rb25 lost oil pressure with new 26 pump

[AS240]

i just finished refreshing my rb25 last week.
new oil pan, new oil pickup, rb25 neo water pump, rb26 oil pump, new belt and tentioner, new head gasket and arp head studs. ran perfect up until yesterday. i was on the highway and i went to neutral to pull into a store and my oil pressure dropped to almost nothing. i pulled in an shut it off. started back up and hear lifters clattering.
oil pressure is about 5psi idling and at 2500 rpm its about 20psi. (using mechanical oil press gauge)
wtf could have happened. if i installed something wrong it should have been evident from the first start up, not 5 days later. nothing is leaking from anywhere.
also i pulled off the oil filter and the oil that came out was incredibly dark and had swirls in it which im guessing are my bearings, despite the oil being brand new.
any comments/advice are appreciated. thanks

[Sileighty_85]

clogged pick up?

Do you drive it hard or bounce off the Rev Limiter?

Did you install the Crank collar? (really only needed if your bouncing off a Rev Limiter)

[AS240]

the pickup is brand new along with its gasket. every pump and seal involving oil and coolant is new. it doesnt have a collar but i hardly every hit the limiter. ive been driving really easy because im breaking in my new clutch. i was just cruising at 70mph on the highway when i pulled off into the store.
the thing that puzzles me is that the oil is crystal clear on the dipstick, but when i pull the filter off its completely grey/dark

[redline racer510]

check oil pickup for any debris

[Sileighty_85]

bouncing off the Rev limiter with out the crank collar will kill the pump.

If you ever looked a the contact area of the pump drive its literally only like 2cm of contact.

So if you bounce off the RL it can slip or round off the area

But id pull the pump and inspect it

[AS240]

yeah i know all about the short crank snout. for a while people thought that the late model rb25s had a longer snout but they dont. i have s2 from a 1998 r33 and its short. the stock pump did have a a couple marks on the pump where you could see the wear, but i never had a problem like this before, even after dailying it for 2 year and through 5 or so drift events.

[Sileighty_85]

why did you use an RB26 pump anyway, FAST shows the pumps as being Engine Speciffic

[AS240]

use the 26 because of the high pressure rating and a lot of people run them. the water pumps and oil pumps are interchangeable between most of the rb motors.

[AS240]

Motors out, pan is off.
Every rod is loose and every crank journal has a groove for the feed hole.
Oil pump screws were tight as hell....tried to get them off and 3 stripped out.
Oil pickup is tight and was completely clean where it sealed.
Everything is completely fcked and I still have no clue as to what happened.
FML

[Sileighty_85]

what do you mean every rod was loose?

Like the connecting rods were loose?

[AS240]

you could jiggle them still bolted to the crank.
hard to see the rod move but you could hear it

[Sileighty_85]

well if your rods are loose that would cause a loss in OP

[DJDANGER24]

who torqued everything when it was built? Take some pics if possible

[AS240]

The bottom end was left untouched when I took apart the first time. The rod bolts weren't actually loose, they were still torqued down but the is play in them now because of the lack of bearing thickness.
I torued everything to factory spec. What do you want pics of

[AS240]

The bottom end was left untouched when I took apart the first time. The rod bolts weren't actually loose, they were still torqued down but the is play in them now because of the lack of bearing thickness.
I torued everything to factory spec. What do you want pics of

[DJDANGER24]

Just trying to understand how the bottom end was left untouched and you took it apart?
As far as the bearing issue, when you removed them and re-install, there will be clearance issues with friction. As heat rises, bearings expand and when they cool down they contract. IMO, you should of had a machine shop measure what bearings you needed when you refreshed it.

[AS240]

i never took the bottom end apart.
when i refreshed it all did did was change the oil pump, water pump, ex cam gear, full timing, and head studs.
i never touched the rods or mains

[DJDANGER24]

Oh ok, now i understand. I was asking for pictures of the oil pump drive, maybe it wore down enough to cause the low psi

Oh and i overlooked something, how long did you drive it around with 5psi of oil at idle and 20psi at 2500rpm? was that just initially when you saw it drop?

