very low oil pressure, was it the nitrous?

fiveohpatrol · 10-05-2002, 07:33 PM

Well I've had my nitrous kit on the car for a couple months now and havent had a single problem with it. Except that the "100" shot only gave me 67rwhp on the dyno. So knowing this, I put the 150jets in yesterday because I was gonna go to the track today and test it out.

A buddy of mine had a full spare nitrous bottle that we decided to go play around with last night to get a feeling of the 150shot. Well it was a blast, but I think it may have done some damage to the bottom end.

Normally at operating temp, I get 35psi at idle and about 50psi at higher RPM's. Well I looked at the gage (autometer) on the way to the track and it was sitting at about 44-45psi at 2000rpm. I pulled into a parking lot and let it idle down, and the pressure went down all the way to 16psi!

Oil level is fine, and the line to the gage isn't leaking anywhere. I do also have my factory gage hooked up, and it was reading just about 1 notch lower at idle than what it was at higher RPM. But I know you can't rely on anything the factory gages are telling you, except that there is atleast a tiny bit of pressure.

Most likely that the nitrous caused this? The motor is a 70k shortblock that I re-ringed and bearing'd over the summer. The bearing clearance was right smack in the middle of their tolerences, and when the motor was first in it had great pressure. But I soon after blew a head gasket and got alot of water in the oil, which is what I think started the horrible wear of the bearings, and the nitrous just pushed it even farther.

I am removing the nitrous kit, and will probably be selling it soon. I also have no plans to go to the track anymore with this motor. So will I be ok for atleast a little while with the pressure that its got? I'll be keeping a very close eye on it to make sure it doesnt get worse.

fiveohpatrol · 10-05-2002, 07:48 PM

I forgot to add, that also lately, I've been getting alot of blue (oil) smoke on startup. When I re-ringed the motor, I was thinking about having the heads milled so I started taking them apart to go to the machine shop. Then I changed my mind, cause I just wanted to get it finished, and put the heads back together.

I think that I didnt get one of the valve stem seals set down over the head all the way, or they may have just gone bad and thats whats causing the smoke. Is there anyway that the bad seal could be causing the low oil pressure? I wouldnt think so, but just making sure.

HotRoddin · 10-05-2002, 08:14 PM

Well I'd say if the drop in oil pressure came all of a sudden then it could be related to the nitrous ... nitrous or a blower does put a pretty good pounding on bearings.
As far as the oil problem, it sounds to me like valve seals or valve guides ... usually they will smoke on start up then subside, where as rings will continue to smoke, especially on acceleration.
Thats my 2 cents worth

fiveohpatrol · 10-05-2002, 08:33 PM

Sounds like its time for some hardened bearings and a pair of GT40P's

stangsrule · 10-08-2002, 03:45 AM

Hey Drew, water in the oil can wipe out bearings pretty quick, not to mention cam, lifters and oil pump too, I know, my motor only had about 2000 miles on it and I had to replace all that crap cause of 2 blown head gaskets last year.

stangsrule · 10-08-2002, 03:47 AM

BTW you should be able to get by on that pressure for a while, you may want to go to thicker oil, 20w50 race oil would be best and try to keep it above 10 psi and idle...

fiveohpatrol · 10-08-2002, 08:35 AM

thanks Mark. Hows your car been?

Something is really odd with this. I drove it yesterday, let it get up to operating temp (and actually got into a race with a Firehawk), and the oil pressure stayed up where it used to be! I drove for another 30minutes just to see if it would go down and it didnt. I'm thinking something is wrong with the gage, or something may have gotten clogged in the poil pickup that finally dislodged.

Maybe it was just ironic that it happened the day after I sprayed it with the 150?

I'm gonna drive it alot today and see what happens.

5000cc · 10-08-2002, 11:13 AM

Why don't you try to change oil pressure sensor unit before you do anything else? It could be just that little simple thing, Mine was reading really low like yours but once I changed the sensor the problem was gone. Try that first!!

fiveohpatrol · 10-08-2002, 12:49 PM

the sending unit is not the problem, because I'm using a mechanical autometer gage. I also have the stock gage hooked up, and its been reading fine all the time. So I'm guessing my autometer is acting up?

