KICK said:
some years ago a vendor managed to sell my employer a bunch of those postlubers you all were talking about.
I saw no evidence that postlubers worked after 12 years of running those vehicles.
it is more of a feel good device,for the handwringing set, because if you take proper care of a diesel powered turbo equipped engine, by observing a short warm up period and a cool down period before you shut the equipment off you shsould never have any trouble with it..
Yes, Kick, thats right, if you observe the cool down period there is little or no advantage to a post luber. In Arizona, New Mexico, Nevada, etc. in the summer after puling off the interstate to fuel up, if you have a realistically low target temp on your EGT pyro you can get a lot of BORING seat time waiting for the temp to drop. Of course you want to run the A/C which delays the temp drop. A postluber will do the cool down for you while you are in the coffee shop having a cold glass of tea and the luber doesn't need the A/C running
There are a lot of drivers that when faced wth the reality of the times involved waiting for the cool down will "negotiate" a new target temp that may not be as healthy for the equipment.
If you kept complete and accurate records and didn't go by guess and by gosh and saw no difference then you had a well disciplined cadre of drivers who did the right thing. I'm a wimp. I prefer the cold glass of tea and the automated cool down.
Chris, The DIY preluber with the ball valve is dead simple and you should be able to make one from my verbal description. It has been 15 years at least since I originally saw the plans. If you want plans (less a well articulated and cross referenced parts list including part numbers and suppliers) I can draw one, scan it, and post it but I warn you it IS DEAD SIMPLE.
One of the BIG decisions is whether to go solenoid valve controlled by a momentary contact normally open single pole single throw switch in the cab (push button like a door bell button) or route the oil line to a ball valve in the cab. The other BIG decision is where to tap into the oil system. You don't want the majority of the oil to get squirted into the crankcase without going past the places needing lubrication. Somewhere along the oil path between the output of the oil pump and the first place the oil is given multiple paths to follow is where you want it. So long as you tap in as stated above the actual tap point is best selected for your installation convenience.
The fuel-less cranking was not something I invented, Cummins had it in a bulletin. It was not intended for everyday operations but just first starts after long periods of disuse (weeks, not days.) It isn't an issue of RPM when comparing dry cranking till it lubes vs dry start right away. When the cylinders are firing there is much more stress on the dry moving parts by far than when the parts are spun by starter motor. Wear on the starter motor shouldn't be much more than the equivalent of 2-3 more starts, not a bit deal and not going to put you into changing a lot of starters.
If you do install a DIY preluber the course of envents is:
1. Before starting the engine you press and hold the preluber button (or flip the ball valve) and note a momentary rise in the oil pressure gauge (you do have a gauge and not just an idiot light, right?)
2. When you see the oil pressure peak and then start to fall you crank the engine knowing you have squirted some oil to your wear surfaces and bearings.
The simple DIY preluber does work and definitely reduces the wear of dry starts which should give a much longer life to your engine. Again, I didn't invent the idea. Automotive engineers make various claims from 40-50% range to the 80% value I have seen touted as what portion of engine wear comes from dry starts. I think an individual's usage pattern would determine the gain they would see with prelubing. Users who rarely shut down (like long haul truckers and such) would get less benefit than someone who did frequent starts (most of us.)
There are varying estimates of how long between runs it takes before you get a damaging dry start. If you start up within a few minutes of a shut down not all the oil will have drained away from bearings and other friction points. Even our MODERN oils thin out in contact with hot metal and tend to drain away from those areas before the engine cools completely. Our modern lubricants remain highly mobile at lowered temps such as you would find in a parked vehicle's engine so drain down continues even after cool down.
This is all simple science/engineering, easily understood by most folks who want to understand it and NOT the overblown imagination of "the hand wringing set" or marketeers bent on selling you a geegaw you don't need like a magnet to put on your fuel line.
Let me know if you want a diagram. I suppose you could Google for preluber DIY plans.
I googled and found this:
Construction Plans
Their plans are a tad more complicated than the ball valve version but I'm sure you an make the appropriate substitutions.
If you are a taxi, buss, long haul trucker, or in a class of use where there are LOTS of miles per startup and few or no long period (weeks) of down time, then prelubing is not particularly cost effective. We personally have many more vehicles than drivers and have weeks (months) between use sometimes on some of the vehicles.
Post lubers are much more important for turbo equipped vehicles because of the extreme temps of the turbo shaft in the direct fire coming out of the exhaust. You should NEVER shut a turbo equipped vehicle off after working it hard without waiting for it to cool properly. The heat stored in the impeller fins and shaft will fry the oil in the turbo shaft bearings before the assy cools down. These carbon/coke deposits in the bearings contribute to rapid failure. A post luber circulates oil through the bearings till they have a chance to cool to acceptable levels which extends the life of the turbo tremendously.
If you are willing to sit and idle for several minutes prior to shutting down then you have little to gain from a post luber. Again, I prefer the air conditioned coffee shop and cold drink to watching a pyro EGT gage.
Pat
