After shooting the quick vid of the nose removal I was ready to put things together for good. Got fluids in it and everything ready to rock, time for a test start. Moment of truth for the wiring. Flipped the main battery switch on and cranked the motor to verify oil pressure… cranked great but no pressure. (side-note, we use a direct mechanical gauge for initial verification so no question of electrical gauge accuracy). It’s conceivable that the pump just doesn’t generate enough pressure at cranking rpms, so we did a start up. Ignition on, fuel on, and she fired right up (yeah baby). Promptly shut it down just a couple seconds later because still no pressure.
The troubleshooting began. I won’t bore you with all the things we checked that weren’t it, here are the important things we did learn:
First, the adapter plate from Keisler:
the ports I had previously marked IN and OUT are in fact the other way around. I can’t recall what we based the original assumption for which was which on, possibly the sensor port location, but one way or another once I had the oil pump out of the motor and blew air through the pump outlet hole in the block it was pretty clear. This wasn’t the oil pressure issue, it just meant the flow through the filter and cooler would be opposite from what I intended, for anyone else who may use this adapter plate here’s the confirmed flow direction:
Now on to things that likely did have something to do with the issue…
Getting to the pump means removing the front engine cover and timing chains. Removing the pan means separating the engine from the subframe. Optimistically, we started with getting to the pump.
Side note about the timing chain: the GM FSM leaves some confusion about the right process to secure the cams, remove the chains and align everything for reinstallation. The process is actually much better covered by this video from Cloyes, and yes you actually lock bank 2 and then rotate the crank almost 90° before locking bank 1… which feels very “wrong” knowing it’s an interference engine.
The one detail they leave out in that vid is locking the cams in place before removing the chain. Use camshaft retaining tools pn EN-48383 available on amazon.
The pump turned out to be dry. Presumably turning the motor upside down on the stand to swap the oil pan drained everything from the pump and now it couldn’t build any suction. However, filling the pump with assembly lube to prime it still didn’t do the trick. So then I replaced the pump with a new Melling unit:
Primed this one with assembly lube as well, still no dice. On to the pan.
Suspended the engine from the top and dropped the subframe and pan:
We even pulled the main caps to check the bearings, which turned out to have an interesting coating here but everything checked out OK:
With no glaring issues with the pan or pickup I squirted as much assembly lube as possible up into the passage in the block that leads from the pickup to the pump, oiled both sides of the o-ring that seals that pickup to the block, and reinstalled the pan. Cranked the engine and voila, oil flow!
It’s likely that the issue was caused by compounding things: the pump being drained dry and needing to be primed, perhaps too large of an air pocket in the pickup tube, and perhaps also the o-ring being dry and not sealing fully. For others to have the best shot at avoiding this, I’d recommend that when you flip the motor to swap pans, fill the passage in the block with assembly lube that’s thick enough to not drain down the pickup when you flip the motor back over, and also lube that o-ring up. With that you’ll probably be good to go. If not, the pump may need to be primed.
Everything’s back together now and the engine fires up and has full oil pressure. Working through many other little things that come with a brand new build right now, will continue to update as I go.