[AS240]

ill post some pics up as soon as i get home

[AS240]

i got the oil pump screws out finally. are the oil pump innards supposed to be scratched up like this?
http://i94.photobucket.com/albums/l99/Deanith/IMG_2089.jpg

[AS240]

journals and bearings
http://i94.photobucket.com/albums/l99/Deanith/IMG_2072.jpg

http://i94.photobucket.com/albums/l99/Deanith/IMG_2077.jpg

http://i94.photobucket.com/albums/l99/Deanith/IMG_2074.jpg

http://i94.photobucket.com/albums/l99/Deanith/IMG_2081.jpg

[AS240]

here is the old stock rb25 pump with 60k+ miles

http://i94.photobucket.com/albums/l99/Deanith/IMG_2092.jpg

this pump looks better than the brand new one. could that be the problem at all?

[xnissan240sx]

Man I personally thought that you were suppose to have the right oil pump for your your RB. Not saying your a lier but you cant be running your car that hard that you need to go up to the 26 oil pump. I mean you had said before "dailying it for 2 year and through 5 or so drift events" so I just don't understand why risk it going with an RB26 pump instead of the RB25 OEM or if thats not good for you the N1 oil pump. Just my :2c:.

[Sileighty_85]

one thing i remember is if your running a higher pressure oil pump you need to run the Tomei oil restrictor for the head or else you will cavitate the oil pump due to the poor drain design of the head

[xnissan240sx]

one thing i remember is if your running a higher pressure oil pump you need to run the Tomei oil restrictor for the head or else you will cavitation the oil pump due to the poor drain design of the head

That wouldn't comply with the RB25 N1 oil pump would it?

[Sileighty_85]

That wouldn't comply with the RB25 N1 oil pump would it?

youp it does

[DJDANGER24]

The bearings dont seem to have any heat marks which is a good thing. Although the mating surface of the oil pump looks to have had a hard time rotating. If i were to guess, i would say the pump was over torqued when installed, not saying you did but thats what it looks like. I would try throwing the old one on and checking to see if the problem goes away

[xnissan240sx]

youp it does

How bad is it to run without that?

[Sileighty_85]

How bad is it to run without that?
ur engine might end up like this guys


journals and bearings


http://i94.photobucket.com/albums/l99/Deanith/IMG_2077.jpg





So wheres the bearing on this one?
Was there even a bearing there?

[xnissan240sx]

So just buy an oil pressure gauge and I am all good!

[Sileighty_85]

So just buy an oil pressure gauge and I am all good!

you would need those Tomei Oil restrictors

[AS240]

with the stock 25 pump, the oil pressure dances around from 45psi to 75psi throughout the rpm range under load. the 26's holds a steady 80psi.
and theres no such thing as a rb25 N1 oil pump, theres just the N1 and its for all 20/25/26 motors because they are interchangeable.
and tomei only recommends using the oil restrictors in the head if you are going to run their pump or one similar like greddy's or jun's because they crank out 100+psi.
nothing was over torqued. and i dont think theres any way you can torque the pump down that much to make the gears shear on the inside, especially since it has that impossible to remove back plate. i shattered 3 bits getting those damn screws out.

[AS240]

heres the bearing from the rod cap
http://i94.photobucket.com/albums/l99/Deanith/IMG_2078.jpg

[usmcgetsome]

keep an eye on future oil pressure

[redline racer510]

I'm running a N1 pump as well because the oem pump wasn't in stock so they gave me the n1 pump for the same price. Lets hope I don't run into any problems. Just curious did you prime the engine before you started it(remove fuel pump relay crank engine until oil is visible on cams).

[AS240]

yep everything was primed. also filled the pump with assymbly lube before i put it on. i cranked it over until i had oil pressure before i started it.

[supersayianjim]

bumping this thread because some similar happend to me. another "suspected" failed n1 pump???

[fliprayzin240sx]

I'm on an N1 oil pump since I did the swap end of Sept. Oil pressure is rocksteady all day long. It jumps up to 8 bar when oil is cold but when oil is up to temp, itll max out at about 6-6.5 bar. I like it at idle even more, almost 2 bar at idle when oil is up to temp.

I daily this, got one drift even under my belt on it and already had a near fatal issue. Snapped the oil filter block snout at the track hitting a straightaway at 110 mph. Get a Raw Brokerage Oil Filter stud and get rid of the OEM oil filter block/oil cooler block.

[supersayianjim]

the 1st n1 i had siezed before i mounted it. and this 2nd one, well won't know till i pull the block apart. but i have my suspicions about the pumps now(for now).