Mack ENDT-673 on WMO - Steel Soldiers::Military Vehicles Supersite

Kalashnikov · 10-25-2010, 00:38

Just wondering if anyone has run the Mack ENDT-673 on 100% or any ratio of WMO or WVO or any other alternate fuels. I run my duece on anything I can get, (WMO, WVO/cooking, hydraulic, ATF, Gear, etc.) but mostly get WMO. I'd imagine it can handle a good ratio like the Cummins 250. I have a lead on an M54 with 22k miles for a good price but don't really want to use diesel. There's another M54 that has the multi but needs some assembly and head gaskets plus its not much cheaper.

Deuce_and_a_Half_Dragon · 11-09-2010, 08:04

We have 2 of those 673's at my school, idk the ratio, but we tend to mix a decent amount of WMO in with what little diesel the school allows us (we tend to try and save the budget money during the course in case something breaks) so I don't see why you couldnt push close to 100% WMO in that truck. Careful with the WVO though, unless you heat it really well and use either diesel or WMO for start up and shutdown so u don't clog the injector lines if it gells

AMGeneral · 11-09-2010, 11:05

1 word,NO NO NO NO!!!!!

It may work OK for a while,but considering the type of IP that is used on the Mack and the cost to rebuild it($1800-$2000),it's not worth the small savings in price.

Kalashnikov · 11-09-2010, 12:33

Quote:

Originally Posted by AMGeneral

1 word,NO NO NO NO!!!!!

It may work OK for a while,but considering the type of IP that is used on the Mack and the cost to rebuild it($1800-$2000),it's not worth the small savings in price.

Can you please explain a little more? What's the difference between IPs and the reason WMO would kill it? It is the oil's viscosity? That could be cured by thining with diesel or gas. I can't see how it would be a lubrication issue?

73m819 · 11-09-2010, 13:50

I would guess it is the crap that is in waste motor oil

AMGeneral · 11-09-2010, 18:34

Ron is correct,

Me personally,I won't run WMO in anything except our WMO heater at work,even with multiple pass filtering it still leaves micron sized particles in,plus just filtering will not weed out the acids and other liquid contamanants in the WMO.

The Mack injection pump differs from the Multi and NHC250 Cummins,the Multi uses just 1 plunger for injection and a distruibter type system to deliver it to each individual cylinder at the proper time,the PT system on the Cummins basically uses a gear type pump and throttling orifice to deliver fuel to the injectors via a passage drilled into the cylinder heads,the injectors are actuated manually from lobes on the camshaft and speed/power is regulated by the pressure at which fuel is delivered.

Both systems can cope with somewhat more viscious fluids than the injection system on the Mack.

The Mack engine uses a American Bosch APE series inline pump(similar to the IP on a 8.3C series or older 5.9 B series Cummins) it has a plunger and delivery sleeve for each individual cylinder,all are actuated by a camshaft inside the lower section of the IP.

Fuel delivery in the Mack IP is controlled by rotating a delivery sleeve that surrounds each plunger,this is accomplished by a toothed shaft linked to the governer at the rear.

Basically it boils down to the WMO would have to be thinned so much to properly work in the IP that all it's lubricating qualities would be washed out,it would cause excessive heat and galling of the plungers and shortly a worn out IP.

And at $1800 to $2000 for a rebuild for the pump and about $150 ea for the injectors, basically $2900 for a new fuel system that,depending on how much you drive the truck and how far each trip was ,could be as much as every year for a rebuild.

Plus given the rarity of Mack powered MVs and parts,prices are bound to keep going up.

Just my