Forged Pistons

[yellgt4]

had some je forged pistons fitted to an st205 running stock boost. now finding that the oil consumption is around 200 miles per litre :( could this be because the boost is not high enough or should i strip the engine again.

have noticed thick smoke on startup, but once engine has warmed up this smoke stops. then there is a little smoking on boost when driving but this smoke looks more black as if she is running too rich. anyone with any ideas, cheers guys

[dawesy]

was the block rebored? and did you run it in on mineral oil for 1000 miles using no more than 0.5 bar boost and under 4000 rpm?

oil consumption will be higher than normal with forged pistons but yours sounds excessive

[yellgt4]

was the block rebored? and did you run it in on mineral oil for 1000 miles using no more than 0.5 bar boost and under 4000 rpm?

oil consumption will be higher than normal with forged pistons but yours sounds excessive

yes mate the block was rebored and was run on toyota running in oil for 1000 miles. driven like a nun with as little boost as i could and no more than 3000rpm. but even during running in period i had to go back to the garage to get more oil because it got down to the minimum mark on the dipstick within 300 miles. looks ill then dont she

[dawesy]

if you have a warranty with it take it back. sounds like the engineering isnt right, either bore finish or rings.

get em to do a leakdown test. if thats ok then it is possible that the turbo is dead

[Teenage_Kicks1980]

Hi Mate,

During the running in, did you do any motorway driving in it or Constantly driving in one gear at constant revs? I ask becasue there needs to lots of variance in RPM's and load to correctly run a engine in.

I really hope i'm wrong, but it sounds like the piston rings haven't broken in correctly, or possibly turbo is on it's way out.

Who did the rebuild?

Why did you have the rebuild, because you wanted to run more power or beacuse something let go?

Tony

[yellgt4]

Hi Mate,

During the running in, did you do any motorway driving in it or Constantly driving in one gear at constant revs? I ask becasue there needs to lots of variance in RPM's and load to correctly run a engine in.

I really hope i'm wrong, but it sounds like the piston rings haven't broken in correctly, or possibly turbo is on it's way out.

Who did the rebuild?

Why did you have the rebuild, because you wanted to run more power or beacuse something let go?

Tony

it was run in on normal roads, but i have noticed if i boot it now that the turbo boost seems to fluctuate. so it may be the start of the end of the turbo.

thanks for your help eveyone

[ag0w]

had some je forged pistons fitted to an st205 running stock boost. now finding that the oil consumption is around 200 miles per litre :( could this be because the boost is not high enough or should i strip the engine again.

have noticed thick smoke on startup, but once engine has warmed up this smoke stops. then there is a little smoking on boost when driving but this smoke looks more black as if she is running too rich. anyone with any ideas, cheers guys

It doesn't seem all that uncommon that GT4 engines suffer this after a rebuild.

I reckon the most likely cause is ovality in the cylinder from 10'ooo of original use --- I'd presume your cylinders were just honed and not re-bored?

Could be the turbo or head obviously - but this is hard to diagnose because of the EGR recirculation means oil seems to end up everywhere.

Pulsing turbo likely to be oil contaminated BOV (same as bypass valve)- take it off and clean with petrol

On the plus side - if it's like many I've heard of it will go on for 10's of thousands - it just gets annoying keep putting oil in :(