No Timing Mark on Jeep 258 Harmonic Balancer with Serpentine Belt

[Thierry]

Hi,

Had a massive oil leak that was caused by a missing seal at the Distributer.

So i pulled it, put a new seal in and just forgot to mark the Position before pulling it out.

Thought that this is no Problem as it can be adjusted.

Well then i looked for the timing mark on the harmonic balancer and there seems to be no mark.

The Motor is from a YJ and has a serpentine belt.

Before i will go and buy a new harmonic balancer i thought you might be able to give me a hint where to search.

Thank you and Greets from sunny Germany.

Thierry

[Moses Ludel]

Hi, Thierry...I'll walk you through the process of static timing your 4.2L/258 without a timing mark.  You may find the damper mark in the process, and if not, you'll be able to make a mark on the damper for TDC.  Here's what I do:

 

1)  Turn off the ignition, set the parking brake, chock the wheels, put the transmission in neutral and remove the high tension spark wire between the coil and center of the distributor cap. 

 

2)  Remove #1 cylinder's spark plug.  Consider removing the other plugs to make turning the crankshaft easier.

 

3)  Rotate the crankshaft in the normal direction of rotation, bringing the #1 piston to TDC in its cylinder.  Watch the piston with a flashlight if necessary.  If you pass TDC, rotate the crankshaft backward a quarter turn and bring it up again.  This will bring the piston to TDC with the timing chain tensioned for higher accuracy

.

4)  If you want to time the engine, make sure you came to TDC on the compression stroke (both valves closed).  You can find TDC at the top of either the compression stroke or the exhaust stroke; however, TDC for indexing the distributor rotor or timing the engine must be at the top of the compression stroke.

 

5)  Once at TDC with #1 piston, the damper mark (a single notch in the harmonic balancer or damper) should align with the aluminum timing cover's TDC mark.  There is a raised casting with "TDC" and "O" through "10" degrees or so on the timing cover.  If you cannot see these marks, clean off the timing marker on the cover.

 

6)  If you're certain the #1 piston (the cylinder at the front of the engine) is at TDC on the compression stroke, you can create a new TDC mark on the damper if necessary.  If a mark is not present, or if the mark turns up some distance from the TDC mark on the timing cover, the harmonic balancer has slipped on the crankshaft pulley.  (Another possibility is that the crankshaft pulley key is either damaged or missing.)

 

You can index the distributor's rotor to the distributor cap position for #1 cylinder while the crankshaft is at TDC for #1 piston on its compression stroke.  (If for any reason you've mixed plug wires, the firing order is 1-5-3-6-2-4 in the direction the distributor shaft and rotor rotate.)  Once you have the rotor indexed for TDC at #1 piston, you can set the initial spark advance.  If you have a timing light with built-in advance, simply dial in the degrees of advance you want, likely 4 to 6 degrees BTDC at engine idle.  Idle advance should be set with the vacuum advance hose disconnected from the distributor's vacuum advance mechanism.  Tape the hose end to prevent a vacuum leak.

 

This should do it.  You can create your own TDC mark on the pulley if you clearly know where #1 piston is setting.  A file edge can make the notch.  Yellow mechanic's paint can highlight the mark for your timing light to pick up.  If the damper has crept on the pulley (indicated by the harmonic balancer mark clearly not being where it should be on the pulley), you have a defective pulley/damper/harmonic balancer.  Consider replacing it, a loose balancer can be dangerous.

 

Moses

[Thierry]

It is alive

Still no timing mark, but i realized that i was allways 180 degrees wrong.

So now it is Running.

Greets

Thierry