They needed to have the flanges faced (done) and im going to wrap them for ***** and giggles Hahaha but mostly for the containment of heat and to help protect my new wiring harness. Whilst inspecting my engine to make sure everything was ok I took pictures inside of the exhaust ports on my LT1.

Cyl 1.


Cyl 3.


Cyl 5.


Cyl 7.


Notice how the valves are whitish on cylinders 1 &3 but on cylinders 5&7 there darker. I know my bad tune and few exhaust leaks that i had on the header could cause something like this to happen. Along with perhaps the first 4 cylinders getting more air through the intake then the rear 4 due to design? What could cause that to happen?

 

The LT1 intake manifold is a great piece it will support cars into the 9s with work done on it. I bet some of your cylinders are burning lean. How many miles on the car? I just pulled my valves and replaced them at 105k.

What is your psi on the fuel rail? The front cylinders will have problems being starved of fuel because the fuel starts at the back of the rail then feeds forward.

 

i rebuilt the engine agood 15k miles ago. I feel the heads arent perfect. I forgot to mention i did a compression test. They were all around 190psi. I didnt do a leak down test but im confident the heads arent perfect. The machinist that rebuilt my engine and heads only hand lapped the valves.

 

I've always heard that wrapping mild steel headers, assuming that's what you have, is a bad idea, at least from a longevity perspective.

 

True, actually helps to trap moisture. Not to mention the fire hazard of say an oil leak on them.

 

Took the words right out of my mouth. Turn good headers into rust.

Al 95 Z28

 

luckily for me i have stainless steel headers along with the silicone coating that prevents the fabric from absorbing oils/fuel

 

Faced my flanges to perfection!



halfway done







This is my first time wrapping headers. At least i knew to wet the material first. Tomorrow i should be done wrapping the passenger side header.

 

Moisture is not the culprit in wrapping headers. Obviously, there is going to be little moisture when the pipes are several hundred degrees. It is the trapping of the heat, causing premature metal degradation and fatigue. Less heat might be good for the surroundings, but bad for the headers.

 

Which i completely understand. There cheap ebay headers in the first place so them getting destroyed isnt an issue. I plan on a set of kooks headers sooner or later. There are afew spots where the header gets close to my harness. My main concern is protecting that. The added heat int eh tube is an added bonus. Metal fatigue is the least of my concerns as of right now. When i get a nicer set of LT's im going to get them ceramic coated by my friend for $200. But until then the wrap will suffice

 

In colder temps, it collects moisture and can trap debris. Your car is not running 24/7 and that is when most of your corrosion damage to any metal exhaust is done. Post heat cycle and humidity.

Spraying them with silicone barriers will do nothing but prevent staining of their material as their water/chemical resistance is gone after a few good heat cycles.

The heat retention and fatigue of the headers on a street NA engine isn't as bad as a turbocharged or road raced engine where heat and cycles are more extreme. I've cracked open a turbo downpipe at a bend from heat on a wrapped 14gauge mild steel pipe. Could have been the thinning of material at the mandrel bend, could have been the wrap holding heat there. Not sure, but I stopped using it when I removed the wrap and found that even though it was aluminized, it was rusting severely compared to the unwrapped portions which looked brand new.