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Low oil pressure


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#51 _Drag lc_

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Posted 29 December 2011 - 12:13 PM

if u have been chasing this for so long might be time to put a drum pump directly onto pressure oil in on block with timing cover,sump side plates off to see what is happening?.so u can pressureise the oil system and see where it is all going.

#52 _WYLDLC6_

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Posted 29 December 2011 - 12:24 PM

We've already done that, with pressure gauge attached and found no pessure loss. this is the frustrating part.
Cheers Chris.

Edited by WYLDLC6, 29 December 2011 - 12:36 PM.


#53 biga064

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Posted 30 December 2011 - 06:10 PM

Hi Ive always used standard volume pumps on my rebuilds , but the last couple of 6s ive done had standard jp brand oil pumps on them and had similar problems as yours . After a whole lot of hair pulling out and mucking around found that the oil pump internal clearances where way to big !! pump gears to body should be 2 to 2.5 thou the jps where 4 to 5 thou . end gears float to cover plate with gasket on was at 10 to 12 thou should have been 2.5 to 3 thou to tops . Fully blueprinted pump using holden original specs and clearances fixed problem straight away. also i noticed you said you shimmed pump about 1 mm this needs to be about 3 to 6mm then you will see a difference !!!! Reworked pumps 15 to 20 psi hot at idle 40 to 55 psi on at highway speeds . Hope this helps !!!!!

#54 _oldjohnno_

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Posted 30 December 2011 - 06:45 PM

Hi Ive always used standard volume pumps on my rebuilds , but the last couple of 6s ive done had standard jp brand oil pumps on them and had similar problems as yours . After a whole lot of hair pulling out and mucking around found that the oil pump internal clearances where way to big !! pump gears to body should be 2 to 2.5 thou the jps where 4 to 5 thou . end gears float to cover plate with gasket on was at 10 to 12 thou should have been 2.5 to 3 thou to tops . Fully blueprinted pump using holden original specs and clearances fixed problem straight away. also i noticed you said you shimmed pump about 1 mm this needs to be about 3 to 6mm then you will see a difference !!!! Reworked pumps 15 to 20 psi hot at idle 40 to 55 psi on at highway speeds . Hope this helps !!!!!


Fair enough, but it has already been tried with a known good pump with no change.

And pressure testing the entire assembly won't show anything because there are no faults on that side.

As I've said before I really really think you need to be looking at the suction side ie. the pickup and sump. If there are no obvious faults then I'd be trying a stock sump and pickup and then running the engine on the shop floor.

#55 _WYLDLC6_

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Posted 30 December 2011 - 06:46 PM

thanks for that mate, just fitted today a used but known working standard factory holden pump today for no real difference.
Is it actually possible to shim a pump that far, because if so i'll definately give it a go.

Have noticed though that there is no pressure loss under acceleration, it does go up just not above 30 psi.

Cheers Chris.

#56 _WYLDLC6_

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Posted 30 December 2011 - 06:55 PM

and yeah johnno, im now trying to get my hands on a standard sump and pickup. so it does look like engine out again. in your opinion will a standard sump be ok for my application.

We may also be looking at changing lifters aswell before engine comes out, last resort lol.

Cheers Chris.

Edited by WYLDLC6, 30 December 2011 - 07:01 PM.


#57 _oldjohnno_

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Posted 30 December 2011 - 07:02 PM

It can hardly be any worse than what you have now.

#58 _WYLDLC6_

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Posted 30 December 2011 - 07:04 PM

Fair call lol.

#59 _Sandman_

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Posted 31 December 2011 - 10:34 PM

Johno may be right about the pickup height.
If your pulling the engine again, you will be able to measure how far from the bottom of the sump the pickup is. It should be 10-12mm. Any closer and you will have problems.
I measure them using a straightedge across the top of the sump, then measure down off the bottom of the straightedge to the bottom of the sump. Write it down.
Then put ruler across the bottom of the pickup. Make sure it's parralell to the bottom of the block. Measure down from the ruler to the block. If you measure to both sides, the readings should be the same if the ruler is paralell.
If the sump was 200mm deep, then you want the pickup 188 - 190mm.

Sometimes when engines are getting shifted around, the sumps get dented and close this clearance up.

#60 _CHOPPER_

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Posted 01 January 2012 - 12:02 AM

So I take it if the pickup is too close to the bottom of the sump it creates a restriction of flow?

#61 _Sandman_

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Posted 05 January 2012 - 05:56 PM

Yeh.
It can be hard to pick as a problem sometimes, because it might have enough clearance to supply oil ok at lower rpm, then loses pressure as the rpm climbs. It depends on design of pickup as well, but is always worth checking when assembling an engine.

