North American Turbocoupe Organization



Cam Timing Belt Replacement and Set Up
andrewjs18 Offline
Administrator
#1
Cam Timing Belt Replacement and Set Up
By Keith Nubel & Pete Dunham

1) Before starting the belt replacement, remove the 2 accessory drive belts and the water pump pulley. Also break loose the crankshaft pulley bolt (22mm), an air gun is the easiest way. Make sure you can easily slide the pulley off the end of the crankshaft.

2) Turn the Crank Pulley so the "V" notch on the crank pulley lines up to the TC (Top Center) position on the timing indicator marks (use timing belt cover) on the #1 cylinder compression stroke. You can determine the #1 compression stroke by removing the #1 spark plug and while turning the crank in a clockwise direction, to bring the V notch into position, the piston will be forcing air out of the spark plug hole.

   

Next carefully note the position of the camshaft timing mark in relation to the three marks on the back cam belt cover (see picture below). Finally remove the distributor cap and again carefully note the exact position of the rotor and where it is pointing.

Now carefully remove the crankshaft bolt, making sure not to turn the pulley and insuring that the notch is still lined up with the "TC" mark on the front cover. Then remove the crank pulley and the front cover and loosen the timing belt tensioner bolts (2). Use a pry bar or a large screwdriver to rotate the tensioner and remove tension from the belt, then tighten one hold down bolt to hold the tensioner in that position. Do not remove the big bolt with the spring on it, only loosen it.

   

Remove the old timing belt and replace with the new one, being careful not to turn neither the cam pulley nor the aux shaft pulley. Verify that the crank is still in the TC position, that the cam pulley markings are still in the same location, and that the distributor rotor is still pointing at the spot noted above.

   

3) The object is to line up the mark on the CAM pulley with the center of the three marks on the back cam belt cover (see above), or alternately, line up the Cam Pulley bolt, Cam Pulley timing mark, and the Auxiliary Pulley Bolt (see #4, below) . Now release the tensioner to place tension on the belt. Inspect to see that nothing moved, not the crank or the cam. Something often moves. Sometimes it’s the crank. More often it’s the cam. If anything moved, you must do it again. Figure out what moved and how much. Then start by that amount, in the opposite direction. The aim is to get it to move INTO the correct position when the tensioner is released.  Once you get this to happen and get the tensioner locked down, then rotate the crank two revolutions clockwise with a breaker bar. Put everything back in alignment as in #2 and #3 above. Does both the cam and the crank line up with their respective marks? If yes, the worst is over and you can reassemble the other parts

If you don’t have the rear cam cover or the three marks are broken off, you can use the method described in #4, below, to align the cam pulley. All the checks and rotating the engine when through and rechecking must be done to assure proper cam timing

4) The alternative method is to turn the cam pulley so that the timing indicator is pointing at approximately the 5 o'clock position. Looking down from over the top of the Cam Pulley you want to "rifle site" the Cam Pulley bolt, timing mark, and Auxiliary Pulley bolt. All three should line up in a straight line.

   

5) Take a piece of string and go from the centerline of each bolt. Turn the Cam Pulley until the timing indicator lines up, under the string, in a straight line with the two bolt centerlines. This should put the Cam Pulley keyway in the 6 o'clock position. Since the bolt is torqued down you won’t be able see the keyway. (See drawing above). Loosen the two bolts that hold the belt tensioner in position and pry the tensioner to the "untensioned" position, tighten the smaller bolt to hold it untensioned. Remove the old belt.

6) Remove the distributor cap and line up the rotor with the # 1 cylinder terminal on the cap (as if the cap was on the distributor).

7) Reinstall the timing belt; slowly release the tensioner to put tension on the belt. Make sure nothing moved.  Rotate the crank two turns and see of all the marks line up. Tighten the tensioner bolts and install all other parts.

8) After you finish reinstalling all other components, set your base ignition timing to 10*, spout connector out. Replace spout. You should be good to go and ready for launch.

9. If you need help with the ignition timing read on:

A. By hand, set the crank to the "TC" mark, on the #1 cylinder compression stroke, just like doing the cam timing. Make sure the cam pulley mark is pointed to the center mark on the back cover.

   

B. Check the position of your distributor compared to the picture above. Note the position of the #1 plug terminal. Now remove the distributor cap. The rotor should point about at #1 plug terminal. If it is very close then loosen the distributor hold down bolt, hook up a timing light and skip to “H” below and finish timing the engine. If the rotor does not point towards #1 plug terminal, then go to “C”

C. Remove the distributor hold down bolt so you can lift the distributor out of the hole far enough to be able to turn the distributor shaft.

D. Look at the picture I attached. See the spark plug wire I put a white mark on. This is number 1 cylinder plug wire and what it fits onto is #1 plug terminal. Note it's position on the distributor and also the bolt on the upper intake manifold that I colored white. Take the distributor out of the hole and on the side of the distributor, just below the cap, mark where the #1 plug terminal is. Now take the cap off the distributor

E. You are going to put the distributor back in the hole. Look at the picture again. See that #1 plug wire lies under an imaginary line drawn between the center terminal (where the coil wire goes) and the white bolt on the upper intake. Look further down and you will see that the TFI module that mounts to the distributor also points roughly at the white bolt. This is the relation ship we want once the distributor is fully seated back in the hole.

F. The distributor shaft is going to turn a little as it drops down the hold and engages the gear on the auxillary shaft. To compensate, we start by turning the rotor a little away from the desired position. As it drops the rotor button need to turn so that it is pointing where #1 plug terminal would be if the cap were on the distributor. Also make sure the TFI is pointing roughly at the white bolt, as should be the rotor. The important thing is that the rotor end up pointing at where #1 plug terminal is. Where the TFI points is secondary.

G. Once you got it in correctly, put the hold down clamp and bolt back in place. Tighten it just enough so the distributor can still be turned. Put the cap back on and get the engine otherwise ready to be started.

H. Put a timing light on it before starting so you can see where the timing is, while cranking it. Remember to remove the spout connector while timing it.

           

The spout is a small plug that hangs down by 2 wires from the TFI wiring harness and inside the end of it is a little plug that pulls out.  It can be hard to see this plug, let alone get to it. The easiest approach to removal is to reach down beside and under the distributor and TFI to feel for this small square plug hanging freely.  With one hand, pull the plug and wire assembly upwards in the opening next to the distributor (note: it will not come up much farther than the bottom of the distributor but at least you will be able to see it).  While holding it in the upright position, take a pair of pliers and gently grab the piece that is inserted in the plug and pull it out.   This spout/plug must be removed while setting the timing and replace when done.

I. When ready, have someone crank the engine while watching the timing marks. Depending on where the marks are, rotate the distributor (don't take it out of the hole, just rotate it) until the timing marks line up with 10* advance (above the TD mark). When it's timed, tighten the hold down bolt, recheck it then replace the spout plug.  

   
Reply





Users browsing this thread:
1 Guest(s)



Theme © iAndrew 2018 - Software MyBB