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Post by deegore on Mar 26, 2017 20:38:46 GMT -5
I had a machine shop rebuild the motor about 2 years ago. A few months later I installed an oil pressure gauge. When it's cold I get 48psi while driving. When it's fully warmed up, it hits 28psi at 3000rpm. The problem is at 4000rpm it's still at 28psi. Also, it idles at about 4psi. The numbers haven't changed since. I read the other day that there should be 10psi for every 1000rpm. Should I be worried? The shop that did the rebuild said they put in a new oil pump and put a bushing in the pump cover. I'm thinking I will pull the oil pan and make sure the strainer is clear and secure, then start checking clearances on the pump and bearings. I've never been inside the engine more than to adjust valves, so I appreciate any ideas or advice.
I don't know if it makes a difference but my distributor leaks quite a bit of oil. About a quart every 2000 miles. I did a compression test a couple days ago. Cylinder#1=183psi, #2=185psi, #3=188 psi.
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Post by madmatt on Mar 28, 2017 9:20:49 GMT -5
What can we say other then... "Welcome to the nightmare!" Those numbers aren't bad for a rebuilt stock motor... They are the sort of numbers I used to get on rebuilds, and what we typically see posted here. If you're "10 lbs per 1000 rpm" came from one of my posts, that's old racing thinking... but it translates well. Good clean oil, and steady state driving and it will last for a while (most of us don't go down the road at more then 3500 rpm for long). But think about how many Justies there were in the wreck yards in 1998 with holes in the block... This is the weak aspect of an otherwise amazing little motor. You have 2 options. Live with it. Upgrade the oiling system Upgrades include adding a cooler to keep the oil temps down at least... this won't do anything for pressure, but if you are climbing hills, it's probably a good idea. (Armegeadous and others have had good success with street cars running forever!) There are 3 options for increasing oil flow. spin the pump faster (recently done by Jasin seen here subarujusty.proboards.com/thread/6419/justy-funcar)Make the pump bigger (done a long time ago by Justyjuggler, and more recently by kcswimrac as seen here in his epic build... subarujusty.proboards.com/thread/5515/subaru-justy-performance-engine-build?page=3)Or dump the pump and get a bigger one... my approach. Mine is not user friendly and has been a ton of work, leaks oil out the pan since it back drains... but oooh isn't it sexy! subarujusty.proboards.com/thread/2915/orange-rally-justy-returns?page=7
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Post by deegore on Mar 28, 2017 22:10:49 GMT -5
Thanks Matt, that's good news. Sort of. At least I don't have to tear the engine apart looking for a problem that's not there. I drive allot at 4000rpm, so I'll probably try to up the flow. Jasin's smaller sprocket idea looks like something I might be able to attempt. I agree, your dry sump setup is very sexy.
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Post by jasin on Mar 30, 2017 12:12:11 GMT -5
Im satisfied of my solution, but it was a ton od work as well. It was quite difficult to build a smaller sprocket and it was quite hard to pit everything together, as there is not a lot of space, when engine is in the car. I would consider to put engine outside if do it again. Anyway you have to have a realy good specialist - miller to build a smaller sprocket.
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