~4th Gen LT1 F-body Cam Swap~

Subject:
Replacement of camshaft, pushrods, rocker arms and valve springs in the LT1, 4th Gen F-body. I have divided the tasks into sections covering cam removal, installation and spring swap. The intent is to logically guide you through the process and supply enough information that you could do this yourself. Some basic skills are assumed and that you have enough knowledge to get by on your own if some of the more boring details are not given. ;-)
This procedure was done on a 1995 Camaro. There will be some slight differences if you have an earlier car (like vent for optispark or no MAF if you have a 1993...), but the bulk of things will be the same or similar enough not to cause you problems.

I recommend that you read through the entire procedure before attempting any work. Use any information provided on this page at your own risk.


Before beginning a project such as this, you will want to gather all the things you need. Some of the items will depend on how great your modifications are. Items I used or recommend are listed below. You will also want to have some clean space set aside for all the items that you take off. Plastic bags, boxes and a marker or some way to identify items is a good idea. The area you have to set aside for removed parts should be out of the way so that the items will not be accidentally disturbed if you lay them out to be put back in order.


Consumables
Parts
Gaskets
Tools/Hardware
  • Coolant/Anti-Freeze

  • Oil and filter

  • Cam lube (a/r)

  • Thread locker - red

  • Thread sealant

  • Permatex Ultra Copper gasket sealer

  • Spray cleaner or solvent for gasket surfaces (brake cleaner works well)

  • Rags and paper towels

  • Towels or fender cover to protect the finish


    a/r = as required/needed
  • Camshaft

  • Lifters (a/r)

  • Pushrods (a/r)

  • Rocker Arms and Nuts(a/r)

  • Valve Springs

  • Valve Cap Locks (keepers)

  • Valve Caps (retainers)

  • Valve Seals (a/r)

  • Valve Spring Shims (a/r)

  • Valve Spring Locators (a/r)

  • Timing gears and chain
  • Valve cover gaskets (a/r)

  • Intake Manifold gasket set

  • Front Cover gasket set

  • Water Pump gaskets (if not incl in timing set)

  • Water Pump O-rings

  • Opti-spark O-rings

  • Oil Pan gasket (a/r)

  • Decent set of hand tools

  • Valve Spring Compressor

  • Magnetic Pick-up tool

  • Valve Spring Height Micrometer or alternate method of measuring spring height

  • Torque Wrench

  • 3 claw puller (a/r)

  • Crankshaft hub removal/installation tool

  • Optional studs or pins for lining up intake on re-install

  • Fuel pipe connector disconnect tool (3/8" and 5/16")

  • Gasket scraper

  • Three 5/16-18x4" bolts (a/r)





    • ~Getting started~


    I used my Rhino Ramps to get the front of the car up off the ground. You can use jackstands if you prefer. Never get under your car without it securely supported and wheels blocked.

    Since you are going to be crawling under the car a lot, the first thing I did was remove the air dam (8mm bolts). It is well worth removing for the elbow room.

    Next was to begin draining the radiator. Get a suitable container, remove or loosen the radiator cap and open the drain valve. Dispose of the coolant properly. I let the radiator drain and moved up to work on intake manifold removal.

    Be warned that the locking tabs that hold electrical connectors on, can be come brittle with age. If flexed too far, they will break. Use as much care as you can and maybe you won't be buying any new connector pigtails.



    ~Removing the intake manifold~


  • Remove the negative battery cable (5/16" bolt). Be sure you know the Theftloc code for your radio, if you have one.

  • Drain coolant from the radiator (if you have not already started). You might also want to remove the block drain plugs to lower the coolant level in the block, so nothing splashes on the opti when you pull the water pump. The drain plug on the RH side of the block can be a little hard to get to. The knock sensor is in the drain hole on the RH side of the block. Squeeze the electrical connector and pull to remove it from the sensor.

  • Remove intake elbow, which will involve unplugging the IAT, MAF, optispark air feed line. Remove any other intake items that are in your way. You may also want to remove the rest of the air intake plumbing toward the air filter for more working room.

  • Relieve the fuel pressure by opening the gas cap to relieve tank pressure and depressing the schrader valve, wrapping a rag around it to control fuel spillage.

  • Unclip fuel line hold down clips (one on side of the accelerator cable bracket cover and another on the LH shock tower) and disconnect the EVAP hose.

  • Release the fuel rail feeder pipe connections using a 5/16 disconnect tool for the return line (rear) and a 3/8 tool for the supply line (Lisle tool shown). Have a rag handy for fuel spillage. Sometimes, these connections are stubborn. Make sure your tool is inserted into the fitting and push the fitting inward while pushing the tool into the fitting. Then, give just a little twist while pulling the tool and fitting outward. Don't overdo it or bend the fitting sideways, because you might break the clips inside the fitting. If you do, buying the whole new fuel line may be your only option, as the fitting alone is sometimes hard to find.
    You can alternately leave this connected and lay the whole assembly out of the way if you want to (you will have to pull the fuel rail and all the injectors, though). IMO, it is easier to just disconnect the fuel lines and pull the whole intake as a unit.

