Oil pressure dropping under load after oil change...
07-20-2011, 01:29 AM
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Oil pressure dropping under load after oil change... I just started having (or at least noticing this issue yesterday) I changed the oil and took the car for a ride. I noticed the oil pressure was very low (under 10psi at idle) but the engine made no noise and while driving the oil would shoot up to about 40psi and NOT go higher than that. Whenever Id put any load (light or heavy) at just about any RPM the oil would dip down about 5-10 psi depending on how much load I put on it and then shoot back up. So I let it cool over night and this morning the oil pressure was back up around 40 at idle and would shoot to around 60 or so by 2k rpm and then when it was fully warmed up it would settle around 15-20psi at idle..and when driving it would do the same dipping. Engine is built, has around 5k miles on it and im using an SLP oil pump with the high pressure spring for the turbo. I checked the old filter and the oil isn't really even that dirty. There is absolutely no metallic "dust" in the filter. I pop the hood and cannot hear anything out of the ordinary except for maybe a slight tick thats always been there even before the engine was built. Any ideas?
07-20-2011, 01:36 AM
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Ok I just checked the old oil container and there does seem to be slight gold swirl. Spun or worn bearings? This is the 3rd oil change. Another thing I noticed which is strange is the oil level seems higher than normal..I had the front of the car up in the air(I usually drain it with the passenger side up in the air) but its above the about a 1/4" above the normal range.
Last edited by Snyper; 07-20-2011 at 02:06 AM.
07-20-2011, 01:14 PM
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I think I might of left too much of the old oil in. I drained some of the new oil to check and its 100% clean. Cut the old filter open and it looks clean. The swirl is only noticable if I move the old oil around..and even then I need a light to see it.
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07-20-2011, 03:28 PM
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Rev car in nuetral and hold it at about 5krpms for.a few seconds and see wut the oil pressure does, if the presure is only drpping under a load while driving im gonna say ur main bearings are shot or ur low on oil, even if u have tiny specs of bearing material in the pleads of the filter, this means ur bearings are up to no good, i wouldnt continue to drive until u fuind the problem
07-21-2011, 10:34 AM
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What are you using for a gauge? Electrical or mechanical?
I would confirm the oil pressure is doing what you are describing with a mechanical gauge if it isn't already.
Sounds like it could be a grounding issue with the gauge, or the sender taking a **** and being affected by heat
My 2cents
I would confirm the oil pressure is doing what you are describing with a mechanical gauge if it isn't already.
Sounds like it could be a grounding issue with the gauge, or the sender taking a **** and being affected by heat
My 2cents
07-24-2011, 12:35 AM
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I'm having all the same issues..except mine did it in between oil changes back last month. I had 40 lbs of oil pressure or more at all times, then after a hard run started getting 15 to 20 lbs at idle, still climbs above 60 through the R's. Under heavy load around 5k she loses about 10lbs all the sudden. Just started on dropping my cradle today, Monday I should have some answers. I'm expecting bearings to have wear even though everyone keeps telling me the material I'm finding isn't "bearing material". Also going to check my end play on the crank before taking the balancer off.
I'll post up what I find.
I'll post up what I find.
07-24-2011, 03:07 AM
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I just pulled the filter (that has 6 miles on it) and replaced it thinking it might be the filter..started it up for about 30 seconds and the oil pressure was at 50 upon start up but when I revved the engine it only went up about 6 psi...so I checked the brand new filter and there was even MORE gold swirl in the new filter so a bearing is either spun or wearing down rapidly. On another note, im parting the entire car out and buying a C6 Z06. I need a 9 second car with AC this time around. Once I pull the engine im going to bring it to the builder and he will (if possible) fix it for parts only.
07-24-2011, 04:09 AM
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I just pulled the filter (that has 6 miles on it) and replaced it thinking it might be the filter..started it up for about 30 seconds and the oil pressure was at 50 upon start up but when I revved the engine it only went up about 6 psi...so I checked the brand new filter and there was even MORE gold swirl in the new filter so a bearing is either spun or wearing down rapidly. On another note, im parting the entire car out and buying a C6 Z06. I need a 9 second car with AC this time around. Once I pull the engine im going to bring it to the builder and he will (if possible) fix it for parts only.
07-25-2011, 06:47 PM
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No endplay on the crank, got the cradle down and out of the way just before quitting for the day. Pulled the oil filter and this one after 500 miles of use has larger flakes than the last filter that ran 3000 miles. Some are gold, some are silver, none are magnetic. Biggest is about the size of the zero on your keyboard. Will have the oil pan down tomorrow, looking at whats in the pan and what the mains look like.
07-25-2011, 11:53 PM
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bummer about parting out the car and the engine woes. With some more ingenuity you could make the a/c work, keep the car cool, and everything else too.... but packaging is always the issue with conversions. Making a/c and a turbo setups jive in swaps is tough.
07-26-2011, 04:55 PM
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Well snyper, hope you find something different than what I did today but I'd bet it's bearings with the gold coloration. Here's what I found under the #3 main cap. This was the worst of the three I pulled.
Not what you expect to see at 5k miles, looks like it's time to find a new machine shop because they definitely didn't get the crank right. On the last two pictures you can see little specks where material has came off the bearings, hence all those little flakes in the filter which supposedly was NOT "bearing material". There's about three or four grooves that you can get your fingernail in and can also see bronze in the groove. Thank God I bought H series instead of something cheap, had it been a regular bearing it may not have took the beating so well and I'd been looking for another block.
Anyway, I'm on to pulling the motor tomorrow and get it back on a stand. So much for the summer time and a vette. Maybe it'll be back together before winter.
Not what you expect to see at 5k miles, looks like it's time to find a new machine shop because they definitely didn't get the crank right. On the last two pictures you can see little specks where material has came off the bearings, hence all those little flakes in the filter which supposedly was NOT "bearing material". There's about three or four grooves that you can get your fingernail in and can also see bronze in the groove. Thank God I bought H series instead of something cheap, had it been a regular bearing it may not have took the beating so well and I'd been looking for another block.
Anyway, I'm on to pulling the motor tomorrow and get it back on a stand. So much for the summer time and a vette. Maybe it'll be back together before winter.