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Low oil pressure


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#1 _WYLDLC6_

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Posted 27 December 2011 - 07:49 AM

Hey guys, as the topic says, just got my engine back again and still having oil pressure issues.
Ive had the block pressure tested, all bearing tollerences checked again, all good, all lifters and lifter bores checked, all good and engine builder prepped a new crank and put that in.
Checked pickup, good and oil pump is new with a heavy spring.
Started engine got pressure straight away but no more than 30 psi and that was using a proper oil pressure tester.
I ve shimmed the oil pump spring with has done nothing and i dont know what else to do, im pretty well over it.
Cheers chris

#2 _rob350hatch_

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Posted 27 December 2011 - 08:04 AM

shit like this is frustrating as, but who built your engine why cant he answer your question provide a solution.
good luck with it.maybe speak to some other engine builders,they might see something obvious.

Edited by rob350hatch, 27 December 2011 - 08:06 AM.


#3 rodomo

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Posted 27 December 2011 - 08:14 AM

Sounds a bit weird? What is the idle oil pressure?

#4 _WYLDLC6_

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Posted 27 December 2011 - 08:18 AM

Very frustrating, the guy who built it is pulling his hair out about it, hes been building these hi performance 202s for over 30 years and hes checked and reckecked everything and says that theres no reason that this is happening.
He says we may need a new block if it didnt fix the problem but i doubt it as my old engine had great pressure with this block.
Little reluctant to take it elsewhere as it is under warantee and im probably going to get bent over by someone else.

#5 _WYLDLC6_

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Posted 27 December 2011 - 08:21 AM

Idle pressure cold is about 25-30 then drops to about 15 hot.
Giving it a few revs it wont go over 30.
Engine sounds real healthy aswell.

#6 rodomo

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Posted 27 December 2011 - 08:26 AM

Have you tried the gauge on another motor?

#7 _Drag lc_

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Posted 27 December 2011 - 08:29 AM

i would think if the oil grade is not matched to the engine application ie bearing clearances , priority oiling mods somthing like this might happen. maybe we need the engine specs to give more detailed answer?.


Cheers h

#8 _WYLDLC6_

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Posted 27 December 2011 - 08:30 AM

No but have an electric and a mechanical inside the car, thought they might be stuffed so went and brought a proper tester and all 3 read the same

#9 S pack

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Posted 27 December 2011 - 08:49 AM

Could be a faulty bypass valve inside the oil pump. (not the one with the spring that you have shimmed).

Edited by S pack, 27 December 2011 - 08:49 AM.


#10 _WYLDLC6_

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Posted 27 December 2011 - 08:49 AM

Which specs, im not sure of tollerences but its got 11.1 comp, solid cam 535 lift 320 dur 1.5 rockers, lots of headwork should make around 280 hp.
It has a brand new standard oil pump. Ive tried shimming the pump and its made no difference. Engine builder put a new crank in this time.
Im using hpr 40.

#11 _Drag lc_

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Posted 27 December 2011 - 08:58 AM

the bypass filter valve if stuck open wont hinder the oil pressure as its just bypassing the oil filter still on the high pressure side of pump.if it is a bit of a racer that valve would have already been removed from the system.

std pump has the clearance been checked on it? i dont know much about the usability of std pumps as ive only ever used hv ones on hotties .

Cheers H

#12 S pack

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Posted 27 December 2011 - 09:06 AM

the bypass filter valve if stuck open wont hinder the oil pressure as its just bypassing the oil filter still on the high pressure side of pump.if it is a bit of a racer that valve would have already been removed from the system.

std pump has the clearance been checked on it?

Cheers H


Ah,my bad about the filter bypass valve (still waking up).
Probably worth trying another oil pump on the engine and see if the pressure improves.

#13 _WYLDLC6_

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Posted 27 December 2011 - 10:05 AM

I do have a hv pump here but not sure if complete as it seems to be missing the little brass looking plunger thing if thats normal.
Could a hv pump help or not.

#14 _WYLDLC6_

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Posted 27 December 2011 - 10:07 AM

Engine does have a large sump with about 7.5 litre oil capacity

#15 _CraigA_

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Posted 27 December 2011 - 10:40 AM

Maybe something silly going on with the oil pick up system?

Is it internal or external type? Maybe it's sucking air?

