who sold it to me. Also supposed to have only about 150k miles, (would be like new if maintained properly and stock chip), but who knows?

The problem is that Diesel engines have a LOT of compression and will still run w reduced compression but with an obvious loss of torque and efficiency. I need to know actual numbers on this before dropping it into the truck, (a lot of work, unfortunately).

If it has ~300lbs, I tear it down and rebuild first. If it has ~400 lbs., (across the board of course), I drop it in. If it has ~500 lbs., I'll be screaming w joy that you can hear in San Diego.

[dad911]

Originally Posted by speeder

A Diesel engine can have 300+ lbs. of compression and be completely shot/needing rebuild. A leakdown test would tell me nothing that I need to know. ....

My bad, missed it was a diesel, sorry.

[pen15]

When doing oil changes or other major services to those engines they seem to take 15-20 seconds of cranking to build any oil pressure. I have had them come into the shop with up to 11 quarts low on oil so I would say 4 quarts in the pan and a prefilled filter should be all you need. As others have said strap it down good.

[JackDidley]

I once took apart an SBC that had been on the stand 4 years. All the crank bearing surface still had a nice coating of oil. I doubt that a short crank over would hurt.

[pen15]

Oh, and to elaborate on the 11 quarts low. The injectors need oil pressure to fire fuel so the high pressure oil pump and injectors will run out of oil and stop fueling just moments after the low pressure oil system loses pressure so pretty hard to damage one of those motors due to running low on oil

[Don Ro]

Originally Posted by JackDidley

I once took apart an SBC that had been on the stand 4 years. All the crank bearing surface still had a nice coating of oil. I doubt that a short crank over would hurt.

Done it this way myself a couple of times. No issues.

[M.D. Holloway]

Originally Posted by JackDidley

I once took apart an SBC that had been on the stand 4 years. All the crank bearing surface still had a nice coating of oil. I doubt that a short crank over would hurt.

and if Slick 50 was used ya might not even need oil...ever!

[asphaltgambler]

I work with these engines everyday. In order to do compression test or leak down you'll need to remove the valve covers, remove 1 glow plug, use an adaptor to thread into that hole with a diesel compression gauge. On the 7.3's most people would like to see at or near 400 psi cranking compression for a healthy status.

But - that's only part of the truth. While it is a very good, robust set up, injector failure, glow plug failure, weak high pressure oil pumps are very common. The real test is when you fire it, monitor if any cylinders are laboring when cold and how much blow by is occouring. Feel free to PM me with any questions.

[speeder]

Originally Posted by asphaltgambler

I work with these engines everyday. In order to do compression test or leak down you'll need to remove the valve covers, remove 1 glow plug, use an adaptor to thread into that hole with a diesel compression gauge. On the 7.3's most people would like to see at or near 400 psi cranking compression for a healthy status.

But - that's only part of the truth. While it is a very good, robust set up, injector failure, glow plug failure, weak high pressure oil pumps are very common. The real test is when you fire it, monitor if any cylinders are laboring when cold and how much blow by is occouring. Feel free to PM me with any questions.

Thanks. I work on them a little too, I've even rebuilt one about 10 years ago. I have a diesel compression tester w the correct glow plug adaptor for the 7.3. I remove all GPs when I compression test in order for it to spin more easily.

Glow plug failure is no big deal, normal maintenance item. The problems come when people use aftermarket GPs and the ends swell and break upon removal. That's a bad day when that happens. Motorcraft/Beru ONLY!!

There is massive ignorance and stupidity surrounding maintaining these engines and diesels in general. That's why I have about 4 of them sitting in my shop w low compression that should be like new considering the mileage, (if maintained properly). The culprit in each case was improper air filtration, usually due to a K&N or similar junk "performance intake".

I agree w you about 400 lbs. of compression being good though I've heard that they have even more when new.

[speeder]

First of all, I'm going to put some oil in it. Thanks for the replies.

I'm sure that there is a light coating on bearings but I'm going to spin it w the starter possibly 8 times, (depending on what the first numbers are, I might quit after 2 or 3).

I've removed the GPs and rigged up this battery set-up. I figured that I would just have to jump the positive terminal on starter to the solenoid terminal but it's just shorting when I do that. I'm doing something wrong.

Help.

[asphaltgambler]

By jumping the batt terminal to the switch terminal with a healthy (12 gauge) wire - the starter should spin. If it has at least 10 Qts or so of oil should be enough, but know the system is going to try to fill the oil reservoir for the HPOP first with some lube to the mains / rods but that is fine for just cranking

[tooms351]

It takes 2 batteries to turn that puppy over! In series I do believe.