MikeXR2t

hey, got a fiesta turbo that ive just rebuilt with new mains, rings and big ends. fired it up and the pressure is at arround 2 bar when cold and drops right down whn warm. the engine was running fine with good pressure before the rebuild just needed a freshen up. new pump fitted and i thought it was that so swapped it for the old one and still no joy. any ideas guys!

B16CVH

What does it drop to on tickover when warm?

MikeXR2t

it drops to, at a guess (cos the guage is in bar!) four or five psi! not good! keep racking my brains thinking im a retard, but with the sump off its all in order and had no wee bolts left. anything in the head that could cause it to drop so much. its got a piper 285 t2. like i said it was perfect before so dont think the head could be an issue. got a wee skim to make sure it seated right but cleaned all the swarf off! tomorrow i think ill disconnect the turbo and try it but not holding any hopes up for it cos its a good turbo. think my brain may explode soon. this was a one week rebuild,a month down the line!!!!!!!

iansoutham

You say that you put new mains in?

If so, did you check the tolerance or just replace with standard as that is what came out?

The tolerance needs to be there on the shells as if the gap is too wide, the pressure can drop excessively.

What grade of oil?

What is the pressure when @ 2000rpm?

2 bar when cold is only 29psi. I would expect to see a little under that when warm, when cold, a lot higher (almost on the relief valve in some cases).

Most pressure light switches come on around 12psi (or similar) I believe.