Jeep Strokers

I Just bought the JP performance timing set with the different keyways for advancing and retarding the timing.
My question is what should I do? I have the stock 2001 cam with 1.7RR
My understanding is that advancing the timing will give more of a high end peak and HP gain.
Retarding the timing will give it more low end grunt.
Is this correct? I very rarly see 5,000 RPM so I am thinking that I should retard the timing 2-4 degrees.

On a side note, I have a question about the 1.7RR. I know that they increase lift, but I have heard rumblings that the increase duration as well?
That just doesn't make sense to me because all you are doing is changing the ratio of lift from the pushrod to the valve.
I don't see how that would increase duration but if it did that would be a plus.
Can someone please explain this to me?

Thanks,
Jake

RAPTORFAN85 wrote:I Just bought the JP performance timing set with the different keyways for advancing and retarding the timing.
My question is what should I do? I have the stock 2001 cam with 1.7RR
My understanding is that advancing the timing will give more of a high end peak and HP gain.
Retarding the timing will give it more low end grunt.
Is this correct? I very rarly see 5,000 RPM so I am thinking that I should retard the timing 2-4 degrees.

On a side note, I have a question about the 1.7RR. I know that they increase lift, but I have heard rumblings that the increase duration as well?
That just doesn't make sense to me because all you are doing is changing the ratio of lift from the pushrod to the valve.
I don't see how that would increase duration but if it did that would be a plus.
Can someone please explain this to me?

Thanks,
Jake

You have it backwards. Advancing the cam helps with low end, retarding the cam for high end. If you are running a stock cam, I would go straight up, or maybe 2 degrees advance for future cam chain stretch. The stock cam is designed for low end torque, so advancing more will only kill the top end, without any low end advantages. You also won't be able to degree the cam unless you know all the cam timing specs, and you might hurt performance more than help. I have seen new cams be as much as 7 degrees off.

From what I understand about higher rocker arm ratios is it does affect duration a little because it opens the valve faster, so its off the seat longer, therefor increasing duration

dwg86 wrote:You have it backwards. Advancing the cam helps with low end, retarding the cam for high end. If you are running a stock cam, I would go straight up, or maybe 2 degrees advance for future cam chain stretch. The stock cam is designed for low end torque, so advancing more will only kill the top end, without any low end advantages. You also won't be able to degree the cam unless you know all the cam timing specs, and you might hurt performance more than help. I have seen new cams be as much as 7 degrees off.

From what I understand about higher rocker arm ratios is it does affect duration a little because it opens the valve faster, so its off the seat longer, therefor increasing duration

I guess that means I'm the one thats retarded?

Thanks for the help, I will run it straight up.

Jake

When I installed my cam from Elgin with the non adjustable timing set it was retarded about 4 degrees. Got an 4 degree's offset keyway and ran it straight up. I went straight up because i thought maybe the computer wouldn't like that and the people who designed the cam probably know more about cams than I will ever know.