Every where I read about setting the timing on my 98 GMC 5.7 vortec says to set the cam % to 0 but my scan tool has no entry for the can timing.
I rebuilt the engine it has a crank sensor but nothing for the cam.
Can some one hit me with the appropriate stick so it clicks in my head.

Thanks A.J.

 

The only way you can adjust cam timing in your engine is mechanically, with an adjustable cam sprocket. Are you talking about cam timing, or ignition timing?

 

ignition timing

 

I am not sure exactly what you are trying to do. There are 2 timings (2 main ones you would deal with), cam timing, and ignition timing. They are not related to eachother (unless you look at the distributor running off of tge cam gear), and have a different effect on your engine. The ignition timing is when your spark plug fires in relation to the degrees of the crankshaft. The cam timing is when the valves open up in relation to the crankshaft. What exactly are you trying to do?

 

I am trying to verify or set the ignition timing on a 98 GMC 1500 with a 5.7 vortec transplanted from a 2500 pickup.
There are no timing markings on the timing chain cover (that I can find) so there must be another way to set the timing on this engine as it has a distributor that can be adjusted.

I hope that clears it up.

 

on that engine there should be a kind of notch sticking out from the timing cover which is some sort of plastic, it will be around the 12 oclock position on the cover. line the marks up, make sure you are TDC #1 compression stroke drop distibutor in rotor toward # 1 wire. The computer take care of the timing advance. Whats going to happen is you will get a engine light if it not right on the money which a scan tool can fix. When ever i had distributors out of that vintage small block i would make marks at the base of the distributor and intake som i could go right back where it was.

 

You need a tech 2 or good snap on otc etc scanner. You start the engine and give it a quick rev above 1200 rpm then set the cmp positioning at 0 degrees. You will need to advance or retard the distributor and after the adjustment give the engine a slight rev above 1200 to get the current cmp. once you have it set tighten the distributor and you are good to go.

 

I guess ill just skip it then, I just saw with the scan tool that I have that the advance was sitting between 18 and 35 depending on the rpm and speed of the pickup but it is running fine so ill not tinker with it till it is broke

 

If it's close, the PCM will take over and you'll be just fine.

 

yup need snap on or tech 2 or otc. the timing has to be set -2,-1,0,1,2 to any of those or the light will be on. hope this helps