I guess it would vary where the piston is on the stroke, if it is near the top I'd imagine the oil squirters would help things out but if at bottom it probably wouldn't do anything. Then again there will also be no delay in the oil pump sending oil out since it is already there.

I wonder if I could make one with my talon's old fuel pump then wire it to go on with the GP relay.

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Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Shoot, we have 2 routes here at school where we rotate busses off of because it is so long. We average across the board.. probably 75-100K per bus a year. Depends on if it is in the shop a lot... our mechanics aern't the fastest in the world.
~D.J.~

In a previous discussion, I think a pre-oiler without a pump was brought up. Apparantly they are used on some stock cars. There is a container, pressurized when the engine is running. It stores the pressure and releases it on demand prior to starting. Seems simpler than the expensive pump systems.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I don't know if that'd be simpler, it would probably take a bit more room for the air tank to hold the oil, then how do you get the right amount into the drain pan? Also when you changed the oil you'd have to drain it as well.

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Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

The product you are speaking about is called an "Accusump" and they are available from HP companies like Moroso. The idea of an Accusump is that it is plumbed into the oil circuit between the oil pump and the oil galleys. Think of it as a metal cylindrical container that is completely sealed except for a port on the bottom center. Generally they are available in 1.5-3qt size range. An extra quart or two is added to the regular oil capacity to compensate for the additional volume of the Accusump. When the engine is started and oil pressure builds oil flows to both the oil galleys and the Accusump. The volume of oil in the Accusump stabilizes when the air pressure trapped above the oil in the Accusump equalizes with the oil pressure. Make sense? The result is an extra quart or two of oil that remains under pressure in the Accusump as long as the engine is running. In racing vehicles that are subject to high G forces sometimes the oil pump pickup starves and it sucks air as the oil sloshes in the oil pan. The pressurized stored oil in the Accusump provides a supply of pressurized oil to the oil galleys when this happens preventing engine damage. Obviously a quart or two is not much oil for a high-reving race engine but since the oil pump starvation periods are very brief the Accusump can provide enough oil to prevent engine damage. Using an Accusump as a preluber is possible simply by installing a cable/electrically operated ballvalve at the bottom of the Accusump. Closing the valve while the engine is running and then shutting the engine down will result in the contents of the Accusump being stored under pressure. Opening the valve when turning the ignition key will provide pressurized oil to the engine at startup. This would be a much simpler mechanical system to instal with the only problem finding a place to mount the unit. Sorry for the long post.... RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

Could a quart and a half be enough to make a difference though? With merely the potential energy stored in the container I wonder if it'd ever make it to that last cylinder. It better be one quick burst to travel through all five of them otherwise I'd think it'd end up filling the line and emptying in the first couple cylinders.

Could oil be sucked through the oil pump while it isn't moving? Along the same lines as a race car pulling a couple Gs, ever think about a "crotch-rocket" popping a wheelie? I bet they must really like that, revving near redline with no oil for as long as the wheelie lasts.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Most (If not all) have a dry sump system. The oil pump pulls it from a tank somewhere off-site from the engine. I bet little to no air can get into that kind of system.

I'll try to answer the original question from a historical standpoint. Diesel trucks became popular in the mid to late 1950s, or about the same time the railroads went to diesel-electric. Before then, trucks were mostly gassers. Three to five mpg was the norm for a gasser semi-truck.

Diesel truck engines, in the US and Canada, didn't really change much until the advent of "low sulfur fuel" and de-regulation. The combination of low sulfur fuel and better generations of lubricants over the years meant that a top-end overhaul went from 300,000mi to a look-see at one million miles. Bottom end went from a look-see at about 750,000mi to a look-see at a million, or when the pan gasket goes. Better materials (steels, gaskets, etc.) over time also helps here.

Deregulation drove the fuel mileage up. A road truck used to get 6-8mpg. Now 10-13mpg is the norm, thanks to new injector pump technology and computer controls. The old trucks used the same technology as our old MBs. New truck injector technology varies, but a common high pressure manifold downstream of the "injector" pump and computer controlled electric solenoid valves for each cylinder is an adequate first description.

Why do trucks last longer? The old trucks didn't. They just had parts replaced on a schedule, for the most part. Water pump would be a good example. Overhaul schedule really isn't much different than for an older MB.

