I have a 96 3.9 that needs a new timing chain. Has anyone had experience with advancing or retarding the cam and if so what was the out come ?? Read an article on it years ago but cant remember the advantages brought about with the changes. Thanks, Terry

 

Quote:

Originally Posted by slowauto

I have a 96 3.9 that needs a new timing chain. Has anyone had experience with advancing or retarding the cam and if so what was the out come ?? Read an article on it years ago but cant remember the advantages brought about with the changes. Thanks, Terry

In general, advance will help low end power, and retard will help high end power. That being said, assuming everything else is stock, I would install straight up, no additional advance or retard. I would think that mopar picked the best position to place the camshaft timing, again for a stock vehicle. But of course, this is just my opinion.

 

except on a dakota doing any adjustments at the timkng chain will yield nought. The timing is controlled by the computer. 0 gains to be had here. Timing can be adjusted however by notching the crank sensor towards the passengerside wheel well. With mixed results.

 

Excellent. I forgot about computer controls. Ran into that problem on an 87 I had. Had not thought about changing the position of the crank sensor ! I forgot to add my 96 is stock with about 180,000 miles. No issues other that the timing chain rattle. Thanks, Terry

 

Quote:

Originally Posted by Toby Warford

except on a dakota doing any adjustments at the timkng chain will yield nought. The timing is controlled by the computer. 0 gains to be had here. Timing can be adjusted however by notching the crank sensor towards the passengerside wheel well. With mixed results.

Thats not true. The ignition timing is controlled by the computer. Not the cam timing.

 

Ah ha, a difference of opinion. So advancing or retarding the cam in my case should make a change in engine performance even though the ignition timing is computer controlled ??

 

Quote:

Originally Posted by slowauto

Ah ha, a difference of opinion. So advancing or retarding the cam in my case should make a change in engine performance even though the ignition timing is computer controlled ??

Not an opinion, a fact!!

If you look at the adjustable crank sprocket, it will be marked 0. -4 or +4 degrees. When using these keyways, it physically changes the camshaft to crankshaft position. This physically changes the point at which the valves open and close in relation to the piston.
Again, cam timing is not the same as ignition timing.
Ignition timing controls when the spark plugs fire based on piston position in the cylinder. Now this can and is controlled by the computer

 

Cool. Now back to my original question. 180,000 miles, no other issues, would it be advantageous to advance the cam 2 degrees since I have to change the chain and gears anyway. Thanks, Terry

 

For the labor your doing,beg borrow buy a degree wheel and re- d gree the cam.It will surprise you in the added performance.Just a thought................

 

Thanks for the info. Have you done this on a used motor and what was the outcome ?? Thanks, Terry