oil pressure problems on new build
Turbo Mini Forums

Hi, iv got more oil pressure problems with my engine.
so start from the begining, after having alot of problems with the old engine i had alot of machiening and new parts bought and quite a bit of rebuilding, So i rebuilt the engine myself mostly. When coming to start it we had quite a bit of problems with wireing, upon cranking there would be a nice amount of oil pressure, about 80psi. Oil pump was primed when fitted, gasket correct way round all the plugs are in the gallerys...oil also back-fed into the pump after final assembly. With the dodgy wireing it was easier to tow the mini behind my volvo than push it, so when it was being towed it was reading good oil pressure again, we eventualy got it started and the oil pressure within seconds had dropped to 0-psi, so i closed down the engine to prevent damage to it.

what i dont get it the amount ot times oil pressure was doing fine when turning over, why would it suddenly drop when it actualy fires up?
anyone any idea what could have caused this? i so cant be bothere taking the engine out the car again oompf.gif hope its an easy enough fix!!!!

Thanks

David.

David.

mechanical or electrical gauge?

if its electrical and you have got wiring problems i would get these all sorted and see what its like then.

mechanicle gauge unfortnuatly.
the wireing problems are just due to changing from pre-engaged starter to inertia and switch wire strangely disappearing from my loom!

David.

just use a screw driver to short the solenoid, that will crank the engine over

do it without plugs in until you get a good reading

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

done that part already, then battery was discharging at a rather fast rate n tis why we were bumping it, oil pressure was good while it was cranking/bumping also but upon it actualy fireing up the pressure dropped

David.

I had a similar thing many years ago on a 998 and it turned out my oil pump had broken a bolt. Always made pressure cranking / cold but as soon s it got hot th epressure fell off We could only presume it was down to metal expanding/ contracting. Have you checked for sh.1t in the relief valve?
Good luck

its a brand spanking new high capasity oil pump i hope its not that >_<
checked the relief valve but ill have to check it again just to make 100% sure

David.

Do you get any pressure now? Have you tried again since you shut it down? What you getting now when you crank it

Im at Uni now so will be the weekend before i can check, after taking relief valve out n quick check, crank over jump starting from volvo battery it wasnt pulling any oil pressure, was reluctent to crank for too long incase it caused anymore damage

David.

If pressure has gone completely now (even when cranking) the pump has lost its prime, ie, all the stuff you primed it with and backfilled it with has been used and it isn't sucking out of the sump....

Far too low level in sump ?
Air being sucked in from:
Gasket behind pump
O ring between engine and box
joint between suction pipe and box or the cover plate outside ?

If it comes back when cranking but disappears when running, very low level in sump - at cranking speed only a small amount of oil flows so it gets back to the sump quickly, when the engine starts a lot gets pumped up to the top and because it's cold, it takes a long time to run back to the sump. It would have to be a seriously low level to exhibit this but I have seen it happen.

Schrödinger's cat - so which one am I ???

level is above min' but not right up there.
between sump and block is a brand new 'o' ring gaskets behind the pump.
I assume the pick up pipe is fine as southam mini metro centre rebuilt it, it was all secure.
We did crack the line off from the oil cooler to see and there was alot of oil in that general area when the pipe was loosened, so much so it came out, tried filling the line again upon cranking and there wasnt really any oil being drawn through just seemed to be natural drain

David.

One last thought, correct length bolts in the pump ?
The threaded holes in the block are quite shallow and if the bolts are slightly too long they'll bottom out in the holes before they've compressed the gasket.

Schrödinger's cat - so which one am I ???

where is your oil cooler located, could be that causing the problem (airlock)

if you back filled it, it will give good pressure while it cranks (500 or so rpm)and pumps how ever much oil you have back filled it with

But if no more oil is getting to the pump from the sump, due to an airlock somewhere (oil cooler are reknowned for this), once it fires and is running at say 2000k, it will run out sharpish

try backfilling it again, also prime the oil cooler too, (have you definately filled the oil filter? (always worth a check on a new build)

once you have done all the above, and towed your mini round the block in 4th gear, giving consistent pressure it should be ok unless you have a leak somewhere?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

another thing to note is make sure your oil cooler cant 'drain back' when the engine is off, i.e. unions pointing upward, or inlet higher then oultlet at least.

otherwise you might find yourself struggling to get pressure everythime you start

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

oil coolers basicly same position as this


when im back home this weekend ill check it all over again, oil up the cooler, re-oil the filter (was full up before)
back fill the pump, reposition the cooler unions if required.
quite alot of people seem to think its not something major and has been sujested as you said before about an air lock but as i said, when cooler pipes were cracked off before oil did come out, so weather there is an air lock within the pump itself...maybe having a week to drain will mean air works itself out
yeah bolts should be fine, there the same ones which came out and the pump itself is actualy thicker, still good thread holding it in though

David.

Take the pipe of the cooler put it in a pint glass and crank for 5sec if the glass has an inch of oil in it then you have a masive oil leak internaly engine out time if not take the oil pump of an have a look

Blocked brick gaurd?

Be careful on which central oil pick up pipe you use, the cheapo ones have very little 'exposed' gauze to strain the oil, and can get clogged very quickly, with all the surplus gasket sealer, lint and anything else that gets into the sump on a new build.

thick moment...brick gaurd??

not really sure which centre pick up it is...didnt really inspect it so much hmm, didnt use tooo much hylomar type stuf anyways, just enough i would think

David.

its the strainer in the sump of an engine. It only stops particles of crap the size of bricks, all the smaller shite eventualy wears the oil pump before it reaches the filter.

Used recently by Fast Carl, which actualy made me giggle in the context it was used

aah i see >_< well at least it stopped the diff teeth being sucked up last time there was engine failure

David.