a friend ran a motor low on oil and then it started knocking...dropped the pan and one connecting rod bearing was half missing and the crank journal is scored...how long can i expect it to last if i just stick in a new c.r. bearing? 5min, a week, couple thousand miles???

 

5-10 minutes if you are lucky.

 

The "friend" that ran it low on oil should take resposibility and make the truck right again. Even if he has to find a good used engine and install it himself.
That is why one should never, ever loan his car, truck or motorcycle. You never know how it was treated while it is in someone else's hands.

 

it was his own car...just a shame im doin all this work for naut...without pulling the crank is there anything else i could do before i put it all back together?...should i even put it back together? lucas?

hmmm...could i pull the piston, disconect the fuel injector and make it a three banger?

 

If the rod bearing spun on the crank the rod will have to be re-sized, and the rest of the rods would be suspect. The engine needs to be replaced or rebuilt. Not worth the time to reassemble.

 

At one time there were machinests that would grind the crank in the car or truck and they still do on some marine engines. It is a difficult, time consuming and expensive job. It is cheaper to just get a replacement from a Pick-N-Pull type yard.

 

he wants it to last the winter...sounds like im just gonna stop where im at now...i have the entire bottom end apart

 

The only way it will last through the winter is to let it sit. There is no way to put a band aid on it and have it last for more than a couple of miles if he's real lucky.

 

i have a friend who recently ran his car without oil...he only changed the connecting rod bearings...it still gets him to the train station a couple miles each day

 

The cost of a one rod bearing and a pan gasket is all it's going to cost your friend to find out if the engine will stay together. I bought a car with a rod knock and just ran it with straight 30W oil in the winter time. It made it to spring but the crank had to be ground .010. when I dropped the pan to check it out. I didn't resize the rod as I didn't want to pull the head to remove the piston. Put it back together and ran the **** out that engine and never had a problem.

 

Moto Mel has it right they did grind a journal in the car or truck. Crank was rotated by an electric motor either thru the rear wheel sitting on pair of rollers (one driven) manual transmission or off the crank pulley in the case of an automatic. Look around you may still find a shop that does it. I had a 56 223 that was ground that way never a problem, and back then it wasn;t expensive. You will have to change the rod. Kotzy