Light knocking noise (vid Inside)

[1fast97Cobra]

I just got my car back together after a long ordeal. I have about 3000 miles on it so far and it has had a ticking or knocking noise. It has done this since the start. I have been taking the car to may shops and no one can figure it out. Did a compression check all numbers are good. It seems to be in the heads. The heads are new ported with blower cams. It sounds like a truck motor. When you start it sounds like a exhuast leak but it is coming form the driver side valve cover. Car runs great. Under load you can here a knocking noise but goes away once boost is applied. Everyone just tells me to drive it until it pops. You can hear it a little in the vid. The car had open headers in the vid.

[nomedia="http://www.youtube.com/watch?v=wFKW4PBzKzs"]YouTube - Open header cammed 97 cobra[/nomedia][nomedia="http://www.youtube.com/watch?v=FtV9A63pVNE"]YouTube - 97 cobra.MOV[/nomedia]

 

[whtcobra1998]

do you have forged internals? mine is fully forged but has piston slap that makes it sound like slight rod knock. sounds similar to yours

 

[98 svt]

^^^
is that safe?
Mine makes the same nosie until it warms up and I thought there was something wrong with it (10:1 Aluminator short block).

 

[svtcobralover]

I have the same problem with mine. Fully built and compression is perfect. Bored .30 over and Flat Top pistons.

 

[CJK440]

^^^
is that safe?
Mine makes the same nosie until it warms up and I thought there was something wrong with it (10:1 Aluminator short block).

Forged slugs expand more by the time they get to operating temps compared to a cast piston so you need to build more clearance when cold. This is normal and a big reason the OE's don't throw forged pistons in if they are not needed.

 

[1fast97Cobra]

Motor specs are

4.6l Bored .020
J.E. SRP 80 pistons
Manley h-beam rods
Cobra crank
B-Heads fully built
Stage 2 blower cams
Vortech s-trim 8lbs
Snow meth stage 2 kit
42lb injectors
255lb TRE pump
Sniper 95mm MAF
MSD coil packs

Compression is around 120 to 130 on all cyclinders.

 

[1fast97Cobra]

What could cause the exhaust ticking sound in the heads. If that is the problem. Will lifters cause this? I am running 10W30 mobile 1 in the motor.

 

[Murder Snake]

injectors can tick. does the noise stay whether the motor is hot or cold? do you have a mechanic's stethiscope you can use to listen to where it is coming from? if not, you can use a long handled screwdriver and see if you can tell. exhaust leaks will tick depending on the size of the leak and can even go away if it is very small, once everything heats up and expands. for me, too hard to hear what you are talking about on those videos, you have a lot of different sounds going on there...goood ones mind you, but still a lot to try to hear what the noise is.

 

[1fast97Cobra]

Here is a video of the car from a cold start. The knock goes away as it warms up.

[nomedia="http://www.youtube.com/watch?v=YsdjxucMP_4"]YouTube - Supercharged cobra knock[/nomedia]

 

[1fast97Cobra]

Update I put some lucas enigne breakin oil and the motor is a little more quiet then before. I still have no idea what the issue is. I think it is in the heads both the Driver and pass side make the same noise.

 

[1fast97Cobra]

Anyone have any ideas?

 

[98 svt]

Have someone look at it.

 

[1fast97Cobra]

I have had two places look at it and can not figure it out. One said it could be wrist pin. Other said its in the heads.

 

[98 svt]

Do you mind if I ask how much did the 2 shops charge you to look at the car?

 

[1fast97Cobra]

They didnt charge me anything they came outside and listened to it run. One seem to think head issues. Other said wrist pin. The one shop my friend works at so he didn't charge me. The other I just asked they to listen.