Leak test done...

[flashyg]

Thanks boyz.
G

[MarkB]

can you not remove the crank and drop them out of the bottom then?

I don't know of any engine you can pull the pistons out from below. Not saying there isn't any, just I don't know of any....

[eddiecrawford]

i.ve never understood why you cannot remove the pistons via crank though? the bore is (presumably) the same size all along its length. there should be a small ridge from wear, might cock up my theory, but then there should be a similar size ridge at the top near the cyl head...

i've never heard of anyone doing it tho, and i dont have any old engines lying around

audi tsb says max 10psi via pressure test. (you dont get any bubbling at that pressure, although i doubt thats why they said 10psi!)

[MarkB]

I think I may need to get myself another regulator for my pressure tester. I had trouble getting it to flow at the lower pressures

[MarkB]

i.ve never understood why you cannot remove the pistons via crank though? the bore is (presumably) the same size all along its length. there should be a small ridge from wear, might cock up my theory, but then there should be a similar size ridge at the top near the cyl head...

Think about the length on the engine and how many pistons are in there. They are all converging in a V and down below you also have the main bearings. It just isn't going to happen.

[eddiecrawford]

i guess it depends on the casting around bearings as you say

the only engine ive had to do big end/main bearing shells was a 4cyl cavalier, and its main bearings (all 5 of them) did not look as though they would impede the pistons coming out the bottom (once crank off)

likely s4 is quite different

idle thoughts like these keep me from working

[MarkB]

isn't it just the cranckcase breather - as in to relieve pressure?

Some air is bound to escape past the rings - especially if the engine has been sat for a long time (overnight) and the oil has drained back down to the sump.

Try it again after a run, see if anything changes.

I did another test last friday after the car had been run up to operating temperature. This time I couldn't hear any hissing and the intake would hold pressure for 30 seconds of so after the supply had been turned of. Tested by pressing on the rubber pipe off the Y-pipe.

I could still hear lots of bubbling. The AWE Tuning instructions say pressure to about 15 psi but the Audi SSP says don't go over .5bar for fear of pushing oil into the inlet system.

How is the air pressure getting into the oil system in a way that can push oil into the inlet?

How is it even getting into the oil to make it bubble?

[eddiecrawford]

thru the oil seals at the turbo?

[MarkB]

thru the oil seals at the turbo?

Eek! Hope not!

[s4woody]

isnt there a crankcase breather take off on the Y pipe just by the bend in it...part of the spider breather i believe...thats how its doing it i would think...

[MarkB]

Yep, but that is unplugged and blanked

[s4woody]

how about from the pipes that go into the turbo,s...theres a small metal pipe that balances the turbo,s and goes back to the inlet manifold...unles the DV's are letting a small amount past..