Oil consumption after rebuild

[M3Philipp]

Maybe they didnt properly measure the cylinder bores. Could be that cylinder bores are oval in top area.
Honing image / cross hatch can look fine, but that has nothing to do with the other.
I think it is better to hone the cylinders if you go for new rings, but as said, if the bore is out of the road, you got the shit anyway.
When I did rebuild my M42, it had 270.000 Km on the clock and the cylinders needed to be bored (totaly oval in top area), and for sure new honed afterwards.
What I can tell is I even used synthetic oil on brake in, (I know many said its wrong, but dont look at that now), and had ZERO oil usage on the first 1000km. Now the engine is on 4000 or 5000km, still zero oil usage.
So Iam not sure if its "normal" like your mechanic says, that your engine now drinks almost as much oil, as it used before your rebuild.
That cant be correct right? For sure it cant.

[valantis544]

I found the spark plugs, i thought they were accidentally thrown away. Here is a picture.



I m thinking that maybe the car has bad injectors and running rich. Is this oil consumption possible from fuel dilution???

[M3Philipp]

On the photo it looks like youre engine is running a bit to rich.
BUT, the looks also depends on WHEN you did remove the sparks. Did you drive a short distance before removing, or a normal way so that the engine really got on operation temperature.

[romkasponka]

I think your problems will be with cylinders, which will be worn or oval, or just not honed. Spark plugs just show that you have the same problem in all cylinders...

[valantis544]

On the photo it looks like youre engine is running a bit to rich.
BUT, the looks also depends on WHEN you did remove the sparks. Did you drive a short distance before removing, or a normal way so that the engine really got on operation temperature.

I didnt know that there was a difference. When i replaced them the car was sitting for many hours.

[valantis544]

I think your problems will be with cylinders, which will be worn or oval, or just not honed. Spark plugs just show that you have the same problem in all cylinders...

If you are right then i have to find an engine but there is no money so....
The thing is that if the car was running rich from before then the rings didnt seated as they should, due to the rich condition and the cylinders are now glazed. Talking about bad luck.

[M3Philipp]

Do you still have the numbers, when cylinders were measured? Diameter...

[valantis544]

Do you still have the numbers, when cylinders were measured? Diameter...

No never saw numbers. The guy from the machine shop came and measured them with his tools and said that the cylinders where within specs and was very sure about that. The rings we used i think were Goetze if anybody knows if those rings are difficult to seat.

[valantis544]

Never found out what was wrong with the oil. Swapped the engine with a 92 m42 and everything is ok now. No oil consumption and no oil leaks. Thank you all for the help.

[romkasponka]

Good to know!

p.s. for future do not trust mechanics in garages except you have recommendation from at least few people. Quite often people think I am professional engine builder because I have a car garage but in my personal opinion lots of them know bullshit about cars and basics how the engine operate. Sad but that is true even in dealership. Recently my E36 m44 engine was rebuild after crankshaft slip bearings failed at 120000km and I was 2200km away from home (Lithuania-Netherlands). I removed engine in one of the colleagues from work garage and send it for rebuild to Lithuania because the price in Netherlands was 1kEur for removal/installation and 3-4kEu for engine rebuild. I did not wanted used engine so it was rebuild in one of the bmwfans.lt forum guys which is doing racing engines, LSD's and so on and received some really good recommendations from engine tuners. Engine had complete rebuild with old pistons, new rings, used repaired crankshaft, conrods and full head job. Compression ratio was raised to 11:1. And I did already ~2000km and engine running perfectly without any oil leaks. Price I paid with all the shipping's, consumables was ~1000Eur and one one box of Lithuanian beer for garage. My recommendations: https://www.facebook.com/donatas.pingvinas/photos_albums

And my engine: https://www.facebook.com/photo.php?fbid=594841120571888&set=a.293214444067892.85716.100001380177879&type=3&theater