Damage from No Oil Pressure?
 

A couple weeks ago one of my oil cooler lines separated from the fitting on the end, promptly emptying the engine of oil all over the front of the car. I noticed the lack of oil pressure after about 30-45 seconds of cruising around 3k rpm (had just gotten on the highway & was merging) before shutting the engine off and coasting to the side of the road.

https://lh5.googleusercontent.com/-q...80-no/RX-7+-+1

https://lh3.googleusercontent.com/-u...80-no/RX-7+-+2

Anyway, the car was towed back to my apt, and I finally got time to replace the oil cooler lines this weekend. She fired up readily (after a bit of cranking w/o the fuel pump) to re-fill the oil cooler & lines, and seems to feel pretty healthy so far.

The question is - what symptoms should I be looking for/aware of from this, or preventative measures against further damage from this?

I'm definitely keeping a closer eye on the oil level in case consumption has increased, and will be on the look-out for metal flakes in the oil when changing it. Also considering changing the oil & filter again after ~200 miles to try to get any flakes out.

Anything else?

I've seen engines damaged from no more than 10-15 seconds without oil pressure. IF you continued to run the engine for any period of time after noting the low/no pressure, you could have done bearing damage, starting with the front main.

Back in like 1999, I bought a non-running FC locally. This was when I was first getting into the game, repairing/restoring non running cars and flipping them. This one had a bad clutch, so I swapped it, unflooded it, cleaned it up, and started it up. Well, on the test drive, I hear an odd noise, a bit of smoke, look at the gauges and see zero pressure. It might have taken me 10 seconds to shut it down. I pulled it back home, only to discover that some retard had replaced an oil cooler line with a GARDEN HOSE using HOSE CLAMPS. Of course the garden hose burst and oil went everywhere.

I installed used oil cooler lines that were good, topped off the oil, and fired it up. It seemed to run okay, but the more I drove it, I could hear a faint knock around 3000rpm. I didn't know it at the time, but that was a spun bearing noise. A few days later, the engine blew up altogether.

I also had a buddy one time that rebuilt his own engine in my garage. Of course the bearings were lubricated with oil during assembly. So come startup time it fires up and runs for 10-15 seconds, then shuts off and won't turn anymore. It was locked solid. Turns out he had let the little oil pump key slip out of place during assembly, so as soon as the cold thick oil primed in the oil pump, the pump stopped turning, and no oil was delivered to the engine from that point on. It ate the front main and front rotor bearing. So again this supports the idea that any more than 10 seconds without oil pressure will cause major bearing damage.

Well, the main bearings are likely damaged then, since it must have been about 45 sec from the event with the highest oil pressure (hit 6000 RPM merging onto the highway) until when I noticed the problem & killed the engine. It still spins freely by hand and seems to crank easily, and I haven't noticed any unusual noises (at least over the viscous radiator fan at low engine speeds, and over the exhaust at high ones).

We'll see how long it lasts, and what the oil consumption seems to be like.

Maybe you got lucky. :dunno:

With rotary engines, most owners do not. :(

Luck really is about all you can hope for in these situations, working at various shops you see lube guys forget oil occasionally, sometimes the cars make it a few miles down the road and back and no side effects after putting oil in and some dont make it off the lot.

Well, fingers crossed then! Thanks!

Why would someone think garden hose was a good idea...?

many of these cars wind up in the wrong hands. i've seen just bout everything also but not garden hose, yet. but i have dozens of stories similar, such as engine harness wiring extensions with speaker wire and poor crimp connections that pulled out sections of harness with a light tug on them like it just went through chemo treatment.

with FCs you always see something new. it's quite rare to see the same shit happen to FDs, but that is because you can't find an FD sitting beside a house with an owner willing to let it go for $0-$500.

you can pull the front stat gear without removing the engine if you'd like a way of knowing what damage you've done. if it's bad i would pull the whole motor and redo it rather than just throwing a new bearing and letting it ride.

this is true! my friend bought a car, and it had some cheesy black crapet (i was going to correct spelling, but crap is more accurate) in it, and i went to vacuum it, because i was bored, and underneath was the factory carpet.

peeling back the 4 pieces of crap, left, right, over the trans tunnel, and then the fix for the that 3rd piece, left use with dirty, but otherwise nice factory carpet.

the rest of the car was a pretty typical bunch of badly, or not masked stuff ruining a good paint job, huge bundles of aftermarket wiring to do who knows what, junkyard writing on everything...

once all the after market BS was ripped out, and the car was just returned to stock, its actually quite nice.

the sad part is that i think the previous owner was really trying to make a nice car, they just failed epically.

Previous owner of my car used a marker cap as a coolant block off on the throttle body. Also the previous engine builder forgot internal oil passage o-rings, used the wrong front cover gasket/o-ring, and forced the teflon ring inside. Oh, and they re-used the 20+ year old factory fuel hoses. Luckily, it was the return line that started leaking. But yeah.. next time I won't be 23 and fully stupid. :)

I rebuilt an rx8 with a sharpie marker body acting as a tube to join the throttle body coolant hoses, for a ghetto "throttle body bypass mod". I shit you not.

That doesn't mean its a good idea. Temporarily , as a band-aid , sure.

Had a small plastic vacuum hose pinched under my oil filter. Leaked most of the oil out as I was driving easy down the street to the gas station. No harm was done and I even inspected the bearings during a later teardown.

when I purchased my engine , it had low oil pressure . no matter what I did thicker oil differnet filters it would never go over 30 psi when warm , at full throttle , and around 10-15 psi when idle ..

eventually it blew catastrophic failure only things salvagable was the irons .

the oil pump was bad looked like someone ran the car without oil which damaged the oil pumpo which then slowly lead to a spun bearing .

no oil pressure is a bad bad thing . IF like you said the car seems fine MAKE SURE that you have good oil pressure . and if you dont save your self a HUGE HEAD ACHE and rebuild .

Uhm, do you think you are educating me about this or something? :scratch:

I guess you took it that I installed it. I found it already installed when the car was brought to me, and promptly removed it and returned the configuration to stock.

Sounds to me like a bad front cover o-ring in your case. That is exactly how it will behave.

IF this guy's engine continues to make good oil pressure, makes no unusual noises and maintains compression, and there are no metal shavings in the oil/filter/pan/pedestal, then I say run it until you have a reason not to.

Its making 30 psi on the gauge when warm & idling, up to 60 psi at 1500 - 2000 RPM consistently (i've checked the gauge a few years back, and its accurate enough for this, and for showing 0 pressure as I found out). I haven't noticed any abnormal knocking or other behavior that couldn't be attributable to the need to re-tune - I've been re-tuning it a little lately since I had a pretty big pre-throttle leak before that I didn't know about & previously compensated for in the VE table. There is definitely a burning-oil smell when I come to a stop & idle, which may be from the turbo, internal oil seal leakage, or just oil that got sprayed all over the engine bay burning off the exterior of the engine/exhaust. Need to look into that one further, although I'm leaning towards the turbo as it seems to be making a little more noise at lower boost than I remember.

Changed the oil at around 700 miles, and it came out looking pretty clean. Definitely didn't see any metal flakes. Oil consumption seems to have increased, so I'm going to try to track it a bit more closely to determine by how much.

You cut open your oil filter?