#16 _WYLDLC6_

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Posted 27 December 2011 - 10:56 AM

Yeah i thought that too. Its an internal pickup. Just odd that there was no issue with the same sump and pickup on my old engine.
Even when that one got real tired and started getting bad it still held good oil pressure.

#17 _CraigA_

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Posted 27 December 2011 - 11:04 AM

Possibly it has a crack where the pipe bolts to the engine and this was done accidentally when it was refitted after the engine rebuild?

The reason I think this may be the problem is because your idle pressure seems ok but doesn't come up with revs. The harder the pump works with increased engine speed the more likely it would be it would suck air instead of oil.



#18 _WYLDLC6_

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Posted 27 December 2011 - 11:11 AM

that makes sense, the pickup was checked when the engine was re assembled but im guessing it a prety hard thing to check.
looks like it could be engine out again, getting sick of doing that.

#19 S pack

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Posted 27 December 2011 - 02:26 PM

that makes sense, the pickup was checked when the engine was re assembled but im guessing it a prety hard thing to check.
looks like it could be engine out again, getting sick of doing that.


I would try another oil pump first before rushing in and pulling the engine out. If your lucky it might save you a lot of work in the long run.

Cheers
Dave.

#20 _CK Block_

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Posted 27 December 2011 - 03:17 PM

try checking the timing gear oiler has been installed. have you got around 4mm of spring sticking out of relief (making it hard to screw in ) try running motul 300v competition 15w50 oil. I got an extra 10 psi at an idle

Edited by CK Block, 27 December 2011 - 03:19 PM.


#21 RJTVX23

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Posted 27 December 2011 - 03:32 PM

My best guess would be the timing gear oiler on the front of the block , from memory looks like a squashed tube , it may have been removed when the machining was done? I seen a few guys with speedway engines has issues with these oilers and low oil pressure, good luck!

#22 Shtstr

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Posted 27 December 2011 - 03:48 PM

never use an old pump unless you rebuild it and set back to std. cheaper to buy a new pump and fit it.have always used a std pump on race engines as a std rule of thum is you only need 10psi of oil pressure for every 1000 rpm. so 3000 rpm have 30 psi oil presure.the gears my be worn in your old pump and that will cause low oil presure so will a old spring in the presure release valve as it will open easyer than a new one. use a heaver spring and see how that goes.
we used to modifi the bolt to have a iner bolt and lock nut to be able to adjust the presure without pulling the pump apart at the track.
used for differnt heat settings for differn't temps around Australia.

#23 _CHOPPER_

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Posted 27 December 2011 - 03:52 PM

The problem could be any one of the oil gallery plugs that might be slightly out of shape, no sealant used...you could be chasing your arse for quite a while yet.

#24 _oldjohnno_

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Posted 27 December 2011 - 05:03 PM

The idle pressure is still acceptable hot or cold, so that would indicate that the problem is unlikely to be downstream of the pump. If there was excessive flow downstream (eg. from too much bearing clearance, loose or missing plugs or nozzle or any other sort of internal leak for that matter) then the low pressure would be more pronounced at idle and it would improve with rpms. I'd be checking the pump first (simply because it's easy to do without pulling the engine) but like Craig I'd be suspecting a suction side problem, either a restriction of some sort or an air leak. These types of problems normally get worse with revs, like yours.

The only other thing I can think of that would do it is a filter bypass valve that has been plugged or is jammed closed. Because the pressure is measured downstream of the filter this would also produce symptoms similar to yours.

#25 _WYLDLC6_

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Posted 27 December 2011 - 06:36 PM

Is it common to have issues with these pumps, as this is a new pump. I do have the old hv pump here which worked fine and has the filter by pass valve removed.
Does the fact that when i shim the pump spring the oil pressure doesnt change, could that indicate an issue.

Is it common to have issues with these pumps, as this is a new pump. I do have the old hv pump here which worked fine and has the filter by pass valve removed.
Does the fact that when i shim the pump spring the oil pressure doesnt change, could that indicate an issue.

Is it common to have issues with these pumps, as this is a new pump. I do have the old hv pump here which worked fine and has the filter by pass valve removed.
Does the fact that when i shim the pump spring the oil pressure doesnt change, could that indicate an issue.

Dont know why that came out 3 times lol.




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