96 vortec 5.7 timing questions

[tommie]

i have a 96 1500 with a vortec 5.7 that i got disasembled in pieces. i have it back together now, and it is running. My question is how do I adjust the distributor timing? it still has the old style distributor hold down and nothing was marked when it was disasembled.

please help...

[bikerbomber]

Hey, figured I'd answer your question! The timing for your year and model of engine state "Cannot be adjusted; Electronically controlled" So the best thing I believe you can do is to find TDC the old fashoned way, set your first spark on that and let the cpu do the rest.

An earlier year for that same engine states TDC as the first spark point so you can't go too wrong.

Good luck and let us know how it goes!

[bwood]

the timing can be adjusted but not in the traditional manner and not for performane. On my 98 305 I pulled the dist for an intake gasket job and while putting the dist back in, the tabs that hold the cap on broke. I found a used one from a GM dealer and installed it. I ended up taking it to another GM dealer to have it set because no matter what i did the light came on. Come to find out, the used deal was for a V6. The computer will only adjust it so much. The tech told me that the dist has to be in at +/- 2 degrees from 0 for the light not to come on. It can only be checked with a scanner designed for it. I know this is kind of random but search this forum, there are some more detailed posts.

[robin58]

From ALLDATA:

Distributor: Adjustments
Timing Adjustment
NOTICE: The distributor is located in a fixed, non-adjustable position. No attempt should be made to adjust the engine base timing by rotating the
distributor. Attempting to do so may result in engine cross-fire and mis-fire conditions.
The distributor ignition system has no provision for timing adjustment. The base timing is preset when the engine is manufactured and no adjustment is
possible.
NOTICE: If the distributor is removed from the engine, It can be re-installed using "procedure A" as long as the crankshaft has not rotated from its
Initial position. if the intake manifold, cylinder head, crankshaft, camshaft, timing gear or complete engine was removed or replaced, "procedure B"
must be followed to correctly install the distributor. A Diagnostic Trouble Code (DTC) code may also indicate an Incorrectly installed distributor and
engine or distributor damage may occur. Procedure B must then be used.

Procedure A:

Distributor: Adjustments
Procedure A

Remove or Disconnect
^ Make sure the ignition switch is "OFF."
1. Spark plug and coil leads from the distributor cap.
2. Three wire hail effect switch plug from the base of the distributor.
3. Two screws holding the distributor cap to the housing.
4. Distributor cap.
A. Use a grease pencil to note the position of the rotor segment in relation to the distributor housing. Identify the mark with a 1.
B. The distributor housing and intake manifold should also be marked with a grease pencil for proper alignment when reinstalling.
5. Mounting clamp hold down bolt.
6. Distributor.
^ As the distributor is being removed from the engine, you will notice the rotor move in a counter-clockwise direction, 42°. This will appear as
slightly more than one clock position. Noting the position of the rotor segment, by placing a second mark on the base of the distributor, will
aid in achieving proper rotor alignment during distributor installation. Be sure to identify the second mark on the base with the number 2.
Install or Connect
A. If the original distributor is to be replaced, rather than repaired, remove the new distributor cap. Using a grease pencil, place two marks on the
new distributor housing in the same location as the two marks on the original housing.
B. When installing the distributor, align the rotor segment with the number 2 mark on the base of the distributor. Guide the distributor into place,
making sure the grease pencil marks on the distributor housing and the intake manifold are in line. As the the distributor is being installed,
you will notice the rotor will move in a clockwise direction, 42°. ONCE THE DISTRIBUT0R IS COMPLETELY SEATED, the rotor
segment should be aligned with the number 1 mark on the base. If the rotor segment is not aligned with the number 1 mark, the gear teeth of
the distributor and camshaft have meshed one or more teeth out of time. To correct this condition, remove the distributor and re-install it
following the procedure at step B.
1. Distributor cap and mounting screws. Do not overtighten the screws as the boss may strip.
2. Distributor mounting clamp and tighten to proper torque.
Tighten
^ Distributor clamp and bolt to 27 Nm (20 lbs. ft.)
^ Distributor cap screws to 4.5-5.0 Nm (40-45 lbs. in.)
3. Three wire hall effect switch connector to base of the distributor.
4. Spark plug and coil leads to the distributor cap.
^ If a check engine light is illuminated after installing the distributor and a DTC P1345 is found, the distributor has been installed incorrectly.
You now must refer to procedure; B or proper distributor installation.

Procedure B:

Distributor: Adjustments

Procedure B
Remove or Disconnect
^ Make sure the ignition switch is "OFF."
^ Bring the engine up to Top Dead Center (TDC) of cylinder number 1. Make sure it is on the compression stroke.
A. Remove the distributor cap screws and cap to expose the rotor.
B. Align the pre-drilled indent hole in the distributor driven gear with the white painted alignment line on the lower portion of the shaft housing.
The rotor segment should point to the cap hold area as shown in the illustration.
C. Using a long screw driver, align the oil pump drive shaft in the engine in the mating drive tab in the distributor.
D. Guide the distributor into place, making sure the the spark plug towers are perpendicular to the center line of the engine.
E. ONCE The DISTRIBUTOR IS FULLY SEATED, the rotor segment should be aligned with the pointer cast into the distributor base. This
pointer will have a "8" cast into it, indicating the distributor is to be used in a 8 cylinder engine. if the rotor segment does not come within a
few degrees of the pointer, the gear mesh between the distributor and camshaft may be off a tooth or more. If this is the case, repeat the
procedure again to achieve proper alignment.
Install or Connect
1. Cap and mounting screws. Do not overtighten as the boss may strip.
2. Distributor mounting clamp and tighten to proper torque.
Tighten
^ Distributor clamp and bolt to 27 Nm (20 lbs. ft.)
^ Distributor cap screws to 4.5-5.0 Nm (40-45 lbs. in.)
3. Three wire hall effect switch plug to base of distributor.
4. Spark plug and coil leads to the distributor cap.
^ If a check engine light is illuminated after installing the distributor and a DTC P1345 is found, the distributor has been installed incorrectly.

[tommie]

thanks for the help guys, its kind of weird they did it this way......

[paaw]

did you put this in you 70 swb, is how hard was it, do you have any pics

[tommie]

no it is in a 96' i nee to update my profile, i don't have the 70 any more, sad days.... i only have a 90' x cab

[edman87]

Abaove posted is correct.
Must be set with a scanner, reading the cam retard I think. Rev engine above 1000 and let it set back to idle, look at reading. Move dist and repeat until it is wothin +2 and -2 degrees.
It took me some research to figure this out on my 98 a couple years ago, my dist gear was worn and comp could not compensate enough to make up for it.