lost oil pressure, engine died, no sweat.(?)

[MonkeyMan]

I was driving on the 405 today when I started to get a funny feeling from the motor - some strange vibes in the seat of my pants. I looked down at my oil pressure gauge and it was bouncing sporadically between 20psi and zero.. not 10 seconds after that, it dropped to zero, engine died, and I coasted about a half mile, got off on ventura and pulled over.
Checked the oil, not a drop. Opened the fill cap, smoke. Shit. Motor's done.
Or is it?
Now before I get flamed for not keeping track of my oil blah blah, let me explain that I've had an oil consumption problem lately (#2 cylinder valve guide/valve stem seal) which goes through a quart every 2 weeks or so.. I added a quart about a week and a half ago, but I guess it just got worse since then - a lot worse.
Anyway, so being one who never goes down without a fight, I had my wife bring me 5 quarts of 10w-40, just to see..
It took 3, so not totally empty, but close. Then the moment of truth..
I cranked her over, but could only put up with the terrible metallic squealing for about 5 seconds. Alright once more and bam, fired right up.
The idle was a little funky for about 10-15 seconds and then settled down into what seemed normal. I gave it a couple gentle revs from under the hood just to get a good listen - sounds ok to me.. So off I went.
I guess it's ok, right? I was staring at my oil pressure gauge for the rest of the drive and took it nice and easy, but everything seems normal.
Is there any precautions I should take? Should I have anything checked out? The motor is pretty fresh (~30k on rebuild) and I've never had any other problems except for a faulty valve guide or valve stem seal..
Did I do any permanent damage or is this M20 in fact just a bulletproof little bastard?

[FLG]

I'd say its done. Only a matter of time before things worsen.

I'd take it apart now and inspect for damage than wait until things fall apart and cause even more damage.

Sent from my Galaxy Nexus using Tapatalk 2

[jlevie]

Drain the oil and check to see if it has a metallic sheen or metal particles. If it does, the motor requires an immediate rebuild or replacement. If there there is no evidence in the oil the chance of much more life out of the motor are pretty slim, but it may run for a while.

[MonkeyMan]

I've been planning on doing a proper rebuild on the motor since hearing the details on the previous owner's build, but not this soon.. and since this is my only set of wheels at the moment, I'm not sure what I'm gonna do.
Apparently he cut some corners here and there - I guess he started to run out of money towards the end and left a few things that should've been changed (like valve guides).. nonetheless, I got a used head a few weeks ago that I've been slowly tearing down and ordering parts for little by little.. looks like I have to bite the bullet and speed that up..
I know that a lot of guys will probably tell me this is a great opportunity to "upgrade" to a M/S50/52 etc, but I love the character of the M20 and I truly believe that this motor is a perfect match for the E30 chassis when built up to it's potential - so I'm gonna stick with it.
I'm gonna drain the oil within the next day or two and report my findings....

[jlevie]

In my opinion there isn't that much of a gain from an M50 engine over a well built M20B25. An M52TU is bit better due to a broader torque curve. An S50/52 is a very different matter. An M20B25 that is in good condition and is running correctly has more than enough power for a daily driver. And in Spec E30 or Pro-3 trim has plenty of performance for the track.

My guess is that the bottom end bearings and the cam journals may have sustained damage as it sounds like the engine stalled from dry bearings. If the crank wasn't damaged a fresh set of bearing and polishing of the crank may be all that is needed there. The head/cam might be a different matter. Until the engine is out and torn down you won't know the extent of the damage.

There is a possible risk to driving the car at this point. If the rod bearings have been damaged one could seize and throw a rod, which would turn the engine into scrap metal.

Do you feel lucky?

[MonkeyMan]

Do you feel lucky?

at this point, hardly.
My car must've picked up on the vibes that I was contemplating an engine build soon, and simply said, "here ya go, f*cker!"
I guess it's a good thing my engine builder has a spare M20 sitting in the shop if things took a turn for the worse..
I'm trying to budget for a worse-case scenario, which includes replacing the S50 rods and 323i crank (which, if damaged, will be replaced by a 2.7 eta crank).. what sucks even more is that I can't really order pistons until the motor is apart and the crankshaft is assessed.
All I know is my car is gonna have to get me to and from work for the next week or so until I can make the 45 mile drive to huntington beach to my engine guy. That would be an expensive tow, but it's a gamble I'm gonna have to take right now.

I got some work to do.

[Bretts85E30]

ill tell ya this i just finally diagnosed a rod knock on my 2.7i engine its got 200k+ miles on it and ran low on oil pressure only once since ive owned it but prior to the low oil pressure i have had a knock at 3k-4k rpms it has changed after that low oil pressure to 2700-3500rpms.

ive been driving on the rod knock for over a year and it hasnt gotten anyworse until the low oil pressure issue which was caused by too thin oil 2 months ago so considering ive hammered the hell outta the engine at times im gonna see if i can salvage the crank without removing the engine for a total rebuild until tax time.
so ill throw new bearings in to keep the thing going just a lil longer that is unless its too far gone ill just save the bearings til the engine goes boom and rebuild it properly.

