hi all
had my engine rebuilt after it went (sti 5)
i have forged pistons steel rods new crank etc.
during the running in period on mineral oil the car used no oil then since getting the oil filter done with millers 10/40 fully sy.
ive been told forged pistons will use some oil but im putting a litre in a month doing about 1000miles a month 2/3 m-way steady 1/3 twisties fairly hard
been told this is quite normal for this set up
anyone else the same how much do you use
car has been mapped
thanks

 

 

A litre per thousand miles is quite normal for 'drop in' forged pistons. Having honed to fit pistons would help reduce oil usage.

 

a litre every thousand miles doesnt sound too bad to say i had an engine built and it was using a litre every 200 miles.but sayin that the engine is now back in bits being rebuilt as the builder said it wasnt supposed to be doing that.

 

hey mick
i got an xmas card from morris lubricants
thats how much i get through
about 2 litres per 1k
plus 1 litre per track day

budgie

 

I get through 1-2 litres per 1k miles depending on how its driven, sounds normal if you ask me, I use Motul 300v from opie oils

 

We use stress plates when boring, and super fine honing stones with a special lubricant. Bare minimum 1000 miles on mineral oil, preferably more if only the owner can be patient! These are not the easiest engines to deal with when rebuilding. The surprising thing is how poorly manufactured they are in the first place! we have to deck virtually every block we build.

 

when you say a minimum of thousand miles on mineral, do you mean to run the engine in.as when i had my engine build he said it would be ok with 500 miles,thought it wasnt enough tbh.

 

Interesting. Had exactly the same experience after my rebuild. The rebuilder was great and had the car back took the engine out and replaced the rings. Apparently there is some difference between A and B rings (not sure what).

If it's burning oil then this has the effect of lowering the octane rating and increasing det on acceleration. So the car will retard the ignition and you'll not make the power you hoped for. I don't think 1ltr per 1,000 miles is "normal". That basically means replacing oil the oil between services just by keeping it topped up!

I'm now close to 1,000 miles on the new rings and will be checking the oil this weekend to see how much it has used.

Not sure if this link is relevant but it does mention the A & B thing

https://www.scoobynet.com/general-te...ton-rings.html

 

i have a MY00 -- had it about 6 mths, i think from the paperwork it had a rebuild using forged piston (sounds v different when started from cold)

and i have to top up the oil every couple of days, but i do do about 200 miles a day -- i think i may have a leak aswell, but I keep a 5 litre can of oil in the back

 

Yeah, they sound really "slappy" when cold, like a diesel because the forged pistons expand at a different rate to the block. But apparently that is normal.

 

im exactly the same mate and had exactly the same work carried out when i had a new closed deck block put in.seems a lot doesnt it,but the work i had done was carried out byRick at RE Motorsport who is 1 of the top 3 subaru technicians in the country so i wouldnt worry as he says they do tend to use a lot.

 

You need to figure out where the oil is going. If you're driving hard, and you don't have an adequate breather/oil control system on the car, you're going to lose a lot into the intake. This isn't ideal but it means there isn't a great deal wrong with the engine which is good news! However if you're just burning the oil entirely within the engine, and it's all going past the rings then I would say 1000 miles/litre with mostly normal driving is on the high side. Pistons and rings have improved over the past few years, and the days of burning a litre of oil in 500 to 1000 miles with a rattly forged engine are gone.

 

Do you think upgrading to a drain to sump catch can from a mocal one and changing the grade of oil will help with oil loss (currently using Motul 300V chrono 10W40)

 

Gulp !

Am I heading that way too ?

DunxC

P.S. Pavlo, what size banjo fitting is needed for a sump return from the catch can ?
TIA !

 

try millers 10w60

 

The point of us using the measures we have taken is to reduce the oil consumption figures commonly reported! We seem to be getting results, taking customers comments into account.
I owned an Evo 6 which we stroked to 2.3. Initially, we fitted Ross pistons which came with a 6 thou bore clearance specified by Ralliart. We queried that big style, but was assured it was ok. We figured there was no merit in arguing, but reduced the clearance to 5 thou anyway. It burnt oil! from day one, I was putting in half a litre a week. (300 miles). Having tolerated that for a while, I had the motor pulled (it helps to own a garage!) and we rebored and fitted JE pistons with a careful 2 thou clearance. The result was negligible oil consumption between changes. I mention this to illustrate that it isn't always the engine design that causes these things, and careful building can help a great deal.
Cosworth say 3000 miles on mineral oil for Subaru. The issue is the valley depth of the inevitable grooves in a fresh bore, and the tendency of the oil to pool in an engine that lies on its side.

 

a 60 rated oil is very thick, it has no real beneficial properties over the 10w40 motul except its better in hotter climates (and because its thicker it takes more to turn the engine over, its thicker so doesnt move as quickly on start up, if its cold it may not protect the engine on start up like the thinner oil)
I would stick with the motul 40 rated oil

Tony

 

Wholeheartedly agreed. After all, 75W is gear oil...........

I recommend fully synth 10W/40 or 50 OR 15W/40 or 50.

I.E. nothing lower than 10W or higher than 50.

ANY proper brand. Not: Motoring Discount Centre own brand, etc

David APi

 

so are you saying that the 10w60 is a bit ott and i should switch to 10w40 or 50.i have always used the millers 10w60 as thats what the engine builder recomended,have just had a look on the millers site and it went from 40 straight to 60 would the 10w40 be ok for over 450bhp and quite heavy driving.

 

What was the bore to piston clearances when the engine was built?

 

is that in the competition run by subaru uk? only asking because i came 2nd and i know who came first but i didn't know who come third

 

for all you guys that have had forged rebuilds and burning quite a bit of oil.....

when running the engine in, did you take it real steady with little or no boost?

 

Have a forged build 2.5, it use to use 1 litre per 1000 miles, Zen fitted a return to sump kit and RCM catch can, and now it hardly use a drop! Well worth the investment, and the consumption was worse on motorway miles than twisties fun stuff.

 

Simon Opie [ Oilman on here ][ and I were arguing good naturedly a year or so back about oils and l learnt a lot from him. He put away a few superstitions and plain wrong theories that l had gained over the years.

The lower number of an oil spec is how it behaves at 0 - 5 degrees below freezing. The bigger number is what the oil actually is permanently.

So I'd be happy to say that 60 is too thick for normal use. It seems to me that you'd have to be working your oil real hard to actually need 60 grade.

That thickness saps power. If you are a dyed-in-the-wool Millers enthusiast [ and why not ] and they don't do a 50 grade, then go 15W 40.

David

 

Who figures out who is the top whatever Subaru technician in the country? Is that a dealer thing ?

David

 

tbh i use the millers because i heard it is good oil and i get it pretty cheap from a shop that is local to me.i wouldnt mind switching to any oil as long as i could get it without travelling the earth.so what make and grade would you recommend for a car that gets driven quite hard,would the 10w/40 be up to the job.

 

Just to re-start this thing about viscosity, I e-mailed Millers some while back asking if it was acceptable to mix different grades of their CFS range as I had a couple of litres of each 10/40 and 10/60 and would I finish with a "hybrid" 10/50 (ish) The reply indicated that it was ok and that although a bit "kitchen sink chemistry" the result would be not a million miles away from what I stated. I haven't tried it yet (I would only use it as a summer oil) but it could be worth a thought?

JohnD

JohnD