Hi All,
New build with a curious oil pressure problem. I’m already in the process of removing the motor to tear it back down for a full inspection, no way around that… but here’s what’s happening:
I’m somewhat familiar with Pontiac’s “series” style oil pathway and have some vague ideas about what might be the issue. The left (driver) side oil galley is showing some oil pressure, but the right side is not. When I pulled the two forward lifters and spun the oil pump with a 500rpm drill, driver’s side lifter bores flow oil, but the passenger side does not. By “some” oil pressure I mean it’s not spraying an oily mess out of the bore, but there is some flow there similar to a slow pour out of a quart bottle I guess. Remember it’s only a 500 rpm drill doing the spinning but I think that is similar to 1000 rpm from the crank so it should be adequate.
Let me cover the few things I do know.
1. Boroscope in the oil pan shows the oil pump drive shaft spinning the pump just fine. Oil pickup still attached etc. Oil pump is a high pressure unit from Summit. I did prime and “bucket” test it prior to installation and seemed fine.
2. Main bearing clearance was right around .0025 and rod bearing clearance .0015 (plastigauge).
3. On initial start up, oil pressure gauge showed 60 psi +/-. Gauge needle very soon started fluttering pretty wildly and then showed something between only 3-5lbs so I shut it down immediately. Running Lucas 30w break-in oil plus a 4oz bottle ZDDP of additive mixed in.
4. Haven’t removed the timing cover yet to inspect the galley plugs. The plugs were staked by my local machine shop. I wish I tapped them in hindsight.
5. These are proper Pontiac hydraulic lifters (Crower Cam Saver) and not Chevy lifters with the oil band too low. Lifter bores don’t seem to have excessive clearance from what I can tell but I didn’t measure. Surely the “cam saver” groove down the side of the lifter wouldn’t cause an issue like this?
6. I know about the hidden galley plug by the diz gear and it’s in place, so it’s not that.
I tried posting a video link below, hopefully it works. Meanwhile there’s a photo with the two lifters out.
Once I get the motor out, obviously I’ll know a lot more. Just curious what the “hive mind” thinks this problem could be. This is my 4th Pontiac V8 motor build and my 9th motor build overall. Not an expert but not completely green either. Super bummed that this one was not successful! Thanks in advance for your consideration.
https://share.icloud.com/photos/0800...xLTGJ2Ii7TJQ1A
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