Im now using Boylestad's book as a reference for making an RC Oscillator. it says in the book that for an RC Oscillator to Oscillate it needs
1) AV >= 29
2) that the phase shift of the RC network to amount 180 total.

the books says the formula F = 1/2pi(C)(R)(√N) will produce a 180 degree phase shift where N is the number of RC in the circuit

my target frequency is 4Mhz, and the available Capacitor is 100pF then
4Mhz = 1/2pi(100pF)(R)(√6)
R = 162

Av for inverting amp is AV = Rf/R1

29V = Rf/162
Rf = 4698 Ohms

but the output im getting is like a noise, and its super small in the femto volts region. at low frequency(60Hz ) this method works, but when i simply changed the values after doing the calculations provided by the book i can no longer make it work pls help

heres the output from my 4Mhz RC oscillator

 

I maybe not right but the resistor R2 Im about sure you need 2 diodes and it's way to low to get any output, I was playing with inverting one of these. over here. have a look at post #17 https://forum.allaboutcircuits.com/threads/a-little-op-amp-troubles.148049/

 

Disconnect R1 from ground and connect it to the right-hand side of C2, putting the resistor between C2 and the summing nose. That might help with the noise. (Seems like a familiar problem.)

The LM7321 might not have enough gain at 4 MHz to oscillate, given its 20 MHz Gain-Bandwidth product.