[2mAn]

time to get a AAA card. ;)

[MonkeyMan]

time to get a AAA card. ;)

time to get me a chair.. I don't remember how much your motor build was on the VR6, but this is probably gonna run me about 5 Gs when it's all said and done..
but if I'm gonna spend any money/time on building this thing, I might as well do it right so there's less of a chance I'll ever have to do it again..
and you know me, if it's worth doing, it's worth doing right :D

btw: I changed the oil today and dragged a magnet through the used stuff - no metal fragments.. I'll be cutting the oil filter in half tomorrow to see if there's any in there (I'll take pics).. let's hope I got lucky.

as far as where the oil went (3 qts in ~2 weeks), at this point the only possibility is down into cylinder #2 through the seal/guide.. there's no oil in the coolant and the bottom of the motor is totally clean and doesn't leave more than a drop or two when it's parked for a while.. I also pulled the #2 plug again today and it was saturated with oil (again, as expected).. it looks like the internal leak has just become worse lately..

the motor does feel a little funky however, even after the oil change.. there's slightly more vibration than normal and it's not as peppy as before - to the point where it makes me nervous about giving it the beans anywhere past 5k or so.. something is definitely not right..

tentative date to begin teardown is December 1st.. stay tuned.

[MonkeyMan]

[quote=Bretts85E30;3466826]ill tell ya this i just finally diagnosed a rod knock on my 2.7i engine its got 200k+ miles on it and ran low on oil pressure only once since ive owned it but prior to the low oil pressure i have had a knock at 3k-4k rpms it has changed after that low oil pressure to 2700-3500rpms.

ive been driving on the rod knock for over a year and it hasnt gotten anyworse until the low oil pressure issue which was caused by too thin oil 2 months ago so considering ive hammered the hell outta the engine at times im gonna see if i can salvage the crank without removing the engine for a total rebuild until tax time.
[quote]

ok so after driving the car the past 3 days, I'm noticing that it's starting to return to 'normal', at least how I remember it. I have been babying it though (took it up to 5k once or twice). the funky vibes are starting to go away, and the motor sounds like a normal M20 under the hood - no rod knock, only the typical M20 valvetrain noise. I'm really hoping the major components (crank & rods mainly) are unscathed, as I really want to reuse them for the build.
that being said, hypothetically can this thing still throw a rod even without any knock? even if I baby it? like go from bad, to better, to worse?

[Bretts85E30]

no but since u had no oil pressure u definitely damaged the bearings to what degree u wont know without pulling the pan and checking/replacing them while ur in there.

i just did it today and it went well even though the #5 rod bearing was toast the journal looked ok just cant seem to build oil pressure so if u decide to go that route make sure u pay attention to how the oil pump came out and went back in and also make sure u prime the system thoroughly

[MonkeyMan]

update: I've enlisted the services of Robert at E30 Motor Werks to do a complete build on a spare motor.. I'm hoping to have it completed in a month or two and we're essentially go balls out from scratch. My thought behind this is to prevent as much downtime as possible, avoid the uncertainty about the condition of my current motor, and ultimately to get a built engine exactly to my specs. Plus there's a good chance I can recover some of the cost by selling my old stuff (including a potentially good 2.6 stroker - http://www.e30tech.com/forum/showthread.php?t=83277 )

Plans for current build:
- proper 2.8 M20 (2790cc)
- eta 81mm crank
- reconditioned S50 rods
- 85.5mm custom forged pistons (10.0:1)
- rebuilt 885 head (new guides, all new hardware)
- ~280* cam (haven't decided yet - Schrick / Cat)
- VAC valve springs
- IE HD rockers
- new valves
- ARP head studs

I'll be carrying over my stock intake manifold and Miller PSIK & WAR chip, and mayyybe bolting on a set of brand new Racing Dynamics equal-length headers (depending on how $$ this gets) and redoing the exhaust. My goals for this engine are 200whp / 200wtq with a healthy powerband to 7k rpm, and of course a wicked sound. This thing WILL be a beast.
I'll be taking pics along the way..

Any suggestions for the cam? Although I'd like great power to 7k, I'm really looking for a healthy midrange (between 3500 - 5500 revs), where an M20 is at it's best.

[Bretts85E30]

Heh cool deal I plan on payin Robert a visit today cuz I need him to listen to the car to see if everything sounds ok after doin the rod bearings

[MonkeyMan]

Robert's a good dude.. he was saying the last couple weeks have been a bit slow for him at the shop.. I figured I'd give him something to do ;-)

In all seriousness though, for those of you in the SoCal area who are new to the E30 scene and/or have not heard about him, his shop (E30 Motor Werks, Huntington Beach) is probably the best place to get any kind of work done on your E30. He's as honest as they come and is extremely thorough and knowledgeable. I recommend paying him a visit.

[BMWManiac]

Would you mind PMing me the cost? My engine just died on the road right after my engine oil pressure light came on....I'm not sure if my motor is toast, and the there was the right amount of oil on the dipstick...

So, what is a reasonable amount to expect to pay (range) for a BMW shop to rebuild a motor with removing and reinstalling it? Let's say, nothing performance, performance reuse all rods/pistons.