Exhaust leaks!

[kcjones]

I need help. I hate to admit it, but I'm running out of patience and sanity. Here's the story:

I have a 67 C20 with a 90-something 350. Installed headers and ran new exhaust 2-3 years ago. No matter what I did, I had exhaust leaks around the header/head...ran different types of gaskets, including copper embossed, tried multiple gaskets, tried some adhesive things, nothing....tick, tick, tick. Since then, I started filling my garage with parts do upgrade the engine a bit - Edlebrock Performer RPM heads/cam/intake, new Hedman headers with 3/4" flange. I blew a head gasket last month, so it was time to finally put all this together.

So, everything's back together, it runs pretty well, but yes, of course, you guessed it...header gasket leaks. So before I sell my truck for 1/10th what it's worth and buy an Accord, does anyone have any helpful experience I can draw on? These are new aluminum heads, new [expensive!] headers with big flanges. I've triple checked valves, but I'm pretty certain it's not a valve train ticking because it makes almost no noise when I'm off the throttle and coasting down a hill.

Right now, I have plain old Edlebrock exhaust gaskets installed...graphite whatever they're called, and have re-torqued the header bolts multiple times.

A few non-helpful cell pics attached.


Thanks, guys.

[stealthy '69]

You might not like my idea, but. Try pulling the headers and put a straight edge on the flanges and make sure they are straight and not any high or low spots.

[kcjones]

Originally Posted by stealthy '69

You might not like my idea, but. Try pulling the headers and put a straight edge on the flanges and make sure they are straight and not any high or low spots.

At this point, I'm into trying everything. Sucks that I have to check this on brand new heads and headers, but I'll do it tonight. Thanks.

[junkyardjohn]

Originally Posted by kcjones

At this point, I'm into trying everything. Sucks that I have to check this on brand new heads and headers, but I'll do it tonight. Thanks.

B-4 YOU DO.. TAKE A LONG SCREWDRIVER OR PRYBAR & USE IT LIKE A STETHISCOPE ON THE INTAKE SIDE OF YOUR VALVE COVERS. IF YOU HAVE TICKING IN YOUR VALVE TRAIN, YOU'LL BE ABLE TO HEAR IT.( IF YOU ALREADY DID.. DON'T TAKE AS AN INSULT TO YOUR MOTOR SAVY, I'M JUST TRYING TO BE HELPFUL) JOHN

[stealthy '69]

Good point junkyardjohn. It never hurts to check these things out before tearing it all down. I'd feel pretty bad if you did and didn't find anything there. But I've herd of new headers having a little bit of a gap, even if it is a very small one, it may be enough to leak. But I would deffinetly look into valve train noise too. Do you see any black spots by any of the header tubes on the heads? Usually you will see some if your headers are leaking.

[kcjones]

Ok...sorry for my ignorance here, but I've heard of using an actual stethoscope to find noises...but a long screwdriver, eh? So I stick this long screwdriver in my ear, and point it at the place I'm listening for? Like the handle end goes in my ear? Again, sorry for the ignorance, but I appreciate the advice and want to try it 'correctly'.

Thanks!

[big mike71]

You put the handle in your ear and the blade on what you want listen to. It sounds corny but it works.

[junkyardjohn]

JUST MAKE SURE THE HANDLE END IS PRESSED IN THE CENTER OF YOUR EAR, & THE BLADE END IS TOUCHING THE PART YOU WANT TO HEAR. IT'LL WORK WITH ALMOST ANYTHING BIG ENOUGH THAT YOU DON'T JAM IT IN YOUR EAR. (THAT MENTAL PICTURE IS HARD TO GET OUT OF MY MIND NOW) JOHN

[Longhorn Man]

push the handle end of the screwdriver up against the flap of your ear with enough pressure to push the flap over the opening of the ear canal. Lean into the running engine compartment (pull back any necklaces, neck ties or hippie hairstyle) and touch the other end of the screw driver onto the valve cover. The noice will be heard easily to you. Move to another area of the valve cover to hear over the other rockers. You'll get the hang of it quickly.
In my mind, odds are against it being a valve adjustment. If you have done this gasket deal over and over, had the noise go away and then return, and now new heads... the odds are towards the gasket IMO.

[Longhorn Man]

man, would you believe I started typing this way before either of you did?

[bigsnookmaster]

I use Mr.Gasket Ultra Seal gaskets with very good results. Checking the straightness of the flanges is where I would also start. Good luck

[big mike71]

Originally Posted by Longhorn Man

man, would you believe I started typing this way before either of you did?

You must type like I do, with one finger.

