I think it was TR who had the story of the 500,000 mile motor with no rebuilds on it..

does that answer your question?

 

Re: PRE-OILING does it actually make a difference?

You can also use an pressurizing oil accumulator to prelube, which also works to lube the motor when the pump sucks air(when you get really steep).

 

Lemme put it this way. You would have to hold a gun to my head to make me light up my SB350 Chev-Lay V8 without first cranking it till the oil gauge showed pressure.

I have a great starter and a good battery so I roll that sucker over till I see oil pressure then I crack the throttle and let it start.

When we had the big Cats on our ranch in CA my Dad always preached to me that I was not to flip on the compression on the diesel engine until the oil pressure was up. We could roll them over with the cranking engine with the intake valves held open for as long as it took to see oil pressure. We never got less than 8,000 Hrs between overhauls.

An oil accumulator is a GREAT IDEA....helps to balance out the pressure and prevents starvation in an off-camber moment as Wayne pointed out. An accumulator is just a metal tank with a bladder inside that acts like a surge chamber.

 

There are plenty of articles, some written by people who should know, that say that the huge majority of engine wear takes place in the first few seconds after starting.

Where did you see that device?

 

Above are answers from two Mechanical Engineers.. and in my book, those answers are good 'nuf for me... but being me I'm gonna throw in my two cents worth from a logical point of view that my dumb the argment down a little.

Have you ever honed a knife edge wet and dry? Which one got the edge sharper, faster?

Yep it was wet honing. This does two things, takes away heat, and helps to remove filings and work them away from the edge being sharpened.

It's the same way with a pre-luber. Without pre-lubing you've got metal on metal sliding past each other under remendous pressure. If you're lucky there is a residual film of oil between those parts. How long do you think that will last?

By pre-lubing there is a cushion of oil between bearing surfaces that sucks up heat, and moves any impurities to the filter to be contained.

Now in my book that's a good thing..

 

CJ dave,

what good would letting it crank till oil pressure goes up? wouldnt you still be wearing out motor in the cranking process? i tihnk thats what prelubers are designed to avoid. the thing im talking about is a seperate motor that presurizes everything right before you crank the motor....kina like how your fuel pump on FI gives fuel before you crank...

sounds good though....the jeep im picking up...(hopefully this weekend)...has 73000 miles on it....so i want ti to last at least 150,000 more miles....so i am picking one of those up as soon as possible!

 

Jim_lou

http://www.enginelube.com

looks easy enough to install and the benifits seem to rationalize the price. Im sure theres other companies that make things like this tooo..

 

Jeepngreg, what CJDave's describing is a "poor man's Luber." Granted the engine is still rotating, but as long as it's not running on it's own there is a LOT less stress on the components than if the cylinders were live and firing. Wnen the engine spins up and not running, then the oil pump can fill the galleys and the bearing journals while the parts are under the least amount of load. It is true that if you could do this without rotating the engine then that would highly decrease wear further. Which is the reason for an accumulator or a pre-luber, decreasing start up wear and tear on components.

 

aah....i understand now....that makes a lil more sense. to bad i will have FI or else i would do that too....

 

Thanks Gregg. Looks interesting. Nothing that would be difficult to make there. I might build one when I put my Jeep back together.

 

sounds like a great idea but $500+ bucks? there has got to be a junk yard solution this problem!!!

Dirt dog, cjdave, leve, will, high5, jim lou, elusive? Whatcha got?

- Tim

 

You can do it with a FI motor also and have an antitheft device at the same time. Put a switch, whether keyed, toggle, or whatever on the ground circuit of your fuel pump relay (you are running a relay I hope

). That will kill power to the fuel pump when off and allow you to crank the engine without it starting. It will also be a theft deterrent. Nickmil.

 

I'd say you should be able to build one... the work almost like a well house captive air tank.

Take a look here.

 

leve, you always talk about oiling an engine by attaching a drill to the oil pump don't you?

So why not get a small motor, or a starter or something, put it on a toggle, and attach it to the back of the pump?

using a starter it would free-wheel when the engine started.. turn it on for 15 seconds, then start it and turn the motor off?

 

Infernozx, the idea is sound, but it's not practical. The place where you attach the bit from the drill is place where the distributor shaft drops in.... so you can't get tot this point unless you have removed the distributor.

One of the reasons I've never made a pre-luber is that the price of the 12 volt pump is quite high for the reliability that's needed. In looking at most pre-lubers on the market about 3/4 of the cost is in the pump.... and you all know how cheap I am.

 

those accusump tanks look great too but they are $300+ there has got to be a way to rig or make something work for much cheaper.

cjdave- if you are cranking the engine until the oil presure comes up dont you put a lot of stress and wear on the starter and the battery?

 

Yeah, but what percentage of the cost of an engine is a starter and battery.

 

Here are the answers to some of the posted questions about pre-lubriction:

YES, you CAN crank a Chev-Lay longer to get the oil pressure up, IF the starter is adjusted perfectly.

As you probably know, them Shiv-Lays do not have a very precise starter mounting system

and must be shimmed to get the correct clearance.

TR told us how to do that and that info flew into my brain and stuck there. You slide a 1/8" drill rod between the starter shaft and the ring gear.

