QuestionI have a 1998 Chevrolet Blazer LT 4x4 4.3l Vortec V6. The engine turns over but wont start. How do I find TDC of the #1 piston without taking the head off and actually looking at the piston? The old screwdriver in the spark plug hole trick doesnt work unfortunately! I have two grooved marks on my flywheel but no actual "0" or any numbers for that matter to indicate TDC which line is it. What number cylinder does the rotor need to be at on the distributor cap? Please Help!
AnswerHi Bill, I can't send pictures on the site so here is the text without the pictures. I hope you can figure it out, if not get a book on it.
To get #1 compression remove plug and put your finger in the hole and have someone crank the engine until you feel your finger being pushed off by the air pressure. Now line up the timing mark.
Rotate the number 1 cylinder to Top Dead Center (TDC) of the compression stroke.
Align white paint mark on the bottom stem of the distributor, and the pre-drilled indent hole in the bottom of the gear (3).
Notice: The ignition system distributor driven gear and rotor may be installed in multiple positions. In order to avoid mistakes, mark the distributor on the following components in order to ensure the same mounting position upon reassembly:
• The distributor driven gear
• The distributor shaft
• The rotor holes
Installing the driven gear 180 degrees out of alignment, or locating the rotor in the wrong holes, will cause a no-start condition. Premature engine wear or damage may result.
Notice: Installing the driven gear 180 degrees out of alignment, or locating the distributor rotor in the wrong holes, may cause a no-start condition. Premature engine wear and damage may result.
With the gear in this position, the rotor segment should be positioned as shown for a V6 engine (1) or V8 engine (2).
- The alignment will not be exact.
- If the driven gear is installed incorrectly, the dimple will be approximately 180 degrees opposite of the rotor segment when it is installed in the distributor.
Using a long screw driver, align the oil pump drive shaft to the drive tab of the distributor.
Guide the distributor into the engine. Ensure that the spark plug towers are perpendicular to the centerline of the engine.
Once the distributor is fully seated, the rotor segment should be aligned with the pointer cast into the distributor base.
- This pointer may have a 6 cast into it, indicating that the distributor is to be used on a 6 cylinder engine or a 8 cast into it, indicating that the distributor is to be used on 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 the camshaft may be off a tooth or more.
- If this is the case, repeat the procedure again in order to achieve proper alignment.
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Install the distributor mounting clamp.
Tighten
Tighten the distributor clamp bolt to 25 N·m (18 lb ft).
Install the distributor cap.
Install two NEW distributor cap screws.
Tighten
Tighten the screws to 2.4 N·m (21 lb in).
Install the electrical connector to the distributor.
Install the spark plug wires to the distributor cap. Refer to Spark Plug Wire Harness Replacement
Important: If the Malfunction Indicator lamp is turned on after installing the distributor, and a DTC P1345 is found, the distributor has been installed incorrectly.
Repeat Installation Procedure 2 for proper distributor installation.