[piecesparts]

Here is what I am doing with my vehicles. I have headers on all of the trucks (3 of them--all with small block V8s in them) and I used to have a set on the wife's 95 Impala SS (but we sold it---got something faster and better). I try to use a quality header with thick flanges. To mount them, I use "FELPRO" gaskets. I coat the gaskets with "Coppercoat" gasket sealer and let it skin over before installing. I then put the headers on the engine with the gaskets coated and I use teflon tape (sealing tape) on the threads of the header bolts. This keeps the bolts from backing out or coming loose as you use the vehicle. It also keeps the bolts from rusting tight or seizing up over time. In the last 12 years, I have not had any header lieakage issues and the truck and the Impala had them on for the full time. If there is an issue, a person could double up the header gaskets, but I have not had that problem, yet. Most of the time th eleaks start when header bolts loosen themselves up and start the exhaust cut on the gasket material, so the bolts staying snug is important. Just put the gaskets on, tighten the bolts with the teflon tape and then after starting the enigne and warming everything up, check the bolt tightness and you are done.

I got the idea for the teflon tape from one of those 100 Great Tips section of Hot Rod Magazine---dang if it didn't work. Before that, I was always fighting loose bolts.

[junkyardjohn]

I TYPE WITH ONE FINGER... & IT AINT PURDY. JOHN

[big mike71]

Originally Posted by junkyardjohn

I TYPE WITH ONE FINGER... & IT AINT PURDY. JOHN

I have to stop and ask wife how spell stuff half of the time.

[El Jay]

Originally Posted by junkyardjohn

JUST MAKE SURE THE HANDLE END IS PRESSED IN THE CENTER OF YOUR EAR, & THE BLADE END IS TOUCHING THE PART YOU WANT TO HEAR. IT'LL WORK WITH ALMOST ANYTHING BIG ENOUGH THAT YOU DON'T JAM IT IN YOUR EAR. (THAT MENTAL PICTURE IS HARD TO GET OUT OF MY MIND NOW) JOHN

Originally Posted by Longhorn Man

push the handle end of the screwdriver up against the flap of your ear with enough pressure to push the flap over the opening of the ear canal. Lean into the running engine compartment (pull back any necklaces, neck ties or hippie hairstyle) and touch the other end of the screw driver onto the valve cover. The noice will be heard easily to you. Move to another area of the valve cover to hear over the other rockers. You'll get the hang of it quickly.
In my mind, odds are against it being a valve adjustment. If you have done this gasket deal over and over, had the noise go away and then return, and now new heads... the odds are towards the gasket IMO.

A chunk of broomstick also works well. You can use almost anything that transmits sound better than air.

And you can also use the same technique to check alternator bearings and other such things that make noises that are hard to pinpoint.

[Longhorn Man]

I type a little faster, but we are still at the hospital and a million things going on at any one moment that can pull me away.
Back to the original topic, I have honestly had more problems sealing up manifolds than headers.
So far, all my headers have been on small blocks, but all I would do is grind the welds flat on the header to head mounting points, and then use normal exhaust manifold gaskets (fel pro normally) tighten the bolts, then retighten them after a test drive of a few miles, and every once in a while (when ever it would seldomly cross my mind) I would put a wrench on them to check the tightness. Even on some dirt cheap craptastic headers I had many years ago (we guessed that they were blackjack headers) I had no issues after doing that.

[Dark Knight]

Back when I was in high school, we would rest the head of a guitar on the wood tables we had in the classroom when we didn't have an amp. It worked pretty well.

[dznucks]

Are you sure its not leaking at the collector flange? Do you have a cross over?

If there is a leak bad enough to hear while driving there will be some very slight noise at idle. you can use a peice of tubing, like 1/4" clear fish tank tubing, the same way you would use the screwdriver and run the tubing along the exhaust flanges. you will be able to hear the leak if there is one.

i find all my leaks with my stethescope. i remove the pointed end and just us the tubing to find exhaust or vacuum leaks.

[1restorick]

On my truck I battled this same problem and finally coated the gasket with Permatex Ultra Copper RTV. That was in 1993 and I still don't have any leaks.

Rick

[kcjones]

You guys are awesome - thanks for all the ideas...I have lots of things to try, so wish me luck. And hopefully all this info helps a few others in the future, too. I do have collector leaks, so taking my rig to A1A exhaust in Santa Rosa, CA to have them fix that. Hopefully I'll be tick-free in a few days!

Thanks again for all the info...

[master 1969 c10]

Hi try remflex headers gaskets about $44 a set. Check out there web. If you do have a leak at the header and head this will take care of it. Doug