Do oil spray jets increase oil consumption?
Turbo Mini Forums

Hi,

since fitting oil spray jets my engine consumes more oil. I recogniced that my engine releases blue smoke from the exhaust on overrun (only). Sometimes it does and sometimes not. Today I removed the plugs and saw that only cylinder No 3 is affected.
The blue smoke only appears when my oil pressure is above the opening point of the built in valves (3,5bar) in the spray jets.
It seems that the oil scrap ring is overworked to handle that much oil! But why only on one cylinder?
Did a compression check on the engine - it differs only 0,2bar from min to max. So rings seem to be ok!

Has anyone a similar experience??

Harry

Bimmer Twinky headed and turboed A-Series:
http://www.minifreunde.at/harry/projects.htm

Hi Harry,
your oil jet should wet the piston undercrown not you oil control ring, so it should not increase your oil consuption, what about a bad valve seal, also if it come when oil pressure rasewhat about a problem from the turbo oil control ring? which is more commun, but this doesn't explain why only on cyl n°3, perhaps your oil jet is bendt a little too much(have you twiked with thejet end to make more a spray than a jet?)
cheers Harry
fab

Hi Fab,

I didn't touch the ends of the spray jet! It should still spray a jet not a mist. Yes I had to bend them slightly to spray into "one corner" of the piston and not to touch the rods.
I changed the inlet valve seals in situ with proper ones from the USA (instead of the rubbish MSC stuff), but it did not change the situation at all.
Seems that my oil control ring on No.3 in combination with the spray jet is the cause of the problem?!!

Harry

Bimmer Twinky headed and turboed A-Series:
http://www.minifreunde.at/harry/projects.htm

Is this a newly built engine, i.e. rebored and using a new set of rings ?

or is it an older motor you have modded ??

are you using a set of old rings (used)

The motor has now about 8000miles on the clock but was fresh bored with +0.40 Mega Turbo pistons and rings.
This winter i fitted the oil jets, but of course I did not change piston position or ring position. Each piston (and ring) is back in his original (bed in) bore.

Bimmer Twinky headed and turboed A-Series:
http://www.minifreunde.at/harry/projects.htm

I've experienced the same thing on a low milage engine that was pulled and put together with the same rings to save some cash. Stripped it and put in a new set of rings and it was fine.

Yes , maybe the oil scrap ring has become weak! Will inspect the bore and hone the cylinders at the end of this season.
Harry

Bimmer Twinky headed and turboed A-Series:
http://www.minifreunde.at/harry/projects.htm