1970 Buick 350 Rebuilt

I have a 1970 Buick 350 professionally rebuilt. No oil coming to the left bank, right bank works great. Not a pressure issue. Any ideas!

You mean left vs. right cylinder heads? Sounds like a plugged oil passage, pull it apart…

Shouldn’t the oil get up to the rocker arm area through the pushrods?

Yes it should but it is not. Left bank (drivers side) - Right bank (passenger side) But it is coming thru the right bank just fine.

Did they prime the lifters? Are you just trying to prime it with a drill or has it run?

Engine was rebuilt 4 years ago - and sat sealed while vehicle was being restored. Engine and oil pump were primed per initial start up instruction to the T. Oil pressure just doesn’t seem to be the issue. Lifter priming shouldn’t be an issue since the lifters on the right bank seem to work fine.

So some passages to the left lifters must be plugged. Are all right side pushrods full of oil, or only a few?

Is it a Buick, Olds or Chevy engine?? About this time, GM was consolidating engine production and Buick and Pontiac were the first to go. Buicks and Pontiacs got Chevy or Oldsmobile engines, then, by 1975, they ALL got Chevy engines.

Take the lifters out and start poking the oil galley holes in the block. Lifters are cheap so buy eight new ones, sixteen if you like working.

Have you verified that the left bank lifters are operating i.e. taking up the valve clearance? If the left side is making valve tapping noise, you probably do not have good oil pressure to that bank. As I remember the oil distribution of GM engines the oil passes up from one of the main bearings to one of the cam shaft bearings which has a circumferential groove. The oil exits the bearing groove though holes in the insert then through a feed passage to the lifter oil gallerys. It is a possibility that that bearing was installed incorrectly so the hole though the bearing is not aligned with the passage. Therefore oil pressure is not getting to the left bank of lifters being blocked by the bearing insert with the misaligned holes.

Hope that is not the case as the cam shaft will have to be removed; the bearing insert removed; and a new one installed correctly.

Have you talked to the engine rebuilder? While they may balk at a 4-year-old job, they still may be willing to help. All problems discuss so far are their fault.