checking bearing clearances
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 52
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checking bearing clearances I've had some low oil pressure problems recently and have swapped the oil pump and o-rings.
The original o-ring was pinched.
I get low oil pressure when the car gets to temp. and it does not rise past mid-high 40s at redline...and once warmed up it drops on load in the 3k rpm range about 10psi into the thirties.
I am going to drop the pan since changing oil pumps and o-rings has not helped. My intent is to buy the BRP bracket which will likely fix the problem.
Then again, that's what I thought about the O-ring and the oil pump.
How can I check to make sure the main bearings and other stuff is in shape?
The original o-ring was pinched.
I get low oil pressure when the car gets to temp. and it does not rise past mid-high 40s at redline...and once warmed up it drops on load in the 3k rpm range about 10psi into the thirties.
I am going to drop the pan since changing oil pumps and o-rings has not helped. My intent is to buy the BRP bracket which will likely fix the problem.
Then again, that's what I thought about the O-ring and the oil pump.
How can I check to make sure the main bearings and other stuff is in shape?
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 52
Likes: 0
no mechnical gauge-
oil analysis revealed excessive bearing wear and they told me to monitor my oil pressure- I put in an aeroforce gauge- they were right....
after I took it apart the first time I saw a pinched oil o-ring
replaced that, problem still there- then swapped oil pump- problem still there.
oil analysis revealed excessive bearing wear and they told me to monitor my oil pressure- I put in an aeroforce gauge- they were right....
after I took it apart the first time I saw a pinched oil o-ring
replaced that, problem still there- then swapped oil pump- problem still there.
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 52
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same exact thing- at 2-3k rpm, once the oil is above 160-170, I lose 10psi INSTANTLY at a certain RPM and it does not build back up- before the oil heats up, I can build 60 psi just fine at middle rpm range
I am trying a BRP bracket next- if that doesn't fix it, then I will be completely lost.
What is this BRP Bracket? Sounds like the air getting in the oil has already damaged the bearings. I think I have the same issue and am planing to drop the engine next week to inspect the o-ring, and inspect the rod and main bearings and the crankshaft. I only have 315 miles on it so I am praying the crankshaft is fine.
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Staging Lane
Joined: Jul 2008
Posts: 52
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it's fine at idle 36-45 depending on oil temp and which pump is in-
lead in the oil was at 25ppm for one oil change interval- unfortunately I didn't send the oil out for analysis until after 1 year. If the oil pressure dropped (high 40s) at redline- then I could only hope that the damage was abated due to the minimal amount of time spent at redline.
I do not have the equipment with which to remove the engine, so the bracket will be my last attempt to remedy this problem.
If it does not, the I will have a more serious engine problem and will be stuck with this car since I still owe plenty on it, and have no warranty.
lead in the oil was at 25ppm for one oil change interval- unfortunately I didn't send the oil out for analysis until after 1 year. If the oil pressure dropped (high 40s) at redline- then I could only hope that the damage was abated due to the minimal amount of time spent at redline.
I do not have the equipment with which to remove the engine, so the bracket will be my last attempt to remedy this problem.
If it does not, the I will have a more serious engine problem and will be stuck with this car since I still owe plenty on it, and have no warranty.
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 52
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When it's cold the pressure continues to build- once the oil gets to about 165 degrees plus, it's like a switch is hit- and at 2500-2700 the psi going up through the 40's, drops 10 psi instantly into the 30's and builds back up slowly
It never gets past the upper 40s. When the oil is cold, the pressure seems to build fine (I see 50psi by 3k rpm), but I don't go WOT since the oil is not heated yet, so I don't know how it would act in that situation.
warm idle is 40-45psi with hp pump, 35-40 psi with standard pump
It never gets past the upper 40s. When the oil is cold, the pressure seems to build fine (I see 50psi by 3k rpm), but I don't go WOT since the oil is not heated yet, so I don't know how it would act in that situation.
