marc_w

So I bought a used set of Dynatech headers and cats. No instructions, no header gaskets.

I installed the system the other day. I have some exhaust leaks. I originally reused the factory head to header (or manifold) gaskets... so I thought that was the culprit. I just replaced those with new factory pieces, and I still have a fair amount of exhaust-leak-sounding-noise. Torqued inner to outer, 11ft/lbs then 22ft/lbs.

Any reason why I shouldn't be using those factory gaskets? I don't "believe" they're the issue....

So then there is the collector gaskets. It looks like the collectors come with little 1/8th inch tall "spacers". I assumed they go between the header flange and the cat flange so that the soft metal cone-shaped donut gasket doesn't get crushed? Yes/No?

I have no FREAKING idea where the exhast leak is coming from, but I'm thinking it's the collectors now.

Should I have used those spacers? Should I take them out?

Should I get new "cone shaped donut gaskets" down there?

How else can I track down where the exhaust leak is? The only thing I can tell you is that it's noisier _under_ the truck rather than in the engine bay, and it sounds like ****.


Thanks...

XLR8NSS

iTrader: (4)

The spacers need to be used so you don't crush the gasket, that is right.

My guess would be that the collector gaskets aren't sealing up right now that the system is on a new truck(might be aligned just slightly different).

Start the truck up and try to feel around the collector connections(without getting burnt ) for exhaust leaks.

marc_w

Crap, I knew someone was going to make me go lay in the snow...

Thank you VERY much for the quick reply... I'll letcha know what's up.

Sport Side

iTrader: (6)

I hate exhaust leaks

If you can get a friend to help you. Have them rev it. see if you can pin point it.

XLR8NSS

iTrader: (4)

Hey, at least your hands will be warm. Check all the connections while you're out there.

marc_w

Okay...

So the collectors to cat connections seem very good. Not a hint of a leak.

The center and passenger side cat slip-fit connections (with the very thin molded bands/clamps) both puff a bit of cool air. (Are those connections only on the 6.0 systems?)

I adjusted the center one so that it puffs 'less', but it's still there. There is still some room for adjustment with the fitting itself, but I'll have to bump the drivers side cat to the passenger side about 1/4" - which I don't feel like doing now. The passenger connection will be very difficult to get to again, but I'll give it a whirl sometime.

Here's the thing though - the noise I'm hearing doesn't seem to "match up" to the puffs of air I'm feeling. The noise seems to be coming right from the collectors (or maybe the headers) themselves. At idle, the noise sounds like valvetrain noise. (which I'm quite certain it's not). I can almost hear each cylinder firing with a 'pinging' or 'piffing' noise. I feel stupid, but is that normal with headers and a cam?

I took the truck for a drive to see what's up with the manifold gaskets. I definitley reduced a fair amount of the noise I had, but there is still a good amount there. It's not as ugly sounding as before. At low throttle openings, it's very quiet forward of the muffler. The more you step on it or more load you put on the motor, the more you hear what sounds like each cylinder firing away in front of the firewall to the floorboards. Actually, right when the cam starts to wake up is where it starts to get noisy. When you let off, it's DEAD QUIET. Is it normal to get more noise from in front of the firewall?

Power is definitely up since doing the manifold/header gaskets. I was getting 15mpg on the highway, which is horrible for me. Hopefully this will increase that.

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Other than the noise here... I'm really liking these things. The fit is awesome. The passenger side header jumped up into place, bolted itself up, and put the dipstick back in while I had a coffee break. The only tweak I needed to do was remove 3 threads off of the steering shaft nut. I didn't have to hammer any heat shields or anything. No vibrations or rubbing at all.

My exhaust note is much... MUCH... more rude now. Anytime I touch the throttle it's making a lot more noise than before. Deeper, "cleaner", and louder.

Another odd thing - the cam lopes less. Now it's even harder to hear.

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Edit: My only rant - the primary on the drivers side that wraps up an around. It's RIGHT in the way of the two back spark plug wires. I had to use my excellent fabricating skills* to make some one-off sheet-metal tabs** that get bolted to the heads... they have a holes in them that I run wire ties through to keep the plug wires pulled up agains the head, and away from the headers.

* Not really.

** They're tremendously crappy.

XLR8NSS

iTrader: (4)

With headers you will definately get some valvetrain noise and the "cylinder firing" noise. The cast manifolds are MUCH better than headers at reducing engine noises in the exhaust.

It sounds like that is what you are hearing besides maybe the slight noise from the other connections. Mine make a similiar noise but, I'm used to it after running headers on other vehicles in the past.

About the slip fit connections. I've never had those type of clamps leak but, if they do I've read about a fix. Take some tin foil and fold it over a time or two. Then wrap it around the pipes at the joint and slide the clamp over everything. Then tighten the clamp and smash the tin foil in the process. Evidently it works great. Either that or once you get things aligned like you want have the joints welded.

Hope that helps out.

edit

**

** = ROTFLMAO at your use of a legend to describe your fabricating skills and brackets.

marc_w

That's an AWESOME idea for those slip-fits. Much easier than tearing it all down and getting a pipe expander.

I'm quite glad to hear the noise is rather normal. I feel like a dummy!

Thanks for the help!

marc_w

I'm glad someone enjoys my odd sense of humor.

I just fixed the noise...

I found an old package of some "Spaced aged exhaust sealant" stuff. It's this stuff that's mainly used for sealing expansion champers and exhaust systems on dirtbikes and quads. It's a lot like old window putty, but it melts and expands with heat. I figured, "what the heck, we're out of aluminum foil."

So I applied this stuff to the main/center connection that was puffing, and I was able to stop it completely. I couldn't feel the passenger side one leaking at all today. Odd. (but perfectly fine with me)

I took the truck for a drive, and all that noise is COMPLETELY GONE. I cannot believe the difference it makes - it's so much more enjoyable to drive now. It picked up a lot of power (odd, since it's after the 02's?), and noticed my DIC mileage at part throttle cruise was back on par with old readings.

I still have that puffing/pining noise at idle, but it sounds real nice. It's clearly just the cylinders firing. I definitely underestimated the noise that this leak was making.

I can hear the headers through the firewall when I get on it, but it's very very mild compared to before.

The motor is back to it's old mild lope now too.

SnakeOiler

iTrader: (6)

marc, do you still have your MSD wires on the engine along with the Dynatech headers?