Mad Hammer

iTrader: (55)

I bought my STI RA after it had already had a re-build with uprated internals etc. I believe it's now covered around 3000 miles since. I have noticed over the last few weeks that it has a taste for the black stuff using around 1 litre in about 500-1000 miles.

I changed the oil soon after purchase and have covered around 1500 miles since, in this time I have added 1.5 litres.

I have to admit I did use 5W40 oil, is this too thin ? Is using this much oil normal ? or a problem ?

Cheers

Clive

Adam M

not normal and I would say it is too thin.

do you know who did the rebuild?

Mad Hammer

iTrader: (55)

The guy did all the work himself, I have reciept for all parts inc. forged pistons, steel crank etc. Other than oil consumption car runs spot on, have gauges to monitor everything and all is well.

Fangoria

iTrader: (1)

Yes I would second the comment by Adam

Who told you to use 5/40 - never, ever use this stuff - otherwise you may be looking at a rebuild - sooner rather than later!! - you should be using Motul 15/50 or Castrol 10/60..(dont use anything like say Magnetec or Mobil - its crap sludge!!)

Re consumption - yes it will increase...... before I had uprated internals my car went through NO oil at all between 3-4k services, after the rebuild (by Professionals) and due to a lot of 'intense' workouts that I give it I typically go through about 0.5 litres per 1000 miles - maybe sometimes a little more!!

You should in any event put in a catch tank so that the oil recirculating doesnt go back into the engine - results in lots of smoke, especially on start up out of the exhaust.................

Mad Hammer

iTrader: (55)

Thanks for your reply, I was going to switch to Mobil 1 motorsport. Surely that isn't 'crap' ?

What's a catch tank by the way?

Butty

iTrader: (2)

I'd also like to know what's wrong with Mobil1 motorsport?
Are you talking fact or bull$hit please?

Hoppy

From years of reading this BBS, Mobil Motorsport 15-50 (check viscosity) is good stuff. In the top three with Motul and Castol 10-60.

Richard.

Mad Hammer

iTrader: (55)

Anymore comments about the consumption? Can anyone explain the catch tank ?

harvey

iTrader: (48)

With 5W-30 oil I use about 1litre/1000mls. The consumption is noticably higher when running hard and with gentle running a lot less oil is used. On Motul 15w-50 oil consumption reduces signifigantly.

"Who told you to use 5/40 - never, ever use this stuff - otherwise you may be looking at a rebuild - sooner rather than later!! " Total cobblers.

The pupose of an oil catch tank is to stop vented air going back into the inlet tract and burned by the engine. The inlet charge contaminated by vented oil laden air could cause det as it is obviously less willing to combust.
There is a breather on each cam cover and one at the rear of the block, near to and below the throttle body. These are routed to the inlet tract by rubber pipes. They can be diverted to a catch tank so the engine has an uncontaminated air supply. If the catch tank is small it will not collect much oil except when an engine lets go. The collected oil has a high water content due to condensation. The catch tank needs emptying from time to time, depending on its efficiency and the characteristics of the particular engine.

I have a nice shiney chrome plated, fairly small, new catch tank with fitting kit for sale. Same as on my WRX. P.M. me if anybody is interested. £70. Looks like the Cusco.

97 rExy

Stock never had any consumption.
My rebuild(forgies 4thou) will go through 1/2 ltr or more every 1500-2000mls and NO oil on catch can.
My understanding with rebuilds has always been:Some of the consumption is due to wider clearances but mostly due to wider tolerances than factory engine, meaning oil siping through rings!

Thicker oil has not solved it!

Mad Hammer

iTrader: (55)

Thanks for the replies on this, have some comfort now as I'm not the only one using oil.

Cheers

Adam M

my engine consumed no oil at all on the dyno, and that was through initial running in.

I am not convinced that the consumption should be anything like the levels that harvey is talking about.

To my knolwedge mobil 1 is very good, especially haveing read a few books on general engine practices. "forced induction performance tuning by a. graham bell" has some favourable opinions on mobil 1.

Personally I will stick with motul 300v 15w 50. I still think Ow 40 or even 30 is way too thin unless youj are running in, which you seem to be so its ok.

A good mineral oil in the beginning, moving over to semi synthetic after a few thousand miles from the rebuild.

greater clearances will mean some oil consumption, but I was under the impression the clearances were to account for the expansion of forged pistons once hot, meaning once hot there shouldn't be greater clearances, plus the rings are still in tact, so it shouldn't make the difference of 0 to 1 litre/1000miles. That is worryingly high in my opinion.

vindaloo

Catch can.

If the engine is blowing oil through the breathers into the inlet (typically on WOT etc), then oil reduces the octane rating of the air/fuel mixture which reduces it's ability to resist det. i.e. A bad thing.

Check the breather pipework and if possible, the inlet piping and i/c. If there's noticable quantities of oil present, you may wish to consider an oil catch can/tank.

Catch can reduces the speed of gas flow from the cam-covers and sump which allows any oil suspended to deposit itself in the can rather than get carried into the inlet.

J.

Fangoria

iTrader: (1)

Mobil 1 stuff was always classed as sludge by the Cosworth tuning people..... I have had it in my Cosworth - took it out after 3000 miles and yes it was sludge.... maybe the Cossie engines destroyed the oil quicker but I doubt it

Harvey - you cant seriously be using the oil you mention....... even 5/40 was always classed as too thin as well - unless your just bedding the engine in gently (or using mineral oil).......

My catch tank will be ala Richi White - a coke can probably - whats the point wasting good money on anything else..

harvey

iTrader: (48)

I think I know what oil I use. 5w 30 Fully Synthetic.

Fangoria

iTrader: (1)

I dare say you do

I wouldn't

Mad Hammer

iTrader: (55)

Now, now chaps. Was only trying to get some opinions !