My SB350 cranks with the smoothness of Butter,

and the starters last a ****'s age,

so I don't worry about "free cranking" it to get the oil pressure to show.

ALso, I use that big two-quart filter

so it does take a little bit longer sometimes to get pressure up if it has been sitting.

THE CATS we ran all had the compression release wherein you could lever the intake valves full open while you rolled the engine over, thereby relieving the pressure on the crankshaft that 20:1 compression on a 4-14" bore diesel engine would normally cause

. That was a great system and saved us a lot of needless crankshaft bearing wear.

BUT.....HERE is the definitive example of ALL TIME, and is what convinced me that pre-oiling was so darn essential.....

I was in a big creamery doing an Infrared Inspection in their "engine room"....actually a room full of HUGE ammonia compressors.....and the head engineer gave me a little demo. He set up a DIAL INDICATOR on the huge compressor shaft with the stem of the indicator vertical. He zeroed the dial and then he went over and pushed the "Start" button on the big compressor motor. The start sequence began with the electric lube oil pump starting up first. within just a few seconds, that HUGE SHAFT raised up just a few thousanths....like maybe three (.003) or four (.004) of an inch. THEN the compressor started and the shaft NEVER DID go back down....it was literally riding on a film of oil, not even touching the big pillow block bearings.

He told me how many hours the machine had on it and it was a mind-boggling amount; almost incomprehensible since the machine dated back to WWII.

The squish tank engine pre-luber would be my choice for since it also helps to smooth the spikes and dips in oil pressure. You could make one if you just got the accumulator from a farm sprayer or a hydraulic system and used a lever valve that you could operate from inside the cab to "trap" oil under pressure in the tank before engine shutdown, and release it as you got ready to restart. It isn't rocket science by any means.

 

You can get a decent accumulator that will pre-oil and feed oil to your engine if your oil is away from you pickup tube on steep angles. It is limited by the capacity, though. Here's a diagram to show exactly how it works. To get this to work as a "pre-oiler" you would either have to manually open and close the valve, or rig up some type of solenoid.

I would go with the smaller 1.5 qt capacity vs the 3 qt so your pan isn't overfilled when the accumulator discharges. Hmmmm.... we use several hydraulic accumators in airplanes, I'll have to see if I can get my hands on one that isn't fit for flight anymore...

 

I read an article on the use of preluber on small aircraft engines and there was no significant advantage. This article was written in a FAA publication and I believe if there was an advantage they would have required engine makers to require it. They sound good at first but seems more checking is required scientifically to see real proof. If you really want your engine to last a long time convert it to propane or natural gas. I've taken these engines apart before and show minimal wear at 200,00 miles.

 

For those of you who were cranking over your big diesel's. While you may have been cranking them to get oil pressure, the reason for the de-compression ability was to allow operators to build some heat in the block and pistons before trying to fire the engine up. As a diesel needs heat to get run, turning the engine over with minimal compression allows the rings to rub up and down in the cylinders creating heat. Flip the valves back to normal operation and it would fire quickly without using an external starting aid (ether).

 

I can't see how cranking with the decompression device activated could possibly build more heat than compressing the air.

When drawing in the air and compressing it your rings are moving against the cylinder walls just as much as otherwise, plus you're also heating the air (by compressing it a ridiculous amount).

That's where the heat to fire it comes anyhow, the compressed air heating, or so I thought.

Then again I've got virtually no experience with a diesel, especially the big ones...

 

There was actually a lot more to it Teem......when we were rollin' those big CAT engines over with the compression off, not much air was actually moving in and out of the system since the same air just went in and out of the intake manifold. At the same time, the exhaust from the cranking engine was ducted in a sleeve over the diesel engine intake manifold and THAT heat helped warm up the air and subsequently the cylinder walls. Once I got oil pressure up I would reach over and crack the diesel throttle just a scooch for about three seconds to leak in a little bit of diesel and THEN I would flip over to normal compression. The small amount of diesel would begin cooking and even though it was not enough to actually start the diesel, it helped make more heat.....and it blew some great looking smoke rings out of the exhaust stack too

. Then once I felt the head of the diesel getting warm, I flipped the compression back to off.....opened the throttle and flipped back to normal compression and the diesel would immediately start.

Just a little routine we had.

All of that was done while squatting on the left side track of the CAT. There was a clutch to clutch the starting engine, and a lever that engaged the bendix drive, a throttle for the starting engine, a throttle for the diesel engine and a lever that operated the intake valve lifter to zero out the compression by holding the valves open.

 

Thanks for clearin' that up Dave...

 

Although a little complex, I always thought that the cranking motor was a real good starting system for big diesels. It took real good care of the diesel engine by not forcing it to "cold start", and it required NO BATTERIES. Yep, the starting engine could be hand cranked if need be. All you really had to do is remember to have a gallon of gas for the starting engine on your fuel trailer or at least a siphon hose so you could get a few qts out of the pickup.

There were some special things that HAD to be done, and one was to shut off the gasoline valve under the small fuel tank that fed the cranking engine and let it run completely out of fuel when you finished with it. If you did not do that the constant rocking of the CAT dozer would jostle the float in the starting engine carburetor and that would keep letting gas flow into the bowl and the carb would run over and fill the starting engine with raw gas, which would go into the cylinders and down past the rings and into the crankcase where it would dilute the oil.