New trucks last because:
1. Engine rpm kept within a 600rpm span, with multi-speed transmissions.
2. Huge air filters, as compared to a car.
3. Multiple large oil filters. My last truck took a gallon of oil to fill the two filters.
4. Some trucks even have coolant filters.
5. Bigger fuel filters.
6. Fuel-water separator. This is the key difference. Diesels don't forgive water in fuel. Truckers figured it out, most car drivers haven't (yet).
7. Better held maintenance schedules because of the capital cost. A rebuildable engine is worth as much as $10,000. Scrap metal isn't worth diddly.
8. Better education of drivers. A truck down for unscheduled repairs doesn't make money and neither does the driver.

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daBenz - 1970 220D

10 - 13 mpg is AMAZING for something that weighs 80000 lbs. That's about what a new Escalade gets or maybe an old 108 bodied MB.

Sholin

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What else, '73 MB 280 SEL (Lt Blue)
Daily driver: '84 190D 2.2 5 spd.

Well, I obviously did not get across my point.

Yes, preoilers do a great job protecting all rotating bearings and journals from excessive cold start wear. That's why they use them in aircraft. I'm quite sure that they will do the same thing for the crank, cam and associated parts on most any engine. I don't disagree at all.

As for the oil squirters in the turbo diesel MB's, they only squirt when the oil hole in the crankshaft and the oil hole in the rod bearing are lined up. This would usually not be the case, thus they would rarely squirt oil when the pre oiler is activated. Additionally, I don't think that they squirt oil on the cylinder walls, they squirt oil on the pistons for cooling purposes.

My whole point is, how often do you see an engine torn down because of worn crank, cam or associated bearings? An engine is almost always torn down because of blown head gasket, leaking valve(s), worn cylinder/piston/rings, etc., So, where's the real practical advantage here?

Also I should have been more clear about cylinder wear protection during cold start. I said that the pre oiler would do nothing to prevent cylinder wear. What I should've said was that it does nothing to prevent cylinder wear during cold start up.

My whole point: the pre oiler saves the cam journals, crank and bearings, so what? You almost never have a problem in this area anyway. When I have seen it necessary to disassemble an engine because of failed engine bearings it has been due to catastrophic loss of oil pressure, not normal wear. The pre oiler would have nothing to do with catastrophic loss of oil pressure one way or another.

Hope this one is more clear.

Have a great day,

Larry, I love seeing you mobilize your energy to fight the Evil Forces of PreOiler Advocates....

and for most engines you are mostly correct... but I have a 6 cylinder gas engine 280se up front whose only problem is a knock.. either rod or pin... so these things do happen once in a while..

However, for the TURBO MB ENGINES I believe your point may be less applicable... and I may have detected the weak point in your force field...

It is this :

"As for the oil squirters in the turbo diesel MB's, they only squirt when the oil hole in the crankshaft and the oil hole in the rod bearing are lined up. This would usually not be the case, thus they would rarely squirt oil when the pre oiler is activated. Additionally, I don't think that they squirt oil on the cylinder walls, they squirt oil on the pistons for cooling purposes." --LarryBible

This is not the case according to my reading of the Factory Shop manual ( pictures to follow ).

My position is that the oil squirters start spraying at a specified oil pressure and continue in a continous fashion until that pressure is not still available from the oil pump.
I maintain that in this mode that either droplets or mist will be available to the bore liner ( just as small engines are splash lubricated ).. and so from the time the piston has made one upward movement in the bore after oil pressure has been established sufficient to open the valve that piston and ring wear will be reduced.

Thus it may be advantageous to have the oil pressure established before any turning of the crank happens on a Turbo MB engine....

PS.... For people who do not take the steel balls out of the rear of the block to clean when doing a rebuld... it is my impression that it is THIS oil system passage which is not being cleaned by that omission.

The big picture...

Attached Thumbnails

 

smaller picture...

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more words...
What a bummer, my dramatic presentation of the evidence in my closing argument gets split between page one and two....

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If you bought a "BRAND NEW" DIESEL BENZ or a PASSAT and drove it only from San Francisco to NYC and back and forth with pretty much only highway driving and NO city driving and changed your oil every 3k miles. I AM WILLING TO BET MONEY that the Benz would EASILY last over a million miles!!