Adjusting timing on an 80

[77crewcab]

In Clymer's it says I have to drill out the "special bolts" and remover them with an ez out then replace them with the same bolts. Is there any reason I can't install a standard style bolt like what is shown for previous years so I can adjust the timing without all the hassle? Also is there an easier way to remove those "special bolts"? My timing is on the 10 degree mark instead of the F mark. I also noticed that the timing indicator/pointer is adjustable is there a way to make sure it is in the correct position?

[DiverRay]

You can replace the "special" screws with a pan head, no problem. If you buy a "left hand" drill bit, it may run out the screws as you try to drill them.
To check the pointer, pull the #1 spark plug, turn the crank to the TDC, and then put a new pencil or a long, thin, wood dowel into the plug hole. GENTLY turn the crank back and forth, until you are sure the dowel is out as farr as it will go. You are now at TDC. Check and see if the pointer lines up.
Ray

[77crewcab]

Okay. Is TDC supposed to point at the F mark?

[mro]

TDC is at the "T" mark.

Adjust pointer to the "T" after doing what Ray said, then you can set your timing.



mro

[John]

The T mark is TDC. The F mark is where the timing should be at idle. The C mark is for adjusting the cam chain.

[webbcraft2150]

Just remember the XS engine spins "backwards" (clockwise looking at the timing plate).

[77crewcab]

Okay the T mark lines up at TDC on #1. I also checked the cam tensioner again to make sure I had done that right. I completely removed the tensioner assy. cleaned and cocked it then put back on and adjusted the tension. Hearing the audible click felt "reassuring" and now it is noticably smoother when turning the engine over by hand with the plugs removed. At the same time I checked for valve clearence. I know I have read to use only MM feeler guages and not the standard with MM equivelent but since that is all I have with me today I use the standards. On the intake side I had all but one valve with the same result of .10mm will slide freely and .13mm wont fit. I don't have a .11 or .12 but this seems to fall in spec. #4 I could only go up to .04mm so I will need to look at a new shim for it. On the exhaust side I got the following #1: .17mm, #2: .24mm, #3 and 4: between .20 and .23mm. So it seems I will also need a couple shims for the exhaust side. I haven't buttoned her up yet to try and redo the timing but I am thinking maybe the chain being out of adjustment might have had a lot to do with the problem. When using the timing light with the vacuum advance diconnected the mark should fall on the F mark correct or should it be on the 10 BTDC mark?

[TopCatGr58]

Crew,

If you look at the Clymer's page 49, it states to test the timing at idle, and it should align with the "F" mark. In step 6 it THEN states to remove and plug the vacuum advance module!

So....it looks like it is to be checked WITH the vacuum advance module connected at idle. Then disconnect and rev to 5200rpm and check for the amount of full centrifugal advance.

However, the cent. advance curve is BUILT into the 81 models, and are therefore not adjustable at all! That's why I haven't checked mine!