Hey guys, heres a strange one for ya.

Just finished rebuilding an S5 T2 engine for my buddies car, got it up and running last week. Everything was totally normal. Lots of oil pressure, engine idled great, just perfect.
I used an S4 front cover so he could run the mechanical OMP as the engine is in his S4 car using all S4 electronics.

He took it for a drive to the gas station to fuel up and on his way back from the gas station the engine started to loose power and sounded like it was only running on one rotor.
He limped it back and I checked everything out, turns out it was two dead spark plugs on the front rotor. (I put a set of used plugs in it to get it running for the break-in period) the exhaust was glowing red since it was spitting raw fuel into the exhaust. So I swapped all the plugs out for a full set of brand new plugs.
Car fired up and ran great, this time smoking slightly out the exhaust.
Oil pressure was still great.
He drove it for 2 hours that night, the next moring he was driving it to the shop and the low oil light came on. We topped it up, oil pressure still good but still smoking.
He took it out for another half an hour and then he said the oil pressure dropped to just above 2 on the stock gauge and it starting smoking really bad out the exhaust.

I pull the plugs and the fronts were full of carbon, the rears looked totally normal.
I pulled the turbo off and the exhaust manifold wasn't coated with oil, the front runner only looked slightly darker than the rear.
Intake manifold came off and the the primary intake runner was sopping wet with oil in the block. The intake manifold was dry.

Is it possible that something happened with the OMP injectors on the front rotor started pouring oil into the intake? I dont see how this could happen and cause lower oil pressure.

I'm probably going to take the engine apart but I just was wondering if anyone else has ever seen anything like this before.

 

if you test the old multi peice metering nozzles like they have in the FSM, they dont pass very well.

you can usually get em to work by cleaning em out.

i'd also look to see if the mop linkage was getting bound up, the s4 t2 can put out a LOT of oil.

 

I'm using the S5 omp injectors, the injectors on the front rotor I can blow and suck air through them....

And Yes the OMP was not fully closing at idle, it was about half way open when the throttle plates were closed.

What are the chances it would lower the oil pressure? if it was pouring oil into the intake

 

The OMP cannot lower the engine oil pressure.

The OMP itself is a OIL PUMP and is supplied residual oil from the ENGINE oil pump, thru the front cover.

The ENGINE oil pump does NOT supply OIL PRESSUE to the OMP. It is written. Done.

A stuck omp rod, in the fully up positon can lead to excessive oil depletion, but NOT lower oil pressure.

The oil injectors should be tested per the FSM. IF you can blow in both directions, then the sucker needs to be fixed or replaced. It has a small, red,rubber poppet valve inside it that is supposed to allow suction in only one direction. Towards the rotor is the direction. See FSM.

In the past I've deliberatly tied the omp rod full up with a zip tie and sure enough that will deplete the oil in the pan right quick.

 

Yeap, ok thats exactly what I thought. Just wanted to confirm.

I guess the engine comes apart now.

I'll keep you guys posted on what I find. I'm kinda interested myself. Out of all the engines I've built, never have I had one with oil problems within the first couple hours of running.

 

Low oil pressure would most likely be the o'ring in the front cover, even though you KNOW you put it on right. Or the oil pumps *key* isn't in the hole no mo and the pumps not a turnin no mo.

 

Well I got the engine apart and once the oil pan was off I knew exactly what it was.

Front main bearing fell apart...

No idea what would have casued it to fail. The front and rear main bearings were a used set and were measured with 2 thou clearance to the e-shaft. They were visually in good shape too.
Baffling, but either way the engine is back together again with new main bearings. Should be running tonight.

 

my buddy around the corner has had a couple of main bearings do that, fd's... i havent been so fortunate, but i do see some really beat up bearings on tear down now (down past the copper!)

i dont think the oil we have works very well

 

Hmm interesting, these stat gears and bearings were from an FD engine. Maybe the FD bearings are shitty.

 

yeah it seems like if they arent really nice, they fail. unlike what i'm used to seeing with the fb/fc stuff