Professional Help Needed
04-27-2013, 05:33 PM
#1
Professional Help Needed Please do not bring in your opinions on this matter, I need answers with experience.
Last year I flycut my pistions and installed a G5X3 112lsa cam and AFR 205 62CC chamber heads. I have been fighting a knock sensor problems ever sense and as you probably read on another thread
, I replaced everything more than once and there was no cure. So I decided to pull the engine apart and check everything. I have the intake and heads off. I checked the flycut depth (Seen below). What do you guys think. There is some differences in the cut depth in the pistons but will the small differences cause an unbalance in the engine as to where it would pick up false knock? The car ran great, it was just that I kept getting the knock sensor fault for the front. Thanks in advance.
Cylinder 1
Intake ~.132
Exhaust ~.079
Cylinder 3
Intake ~.079
Exhaust ~.075
Cylinder 5
Intake ~.084
Exhaust ~.083
Cylinder 7
Intake ~.088
Exhaust ~.094
Cylinder 2
Intake ~.081
Exhaust ~.088
Cylinder 4
Intake ~.087
Exhaust ~.092
Cylinder 6
Intake ~.090
Exhaust ~.077
Cylinder 8
Intake ~.078
Exhaust ~.072
Last year I flycut my pistions and installed a G5X3 112lsa cam and AFR 205 62CC chamber heads. I have been fighting a knock sensor problems ever sense and as you probably read on another thread
, I replaced everything more than once and there was no cure. So I decided to pull the engine apart and check everything. I have the intake and heads off. I checked the flycut depth (Seen below). What do you guys think. There is some differences in the cut depth in the pistons but will the small differences cause an unbalance in the engine as to where it would pick up false knock? The car ran great, it was just that I kept getting the knock sensor fault for the front. Thanks in advance.Cylinder 1
Intake ~.132
Exhaust ~.079
Cylinder 3
Intake ~.079
Exhaust ~.075
Cylinder 5
Intake ~.084
Exhaust ~.083
Cylinder 7
Intake ~.088
Exhaust ~.094
Cylinder 2
Intake ~.081
Exhaust ~.088
Cylinder 4
Intake ~.087
Exhaust ~.092
Cylinder 6
Intake ~.090
Exhaust ~.077
Cylinder 8
Intake ~.078
Exhaust ~.072
04-29-2013, 08:20 PM
#4
The tolerances on a stock motor are all over the place. That's not causing the problem. If you actually look at the A/F ratio on each cylinder, you're see they are all different too (flycut or not).
Throw race gas in there. See if you're getting actual KR or false KR. If it's still knocking with 100 octane, then it's a false knock. You can tune some of that sensitivity out. If it's from the front knock sensors, it might be the timing chain (double roller?).
Throw race gas in there. See if you're getting actual KR or false KR. If it's still knocking with 100 octane, then it's a false knock. You can tune some of that sensitivity out. If it's from the front knock sensors, it might be the timing chain (double roller?).
04-29-2013, 09:54 PM
#5
The tolerances on a stock motor are all over the place. That's not causing the problem. If you actually look at the A/F ratio on each cylinder, you're see they are all different too (flycut or not).
Throw race gas in there. See if you're getting actual KR or false KR. If it's still knocking with 100 octane, then it's a false knock. You can tune some of that sensitivity out. If it's from the front knock sensors, it might be the timing chain (double roller?).
Throw race gas in there. See if you're getting actual KR or false KR. If it's still knocking with 100 octane, then it's a false knock. You can tune some of that sensitivity out. If it's from the front knock sensors, it might be the timing chain (double roller?).
04-29-2013, 11:57 PM
#6
If you have any interference there it could be perceived as knock, even though the frequency would probably be wrong. Even if not, double-rollers are pretty damn noisy, but again, the frequency shouldn't be where the sensors are "looking." Still might be worth a look.