I know that at 2000 RPM it should be at about 55 psi, well, it's down between 35-40 psi after the engine is warmed up. And, when its at idle speed at a stop light or whatever, its all the way down to the red line, what might be causing this?
It used to be great, right up where it used to be, but after I installed my cam, its been down really low, the cam wouldn't effect this, would it? Anyway, any ideas you may have are welcome, thanks!


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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End with 2.77:1 Gears.

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Catco 3" High-Flow Catalytic Converter, Hooker 3" Aerochamber Cat-Back System, Transgo Shift Kit, Performance Resource Chip, Accel Ignition, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET: 14.32 @ 97.7mph
(corrected for elevation)

 

I would think that is great oil pressure, especially after the engine warms up. I'm usually at 25psi at 2000rpm.

------------------
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat
2:73 GEARS
Rebuilt 700R4, with manual valve body
B&M Megashifter
Soon to be installed
Exhaust Cut-Out and different gears, either 3:73 or 3:42
"There is nothing more addicting than speed"

 

The Chiltons says it needs to be at 55 PSI at 2000 so I am juts going off that, but maybe it is ok.....

------------------
1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End with 2.77:1 Gears.

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Catco 3" High-Flow Catalytic Converter, Hooker 3" Aerochamber Cat-Back System, Transgo Shift Kit, Performance Resource Chip, Accel Ignition, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET: 14.32 @ 97.7mph
(corrected for elevation)

 

"it's down between 35-40 psi after the engine is warmed up"

I Looked at a mint IROC That was a steal! And it had the same oil pressure and my dad told me not to buy it

 

First, an SBC will make less oil pressure as it gets older, plain and simple. This is because the bearings have more "wear".

But Chevy's have very efficient oiling systems. The minimum oil pressure required per my GM Shop Manual is 7 psi @ Idle and 20 psi @ 2,000 rpm. Sounds like you are within tolerance.

But, to be sure, change the oil pressure sensor. This may help as they do become less accurate as they get older.

Lastly, the oil pressure guage on these cars are not them most accurate. Only a true oil pressure guage should be relied upon.

[This message has been edited by Glenn91L98GTA (edited July 08, 2001).]

 

Glenn is right about the oil pressure gauges... the factory treats them as "interior trim options", not as any kind of accurate instrumentation. Take one apart some time and look at how it's built; then look at how a real instrument like a Simpson 260 or something is made, I think you'll notice a slight difference.

Change the oil pressure sender though. While the gauge system doesn't have any kind of reliable absolute accuracy, any time it changes, it's cause for concern. Make sure the gauge works right. Then if it turns out that the oil pressure really has dropped that much, you know it's time to start saving up for a new short block.

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"So many Mustangs, so little time..."
ICON Motorsports

 

General rule of thumb....

You need 10psi of oil press. for every 1000rpms. So at idle its ok to get 5-6psi, as long as the guage is steady and not bouncing all over. If it does bounce, the spring in the oil pump may be wearing out. Also, listen for knocks when the engine is cold (not been started yet that day).
If you hear the slightest bit of knock, then the bearings' days are numbered.




------------------
Mike L.
It ain't pretty.......

1987 IROC Z TPI 350 A4 3.27 Borg-Warner.

Mods: 2300-2500 Stall Converter, Shift Kit(GM parts), TPI Specialties Stage 3 PROM, Modified Airbox w/ K&N's, homemade cold air, Relocated MAT sensor, Gutted MAF, 160* thermostat, Accel 8mm Wires, bypassed TB coolant, Flowmaster 3 chamber single 3" in/out muffler, 3" MAC mandrel intermediate, custom dual !cat Y-pipe. airfoil, ported plenum. !smog

http://www.MichaelLasiuta.home.att.net

**BOYCOTT LAPEER DRAGWAY**

 

To answer your orginal question, Dan: Yes, the cam can affect oil pressure. The cam bearing to cam clearance is a prime player in oil pressure. If you scratched a bearing or (not likely) bumped a bearing out of place removing the old cam or installing the new one, or the cam journals are not the correct size (again not likely), then you could adversely affect your oil pressure.

The other possibility is that it has gotten warmer outside since you changed your cam. Or, you changed oil viscosity since changing the cam. Oil diluted with gas would also drop the pressure.

------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

Okay, thanks a lot guys. I usually use Mobil 1 synthetic 10W-30 oil, if I use a different oil, will it help? Which oil, or viscosity, would you guys recomend? What does a new oil pressure sender cost?

------------------
1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End with 2.77:1 Gears.

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Catco 3" High-Flow Catalytic Converter, Hooker 3" Aerochamber Cat-Back System, Transgo Shift Kit, Performance Resource Chip, Accel Ignition, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET: 14.32 @ 97.7mph
(corrected for elevation)

 

An oil pressure sensor can be anywhere from $20-$35 depending on how much your local parts store marks them up. you will need a special socket which is around $5-$10.
Installation is very easy.

------------------
89 RS 350 TBI auto Hooker SC/LT headers Open element 3in K&N CVT protorque mini-starter

Daily driver 91 RS auto LO3 63k

New project- 89 Formula 350 WS6
383 or 400 to come!

 

Where is the sender located?

------------------
1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End with 2.77:1 Gears.

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Catco 3" High-Flow Catalytic Converter, Hooker 3" Aerochamber Cat-Back System, Transgo Shift Kit, Performance Resource Chip, Accel Ignition, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET: 14.32 @ 97.7mph
(corrected for elevation)

 

Back of the engine bay, close to the firewall, near the back of the driver side rocker cover. It is screwed into a brass pipe system that screws into the block right on the block surface where the back of the intake seals against the block. It is a fairly big, brass colored, round unit that has a one blade connector on the end of it.

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1987 GTA L98 MD8 GH3
355 '97 Vortec 4-bolt block, TRW(suck) forged pistons 10:1 CR, TFS 23*, LT4 Hot Cam, Ported plenum and intake, SLP Siam Runners, Edelbrock TES, gutted Cat, Flowmaster, K+N cone, AFPR, TB bypass, AirFoil, !AIR, !A/C, !EVAP, ARAP, 2300 stall, Hotchkis STB.

 

------------------
1986 Camaro Sports Coupe
T-tops, power hatch, third brake light
LG4 305 V8, "Damonized" Q-Jet 4bbl, K&N filter
Crane ignition kit, TH700R4 transmission
Air, pw, pl, pb, ps
Kenwood cassette, Pioneer 6x4 component front speakers
Rockford Fosgate 6x9 Punch rear speakers
Aluminum slots and Goodyear 225x60R15 Eagle HP tires