Models: ALL, Years: ALL

Your engine needs regular maintenance and one of the key things is the adjustment of the valves.

Firing order:  1-2-4-3
Valve clearance: 0.2mm, intake and exhaust, to be adjusted cold.
Tools needed:  0.2mm feeler gauge, screw driver, a few combination wrenches, chalk or other marking device, socket set to remove rocker covers and to turn crankshaft pulley, new gaskets or RTV silicone.

Step 1.  Remove the engine cover, all 4 rocker arm covers and the distributor cap. Find the timing mark on the crank shaft pulley and make another mark with chalk or other 180 degrees (half way around the pulley).  This mark and the timing mark are used to position the  engine properly to adjust each cylinder’s valves.

Step 2.  The piston must be at top dead center (TDC) of the compression stroke in order to adjust the valves for that cylinder.  We start with #1 cylinder.  Rotate the crankshaft with a suitable socket and ratchet until the timing mark aligns with the pointer and the distributor rotor points at the #1 spark plug wire on the distributor cap. This is important because the #1 piston will only be at TDC when the rotor is in this position. There is a mark on the distributor as shown in the drawing. If your distributor is installed properly, the rotor will be pointing at the mark

Step 3.  You now can adjust both valves for #1 cylinder. Insert the feeler gauge between the top of the valve and the rocker arm.  When the valve is adjusted properly, the feeler gauge will slide in with some resistance.  This is hard to describe but you should be able to insert it and pull it through while feeling some drag. If there’s no resistance or you can’t insert it without a lot of difficulty, the valve needs adjusting. To adjust, loosen lock nut on rocker arm and turn adjusting screw until the proper drag is felt. Hold adjusting screw and tighten lock nut. Recheck clearance, it may change after tightening nut.

Step 4.  Rotate the engine one half turn in the direction of normal rotation (the way it turns when it runs), until the chalk mark is aligned with the pointer and adjust the valves of #2 cylinder. Rotate another half turn until the timing mark is aligned again and adjust #4 cylinder’s valves, another half turn and adjust the valves for #3 cylinder.

Contributed by: Chris van Wolbeck

Remark:
The most important thing are the head gaskets. If they are defective or not installed properly the engine will be “toast” soon. The gaskets tend to deform and will then be sucked inwards. The loss of oil, even on a short highway trip, is large enough to ruin the engine due to insufficient lubrication. Unfortunately this has happened before.....
“Blue RTV” sealant is a no-no for the Pinzgauer. The stuff only makes the gaskets slick even if they are new.
In theory the carburator synchronisation has to be checked after a valve has been adjusted. Wouldn’t it be a pitty if a nice Pinzgauer engine would be ruined by neglecting such “little details”?
 

Alternate method:

This procedure requires that you remove your spark plugs to set the pistons to TDC. Note that the engine will turn easier with the plugs removed.

Time required: With practice and some good luck you can adjust your valves in under 30 minutes.

Set-up:
1. Your engine must be cold to do the valve adjustment. Consider parking your truck in a suitable location the night before you do the work. Park your truck with the front pointing down a mild slope if possible. This will help oil flow into the drain ports located on the bottom front of the cylinder heads (= less oil dripping onto your exhaust and driveway).

2. Remove the engine cover. Remove the throttle linkage from both carburetors. Remove the linkage return spring and throttle linkage from valve cover #3. Remove the four valve covers. Remove the spark plugs and wires. Keep track of your wires and plugs so you can put them back on the same cylinders you pulled them from at the end of the procedure.

3. Inspect the plugs for signs of running lean or rich. If the plugs are oily you may have a bad piston ring. Consider doing a compression test to verify the problem. Properly burning plugs are gray/tan.

TIP: Here are some good resources (with photos) for spark plug inspection:
http://www.classictruckshop.com/clubs/earlyburbs/projects/spark/plugs.htm
http://www.ngkspark.com.au/spark_plug_analysis.htm
http://www.xs4all.nl/~ekieboom/spit/plugs.html

4. Check your spark plug gap. It should be 0.6 - 0.7 mm (0.024 - 0.028 in.) for OEM plugs. If you are running civilian plugs and Pertronix go slightly wider to 0.76 mm (0.030 in.).

Valve adjustment:
5. IMPORANT -- Set your parking brake well. Consider chocking a wheel for added safety. Then place the transmission in NEUTRAL.

6. To set cylinder #1 to TDC: Place a finger from you right hand firmly over the spark plug hole for cylinder #1. Grab the fan with your left hand and rotate it clockwise. The fan belt will turn the crankshaft. For reference the driver's seat would be 3 o'clock and the passenger seat would be 9 o'clock.

TIP: Rotating the crankshaft via the fan works well when your fan belt is properly adjusted. If you have problems turning the engine see note 5 above. If you are in neutral and still having problems put a 27 mm socket on the crankshaft bolt and turn.

Keep turning the engine. Pressure during the compression stroke will push your finger off the spark plug hole. The pressure will stop and you will be at TDC. (If you go to far you will feel a vacuum as cylinder #1 goes into the ignition or power stroke.)

To set TDC on #1 precisely, watch the rocker arms on piston 4 while slowly turning the engine clockwise/counterclockwise at the point where you feel cylinder #1 is at TDC. Cylinder #4 will be exactly between the exhaust and intake strokes when piston 1 is at TDC. This is what the repair manual describes as "valve overlap".

Note: The intake valve actually starts to open 8 degrees before the exhaust valve is fully closed.  When both the intake and exhaust valves are open on #4 (both push rods are still pressing firmly against the rocker arms) they are overlapping. That is when you should check the valve gap at cylinder #1.

7. Valve adjustment. This is the same as described by Chris van Wolbeck.

8. The firing order is 1-2-4-3. So you will adjust the valves on #2 next. Place you finger over the spark plug hole in #2 turn the engine clockwise. Feel the pressure at the top of the compression stroke for #2 while watching for valve overlap on #3. Repeat step 7 and so on for cylinder 4 (watching for overlap on #1) and then cylinder 3 (watching for overlap on #2).

Wrapping-up:
9. Install your spark plugs. Add a dollop of dielectric grease to your spark plug wire boots if applicable. Attach the wires to the plugs paying attention to the firing order.

10. Inspect your valve cover gaskets. Replace if needed. Install valve covers. Attach throttle linkage, etc.

Discussion: Why does this work? We find TDC when the piston is at the very top of its compression stroke for each cylinder. Both valves are closed during compression. As air is forced out of the cylinder we feel the pressure against our finger.
It's foolproof (or as close as we can get!) since we are guaranteed not to be 180 degrees out-of-phase using this method. The exhaust stroke is 180 out-of-phase and the exhaust valve is open during this stroke. Air is forced out the valve as the piston moves up the cylinder and we do not feel pressure against out finger.

Contributed by: Christopher Scarlata