  • Remove the fuel injector harnesses, noting that they are numbered by cylinder (1994-up), so you can put them back correctly. Press in on the center of the spring clip. When you press in on the clip, it makes the sides bow out. You can then pull up on the connector and it should come off.

  • Unclip all the wiring harness hold down rings so that you can lay the harness out of the way as you disconnect things.

  • Remove the cover on the accelerator cable bracket (7mm screw) and cables from the throttle body. Open the TB blades to assist in getting slack to get the cables off. The cruise cable connector needs to be pushed forward to release it from the button. If you try to just pull it off from the side, you may break it.
    The accelerator cable is attached like a bicycle brake cable that has a lead end. Open the throttle blades to relieve tension on the cable, then slide the lead end and cable out of the slot. Look carefully at how the cruise cable is mounted at the bracket and release the small locating pin on the bottom side. You can then slide both cables out toward the LH side. If you don't want to take the cables off the bracket, just remove the bracket from the manifold with cables attached (three 10 mm bolts).

  • If there is a lot of loose dirt and crud on the top of your intake, blow with compressed air or vacuum it off. You don't want dirt getting into passages when parts are removed.

  • If you want to remove the fuel rail, remove the fuel rail bolts (four 10mm bolts) on the top of the intake manifold.

  • Remove the fuel pressure regulator vacuum hose.

  • Wiggle the fuel rail with injectors connected, out of the intake manifold. Watch for o-rings that might want to get away. Lay the assembly aside. As a precaution, stop up the injector holes so you don't drop anything into them.

    Fuel rail diagram

  • Remove all the vacuum hoses from the sides of the intake. Mark and note as you need to. (ex. HVAC vacuum hose)

  • Remove the electrical connections to the optispark, EVAP, MAP and EGR solenoids, TPS, IAC and water pump temperature sensor. Lay the wiring out of the way.

  • Nuts, studs and bolts for attaching the intake to the head are 9/16".

  • Remove the serpentine belt by releasing the tensioner. A 13mm socket placed on the tensioner pulley bolt and pulled clock-wise will take tension off the belt. You will need to leave yourself room to get your socket and ratchet off, as the tensioner will return farther CCW with the belt off.

  • Remove the battery cable to the alternator and remove the alternator. All the bolt heads are 13mm and there is one nut on the long, bottom bolt that is 15mm. Be careful of the small wire attached to the bottom, back of the alternator. It does not have a lot of slack in it. Rotate the alternator up until you can get to the connector and release it.

  • Remove the alternator brackets attached to the RH front intake manifold stud. (9/16" nut)

  • Remove the EGR and the EVAP solenoids. The bolt for the EVAP solenoid (8mm) can be loosened and the slotted bracket slipped off by pulling up (my pic shows the solenoid laying on it's side).

  • Remove the EGR pipe from the RH rear of the intake manifold. (two 1/2" nuts)

  • If you still have coolant hoses on the throttle body, remove them. Protect the optispark from any residual coolant. If you have done the throttle body bypass, you're one step ahead.

  • Remove the steam pipe connection. (my pic has the throttle body bypassed)

  • It is a good idea to remove the throttle body to get it out of the way. (4-10mm bolts)

  • Remove all the intake manifold bolts and studs (9/16"), noting their location.

    Intake diagram

  • Pry up the intake as needed to break the seal to the block and heads. Don't gouge the mating surfaces.

  • Set the manifold aside for cleaning later.

  • Remove the oil pump drive assembly (13mm bolt).

    Oil pump drive diagram

    Block the intake passages and any open orifices you see in the lifter valley that you could accidentally drop something into.



    ~Removing rocker arms, pushrods and lifters~


  • Remove AIR diverter valves and hoses. (7/8" fitting)


  • Remove valve covers. (3/8" bolts)


  • Remove the rocker arm nuts (5/8"), rocker arm balls and rocker arms. If you are going to reuse any of these items, keep them in order for re-install.


  • Remove the pushrods, keeping them in order if you will reuse them. There will be some oil in the pushrods that you may wish to let drain out.

  • Remove the valve lifter guide retainer (spider) (three 1/2" bolts).

  • Remove the dual lifter guides (I just set mine in the lifter galley).

  • Remove lifters and keep in order if being reused.




    ~Disassembling the front of the engine~


  • Remove all hoses to the radiator.


  • Remove the radiator cover. (three 8mm bolts on top)

  • Disconnect and remove fan assembly. The fan assembly is hooked to the radiator side tanks and can be lifted up to unhook it and then lowered out the bottom.

