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Post by lgpots on Feb 17, 2004 18:50:37 GMT -5
I'm wondering if my low oil pressure problems are solely due to worn out bearings, or is there a common problem with the oil pump as well. There's been more than once, I've started the car, and have had 0 oil pressure, and had to play around a little bit before it would come up again (restarts etc.) Seems to me a gear type pump that can't get a suction is a worn out one. Has anyone else done much with the oil pumps in the 1.2 engine, and is it sufficient to replace the inner and outer rotors, or do you need to replace the crank and balance shaft seals as one person suggested to me.
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Post by DoItSidewayz on Feb 17, 2004 19:06:47 GMT -5
the problem with the Oil pump is the shaft and housing.
The shaft has no Oil grove in it, and it does not get proper lubrication, and ends up wearing the Oil Pump housing out, as it is an aluminum housing.
Get a new housing, and new pump shaft and you will be good to go.
The Oil pump is the single reason why Justy's throw rod bearings.
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Post by JLantz on Apr 9, 2004 18:07:01 GMT -5
I looked into this at the Subaru dealer: Oil Pump Housing cover- $12.48 Oil pump housing cover seal- $3.92 Oil Pump shaft- $20.82 I'm planning on removing mine and inspecting it, replacing if necessary. I haven't seen one apart yet, but do you think the shaft could be modified with a lubrication port drilled into it to solve this problem?
By the way, I'm going to install an oil pressure gauge, I don't like being kept in the dark by the idiot lamp. What is the Justy's normal working oil pressure? I need this to know what gauge range to buy.
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Post by DoItSidewayz on Apr 9, 2004 18:54:48 GMT -5
yes the shaft can be modified. A dremel is your friend
I have an oil pressure gauge, and it runs about 46 PSI.
The stock pressure relief valve opens at 46 PSI so that's all you are going to get
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Post by Justyracer on Apr 11, 2004 15:19:16 GMT -5
im going to have a friend(that know what he is doing) to modifie the pump to get more oil pressur.
this should help alot...its on my list of to do thing for this summer.
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Post by JLantz on Apr 11, 2004 18:34:25 GMT -5
This pump was pulled from an engine that had major mechanical destruction including large holes punched through each side of the case at cyl#1 and a sheared balancer shaft. The wear on the oil pump shaft is extensive. When I pulled this pump yesterday, I wasn't clear on what components were actually wearing out so I didn't check the housing, but I bet it was toast, also. Please describe the modfications you have performed to this pump.
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Post by DoItSidewayz on Apr 11, 2004 21:47:12 GMT -5
yes the aluminum housing will be toasted. will be worn all to crap.. I don't think it is grossly expensive from subaru.
Seems like the problem with your motor is the same as everyones. the pump wears out, oil pressure goes down, and you end up wearing the rod bearings. i'm betting yours got un noticed, and it finally pitched the rod through the block.
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Post by JLantz on Apr 11, 2004 23:48:50 GMT -5
This pump isn't from my engine, I got it from one at the junk yard. I'll find out soon how bad the pump in my engine is, though. Sidewayz, you have modified the shaft before-will you explain what you did?
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Post by DoItSidewayz on Apr 11, 2004 23:52:15 GMT -5
sure...get out the dremel. and cut a slot in the shaft
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Post by Justyracer on Apr 12, 2004 8:46:04 GMT -5
for boosting oil pressur...i dont know how it can be done...its friend that is seriously into mecanic machining and top rallyracing that told me he would do it and that it should be easy...so..until its done i cant help.
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Post by DoItSidewayz on Apr 12, 2004 10:04:08 GMT -5
raising the pressure is easy too
There is a pressure relief valve, which is basically just a ball valve, with a spring behind it. At like 46 PSI the spring opens and the excess pressure is bled off.
All he's gonna do is change out the spring for a better one.
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Post by Justyracer on Apr 12, 2004 12:09:44 GMT -5
were is that valve ?
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Post by DoItSidewayz on Apr 12, 2004 14:12:27 GMT -5
i can't remember exactly. i have a feeling it sin the oil pump housing someplace.
I might go disassemble the spare block i have in the garage and see
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Post by JLantz on Apr 12, 2004 18:03:42 GMT -5
The relief valve is in the crankcase cover (oil pump housing). The price from Subaru for a new crankcase cover is $440. What about reaming out one and installing a bronze bushing? Did you replace your crankcase cover or just install a new pump shaft, sidewayz?
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Post by Justyracer on Apr 12, 2004 19:03:47 GMT -5
I have a cover that was repaired whit a bushing like that. the guy hoo sold me that engine burned a rod bearing after doing a HW style rally stages at 7.5/8 000 RPM for 15km... no wonder he burned it... but i was always consurned if it mite not be becose of that bushing ?...so i always avoid to use that cover. JLantz if you want i can check if i dont have a extra crankcove that i could sell ?
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Post by DoItSidewayz on Apr 12, 2004 23:35:15 GMT -5
dude. i know for a fact i didn't pay that much for the cover. I think it was maybe 100 bucks
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Post by JLantz on Apr 13, 2004 0:38:20 GMT -5
Thanks for the offer. I'll get back to you if I end up needing one in good original shape. I'm going to pull the one at the junk yard and explore modification options. The only concern I have with installing a bushing is the rate of expansion of the aluminum housing vs. a bronze bushing might lead to the bushing coming loose at operating temperature. Then again, I'm sure machinists deal with that sort of thing all the time. I'd really like to come up with a solid modification that would end this issue. You know the comparison of the oil pump being like a heart pumping blood through the body, this issue is like having a bad heart ready to go into cardiac arrest. If there is enough material around the shaft support, there might be a way to drill a passage that would connect the shaft to the pressure side of the pump, ensuring positive lubrication at all times. Another useful modification would be to make the relief valve adjustable without having to remove the crankcase cover or the oil pan. I've seen relief valves that are adjusted three ways: stronger spring, spacers under spring, and adjustable screw that increases the spring compression. Maybe the third option would be possible. Keep in mind I'm just brain storming, I'll look more into it when I get the cover.
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Post by PaulM on Apr 15, 2004 7:36:15 GMT -5
As long as the oil pressure stays above 20psi, you'll be fine anymore and loosing hp by increasing drag. 46psi sounds a good cold pressure, I would imagine it will drop to about 25 when hot.
Paul M
if its 46 when hot thats more than enough, in production engines obvioulsy the manufacturer will err on the side of saftey and longevity rather than performance.
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Post by DoItSidewayz on Apr 15, 2004 21:47:10 GMT -5
well. i do run heavy oil (20w50 race oil)
it runs 46 or more PSI when it's cold, no matter what RPM's
When it's hot. 46ish PSI when driving, If you let it idle the pressure drops a litle. but i think that's ebcause i'm running turbo suply lines, which effectively just dump pressure into the oil pan
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Post by Minijusty on Apr 16, 2004 1:40:24 GMT -5
That sounds healthy, the way it should be
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