Resolved Tapping sound on passenger side of engine

[sav22rem22]

Hello everyone, been a little while since my last post. I decided to throw my engine back together with my new AFRs and custom cam. When I measured for pushrods I needed 6.400 pushrods but ended up using some 6.350 trickflow pushrods I already had to get by until I could get the 6.400s in. I’m using 7/16 stud mount scorpion 1.6RRs.

As I expected the 6.350s were a tad noisy but after I ran the car for a couple hours I did some other things on the car like swapping to 94-04 cobra brakes all the way around so that took me a couple weeks due to work and other life things happening and then I finally swapped in my 6.400 trickflow pushrods.

I did 3/4 turn past 0 lash on all lifters. Everything is much less noisy except for the tapping sound on the passenger side. I genuinely can’t tell if it’s an exhaust leak or some kind of valve train noise. I’ve made sure the header bolts have been tightened after every heat cycle and I honestly am not sure if the sound was there with the shorter pushrods or not because it was all so noisy and I was more focused on getting the base tune set up with the new Pro M EFI.

Here’s a video of what I’m talking about.

Let me know what you all think. It’s also worth noting that the collector to H pipe fitment is great with my new exhaust and I’ve made sure the flange is nice and tight so I don’t think it’s coming from there.

The sound is very noticeable in the car and it happens all the time whether it’s hot or cold.

 

[Noobz347]

Hard to say but here are my guesses:

1. Exhaust leak
2. Bad lifter
3. Bad or worn rocker.
4. An electrical short from one of the lightning hoses

 

[Mindseye007]

I would just pop the valve cover off and see what's up sounds like something is loose inside? Maybe the rockers need more adjustments, or it could be a bad lifter.

 

[sav22rem22]

So I took it on another drive and noticed that when decelerating, the noise almost completely disappears. Upon pressing the gas again, the noise comes back which leads me to believe it’s an exhaust leak. Pro M EFI has DFSO which would make sense as to why the noise disappears on deceleration.

I’ll most likely still pop the valve cover off and go over everything again. Pretty frustrating that I keep getting exhaust leaks. I even used the AFR recommended gaskets. I don’t think it’s coming from the collector or at least I hope it’s not.

 

[AeroCoupe]

I will get leaks unless I retorque the headers when the motor is hot. Install new gaskets, get some heat in the motor and retorque.

 

[limp]

I have seen exhaust leaks that I would of sworn were noisy lifters or a rattle.....

 

[Mindseye007]

So I took it on another drive and noticed that when decelerating, the noise almost completely disappears. Upon pressing the gas again, the noise comes back which leads me to believe it’s an exhaust leak. Pro M EFI has DFSO which would make sense as to why the noise disappears on deceleration.

I’ll most likely still pop the valve cover off and go over everything again. Pretty frustrating that I keep getting exhaust leaks. I even used the AFR recommended gaskets. I don’t think it’s coming from the collector or at least I hope it’s not.

Do you have full length or shorty headers?

 

[2000xp8]

Pretty frustrating that I keep getting exhaust leaks.

I had an exhaust leak that i chased for a long time, turned out one of the mac shorty headers i was using was leaking at the collector where all the pipes meet. You couldn't see it from the outside but as soon as i took them off and held them up to the sun i could see all the cracks.
Just part of my horrible history with mac products.

 

[sav22rem22]

Popped the header off this afternoon and at first everything looked pretty normal but then I saw that there was a buildup of some sort on the bottom of the exhaust ports on the head and the gasket itself. Header was clean oddly enough and didn’t require any scraping.

It appears that there’s a small “ooze” of oil coming from the valve cover and my guess is that it penetrated the exhaust gasket and caused them to blow out at the bottom. I’ll fix that before the car is even fired up again. I also put a thin layer of copper rtv around where H pipe meets the collector ball.

 

[sav22rem22]

I had an exhaust leak that i chased for a long time, turned out one of the mac shorty headers i was using was leaking at the collector where all the pipes meet. You couldn't see it from the outside but as soon as i took them off and held them up to the sun i could see all the cracks.
Just part of my horrible history with mac products.

After reading this I held my headers which are BBK shortys up to the sun and thankfully didn’t find any cracks or any daylight intrusions. It’s seeming that quality parts are getting harder and harder to find and I’d imagine it’s not going to get any better unfortunately

 

[sav22rem22]

Do you have full length or shorty headers?

BBK 1 5/8 shortys

 

[sav22rem22]

I will get leaks unless I retorque the headers when the motor is hot. Install new gaskets, get some heat in the motor and retorque.

Interesting. I’ll be sure to try that this time as I didn’t do that initially but it does make sense.

 

[sav22rem22]

I have seen exhaust leaks that I would have sworn were noisy lifters or a rattle.....

Yeah it’s wild how closely header leaks resemble mechanical noises. Now I’m wondering if the “tapping” I heard with the shorter pushrods was instead an exhaust leak of some sort

 

[AeroCoupe]

I use the metal core FelPro 1415's with zero rtv on aluminum heads with BBK equal length 1-5/8" shorty headers. I torque them down tight, start the motor and get it hot, shut the motor down and and retorque. I will admit that I use my bbq gloves to do this so I can get on them as hot as I can stand.

I ended up "porting" the headers as the welding from the primaries to the flanges was not great and the fire cones were more like 2-1/8" vs 2-1/2". Opened the primaries up and then opened the fire cones up to 2-3/8". I had time to kill over the winter when I built the motor so that was my excuse for doing it.

Before: After:

______

Fire cone before (I started grinding on it and then
realized I had not taken a picture): After:

______

I am sure I gained 1 hp and 1/2 ft-lb of torque...ha ha ha!!! Again, I had time and it was over the winter so the car wasn't going anywhere.

 

[Rdub6]

one of the lightning hoses

Somebody’s been watching Roadworthy Rescue/Vice Grip Garage!

 

[Noobz347]

Somebody’s been watching Roadworthy Rescue/Vice Grip Garage!

Love that guy.

 

[Rdub6]

Love that guy.

Yeah….. he’s pretty much as real as it gets as far as TV car shows! I gotta check out more of his Vice Grip stuff……. Just not enough time in the day, any day!

 

[sav22rem22]

I let the copper RTV set up around the collector to H pipe flange for about 24 hours and started the car up when I got home from work about an hour ago.

Unfortunately the exhaust leak is still there but it’s most definitely not coming from the collector. Before everything got too hot I put my hand down near the primaries and on the #2 cylinder primary on the left side I felt puffs of air. Tried to tighten the bolt on that side down while it was running and it made no difference.

Honestly not sure what to do at this point. Unless I have a pinhole or a very small crack around the flange to primary area I have no clue what it could be. The drivers side is fine and I did them both identically on install.

Would prefer to not buy new headers again but at this point I’m willing to do almost anything to get rid of this exhaust leak. Im hoping the valve cover gasket leak didn’t warp the header.

 

[AeroCoupe]

One of two things, either the header flange is not flat (check with known straight edge) or the primary needs to be welded up at the flange.

If the flange is flat the I would think you could press something across the #2 opening to seal it. Fill the primary tube from the collector with water and see what leaks.

 

[limp]

Most exhaust shops have a large belt sander to sand exhaust manifold flanges.. Not sure if they can do header flanges.. If yours is not perfectly flat, you might want to call around locally to see if they can sand yours?