krystar

so got the engine on the stand flipped it over and popped the oil pan off and lo what do i find....no wonder i got really low oil pressure looks like it was definitely cracked...around 360degrees of crackage.

KuHL 951

Wow. Did you have ANY oil pressure at all? I have to think part of that separation must have happened when you dropped the pan. I can't imagine that pickup working at all to keep the oil pump primed.

krystar

I had enuff oil pressure to drive it as long as i was careful.

yea i must have seperated it when i took the oil pan off.....but I know i wasn't harsh. the engine was upside down and i literally just lifted the oil pan up. it must have been just hanging by the last nub and i just ripped it off the stub.

knfeparty

Man, where were you last semester? This would have been a great failure analysis. I wish I had time to look at it; I would say send me the two pieces in the mail and I would see what I could find...

Just at quick glance of that last picture most of it looks like brittle fracture except the bottom part where it does look like it was ductile a bit- I think that was your nub hanging on. Was this from a race car?
Also I've never had the oil pan off, does the pickup screen rest directly on the bottom surface of the oil pan?

joonas

Do you run engine without balance belt and did you notice heavy vibrations, bigger than normal?

krystar

i bought the car with a blown headgasket so there could have been all sorts of problems. very possible the balance shaft was out of phase. i've already done headgasket, valves, valve seals, timing belt, water pump, radiator..prob more on this car. it's my "learning the in and outs of an engine" project car.

DJCarbine

The car had enough oil pressure to get 3-4 bar on a cold start, warm running at high rpm netted 2 bar or so, slowing down to an idle or turning dropped the pressure to 0 and had the lifters rattling like marbles in a can lol

Thats the thing.... I've heard of peoples engines blowing after losing oil pressure for just a few seconds on the track.... but an hour of shennanigans in an empty parking lot in the snow didn't hurt it at all, minus a few peices of bearings in the next oil change

robert944h

What is the condition of your motor mounts?

krystar

i can certainly check.....how do i know if they're still good or not?

joonas

http://www.clarks-garage.com/shop-manual/eng-11.htm

krystar

not sure where are the two surfaces i need to measure at.

is this the correct two surfaces?

ausgeflippt951

What you're referring to as a "brittle failure" is simply due to the fatigue stresses. Cyclic loading will typically manifest itself by that which is characteristic with brittle failure. Fatigue cracks propagate at the grain boundaries and, despite the cyclic load not being high enough to exceed the YS, the moment of inertia of the part is constantly decreasing. Thus, the relative amount of stress the part can handle will also be decreasing. Ultimately, the applied stress (due to cyclic loading) will equal the YS and the part will fail completely. The ductile failure area was most likely from when he separated the pan.


Just a short materials science lesson


I'm amazed you were getting any oil pressure at all -- what were you reading?

krystar

lol that was quite an interjection. not unwelcome though.

yea looking at it now, i'm amazed too. but we had oil pressure for sure. otherwise the engine would be toast by now since i had driven it at least a couple hundred miles since i got the car running.

Randy V

You might be onto something.

joonas

Yes.