Just removed the heads after experiencing a head gasket blowout with my 85 VG30ET.
There was black oily soot (equally on everything following) on the center of all the piston tops, in the intake runners of the heads, in the intake manifold, and in the lower portion of the plenum. The plenum intake was clean as was the upper part of the plenum, so it looks like it is caused by blow back.
I change the oil every 10 hours (autocrossing only - so maybe only 1 hour under load – the rest idling or at low revs), and have not had to top off the oil in between oil changes.
Engine rebuilt 49 hours ago.
Stock valves, Schneider 120# valve springs.
EGR is disconnected from the intake piping, and just vented to the air – a catch can.
Leak down test: 8% ON # 2 (exhaust valve), Less than 4% on the rest.
Nistune is installed: calls for 20 degrees advance on the distributor, and adjusting the spark advance via Nistune after that.
Russ’s adjustable cam gears: set at 5 degrees (maxed out) advance.
NISMO Euro cams; not much more overlap than stock.
Rocket 100 octane fuel.
14 lbs boost.
Any insights you can offer to identify and stop the oily soot deposits would be gratefully appreciated.