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Location: Ballarat
Registered: January 2005
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18RG oil pressure issue.
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Fri, 07 January 2005 02:10
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Hey guys, got another issue i need help with.
I've rebuilt an 18RG engine with the Yamaha twin cam heads and fitted it to my RA28 Celica. The issue is that the oil pressure drops to nothing at an idle of 800 rpm. it's got a high flow pump and all of the crankcase, rocker cover breathers are correctly installed. An ideas as to what's causing the issue? this is the second rebuild of this engine(as i didn't fit new main bearings on the first rebuild ) an i made sure there was no issues with the oil pump. Any common problems i should know of? The oil pressure seems to be fine on anything above idle and i used an original Toyota factory manual for the 18RG when rebuilding. The timing chains, bearings and rings are all new and the bores have been honed. Hope someone can help
Cheers
Stevie K
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Location: brisvegas
Registered: August 2004
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 04:49
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i know for a fact that it's supposed to be idle at 950-1000rpm.. maybe you should change the oil your using..
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Location: Ballarat
Registered: January 2005
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 05:03
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Your right there, but that doesn't seem to resolve the issue. Also the oil is the highest density i could find (can't tell you off the bat what that is ). seems to be only at low idle and that included when i upped the RPM to 1200 RPM. Strange, because it's pumpin heaps of pressure as soon as i put my foot on the gas. This baby goes like a Mother and revs to 6000 RPM without breaking a sweat (extractors, solex carbs and ramflow filters - makes it sound like a jet sucking air ). Just this one little problem that's got me beat. I'm hoping i can find an "expert" to help me out. Thanks for the quick thinking though, it's the little things that can be missed.
Stevie K.
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Location: Canberra
Registered: December 2002
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 05:05
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yup wind the idle up and check again. Most likley is the pump being worn if so i have one that is in ok nick just pm me.
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Location: brisvegas
Registered: August 2004
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 05:07
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befor the rebuild on mine it used to crack 80psi on cold starts, thats just with GTX2 20w50..then once warm dropped to 60-65psi..dunno what it is now..i got rid of that gauge...it just goes between the 2 lines on the stock gauge!
hope you find out what it is..these arn't cheap to rebuild!
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Location: nth ringwood, Victoria
Registered: August 2002
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 09:31
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there is a bolt that goes near the top chain oil squirter have you put that in also these engines are pron to blow the tiny welsh plugs from the back of the cams check that also .when we checked the top squirter to see we found a bolt missing thats why the oil pressure could be low ,you have to check it running thou it will spray a bit of oil all over the place ,but still you can see if you have left something out
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Location: Ballarat
Registered: January 2005
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 13:22
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There is no spoon.....
I mean oil leak! . I have also worked off the factory manual when putting this engine back together so i know it's done right. Just to recap: there is no oil pressure at idle (anywhere from 800-1200 rpm tested) but as soon as you put your foot on the gas it jumps to 40-60 psi. I have tried this engine with it's original oil pump and a new oil pump so i know the problems not there. The crankcase breather is properly hooked up through the correct valve to the inlet manifold. The valve cover breather is hooked up to the ramflow air filters. All gaskets, bearings, timing chains, valve springs and rings are no more than 1500 k's old, and the engine goes like shit off a shovel! This puppy will happily pull past the 6500 RPM mark if you let it! I am using a high density oil so that can't be the problem, and the oil and filter were replaced 2 weeks ago. The problem seems to be that the pressure in the crank case does not build up until you put your foot on the gas... If there is anything simple i've missed, don't hesitate to add to this topic, but so you know my background, i'm 35 years old and this will be the 17th toyota that i have rebuilt since i was 15, so i kinda know my way around engines, transmissions, whatever. This problem just has me beat and i'm sure there is someone out there in the big wide world who will know the answer, so post away!
Cheers
Stevie K
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Location: tallahassee FL usOFa
Registered: May 2002
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 14:20
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gauge, and/or relief valve and/or pump.
i don't care at all about the breather or timing chain or valve springs or rings or bore condition.
CelicaRA45 has engine specific knowledge - i have none.
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Location: nth ringwood, Victoria
Registered: August 2002
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 21:46
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are you going by the guage in the car or have you put a mechanical oil pressure guage into the block and are coming up no oil pressure on idle
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Location: On your mum!
Registered: May 2002
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Location: Ballarat
Registered: January 2005
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 22:19
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I'm going by an aftermarket oil pressure gauge mounted inside the car. Also the oil light comes on when there is no pressure reading on the gauge. This engine was from a wreaked toyota corona and i had not seen it running before the rebuild. The quetions i'm getting now are a lot more specific and are going to help with the issue. I can tell you all one thing, I have rebuilt 3 18RC engines and never had this problem before. Now... cam tunnel bearings were not replaced, as the engine was rebuilt because i was told it was smokey, so it got rings, bearings, timing chains and a hone. One pump was from the original motor with the spacer fitted, this was dismanteled and reassembled. Then a new oil pump was primed and fitted on the second go at the rebuild.Welch plugs usually stop water from getting out and the 2 half moon plugs at the back of the cams would create a shit storm of oil flowing up the windscreen of the car if they were misssing so i'm pretty sure i would notice. No changes were made to the crank when fitted, the dizzy is standard and everything else went back where it should. The only thing is that 19mm plug behind the timing case. I am sure i didn't remove it an i work in a "clean room" enviroment, with stainless steel benches wiped down and floors cleaned before i start a project, so i know i didn't "forget" anything. Still, i'll pull the timing case off and have a look. Thanks!!!
Stevie K
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Location: nth ringwood, Victoria
Registered: August 2002
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 22:26
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steve hello im saying there are 2 welsh plugs that go into the back of the cam shafts if they have poped out it halfs your OIL pressure the only way to see THIS is to take the ROCKER off and START the motor with leads connected to see if that is your PROBLEM
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Location: Ballarat
Registered: January 2005
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 22:36
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Cool!
That makes a lot more sense, i'll have a look this morning and let you know, but as to my reply "i work in a "clean room" enviroment, with stainless steel benches wiped down and floors cleaned before i start a project, so i know i didn't "forget" anything".
Still you never do know....
Thanks Again
Stevie K
BTW
Are you saying that all oil pressure would be affected or only that at idle?
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Location: nth ringwood, Victoria
Registered: August 2002
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Re: 18RG oil pressure issue.
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Fri, 07 January 2005 22:42
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mainly on idle also check the frt near the oil squirter sometimes people for get to put a bolt in its place .the welsh plugs can pop if there is 2 much oil pressure they will be sitting near the oil return holes in the head
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Location: townsville NQLD
Registered: February 2004
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Location: Adelaide
Registered: June 2003
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Re: 18RG oil pressure issue.
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Sun, 09 January 2005 07:09
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Yeah, check everything that CelicaRA45 has said. They are the most likely things.
My 18rc (HM 5 Star recon 50,000km ago) loses oil pressure to the head anywhere below 900 RPM (moved oil pressure sender to head). I reckon during the rebuild they remachined everything and them didn't use undersize bearings, so it leaks like a bitch inside the engine.
In hot weather when it gets a beating (temp reaches 1/2 way mark) it loses oil pressure to the head then too but below 1500 RPM.
I am glad this engine came with the car, if I'd paid for it I would be pissed, the work done was really, really SHIT.
Brett, you'd be right about the dizzy not running the oil pump, it is the little dummy shaft that does it.
Oil delivery is kinda important so make sure you check very thoroughly the cam welsch plugs and the little bolt/oil squirter just under the top timing damper on the head.
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