Reverse Oil Pressure???
01-04-2004, 03:34 AM
#1
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Reverse Oil Pressure???
OK What the heck would cause the oil pressure to go the opposite way while building RPM's? Like my oil pressure will be at 50psi at like 3k, then I floor it in 4th gear and it goes the opposite direction, like LOWER psi 
I have an autometer electric oil pressure guage, check the connections and that's fine... This did this on my last motor too. I just barely rebuilt my motor just like I do almost every winter (new bearings, rings etc) and I just got done breaking it in and finally got a chance to get on it this weekend and I noticed that it's doing this all over again.. I can't figure out why it would be doing this...
Im going to install my stock oil pressure sender tomorrow to see if maybe the sender is bad. Has anyone else had this issue?
I have an autometer electric oil pressure guage, check the connections and that's fine... This did this on my last motor too. I just barely rebuilt my motor just like I do almost every winter (new bearings, rings etc) and I just got done breaking it in and finally got a chance to get on it this weekend and I noticed that it's doing this all over again.. I can't figure out why it would be doing this... Im going to install my stock oil pressure sender tomorrow to see if maybe the sender is bad. Has anyone else had this issue?
01-04-2004, 08:25 AM
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Re: Reverse Oil Pressure???
Originally posted by InjectedSS
This did this on my last motor too. I just barely rebuilt my motor just like I do almost every winter (new bearings, rings etc) and I just got done breaking it in
This did this on my last motor too. I just barely rebuilt my motor just like I do almost every winter (new bearings, rings etc) and I just got done breaking it in
Why on earth would you overhaul the bottom end every year
Don't trust any gage until you check it out first.
What is the clearance of the oil pump pickup to the oil pan? What is clearance with the bearings installed?
01-04-2004, 10:34 AM
#5
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3 Scenarios :
1: Pump is too close to the bottom of the pan causing it to fight for oil.
2: You didn't replace the pump and it's shot
3: You've got toasted bearings
Either way, looks like your pulling the engine again. Might want to let a reputable shop rebuild your engine. I built 2 that didn't last over a thousand miles before I plunked down $1600 for a rebuild.
-Shannon
1: Pump is too close to the bottom of the pan causing it to fight for oil.
2: You didn't replace the pump and it's shot
3: You've got toasted bearings
Either way, looks like your pulling the engine again. Might want to let a reputable shop rebuild your engine. I built 2 that didn't last over a thousand miles before I plunked down $1600 for a rebuild.
-Shannon
01-04-2004, 03:00 PM
#6
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Originally posted by NOMAD
3 Scenarios :
1: Pump is too close to the bottom of the pan causing it to fight for oil.
2: You didn't replace the pump and it's shot
3: You've got toasted bearings
Either way, looks like your pulling the engine again. Might want to let a reputable shop rebuild your engine. I built 2 that didn't last over a thousand miles before I plunked down $1600 for a rebuild.
-Shannon
3 Scenarios :
1: Pump is too close to the bottom of the pan causing it to fight for oil.
2: You didn't replace the pump and it's shot
3: You've got toasted bearings
Either way, looks like your pulling the engine again. Might want to let a reputable shop rebuild your engine. I built 2 that didn't last over a thousand miles before I plunked down $1600 for a rebuild.
-Shannon
Bearings are BRAND NEW just as they are everytime.
Don't know about the pickup though. Maybe my 15W-50 oil is too thick
Welll Im off to try the different sender today. I will let you guys know how it turns out. Hopefully it's just the sender.. If that doesn't work Im going to try thinner oil... If that doesn't work then I dunno WTF
Originally posted by slopokrodrigez
And to think I only vacuum it out every winter?
Why on earth would you overhaul the bottom end every year
And to think I only vacuum it out every winter?
Why on earth would you overhaul the bottom end every year
Besides I wanted to change ring gaps and change a few other lil things 
You guys act like it's a big deal pulling the engine out or something. With a 2hr 42min record time to remove the engine, I can't see it bothering me anytime soon 
01-04-2004, 03:29 PM
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I stand corrected, I never knew you had a bruiser. By all means, what you are doing would give a person piece of mind.
You obviously pull the engine from the top then, yes?
Have you chamfered the bearing cap hole where the oil enters from the pump? Helps prevent cavitation.
