Camshaft installation

Tiny
1WARPIG1
  • MEMBER
  • 2001 DODGE TRUCK
  • 5.2L
  • V8
  • 80,000 MILES
I removed the camshaft and lost the position of the oil pump drive gear, it has a slot that the distributor sits in. How do I get it in the right groove so it is pointing to number one cylinder?
Tuesday, February 5th, 2019 AT 9:16 AM

4 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,858 POSTS
That is not critical, but if you want to turn that gear, use a long flat-blade screwdriver in that slot in the gear. I can't remember which way to rotate it, but one way the helical-cut teeth will make the gear and oil pump drive shaft lift up, then you can keep on rotating it as necessary. Be aware that sludge or carbon has built up on that shaft right below the bushing it rides on. You may find you can't get the gear and shaft to lift up, or it might only come up a little. During a total rebuild, that shaft can be tapped on from the bottom after the oil pump is removed. If that carbon buildup is bad enough, you'll actually push the bushing right out along with the shaft.

Chrysler's small block V-8s came from the factory with the tip of the ignition rotor pointing to number one cylinder when that piston was at top dead center on the compression stroke, but that doesn't mean it has to be set up that way. Typically if you're off a tooth or two, you can turn the distributor just fine to set ignition and injector timing. If you're off more than that, you'll need to move the spark plug wires on the distributor cap so they're over the rotor's tip at the right time.

There's two things to watch for when spinning the distributor. On older engines that used a vacuum advance assembly on the distributor, that must not end up close to the firewall. When the engine lifts under hard acceleration, the advance unit could be broken if it hits the firewall. You don't have to worry about that on your truck. Timing advance is handled by the Engine Computer.

The other thing to watch for regardless if you rotate the distributor or not is to place the number five and number seven spark plug wires as far apart as possible in the plastic holders they're snapped into. This is more important with high-compression race engines, but it provides an expensive lesson learned the hard way. Current flowing through a spark plug wire, (or any other wire), sets up a magnetic field around it, and that magnetic field will induce a voltage into adjacent wires. (That's how ignition coils and transformers work). With a strong ignition system, that induced voltage can be strong enough to cause a spark to occur in the spark plug hooked to that second wire. In this case, cylinder seven fires right after cylinder five fires. If a spark gets induced in the spark plug for cylinder seven, it will occur long before that piston reaches top dead center. Since cylinder seven is already filled with fuel, a spark that early can crack the piston or even cause the cylinder wall to explode. The simple way to insure this doesn't happen is to snap the spark plug wires into the holders on the far ends, and put the plug wires for cylinders one and three in the middle.

You aren't likely to damage a regular engine, but it can cause an elusive intermittent backfire. There's a better chance of this happening when doing the types of tasks you're doing where plug wires might get rerouted. This also applies to GM engines, again with cylinders five and seven. Ford uses a different numbering pattern, but mechanically there will always be two adjacent cylinders firing one right after the other. For Chrysler and GM engines, that order is 1-8-4-3-6-5-7-2. Four and three are next to each other in the firing order, but physically. Their two spark plug wires won't be near each other. Only five and seven are right next to each other physically and in firing order.
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Tuesday, February 5th, 2019 AT 5:41 PM
Tiny
KENW1
  • MECHANIC
  • 213 POSTS
Thanks for visiting 2CarPros.

You'll need to first bring the crankshaft to top dead center of the compression stroke. Removing the number one spark plug and having a helper turn the crankshaft until you feel air push against your finger in the plug hole well get you close, then line up the marks on the balancer and timing tab to top dead center.

Now you need to align the rotor to the mark in the distributor body. You can look at the bottom of the distributor shaft and get an idea of where the oil pump shaft needs to be. Using a long flat blade screwdriver you can turn the oil pump shaft so it's in proper position to engage when the distributor is dropped in on it's mark to number one. I'll post some images below along with the factory steps.

REMOVAL

CAUTION: Base ignition timing is not adjustable on any engine. Distributors do not have built in centrifugal or vacuum assisted advance. Base ignition timing and timing advance are controlled by the Power-train Control Module (PCM). Because a conventional timing light can not be used to adjust distributor position after installation, note position of distributor before removal.

