Wild1

Guys... did I blow it? I installed the CC306 Cam but I left the stock oil pump in... it doesn't even idle. Is it because there is little vacuum on the CC306 Cam? Does it mean the lifters aren't pumping up with the stock oil pump?

I'd really hate to open the bottom of the LT1 just to replace the stock oil pump.

shoebox

That's got nothing to do with the oil pump. It should be fine (unless you now have no oil pressure). Did you get a tune for the cam?

Injuneer

Are you sure you set the oil pump drive gear (off the back of the cam) up correctly, installed the drive shaft and intermediate shaft, and didn't crack the plastic hold down? If no oil pressure, that would be the first thing to check.

Wild1

Thank you for confirming that oil isn't the likely problem.

It is really running rough and we haven't been able to dyno tune the engine. It barely idles.

I may have to pull the front timing cover to confirm the timing.

Also, the fuel pressure is at 40. Is that low for a 383 with a CC306 cam? Maybe a stronger fuel pump or pressure regulator?

If oil isn't a problem, I'm starting a list of possible other options... which can be overwhelming. I figured the top two would be to confirm cam timing and determine if the fuel pressure is too low at 40psi.

Thank you in advance.

Injuneer

Oil's not a problem, unless you have low oil pressure, which you seem to suggest in your original post. The problem would be engine damage, not likely a rough idle. Do you have good oil pressure or not?

For fuel, you want 43.5 PSI at idle with the vacuum line off the fuel pressure regulator. GM accepts anything from 41 to 47 PSI as being within spec. When you reattach the vacuum line, with that cam, pressure should drop about 5 PSI below the "no vacuum" reading. In other words, if you had 43 PSI with no vacuum, you would see ABOUT 38 PSI with the vacuum line connected.

Pressure requirement is set by the fuel injectors, not the size of the camshaft. What size injectors are you running? Did you tell the tuner you would be running them at stock PSI?

The link in your signature is confusing, with no mention of a 383, and dated 3 years ago. Has it been tuned, by whom?

Wild1

Yes, I should update my signature... it has been a while. I survived a divorce and I was able to keep my cars. Pulling them out of storage now.

I probably should start a new thread since oil has been determined not to be the problem. Oil pressure is 40 psi cold. So, I believe that is good.

Idle is really rough at 600 rpm... barely idles then stalls out. However, I was able to get a reading of 41 psi with the vacuum line on. So, if it is about 5 psi lower connected, then that would be around 46 psi with the vacuum line disconnected. I will verify this in a new thread.

Injectors - they are the Delphi 38# injectors with 6-holes in the disks. The tuner recommended I change those out to SVO 42# injectors. I told the tuner that I have installed a Racetronix fuel pump with the additional harness that goes directly to the alternator. Unfortunately, I did not tell him that I was running them at stock PSI. Perhaps the injectors were starved? Wrong injectors? He said he didn't have the data (I recall for the offsets) for the Siemens injectors.

It was tuned in California (attempted tune no fault to the company) at Haddad Motorsports in Inglewood, Ca. I forgot the tuner's name but I may have it in an email. Always open for references in So Cal if you know a good tuner in the area. The tune was unsuccessful since we couldn't get the car to idle or run over 3000 rpm.

I have several camshafts I can swap in if that would make a difference for the 383: CC306, CC305, Isky 272/282, Stock

Signature - In the next post. I can't get into the other website for the signature edit.

Thank you.

Wild1

95 Z28 / 1LE - T56
Induction - SLP CAI, K&N dual air filters, 58mm Edelbrock TB, TB Bypass
Valvetrain - Ported & Polished Trick Flow Heads by JMS Racing Engines, Manley Undercut Valves, Comp Cams 280/288 XFI Grind, 1.6 RRs Pro Magnum, Manley Pushrods, Forged Stroker Crank, H-Beam Rods, Rod Guide Plates, Beehive Valve Springs, LT4 Composite Valve Covers
Block - Bored 0.030 Over, ARP Studded Mains & Heads, Eagle Forged 3.75" Stroked Crank, Eagle H-Beam 5.85" Rods, JE Forged Pistons with 7cc Valve Reliefs, Zero-Decked, 0.039 Felpro Head Gaskets
Fuel - Walbro 255 pump, Racetronix fuel pump harness, Delphi 6-hole #38 Injectors
Exhaust - Edelbrock Ceramic Coated TES Headers, Off Road Pipe, Ex. Insert Cone, Edelbrock Cat Back Exhaust
Ignition - Jacob's Ultra Pack Ignition, Coil, Trigger, MSD 8.5mm Plug Wires, NGK TR55 Iridium Plugs, MSD Opti-SparkDrivetrain - Hurst Short Throw Shifter, SLP Alum Driveshaft, LG Torque Arm, GM 4.10s with Eaton Posi, SLP Lightened Flywheel and Centerforce Dual-Friction Clutch Package, TWM Performance Custom A6 Leopard Shift ****
Cosmetic - Ported Hood Heat Extractors
Suspension - Hotchkis Front Springs, Welded Sub-Frame Connectors, Hotchkis Lower Control Arms, Hotchkis Strut Tower Brace, RK Sport LCA relocation brackets, Rear weight jacks by Ground-Control with Eibach 175# springs, and Spohn Adjustable Panhard Rod, Bump Steer Tie Rod Ends by Baer, 285/50R17 Goodyear D1-GS D3s, custom powder coated 17" wheels

Chimera96

OP

If I understand correctly you do have some form of tune for the motor/cam combo you have, right?

Haddad should have been able to tune it....but

you have a 58mm TB...what are your IAC counts?

likely pegged at 160 so you need to do the drill mod or crack the throttle blades open more and then clock the TPS back by elongating the 3 mounting holes on it. You need scan software to first read wtf your iac counts are before touching anything

a camed un-tuned motor will idle low and stall

a just bolted on 58mm TB will often, especially on camed motors, cause it to idle low/stall because IAC is maxed out

The tuner you noted likely wanted you to run the Ford SVO's as he is more familiar with those injectors. 30 lb would be fine for a 306 camed 383

In Orange Co. contact Tad at Tuned by Tad. he is very familiar with the LT1 platform

Wild1

Will do. Thank you. I'll also contact Tad.