  • Disconnect the transmission oil cooler lines from the radiator (if applicable). (1/2" fitting - flare nut wrench recommended) A small amount of transmission fluid will come out. I used a couple of plastic plugs I had to cork the transmission line fittings in the radiator, so that it would not drip as I removed the radiator.

  • Unplug low coolant sensor connector.

  • Release a/c condenser line from guide on bottom passenger side of radiator tank.

  • Lift up on a/c condenser to unhook it from the radiator. Remove the radiator by pulling it up out of the lower saddles. Try not to damage the fins.

  • Remove crank pulley (three 5/8" bolts). Use claw puller if needed. The 1996-97 pulley may have some threaded holes in it between the spokes and look slightly different. You can use the threaded holes and a normal balancer puller (crow foot) to pull it off.


  • Disconnect and remove coil/ICM assembly (9/16" nuts and studs). (This is optional)

  • Disconnect and remove AIR pump (three 10mm bolts).

  • Remove left bank spark plug wires from optispark. Label if needed.

  • Remove 10mm bolt holding AIR pipe and wire loom from back of AIR pump bracket.

  • Remove AIR pump bracket (two 9/16" bolts).

  • Remove the water pump (six 9/16" bolts/studs). It would not hurt to inspect the drive coupler and splines for excess wear.


  • Rotate the crankshaft so that the mark on the hub is at 12 o'clock. When this mark is straight up, one spoke of the hub will be pointed straight down. This can help you later when you need to put the hub back on and get it oriented correctly.

  • Remove vacuum/vent hoses and spark plug wires fromt the optispark (distributor). Remove optispark (three 3/8" bolts). Pull straight out.


  • Remove the hub with a normal balancer puller, trying not to disturb the position of the crankshaft (not always the easiest thing to do). Note that the LT1 hub is closed around the bolt hole. This means the end of the crank is not exposed like on a normal SBC. To use the balancer puller, you have to insert a rod or bolt of sufficent length (around 4 inches) into the crank bolt hole for the center of the puller to push against.
    The rod or bolt must be sufficently strong, so it won't bend, I have used an old, long head bolt with the threads ground down, so it will slip in/out of the hole. The last thing you want to do is jam something in the hole.
    You don't want to use the crank bolt as this can cause stress and possible stripping of the threads the bolt or crank bolt hole. As the hub comes off, the distance from the end of your rod to the center of the hub will decrease, so you need to be mindful of the hub center bottoming out on the end of your puller. Go to a longer rod, if needed.
    To aid in holding the hub in position, blocking the flywheel or carefully wedging a rod in the spokes of the hub or chaining a puller bolt to something solid can work for automatics. Manual transmission cars can be put in a high gear and parking brake on.

  • Remove or loosen the oil pan enough so that the front of it will drop down to clear the front cover lower flange. The front of the oil pan seals to the bottom of the front cover. If you don't loosen the pan, you will likely tear the oil pan gasket and have a leak later. Oil pan corner bolts are 1/2", the rail bolts are 3/8" with the transmission cooler line clip stud nut being 7/16". With most of the forward bolts removed and the back ones loosened, the pan should sufficiently drop down in the front (just don't pull on and bend the pan).


  • Remove the remaining front cover bolts. (3/8") There should be eight. Three already removed, hold the optispark and front cover on.


  • Remove the front cover assembly after lowering the front of the oil pan. You will need to pry/slip the oil pan seal off the bottom of the cover as you remove it. If you are careful, you won't tear it and it can be reused (worked for me).

  • Remove the camshaft sprocket bolts (three 1/2" bolts), slide off cam sprocket and timing chain.


  • Remove the crankshaft sprocket with a puller (this is if you are replacing the timing set). A two or three jaw puller will work. Protect the crank threads during this operation.


  • Remove the camshaft retainer bolts (two T30 Torx) and retainer.

  • The a/c condenser will have to be moved out ot fhe way. It can be done without discharging the system if you carefully/slowly swing it up and use something to mechanically brace/hold it out of the way. Remove the bolt holding the receiver/dehydrator (shiny canister looking thing) on the RH shock tower, so you can have a little more slack) I ended up balancing the LH bottom corner of the condenser on my ABS unit. That gave just enough room for the cam to slip by. You will also have to deal with the air baffle that is attached by "Christmas tree" fasteners at the sides of the condenser and just under the hood latch.

  • Use a cam holding tool or three 5/16-18x4" bolts threaded into the end of the cam to initially act as a handle (you will have to remove them later for room), to give you leverage to guide the cam out without banging it around on the cam bearings. Slowly bring the cam forward, keeping it level as possible. Turn the cam as necessary to aid in getting the lobes clear. As the cam comes out, you will be able to get more leverage. There will be just enough room to get the cam out as long as it can clear the a/c condenser.






    edited 8/6/2014

    Cam Install
    Valve Spring Swap
    Fastener Torque Matrix
    Tech Page - Component Views, How To's, Diagrams


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