banks twinram

i bought a 94 dodge a while back with a worn out engine. the truck only had 150,000 miles on it. and i was looking at the filter-air box the other day and noticed the filterminder was sucked all the way together. and the filter wasn't even all that dirty. i also looked at the fuel plate and the injectors and turbocharger, and no sign of the motor being anything other than all stock. the #6 hole was so worn out that it had to be sleeved, and the rest were worn out enough to need a .020 over. question is, can a dirty air filter and-or not changing the oil often enough be the cause of pre-mature engine wear? at 150,000 miles. i do not know what they used the truck for, but it shouldn't have burned u the engine in that ammount of time. p.s. the crank and rods looked fine, just the bores were bad. and another question, has anyone ever re-routed the crankcase vent onto the air box or anywhere else to keep oil from coating the underside of the truck? i don't really want to get my truck all dirty since i just spent 2500 gettin the motor rebuilt.

ratsun

Yep..
No questions, poor filtering and low quality lubes that are not changed out reg cause very premature wear. In a engine with high wear in the cyls only it sounds to me like a engine that was operated with low oil levels and or low quality lube for extended time, however I'm no expert just taking a stab at it. Knowing #6 was the worst I would take special note of the 5/6 rod side clearence as it may be to tight for proper oiling? I wouldnt like the idea of routing the vent into the intake but this spring mine is gonna find itself hooked up to the exaust

mishkaya

Almost sounds to me like it might have been a truck that sat idling most of it's life. Would explain the premature cylinder wear. Just a thought.
Mishkaya

banks twinram

i guess that would be good as long as you can get a sort of "erp gun" effect going for ya. i dunno what the correct term is but i'm saying you wouldn't want exhaust putting any kind of positive pressure in the crankcase. kinda like a siphon but not really. do you know what im talking about??

ratsun

Yeah, a check valve will make it a one way street

banks twinram

my cousin never turns his haul truck off sometimes for weeks at a time. and it has 600,000 miles on it. can idling an engine speed up the wearing process? my uncle leaves his duramax idling all night cuz he forgets to turn it off at least 3-4 nights a week... it don't have many miles on it, but we'll see if it wears out premie.

ratsun

_____________________________

Good point
I never thought about that.

banks twinram

and then you could blow oil all over ricers instead of on your pretty cummins.

Lil Dog

Just idling is not good for any diesel engine, no matter how new/old it is. And that would explain the high liner wear and no miles on the odometer.

Everyone says "its a diesel, let it run".. What a bunch of horse pucks. I would rather pay for a new starter than have to rebuild the engine.. The low temperature firing at idle just washes the cylinder walls down, removing the lubricaiton of the oil as well as dilluting the oil with excess unburned fuel. The damage from idling can't be undone. If you are going to run it, run it. If not then shut it off.

J-eh

infidel

I know a couple of folks who have teed in the blowby line to the exhaust past the muffler. Ahead of the muffler can have too much back pressure. Requires a check valve and a couple feet of high temp hose. Works great.

Running the blowby back to the airbox would make an oily mess of your intake system and could cause out of control engine run on.

jrs_dodge_diesel

Also known as diesel runaway. You can't shut down an engine that is a runaway. Only chance is to stop the air getting in. If you can't shut it down that way you should get away from it because that thing may cause a little destruction.

The prolonged idling can also cause wet stacking, which unburnt fuel collects on the valve stems and turns into a gummy varnish which can cause the valve to stick and your engine can suffer a bent push rod (Cummins calls 'em push tubes). I assume that when you had the motor rebuilt they also cleaned up the head right?

wannadiesel

A new motor shouldn't blow oil out the blowby tube. I don't know how many miles are on the motor in my truck, and it doesn't oil down the underside.

rockwithjason

You can stop runaway by pulling the fuel filter. No fuel no worky.

jrs_dodge_diesel

However, if the engine is running of of its own oil supply then pulling the fule filter won't do squat. We had a 110' cutter (Coast Guard) that had a catastrophic failure on one of its diesel generators. The block cracked up near the intake manifold and was feeding oil into the intake. The engine room crew pulled all the fuel cutoff's after seein all the smoke which stopped both main propulsion and the other generator. However the failed generator kept running. Ran for over 20 min's until it ran dry and siezed.

I remember a post a while back about air intake cutoffs for trucks that work in the oil field and refineries. The engines can run off of stuff other than diesel fuel if there is enough to sustain combustion in the cylinders.

WANNADIESEL - you are right, a new motor should not be blowing oil out of the tube. There should only be crankcase gases coming out.

infidel

Common cause of runaways that you hear of is when a backhoe hits a natural gas line. The natural gas in the air will keep the engine running even with everything turned off till it hits 20,000 rpm and flies apart. Guys who hit a natural gas line and don't pull their machine away right away usually end up losing their job.