No Oil Pressure Dramas, Advice Please

[TRB-001]

hey,

iv recently done a rb30det conversion into my r32, very budget build so the bottom end only got a new set of big end bearings, original mains and oil pump. anyway engine is up and running, runs fine, my issue lies from as soon as iv started this engine iv low oil pressure, i was running 15w40 in it, oil pressure tested at 30psi at approx 3000rpm, 15psi and idle WHEN COLD and 15psi at 3000rpm and about 2psi at idle WHEN HOT.

so i pulled the sump off, pulled out the pressure relief valve at the bottom of the oil pump, it didnt seem stuck or anything, so i cleaned it up to make sure it was sealing well, lubed up well and shimmed the spring abit to hopefully lift oil pressure.

filled with 25w50 castrol edge oil, cranked and now i cant get ANY oil pressure.

i have primed it for awhile and im not getting anything, i searched the forums and i found a thread about possibly having an air lock in the oil pump, so i as someone in that topic suggested, i cut the top off the oil filter, gutted it, filled with oil and wound the engine backward in hope to suck oil into the oil pump and get rid of the air. i didnt it for awhile, probably put atleast 2 oil filters full of oil back thru the engine and i could see it go down as i wound it.

put it back together with the 25w50 and still no oil pressure at all. iv tested with 2 different guages and im definately getting nothing.

so the engine used to have oil pressure, all i did was remove sump, remove and refit the oil relief valve (second time triple checked it was fully closed) and refitted it all again.

only thing i can think of is when i removed the sump, due to very small clearances between engine and crossmember, the guaze on the end of the oil pickup is alittle dented, nothing back at all, still clean, just not perfectly round.

any suggestions what i can check next, now im stuck....??

p.s sump is 3L sump with fins ground down

[SirRacer]

Looking forward to how you are getting on mate as ive just had the same problem with my engine.

My engine on the dyno recently lost all oil pressure and now reads nothing. Will be pulling in a few days with a hope to finding out what the issue is.

[TRB-001]

if yours happened on the dyno while running u may have oil pump failure. the reason i dont think this is the case for me is becoz it only dropped to no oil pressure after touching the relief valve.

[Bliksem]

I had this problem on my first RB30DET, swapped to a new RB26 pump, problem solved. I suspect that the RB30E pump is un-suitable for the twin cam head (although Ive read of some working??)

[SirRacer]

My engine was about 2000 kms old and i had an r33 gtr pump in there. Weird one for sure.

[bubba]

Are these engines with oil pressure problems running stock cranks and stock bearings? Do you get oil pressure back when you put your foot on the clutch?

When I first built my 30 we didn't check any clearances, just slapped it together. Turned out the crank had a heap of endfloat which destroyed the thrust washers, scored into the back of the oil pump a good 4mm or so and started to eat the webbing in the block for the main journals.

It was so bad, that you could actually see the harmonic balancer move when someone put their foot on the clutch.

Ended up pulling engine out, crank ground .010 over and a set of matching bearings went in and she was mint. Certainly learnt my lesson there

[SirRacer]

Are these engines with oil pressure problems running stock cranks and stock bearings? Do you get oil pressure back when you put your foot on the clutch?

When I first built my 30 we didn't check any clearances, just slapped it together. Turned out the crank had a heap of endfloat which destroyed the thrust washers, scored into the back of the oil pump a good 4mm or so and started to eat the webbing in the block for the main journals.

It was so bad, that you could actually see the harmonic balancer move when someone put their foot on the clutch.

Ended up pulling engine out, crank ground .010 over and a set of matching bearings went in and she was mint. Certainly learnt my lesson there

Mine was built by an engine reconditioner, however im not too sure now how good the job was. My engine has ACL race bearings with stock crank. I replaced the release bearing the week prior due to it being noisey, however i think that was more a problem with the engine sitting for quite sometime.

Your comments are pretty interesting though and certainly could be bang on for my setup. Will let you know once its out.

[STATUS]

Mine was built by an engine reconditioner, however im not too sure now how good the job was. My engine has ACL race bearings with stock crank. I replaced the release bearing the week prior due to it being noisey, however i think that was more a problem with the engine sitting for quite sometime.

Your comments are pretty interesting though and certainly could be bang on for my setup. Will let you know once its out.

he means the thrust bearings in the engine (middle crank main), your refering to the throw-out bearing in the gearbox bellhousing.

[TRB-001]

yeah mine was just a slap together (didnt pull crank out) but i still dont see how b4 i atleast had some oil pressure, now got nothing at all...

im going to pull off my rb20 one, check it!!!! then if its ok ill put it on and see how we go

[bubba]

he means the thrust bearings in the engine (middle crank main), your refering to the throw-out bearing in the gearbox bellhousing.

Yeah, the thrust surface on the no.4 main bearing

yeah mine was just a slap together (didnt pull crank out) but i still dont see how b4 i atleast had some oil pressure, now got nothing at all...

im going to pull off my rb20 one, check it!!!! then if its ok ill put it on and see how we go

Mine got gradually worse (as it ate out the thrust bearing), it wasn't a sudden catastrophic failure.

So you didn't even freshen up the bottom end? just slapped your head on it?

[TRB-001]

it got new bigend bearings, but at the time i wasnt going to replace the oil pump, and the crank timing gear was seized onto the crank and i didnt want to damage the oil pump or anything in the removal process, so i just decided to leave it and hope the mains were ok.

[T04GTR]

this may sould dumb, but it hasnt already had an undersize grind on the crank has it? you got the old bearings? take a pic of the part number on the back of the bearing and post it up

[bubba]

Cost me $100 for a crank grind and ~$80 for a new set of bearings (oh and a new oil pump heh), might be something to think about if the mains are in unknown condition..

[T04GTR]

very rarly do mains go.. unless the thust is rooted. but you will still get 60+ oil pressure when cold.

if you have only 10 or so pound the head will be very second hand very soon.

can only be a rooted oil pump or wrong bearing size.

[NYTSKY]

We had the same problem with an XR6T engine, turned out to be excessive bearing clearances.

[TRB-001]

thanks guys,

pulled the oil pump off and it was the typical problem, the phillips head screws that hold the plate onto the back of the oil pump had come loose hence was loosing pressure.

put a genuine rb25det ($250 from usa ebay thank you!) and shes pumping again.

thanks for ur help

[unique1]

thanks guys,

pulled the oil pump off and it was the typical problem, the phillips head screws that hold the plate onto the back of the oil pump had come loose hence was loosing pressure.

put a genuine rb25det ($250 from usa ebay thank you!) and shes pumping again.

thanks for ur help

good work i hope you loctited the new one so they dont do the same thing!