First question is, has anyone tried it?

What you need to know:
1 its 100% reversible
2 It only takes your time no cost.


How to:

Tone ring mod = MPG gain



This mod is free for the 3rd gens other than a little bit of time under the truck, So heres the deal: Basically, it is doing about the same thing as the RokkTech Cam sensor by advancing the timing 2 maybe 3 degrees. Behind the Crank Pulley for the serpentine belt there is a Tone Ring. It has 4 bolt holes and a dowel pin hole. Take off the belt, loosen up the crank pulley and remove, the tone ring will then slide off. Now you will see the tone ring has the 4 bolt holes and an alignment pin, use a Dremel tool or a good round file and remove about an eighth inch off the left side of the hole as you look at the front of the tone ring, don't worry about taking too much off and the 4 bolts will only allow the tone ring to adjust so far. Now reinstall the tone ring and the belt sheave and finger tight the 4 bolts, install serpentine belt and make sure it is clear of the crank position sensor as it is a close tolerance . Now with the bolts just finger tight rotate the tone ring in a clock wise rotation as far as it will go...........this is looking at the FRONT of the motor. Secure the 4 bolts to 30ft.lbs. plus another 60 degrees per manual ( weird I know) So the end result is you just advanced your timing about 2 or 3*. This mod is very simple to do and well worth the time, If you have a manual tranny it will be easy to do the bolts, if you have an auto tranny you will need a hammer to loosen them so the motor just doesn't rotate. Also check the bolt torque again after a week or so.


Tools needed
15mm socket and breaker bar or ratchet long handle.
hammer if auto tranny
dremmel tool or good small round file
1/2" ratchet for the belt tensioner



Other useful info! each tooth is 3 degrees and each gap is 3 degrees. Thought this may be helpful, for those of you concidering a crank tone ring mod, in figuring the advance you want.


Overall explanation of what you are doing:
tone ring has [COLOR=blue !important][COLOR=blue !important]nubbins[/COLOR][/COLOR] that the sensor reads as the crank turns and sends signal to ECM where timing is controled or set

in a nut shell we are basically rotating the tone ring to falsify the timing so the ECM will adjust for us