diggingcontractor

just had an engine built for my 2.5 hawkeye before build we dynoed the car it only put out a small amount of black smoke when we let off revs pritty normal but now its been rebuilt we have blue smoke (burning oil) we havent changed the heads so presuming stem seals are ok ive had the block bored and mahle pistons and rings williams rods put together by a very reputable subaru garage who has suggested running it in that mahle rings can take time to bed in ive now done 700 miles and still smoking its used 1.5 litres of oil in the 700 miles there are no leaks anywhere im running the same turbo so thats ok anyone any other ideas other than rings otherwise its engine back out or anyone whos got a stroker with mahle pistons and rings with the same issues and how they cured it

chasey

iTrader: (2)

ive got a built ej257 from the US, mine use to smoke on startup quite bad but clear within a few minutes. I also thought it could be valve stem seals, i fitted an oil catch tank which pritty much cured the smoking issue. Ive done 3000 miles and its used a bit of oil, the engine runs fine and simon JGM said the engine sounded quite during mapping so im happy. Im putting it down to the rings not being bedded in, now i have no smoke but it does use a bit of oil.

diggingcontractor

yeah when i went to get this engine built i was told they do burn a bit of oil all the ej25 strokers do but mine smokes while im driving its constant but not a lot of it but same as you engine is quiet and runs perfect but the problem is if i put it up for sale and someone came out to see it they see blue smoke they wont want to buy it theyll presume its fxxked or do you think in a couple of thousand miles it will be all gone

chasey

iTrader: (2)

I would try to fit a catch tank see if that helps

WMS

iTrader: (2)

Hi, just to clarify you have used my rods but I never built the engine :-) It does sound like it's using alot of oil. A problem with the Mahle pistons is that the ringland that supports the oil ring is a narrower o.d. than the piston, I have known the oil ring fold over as it's pushed into the bore. There's no way of telling until you run it, may not be that but if it gets worse it may be.
Andy

diggingcontractor

Yeah Howard built it you sent him the rods it doesn't seem to be getting better or worse Howard's going to have a look next week when it gets back from body shop but you might be right

scoobaru mad

iTrader: (2)

Sorry to butt in on this conversation

I've read on certain websites and tuner guides that an AOS (air oil separator) or oil catch can so to speak, is essential on imprezas because of the intercooler issues? Ie oil vapour fouling the tube an fins within.

My question is. How the hell do you fit one. There's a million vacume pipes, an I cant find any guides?

As for the smoke issue.

Is there smoke on lift off on the down revs (turbo oil seal)

Is there a bed in time for the rings? Also, do you have to use a bedding in oil, or a semi synth for the first 1k and a limiting of revs?

Hope you get to the bottom of it bud

WMS

iTrader: (2)

Howard is a very good engine builder, i'm sure He will resolve it. Ive used Mahle in many many engines and it only happened once, it was a nightmare to find as compression was good etc etc, it was only when I pulled the pistons out I found the top oil ring folded over slightly :-(

diggingcontractor

Yeah mineral oil I've had air pump removed and mapped out as for oil catch tank I'm trying to get one now I'll let you know how it fit turbo was fine before rebuild and it has smoked since we rebuilt it I think Andy may be right and it's ring land failure

WMS

iTrader: (2)

A catch tank is a good idea on tuned cars as it keeps the intake air nice and clean, what you need to do is pipe the breathers from the engine into it, and block off where they went into the intake obviously. The breathers are on top of the rear of the block and on top of the cam covers.
As for running in, well, it's a matter of opinion and much debate amongst us engine builders, my advice is around 200 miles on running in oil/mineral oil, keeping below 3500rpm, then switch to semi for 1000-1500 miles allowing gradually more revs/boost, then change to fully synthetic.
If you can run it in on a dyno thats even better and how I do it if possible, well Graham (Enginemapper at Group B motorsport) does for me

diggingcontractor

That's easy for me then just need a pot

diggingcontractor

How do you do it on a dyno I can use one when every mate owns Trl developments