If your replacing the pump everytime, why wouldn't you check the clearance?
Are you running oil restrictors? Maybe the oil is staying up at the top too long?
How about a high volume pump with a shallow oil pan? Could that be the problem?
I won't bother you, just curious. Asking questions sometimes is the only way to learn.
You obviously pull the engine from the top then, yes?
Have you chamfered the bearing cap hole where the oil enters from the pump? Helps prevent cavitation.
If your replacing the pump everytime, why wouldn't you check the clearance?
Are you running oil restrictors? Maybe the oil is staying up at the top too long?
How about a high volume pump with a shallow oil pan? Could that be the problem?
I won't bother you, just curious. Asking questions sometimes is the only way to learn.
Last edited by slopokrodrigez; 01-04-2004 at 04:15 PM.
01-04-2004, 07:54 PM
#11
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Well I tried a STOCK oil pressure sender and it's doing the same thing 
What's weird is if Im sitting idle, and I rev the motor up to redline the oil pressure is fine, doesn't drop at all... Even if I HOLD it up to like 5k rpms it stays up just fine. BUT like I said, when I get on it, it starts to go the opposite direction 
I dunno WTF the deal is.. I guess I will try thinner oil and see how that helps...
Hey BTW Im using the LONGER M1-302 filter does anyone know if that could be causing issues as well?
What's weird is if Im sitting idle, and I rev the motor up to redline the oil pressure is fine, doesn't drop at all... Even if I HOLD it up to like 5k rpms it stays up just fine. BUT like I said, when I get on it, it starts to go the opposite direction I dunno WTF the deal is.. I guess I will try thinner oil and see how that helps...Hey BTW Im using the LONGER M1-302 filter does anyone know if that could be causing issues as well?
01-04-2004, 09:17 PM
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First thing you should do is switch to a K@N filter as the M1's are pretty restrictive, especially compared to the K@N. Also, did you replace the pressure relief spring? Get a higher pressure spring and see if the pressure still drops at prolonged high rpms. If you're seeing 50psi, you still have the stock spring in there, and it may just be getting worn, never know. Since you replace bearings and oil pump each year, I'm gonna assume the motor and the pan and pickup are all clean with no sludge blocking any oil passages. But if you still have the stock/original pickup, at least take that out and put it back in again, paying very close attention to how low it goes down into the pan. Finally, unless you set the clearance loose for 50wt oil, get that stuff out and switch to M1 0w40 or better 40wt synthetic (Redline, maybe Royal Purple).
Jason
Jason
01-04-2004, 09:44 PM
#15
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Originally posted by mebanditws6
First thing you should do is switch to a K@N filter as the M1's are pretty restrictive, especially compared to the K@N. Also, did you replace the pressure relief spring? Get a higher pressure spring and see if the pressure still drops at prolonged high rpms. If you're seeing 50psi, you still have the stock spring in there, and it may just be getting worn, never know. Since you replace bearings and oil pump each year, I'm gonna assume the motor and the pan and pickup are all clean with no sludge blocking any oil passages. But if you still have the stock/original pickup, at least take that out and put it back in again, paying very close attention to how low it goes down into the pan. Finally, unless you set the clearance loose for 50wt oil, get that stuff out and switch to M1 0w40 or better 40wt synthetic (Redline, maybe Royal Purple).
Jason
First thing you should do is switch to a K@N filter as the M1's are pretty restrictive, especially compared to the K@N. Also, did you replace the pressure relief spring? Get a higher pressure spring and see if the pressure still drops at prolonged high rpms. If you're seeing 50psi, you still have the stock spring in there, and it may just be getting worn, never know. Since you replace bearings and oil pump each year, I'm gonna assume the motor and the pan and pickup are all clean with no sludge blocking any oil passages. But if you still have the stock/original pickup, at least take that out and put it back in again, paying very close attention to how low it goes down into the pan. Finally, unless you set the clearance loose for 50wt oil, get that stuff out and switch to M1 0w40 or better 40wt synthetic (Redline, maybe Royal Purple).
Jason
It's just a stock replacement M1-55 Melling oil pump.. The pickup and EVERYTHING is BRAND NEW EVERYTIME.. I don't take ANY short cuts...
So you think the M1's are too restrictive?? Im using the friggin $10 M1 oil filter. Is that the one your thinking of?