exhaust manifold question 250eng

[dave`12]

67 c10 250eng. When I got it, there was a massive exhaust leak where the exhaust manifold meets the pipe. I'm thinking a heat riser or something was there, because I see some springs in the vicinity. The PO just stacked some gaskets there, but it is a massive fail. I unbolted it and the pipe is a good inch or 2 away from the exhaust manifold. Does anyone know how I can fix this? The PO tried to just pull it up, but it did not work. Do they make spacers? or if I get a riser, could I just disable it, as the rest of the mechanism is not there that would make it work. any advice appreciated.

dave

[frankslagoon]

I think the surfaces between the manifold and the heat riser are flat but the surface between the heat riser and the pipe uses a donut gasket. question. the pipe is flanged where it contacts the manifold ?

[frankslagoon]

Originally Posted by frankslagoon

I think the surfaces between the manifold and the heat riser are flat but the surface between the heat riser and the pipe uses a donut gasket. question. the pipe is flanged where it contacts the manifold ?

here's a system. don't know if it's like yours. looks like the man. is flanged , then the donut gasket. then there is a short piece between the donut gasket and the pipe

[dave`12]

thanx Frank that helps. i took it apart and the heat riser is not between them like I thought, it's in the manifold itself. So I guess I just need to find a fatter doughnut. the PO replaced the exhaust, and it just does not line up well. Gonna look for the doughnut.

[Lugnutz65]

Originally Posted by dave`12

thanx Frank that helps. i took it apart and the heat riser is not between them like I thought, it's in the manifold itself. So I guess I just need to find a fatter doughnut. the PO replaced the exhaust, and it just does not line up well. Gonna look for the doughnut.

I used the donut style but you have another option. I installed mine by myself after the muffler shop bent the pipes. There are 2 options for where the exhaust manifold connects to the downpipe.
Option 1: The parts stores sell an off the shelf pipe that has a bulge that is shaped just like the donut. See photo for part # on red sticker. It's a Walker pipe and doesn't need a donut. You just need a flange. It only comes in the long bed length all the way back to the muffler and if you have a short bed you'd need to cut it shorter. Then add the muffler and tail piece and mounting brackets.

Option 2: Use a pipe with a donut and the original style insert tube. The insert fits inside the donut and inside the end of the downpipe. You can see it in the photo.

I had my local muffler shop bend the pipes. He had a "recipe card" for the 1965 C10 short bed and it fit just great but I did need to use a donut since he could not make the special bulge where it meets the manifold. It works great and is just like the factory.

As far as the place where the intake manifold meets the exhaust manifold, there is just a square type gasket between the two. The flap inside the exhaust manifold diverts heated exhaust to warm the intake until the spring gets warm enough to close the flap. Some people remove the flap but then the intake might actually get too hot. Some close the flap permanently and that just delays the warming of the intake. If the intake is not warmed appropriately then performance will suffer due to condensation of fuel inside the intake. If you need pictures of the flap just let me know.

[Lugnutz65]

one more picture - these are the pipes bent by the muffler shop.

[dave`12]

thank you lugnutz, that's quite an informative responce, and I appreciate your taking the time to help.

But doesn't that seem like a very expensive problem to the solution? My Exahaust manifold to down pipe looks factory and would seat fine if I just had a gasket about an inch or so wider than the one(s) it had. Looks like the original down pipe, but it was cut and welded further down, and now it's just a bit off.

I would love to just find a simple gasket that is an inch wide??

[Lugnutz65]

Originally Posted by dave`12

thank you lugnutz, that's quite an informative responce, and I appreciate your taking the time to help.

But doesn't that seem like a very expensive problem to the solution? My Exahaust manifold to down pipe looks factory and would seat fine if I just had a gasket about an inch or so wider than the one(s) it had. Looks like the original down pipe, but it was cut and welded further down, and now it's just a bit off.

I would love to just find a simple gasket that is an inch wide??

I actually wasn't trying to solve your problem. Just was offering info with pics so you could see what it's supposed to look like. I'm sure other solutions exist but I have no idea of what it will take to fix your particular problem. Sometimes going back to the way it was meant to be is the most direct and cheapest solution. I am not aware of where you could get a larger or thicker gasket. Good luck.

[dave`12]

I wish I had the money to do it like that, looks great!

[dave`12]

Went to a muffler shop, they sold me a gasket. Told me to NEVER stack them. Installed it, tightened it until the bolts bent (super tight). Tiny leak now, almost undetectable. For the $4 I spent on the gasket, gonna call it a win.

thanx

[GASoline71]

Bent fasteners and warped flanges are almost 90% of the cause of exhaust leaks.

Gary