Low comp and oil pressure
 

I dont know if anyone can help but major problems, to cut a long story short, i had my engine rebuilt and i had some wossner pistons fitted and it turns out the builder didnt skim the pistons properly so they clipped the top of the head, so I had them done and the pistons shaved down to 7:5:1 comp ratio, now im having some bad oil pressure problems it seems the oil is creeping up the bailey breather from the crankcase pipe and then straight into the metering unit and getting sucked in the engine again as all pipes are full of oil, now would I need a bigger breather system fitted to combat the pressure problems, I also ran a compression test which was about 120psi, Any help would be appreciated Tel

The oil isn't getting "sucked" in as you say, but simply being forced through the breather system. This is caused by incorrect bore/ring seal. It would seem that the bores haven't been honed to the pistons. Wossner pistons are forged - and require different clearances to cast pistons. My guess is your builder hasn't taken this into account.

As above, plus


is it run in yet? if not it might just need bedding it.


1- i would remove the breather pipe from the metering unit and inlet, block the MU and the inlet pipes off (air tight, so no air leaks) and put the bailey's breather into a clear bottle. this way you can see what the engines breathering and how much.
2- get a leak down test done.