600CI ENGINE FALIURE

hops

4.72 wrote:We Have 2 engine failure at the same con rod #2 #6 1 Block complete distraction the second repairable damage,Al this happened after vacuum pump installation,we have 1096 HP, MAIN BEARING LIKE NEW. please help if you have any information in this regard.
Thanks 4.72

Wet or dry sump. How much vacuum was it pulling?

On the surface, it sounds like an oiling problem. Most likely you are drying out the wrist pins with too much vacuum. Remember that a vacuum pump and an wet sump oil pump are in a "tug of war" with each other.

Another thing I would take a long hard look at is the crankshaft, and look at the "clocking" of the oil holes that feed #2 & #6 rods, since they are both on the same rod journal. # 2 gets it's oil from the #2 main and #6 gets it's oil from the #3 main. I would maybe enlarge or redrill the oil holes feeding them and make sure I had a big chamfer on the crankshaft poiling holes.

Hope this helps,

Charlie

Did you notice any change in oil pressure [at w.o.t.] after installing the vac. pump?

what does the bearing look like? crank blue? rod broke at little end? or big end, ?

i would get you wrist pins coated costs some but cheaper in the long run if you have a lot of vacuum.

A wet sump and a vacuum pump are not in a tug of war working against each other because the differential pressures across the oil pump are the same irregardless of the pressures in the crankcase. If the vacuum pump reduces the crankcase pressure too much the oil entering the pump can flash/boil and make it so that the pump can't supply adequate volume to the engine. Remember that oil pumps rely on absolute pressure to avoid cavitation. Running a large amount of vacuum in the case can also cause problems with any area that's "splash oiled" such as springs, wrist pins, distributor gears and timing components just because the lower pressure in the case lowers the density of the air and makes it harder for it to carry the oil mist around inside of the engine. If something needs oil you have to put it there by using jets etc which can get complicated.