#62 _WYLDLC6_

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Posted 11 January 2012 - 04:40 PM

Bit of an update guys, engine out and on stand, sump off and interesting.
Pickup seems to be tilted back so front opening tilted down which may have only been 8 or so mm from sump. As the angle it was on
measured about 14mm from the half moon thin plate on bottom of pickup using sandmans method.
Ive removed pickup and done a dye penetrant check on it and found no cracks, maybe only a couple of pin holes in solder but dont think they go through.
Ive now put pickup back on engine and straightened up so that the face is parallel to the block and using some blue tac set it at aroun 12 mm from sump.
Does this sound right.
Should i still go with another sump first and check.
Cheers chris

#63 gtr_161

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Posted 11 January 2012 - 05:30 PM

I had the same trouble with my 161s, had a rebuild done and drove upto toranafest last year. Got about half hour from newcastle and the oil pressure dropped to 20 psi at 110km and 0 at idle. I called my engine builder and e suggested to grab some hrp 30 so i could make it home to melbourne.
When i got back we dismantled the j.p pump and couldnt see any reason for it. I fitted a n.o.s std holden pump and used hpr40 oil and now have 32 psi at 110km and 22 at idle. If i rev it it goes upto 32 psi and nothing over. I have been told that is normal as thats where the releif valve opens. Hope this helps :)
Darryn

#64 _WYLDLC6_

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Posted 11 January 2012 - 06:08 PM

Im not to sure if thats normal. Probably also a case of completely different engines also. I dont think i only want 30 psi at 7000+ rpm. Your seem to have the same issue as me but im not sure how far you push your engine.
Cheers Chris

#65 gtr_161

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Posted 11 January 2012 - 06:14 PM

No worries mate, I hope you get it sorted. Give the guys at m&w engine services in ballarat a call, ask for Damien 53395159 they do a lot of modified and speedway engines. They will get it sorted.
Darryn :)

Edited by gtr_161, 11 January 2012 - 06:17 PM.


#66 _oldjohnno_

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Posted 11 January 2012 - 08:11 PM

Doesn't sound like the pickup was low enough to be a problem. Do you know exactly how far the pickup was submerged (I remember you mentioning a problem with the dipstick)? If you know how much oil was drained out you could pour that amount into the sump and measure the depth. If this checks out OK I'd be trying a stock sump, everything else has been checked.

And gtr_161 - your "engine builder" is bullshitting you.

#67 _WYLDLC6_

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Posted 12 January 2012 - 05:21 AM

Yeah i didnt think so either. It was about 7.5 lts of oil. I'll put it in the sump and check that then.
I think i'll just change it anyway, atleast i'll know one way or another.
With the dipstick it hits one of the welded plates inside the sump that stop the oil splashing inside then when the engine runs something hits it and pushes the dipstick out so i only use it to check the level.
Cheers chris.

#68 _Bomber Watson_

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Posted 12 January 2012 - 07:19 PM

speedway engines.


Theres the two words that should make you walk out of any engine builders shop....If they advertise they build them, run away.

#69 _oldjohnno_

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Posted 12 January 2012 - 07:59 PM

That's a bit harsh Bomber, the speedway crowd aren't without their good points. For example, they generally have pretty impressive sideburns.

And that's just the women...

#70 _Bomber Watson_

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Posted 12 January 2012 - 08:02 PM

Yep and they manage to talk up being able to spin the tyres on wet gravel and make it seem impressive, that must take some practice considering i can get my pushbike to do it!!!

#71 greens nice

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Posted 13 January 2012 - 12:25 AM

Yep and they manage to talk up being able to spin the tyres on wet gravel and make it seem impressive, that must take some practice considering i can get my pushbike to do it!!!

. Lol sounds like there are some numpties/turkey's up rockhampton way eh?

#72 orangeLJ

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Posted 13 January 2012 - 10:11 AM

Nothing wrong with speedway! its for people who like going sideways without wearing out our tyres! haha.

I think in the old days, speedway engines meant ALOT more than it does today, We just run slap togethers with big compression, big cam etc. Pity we are restricted to 2 barrells of OEM fury....

and we race on clay bomber, not gravel! haha

#73 _oldjohnno_

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Posted 13 January 2012 - 12:04 PM

To be fair I have to admit I haven't been to the speedway for years. Last time was when I took my young bloke to see the sprintcars and we had the best night. The people were unbelievably friendly (as soon as we sat down the family next to us wanted to share their chips and scallops) and everywhere we wandered it seemed people wanted to say g'day and have a yarn. It certainly was a nice change from the sea of lebs with penis-haircuts and bad attitudes that you seem to see at the drags.
One of the racers had a breakage and an announcement was made that he needed a particular part (an axle I think) to continue. Next thing you know half the spectators rush out into the car park to pull the axles from their family cars to help out so old mate was able to keep racing. But the thing that stuck in my mind was how it seemed every second driver had big truckdriver/Elvis style sideburns...

#74 orangeLJ

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Posted 13 January 2012 - 12:35 PM

Times have changed a bit Johnno, but same as anything.

There is still a relatively friendly atmosphere compared to the drags, but the sprintcar thing has turned into a V8 supercar style of class, heaps of them think they are gods gift, those with too much money think they somehow classify for more benefits than those without etc.

Heaps of nice folk there still, heaps of toothless hillbillies and bogans too! lol

#75 _oldjohnno_

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Posted 13 January 2012 - 01:32 PM

Heaps of nice folk there still, heaps of toothless hillbillies and bogans too! lol


Wall to wall flannelette always makes me feel at home..




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