Engine Using Oil / Water

[Doof 11]

Ok, rather than selling up, i'm going to try and fix all the problems with my car. First up, the new engine that I've just built, and has only done 3-4000 miles seems to use oil and water. Now, I can't be sure that it's "using" it, but certainly the levels are going down. The water leak is most likely the expansion tank cap. I tested it a while ago and remember seeing water leaking out the overflow. When I get chance, I'm going to stick a coke bottle under the expansion tank and then measure how much water runs out the overflow.

 

The oil is where I'm worried. There is mayo in the dipstick and the catch tank (which was full after <1000 miles) was filled with a very creamy oily mess.

 

What is up? Premature head gasket problems due to me screwing something up? Incorrect breather set up causing excessive crankcase pressure and thus lots of blowing out through the expansion tank?

 

Any ideas greatly appreciated.

 

Lewis

[Anthony 1,003]

What engine is it? I vaguely recall that it's a high capacity S16 build?

[Doof 11]

Iron block XU10J4 with 11.4:1 compression (something like that anyway). Flowed head, petert cams, 4 branch exhaust from Miles, standard GTi-6 inlet running on DTA.

[welshpug 1,657]

have you been driving to the shops a lot?

 

why do you have a catch tank? which breather system?

[Doof 11]

Not been used for short journeys. Only really 100+ mile drives!

 

Here's the breather setup. Looks quite simple and probably wrong:

 

 

Any thoughts? Is it wrong? Is this why it's using oil?

Edited January 7, 2012 by Doof

[Henry Yorke 269 3 Cars]

Have you tried buying a new expansion cap to reduce the water usage? Any water coming out of the expansion cap has a high chance of evaporating away so you may not see it. The other could be a pin hole in the rad where the water turns to steam and disappears.

 

I have had the failed expansion cap which then highlighted a pin-holed rad once I had fixed that. I only happened to spot the rad by a very small bit of steam as I walked round the front of the car when i left it running after a drive.

 

IIRC there was a test on caps done by someone in the PSOOC once and 9 out of 10 had failed to make close to their originally specced pressure limit

[Miles 331 1 Cars]

Yes thats very wrong as the crankcase breaths thru the large tube at the front of the engine, Normally this goes back into the filler cap to drain the oil back to the sump, will expain the mayo as the damps getting into the engine

[kyepan 291]

also when you say it used oil, in the first 50 miles of my rebuilt mi it used at least litre as the rings sealed, how much oil is it using now?

[Doof 11]

Hard to say how much oil it's using. i suspect once I sort the breathers out it probably won't actually use anything. Certainly the compression was great last time i checked.

 

So for sorting the breathers out. The main filler should come up to a filler cap which would have a filter on it (as i don''t need the filler cap it can just come up to a breather). Where should the others connect up?

[Doof 11]

Ok, after some digging around I propose this new oil breather setup:

 

 

I suspect this will help the engine no end. The oil has been a bit sludgy coming into the catch tank and poping the dipstick out points to high crankcase pressure!! Can't believe I messed this up!

 

As an added bonus. The catch tank effectively becomes the oil filler and will be nice and easy to fill.

Edited January 9, 2012 by Doof

[Anthony 1,003]

Why not just use the standard breather/filler setup? It's proven, works and the car won't stink of oil either...

[Doof 11]

Purely because I can't remember what it's like and don't have the standard filler cap. It probably makes sense but if i go to ITB's then I won't be able to run the inlet pipe anyway...