1. Remove air cleaner assembly.
2. Disconnect negative cable from battery.
3. Remove distributor cap from distributor (two screws).
4. Mark the position of distributor housing in relationship to engine or dash panel. This is done to aid in installation.
5. Before distributor is removed, the number one cylinder must be brought to the Top Dead Center (TDC) firing position.
6. Attach a socket to the Crankshaft Vibration Damper mounting bolt.
7. Slowly rotate engine clockwise, as viewed from front, until indicating mark on crankshaft vibration damper is aligned to 0 degree (TDC) mark on timing chain cover.
8. The distributor rotor should now be aligned to the CYL. NO.1 alignment mark (stamped) into the camshaft position sensor. If not, rotate the crankshaft through another complete 360 degree turn. Note the position of the number one cylinder spark plug cable (on the cap) in relation to rotor. Rotor should now be aligned to this position.
9. Disconnect camshaft position sensor wiring harness from main engine wiring harness.
10. Remove distributor rotor from distributor shaft.
11. Remove distributor hold down clamp bolt and clamp. Remove distributor from vehicle.

CAUTION: Do not crank engine with distributor removed. Distributor/crankshaft relationship will be lost.

INSTALLATION
If engine has been cranked while distributor is removed, establish the relationship between distributor shaft and number one piston position as follows:

Rotate crankshaft in a clockwise direction, as viewed from front, until number one cylinder piston is at top of compression stroke (compression should be felt on finger with number one spark plug removed). Then continue to slowly rotate engine clockwise until indicating mark is aligned to 0 degree (TDC) mark on timing chain cover.

1. Clean top of cylinder block for a good seal between distributor base and block.
2. Lightly oil the rubber O-ring seal on the distributor housing.
3. Install rotor to distributor shaft.
4. Position distributor into engine to its original position. Engage tongue of distributor shaft with slot in distributor oil pump drive gear. Position rotor to the number one spark plug cable position.
5. Install distributor holddown clamp and clamp bolt. Do not tighten bolt at this time.
6. Rotate the distributor housing until rotor is aligned to CYL. NO.1 alignment mark on the camshaft position sensor.
7. Tighten clamp holddown bolt to 22.5 Nm (200 in. Lbs.) Torque.
8. Connect camshaft position sensor wiring harness to main engine harness.
9. Install distributor cap. Tighten mounting screws.
10. Refer to the following, Checking Distributor Position.

Checking Distributor Position
To verify correct distributor rotational position, the DRB scan tool must be used.

Warning: when performing the following test, the engine will be running. Be careful not to stand in line with the fan blades or fan belt. Do not wear loose clothing.

1. Connect DRB scan tool to data link connector. The data link connector is located in passenger compartment, below and to left of steering column.
2. Gain access to SET SYNC screen on DRB.
3. Follow directions on DRB screen and start engine. Bring to operating temperature (engine must be in "closed loop" mode).
4. With engine running at idle speed, the words IN RANGE should appear on screen along with 0 °. This indicates correct distributor position.
5. If a plus (+) or a minus (-) is displayed next to degree number, and/or the degree displayed is not zero, loosen but do not remove distributor holddown clamp bolt. Rotate distributor until IN RANGE appears on screen. Continue to rotate distributor until achieving as close to 0 ° as possible. After adjustment, tighten clamp bolt to 22.5 Nm (200 in. Lbs.) Torque.

The degree scale on SET SYNC screen of DRB is referring to fuel synchronization only. It is not referring to ignition timing. Because of this, do not attempt to adjust ignition timing using this method. Rotating distributor will have no effect on ignition timing. All ignition timing values are controlled by power-train control module (PCM). After testing, install air cleaner assembly.
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+1
Tuesday, February 5th, 2019 AT 5:44 PM
Tiny
1WARPIG1
  • MEMBER
  • 7 POSTS
Thank you for giving me the answer to my problem very thorough explained so I could understand I appreciate that thank you very much
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Tuesday, February 5th, 2019 AT 6:39 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,185 POSTS
Good to hear, please use 2CarPros anytime we are here to help.
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Wednesday, February 6th, 2019 AT 12:33 PM

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