I have a popping sound around 5,500 rpm. I'm thinking with the cam I have could be valve float. I believe it still has the stock springs with what I was told was a stage two TrickFlow cam. I'm not positive it's stage two, but I know it's not stock.
it sounds like gnnnnnnngnnnnnnnnnngnnnnnnnnnngnnnnnnnnnnngnnnnnnnnnnnnnngnnnnnnnnnnnngnnnnnnnnnnnnngnnnnnnnnnnnnnngnnnnnnnnnnnnnngnnnnnnnnnnnnnnnngnnnnnnnnnnnnnngnnnnnnnnnnnnnngnnnnnnnnnnnnnngnnnnnnnnnnnnngnnnnnnnnnnnnnngnnnnnnnnnnnnnngnnnnnnnnnnnnngnnnnnnnnnnnnnnnngnnnnnnnnnngnnnn Hard to explian really. I doubt you would hear it at 5500 rpm. Do you have a stock or aftermarket tach.
valve float is quickly followed by lack of power. basically when the valves start to float the engine stops pulling. hence my reference to lack of power.
I know exactly what you're talkin about Roland. I've heard that and thought that's what it was. My car is throwing a handfull of gravel at a piece of aluminum sheeting or somethin around 5,500 or a popping sound. Sounds like it's coming from the exhaust.
do you have an aftermarket tach as roland suggested? the reason is the factory tach is very in accurate. or at least it can be. maybe you are turning more rpm then you think you are.
No still have the stock tach. I figure it's probably off some, but I've determined the sound I'm hearing isn't valve float because I knew exactly what Roland was talkin about as soon as I read it from other Mustangs I've had. I figure if i was runnin rpm's too high I would get valve float not a popping sound. Not like backfire either never does it under 5,500 rpm. Runs great and pulls hard up until I hear that sound then it just looses power. I'm sure rev limiter doesn't make that sound I've hit that a million times on other cars. I've backed off timeing, bumped up FP to 42# with vac line off, new plugs, newer MSD wires. I was wondering if the spark might be arking in cap at upper rpms? If anybody has any other ideas let me know.
Thanks
I'm pretty sure it's not detonation. I can put it in 3rd or 4th at low rpms and nail the gas and get no detonation. I'm guessin if it was gonna do it it would come on before 5,500 rpms. it is the same 1st thru 3rd haven't tried in 4th or 5th.
Could it be the C&L meter?
I'm thinkin if it isn't the cap and rotor or ignition module that i'm gonna have to put tighter valve springs on it. The best description I can think of for the sound is like a handful of gravel flyin through the exhaust or the sound a handful of gravel would make if you threw it at a metal slide or somethin. Startin to drive me nuts tryin to figure it out.
My car has what i was told was an E cam in it, I can't say for sure it is but i know it's not the stock cam. When i pulled the valve covers off i noticed it had stock springs and rockers. When i rev the motor under load (racing) i have to shift at about 5,000 (aftermarket tach) or else it makes that horrible sound and falls on it's face. It runs like a champ till around 5200 or so.
I call it valve float because of the aftermarket cam and stock valvetrain.
I'll either be getting a set of heads real soon with some good springs already in them or i will be adding some comp cams springs and roller rockers.
It ***.king sucks knowing theres more rpm i could be turning and not being able to because some ass.hat put a cam in it and didn't change the springs.
It's supposed to have 1.6 Cobra roller rockers in it, but I doubt the springs are aftermarket. I'm hoping that's all it is. Still don't really wanna screw around with changin the springs though.