10-05-2002, 07:33 PM	#1
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	very low oil pressure, was it the nitrous? Well I've had my nitrous kit on the car for a couple months now and havent had a single problem with it. Except that the "100" shot only gave me 67rwhp on the dyno. So knowing this, I put the 150jets in yesterday because I was gonna go to the track today and test it out. A buddy of mine had a full spare nitrous bottle that we decided to go play around with last night to get a feeling of the 150shot. Well it was a blast, but I think it may have done some damage to the bottom end. Normally at operating temp, I get 35psi at idle and about 50psi at higher RPM's. Well I looked at the gage (autometer) on the way to the track and it was sitting at about 44-45psi at 2000rpm. I pulled into a parking lot and let it idle down, and the pressure went down all the way to 16psi! Oil level is fine, and the line to the gage isn't leaking anywhere. I do also have my factory gage hooked up, and it was reading just about 1 notch lower at idle than what it was at higher RPM. But I know you can't rely on anything the factory gages are telling you, except that there is atleast a tiny bit of pressure. Most likely that the nitrous caused this? The motor is a 70k shortblock that I re-ringed and bearing'd over the summer. The bearing clearance was right smack in the middle of their tolerences, and when the motor was first in it had great pressure. But I soon after blew a head gasket and got alot of water in the oil, which is what I think started the horrible wear of the bearings, and the nitrous just pushed it even farther. I am removing the nitrous kit, and will probably be selling it soon. I also have no plans to go to the track anymore with this motor. So will I be ok for atleast a little while with the pressure that its got? I'll be keeping a very close eye on it to make sure it doesnt get worse. __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

10-05-2002, 07:48 PM	#2
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	I forgot to add, that also lately, I've been getting alot of blue (oil) smoke on startup. When I re-ringed the motor, I was thinking about having the heads milled so I started taking them apart to go to the machine shop. Then I changed my mind, cause I just wanted to get it finished, and put the heads back together. I think that I didnt get one of the valve stem seals set down over the head all the way, or they may have just gone bad and thats whats causing the smoke. Is there anyway that the bad seal could be causing the low oil pressure? I wouldnt think so, but just making sure. __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

10-05-2002, 08:33 PM	#4
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	Sounds like its time for some hardened bearings and a pair of GT40P's __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

10-08-2002, 03:45 AM	#5
stangsrule Registered Member Join Date: May 1999 Location: Indiana Posts: 512	Hey Drew, water in the oil can wipe out bearings pretty quick, not to mention cam, lifters and oil pump too, I know, my motor only had about 2000 miles on it and I had to replace all that crap cause of 2 blown head gaskets last year. __________________ 92GT Lowered with Ebiach's and Koni's, Kenny Brown subframe connectors, lower G-brace and jacking rails. BBK upper and lower control arms, polyurethane bushings all around and Ken Bell blower, ram-air, 80mm mass air, SMC Alky Injection kit, J&S Knock Gaurd, TwEECer RT and a bunch of other stuff!

10-08-2002, 03:47 AM	#6
stangsrule Registered Member Join Date: May 1999 Location: Indiana Posts: 512	BTW you should be able to get by on that pressure for a while, you may want to go to thicker oil, 20w50 race oil would be best and try to keep it above 10 psi and idle... __________________ 92GT Lowered with Ebiach's and Koni's, Kenny Brown subframe connectors, lower G-brace and jacking rails. BBK upper and lower control arms, polyurethane bushings all around and Ken Bell blower, ram-air, 80mm mass air, SMC Alky Injection kit, J&S Knock Gaurd, TwEECer RT and a bunch of other stuff!

10-05-2002, 08:14 PM	#3
HotRoddin cranky old man Join Date: Sep 2001 Location: Longview Texas Posts: 683	Well I'd say if the drop in oil pressure came all of a sudden then it could be related to the nitrous ... nitrous or a blower does put a pretty good pounding on bearings. As far as the oil problem, it sounds to me like valve seals or valve guides ... usually they will smoke on start up then subside, where as rings will continue to smoke, especially on acceleration. Thats my 2 cents worth

10-08-2002, 08:35 AM	#7
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	thanks Mark. Hows your car been? Something is really odd with this. I drove it yesterday, let it get up to operating temp (and actually got into a race with a Firehawk), and the oil pressure stayed up where it used to be! I drove for another 30minutes just to see if it would go down and it didnt. I'm thinking something is wrong with the gage, or something may have gotten clogged in the poil pickup that finally dislodged. Maybe it was just ironic that it happened the day after I sprayed it with the 150? I'm gonna drive it alot today and see what happens. __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

10-08-2002, 11:13 AM	#8
5000cc Registered Member Join Date: May 1999 Location: Hialeah,Fl,USA Posts: 57	low oil pressure Why don't you try to change oil pressure sensor unit before you do anything else? It could be just that little simple thing, Mine was reading really low like yours but once I changed the sensor the problem was gone. Try that first!! __________________ 93 Lx coupe,125 shots wet system,BBK headers,pully,ported performer intake,24 lbs,short belt,Headman x pipe,mac catback,upr blue thunder shifter,73 mm mass air,k&n panel filter,king cobra cluth, aluminum driveshaft, 4.10 gears, cobra tranny, welds 15/6 on front and 15/10 rear.

10-08-2002, 12:49 PM	#9
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	the sending unit is not the problem, because I'm using a mechanical autometer gage. I also have the stock gage hooked up, and its been reading fine all the time. So I'm guessing my autometer is acting up? __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

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