warm idle is 40-45psi with hp pump, 35-40 psi with standard pump
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 52
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My o-ring was pinched and warped when I pulled it- probably indicative of some motion and instability in the seal-
Hope this piece helps-
When it's cold the pressure continues to build- once the oil gets to about 165 degrees plus, it's like a switch is hit- and at 2500-2700 the psi going up through the 40's, drops 10 psi instantly into the 30's and builds back up slowly
It never gets past the upper 40s. When the oil is cold, the pressure seems to build fine (I see 50psi by 3k rpm), but I don't go WOT since the oil is not heated yet, so I don't know how it would act in that situation.
warm idle is 40-45psi with hp pump, 35-40 psi with standard pump
It never gets past the upper 40s. When the oil is cold, the pressure seems to build fine (I see 50psi by 3k rpm), but I don't go WOT since the oil is not heated yet, so I don't know how it would act in that situation.
warm idle is 40-45psi with hp pump, 35-40 psi with standard pump
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 52
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When the stock pump came off, the o-ring was inside the pump- When I put it back together, I put the o-ring on the pick up tube-
There was no problem getting the pick up into the oil pump-
There has to be some shifting inside that is causing the seal to break and let air in.
This next time, I'm going to put a new o-ring in the pump, and leave the old one on the pick up tube and then follow it with the bracket-
If the pressure still drops there are bigger issues going on-
The problem isn't the pressure at idle-
At load (WOT included) the pressure drops into the 30's and recovers very slowly but never gets higher than 40's even at 6800 rpm redline.
It just doesn't build right-
If this doesn't fix it, then I may just get rid of the car since the repairs may get out of budget and above my abilities to repair-
I just want to make sure I exhaust my possibilities.
There was no problem getting the pick up into the oil pump-
There has to be some shifting inside that is causing the seal to break and let air in.
This next time, I'm going to put a new o-ring in the pump, and leave the old one on the pick up tube and then follow it with the bracket-
If the pressure still drops there are bigger issues going on-
The problem isn't the pressure at idle-
At load (WOT included) the pressure drops into the 30's and recovers very slowly but never gets higher than 40's even at 6800 rpm redline.
It just doesn't build right-
If this doesn't fix it, then I may just get rid of the car since the repairs may get out of budget and above my abilities to repair-
I just want to make sure I exhaust my possibilities.
If you are dealing with an aluminium block, the issue is excessive bearing wear caused by the initial o-ring problem.
In short, you bearing clearances are too high and once the oil and the block get up to temp (the block grows as it heats up,) the clearances are just too large for the oil pump to keep up with.
I wish I had better news but this sounds like the most probable cause by a wide margin.
Shane
In short, you bearing clearances are too high and once the oil and the block get up to temp (the block grows as it heats up,) the clearances are just too large for the oil pump to keep up with.
I wish I had better news but this sounds like the most probable cause by a wide margin.
Shane
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 52
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Thanks- To be honest, I've been trying to convince myself otherwise, but I agree with that.
Would it be safe to assume that if the pressure is still well at idle, that I still have life in the engine-
What could potentially happen?
Rebuild would be cheaper than a new block I'm sure-
What would I be looking at parts wise?
If you have a chance, let me know- I can't afford to repair at this point and it is my only car.
Would it be safe to assume that if the pressure is still well at idle, that I still have life in the engine-
What could potentially happen?
Rebuild would be cheaper than a new block I'm sure-
What would I be looking at parts wise?
If you have a chance, let me know- I can't afford to repair at this point and it is my only car.
TECH Apprentice
Joined: Sep 2006
Posts: 328
Likes: 3
if you can pull the pan and pick up, you should be able to pull the main caps and see what the bearings/crank look like, and even change the bearing shells (in a perfect world you would want pull the engine, do a complete tear down/clean and polish or grind the crank, but when in a pinch new bearings should help quite a bit)
Thread Starter
Staging Lane
Joined: Jul 2008
Posts: 52
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I just looked up some pricing- aside from the work this doesn't seem too bad
the bolts and bearings come to about 350- that would be everything it seems I would need to buy.
I saw main caps too, but would there be any way to tell if it were necessary to replace those?
I may just feel up to this next spring- if the car can hold out.
the bolts and bearings come to about 350- that would be everything it seems I would need to buy.
I saw main caps too, but would there be any way to tell if it were necessary to replace those?
I may just feel up to this next spring- if the car can hold out.