ok, guese you all know my 940t..uses huge quantities of oil, doesnt leak it burns the stuff - but no great clouds of smoke...anyway...

i recently scored a spare inlet manafold (inc injectors, fpr etc) from ebay and although the outside was filthy the inside was very clean....

I was struck by the thought that mines clean on the outside but filthy on the inside...

now i have a theory that the oil usage is down to valve seals...(compresion good etc) and haveing read some stuff on here about 'sea foam' which we dont get in the UK thought i would try a similar trick with redex (similar stuff fuel system cleaner etc) ...now being a cautious so an so and not wanting to risk hydrolocking the engine i decided to stick 50ml in via the vacume line to the manafold (using a small funnel so i could put it in over about 2 minutes in a very slow trickle...at idle)

after this i let it sit for 30 minutes (they recomend this if you squirt it direct into the cylinders) to soften the crap...

started it up and had an instuntanius and solid miss on one cylinder....took it for a run thinking the crap might blow out...nope...

so i took the plugs out - being carefull to know which plug from which cylinder...- now the plugs hade been in about 4-5k miles and have been there thru heavy oil use, auto rx etc...the results are as follows...

cylinder no 1 (fan end of engine) - heavily fouled, wet. oil nasty
cylinder no 2 - fouled, not wet, better than 1
cylinder no 3 - fouled, not wet, better than 2
cylinder no 4 - ok (ish) looked like its been runnign a tad rich...

after cleanign the plugs went back in and she runs sweat as a nut...even sorted out a bitt of a rumbling idle...

the majority of the fouling came off with methalated spriit, a tooth brush and paper towel - although some of it looked quite burnt on suggesting the conditions had ewxisted for some time but the redex had just shifted a load of loose crap and made it worse...

now my question is...what would produce this heavy foulfing on cylinder no1 geting better towards cylinder no 4..., I am thinking cross talk from inlet valves via the manaofld with say no1 leaking like a bitch....but could it be to do with oil prusure diferences in the head etc...??? any thoughts?