Oil pressure issues on rebuild

[JasperG]

Hello, Many of you know I have freshened up a LD28 for my rover. (new rings, seals,head fully serviced, headgasket, rod bearings, etc etc. Well Friday we got it bleed and to my surprise it ran great. I was so excited I forgot to check the oil pressure gauge. It seemed very low. The next morning I went out and changed the oil, checked/cleaned the pump and reinstalled. I must have put the pump gear in incorrectly as it worked okay (still low pressure) but it busted a tooth or two on the pump gear. Careful examination of the drive gear on the crank looks "okay". So I went down to the you pull and pulled a pump out of a gasser late 80s 90s PU. The shaft was similar but longer, so I cut it down to the same size as the LD28. Its pumping pressure but it seems very low, almost 0 at idle when its warm. I shut it off. At start up it struggles to get to 40lbs at speed and drops down to 10-15 and then down to 5 or so pretty fast. I pulled the oil pan and noticed that the pickup tube didnt have a gasket so I put some right stuff in there. Seems to help a bit but its still low and I dont even think its up to ops temperature yet. (IM not a 100% sure though, I havent got the water circulating yet either. I think I am going to remove the thermostat tomorrow.) Open to ideas of where to look, everything in the pan was good, some little pieces of metal but likely from the oil pump gear.
I plan on trying the 280ZX turbo pump as I found that searching all over this board. It runs so good but this oil pressure makes me nervous. Ive also tried another gauge and the line is new.

[nogrip]

oil pickup clear and not fouling on the oil pan at all?

[JasperG]

Its clear, I removed the pickup yesterday and there wasnt a gasket underneath it. I figured it was sucking air there so I put some gasket maker underneath it but really no change.

After some research, it appears I have the high volume pump already, but to be safe I ordered a new one. The gear at the pump seems fine now.

My next question is can I change the main bearings while in the car? It looks like I can get to the front 4 but not sure about the thrust bearing in the rear...Im thinking probably not! Gordo.

[minimog]

Have you changed out the main and thrust bearings? Oil pressure at idle is governed by the amount of wear in this area.

[JasperG]

Hi, pulled the pan back off this evening and popped two caps off the mains. They look pretty worn, down to the copper, so I am going to change them and see what happens! Looks like I can do them in the truck without any issues? The thrust bearing was tough to get off without the tool but I made a little slide hammer and it works. Im a bit worried about sliding that thrust bearing around but it should go. A little trick I saw online to install/remove the old upper shells is to make a small T handle just big enough to grab the bearing side and stick the handle in the oil journal and have someone slowly turn the engine over pushing the bearing out or in? Pretty clever. Ive done it before on a Rover V8, but never thought of that, should be easier. I ordered the new pump as I found one for 50 bucks on ebay.

[rlaggren]

Plastigage may let you "mike" the journal clearance w/out taking the crank out. Not sure because the cap is on the bottom w/the engine in the car and that may skew the test, but the stuff is cheap. Pretty quick to put an inch on the bearing and torque the cap back on, then take it off and measure the squash. If it shows large clearance, that's pretty definitive. if it shows spec clearance, you need to consider whether the test is working right; but if the gauge material is available easily, nothing to lose.

Rufus

[JasperG]

Thanks for the advice! From the looks of the first two bearings it needs new ones. The journals looks very nice though. I may try the plastiguage though to see if it is w/i spec. Honestly if I can just get the pressure up I will be happy. its just an offroad trailer queen so it wont see many miles, except in the woods.

[JasperG]

Figured I would update everyone. Installed new crank bearings into the engine through the oil pan. I was able to get all the bearings replaced with some patience and my internet trick I mentioned earlier. I found some small sliding door screws that fit perfectly into the oil galley on the crank and turned those bearings in and out with ease by myself. I also installed a 280zx turbo auto pump I got off ebay for 60 shipped. Fired it up tonight and it pegged 30 at idle and easily went to 40. It was late so I didnt get to really heat the engine but after 10 minutes it was still at 25lbs. Im happy. Thanks to everyone for the help. Gordo

[rlaggren]

Good to hear you done it and it helped. No excuses now for the next guy. <g>

Rufus

[windsock]

Hi JasperG,

I'm glad to hear you got it sorted. I'd be interested in knowing what weight of oil you've been using.

I use a Penrite 15W-50 semi-synthetic here and I sit on 35-55*C on cold idle and 15-20*C hot.

I think we are overdue some photos actually...

Cheers,

Phil

PS, I have seen aluminium rivets (minus the steel pin) used in the oil-hole of the crank and then turned to push a shell out. Same process to get the new one in.

[JasperG]

Hi JasperG,

I'm glad to hear you got it sorted. I'd be interested in knowing what weight of oil you've been using.

I use a Penrite 15W-50 semi-synthetic here and I sit on 35-55*C on cold idle and 15-20*C hot.

I think we are overdue some photos actually...

Cheers,

Phil

PS, I have seen aluminium rivets (minus the steel pin) used in the oil-hole of the crank and then turned to push a shell out. Same process to get the new one in.

Hey Phil, oddly it only goes up to 30 at idle and wont go up or down. Its got good pressure but I still think something else is up. I ordered a new pressure relief valve, the one that is behind the oil cooler, hoping that might be it. Figured I would check the regulator valve at the pump too, never know. I am having a BEAR with my clutch though...I started a new thread, let me know if you can help!
Not real sure how to post photos up? Let me see if I can figure that out. Thanks Gordo