So, I thought I had my exhaust leak licked as all was quiet for the last 3 weeks of cruising. Last time out, the noise returned and after cool down, I checked torque on all bolts, The nut on the front stud, drivers side was loose AGAIN which along with the center 2 bolts used to get loose after every cruise. 3 weeks ago I removed the conical washers that I used on the center bolts and they remained tight without the washers. I left 4 on the drivers side 2 front 2 rear the other 3 remained tight. When I went to torque the front I noticed a crack around the bolt tab that I never noticed before. I guessing it may have been there all along and was the source of my leaks and the reason that nut used to loosen every time I took a ride.
With all that said, here is pics of the crack and the question, Can this area be welded or is it new manifold time??
I would think a good welder could fix it. I'd put a straight edge on it to make sure it's not warped. If it's a common manifold it might be easier to get another one.
Quote from: Rich G. on July 25, 2020, 07:06:56 AM
I would think a good welder could fix it. I'd put a straight edge on it to make sure it's not warped. If it's a common manifold it might be easier to get another one.
I was just getting ready to type the same thing :worship: :drinkingbud:
Yes it's possible but it's a high stressed area. I'd get a replacement? :alan2cents:
My understanding is the factory installed conical washers to allow the manifolds to expand and contract and not crack doing it. No gaskets needed iron to iron. I had a hemi exhaust manifold welded that was broken like that and it never broke again but the welder really knew what he was doing. If you can find a good manifold easily that will be your easier route though.
So THAT is what those washers are for... thanks! :)
Quote from: RUNCHARGER on July 25, 2020, 08:08:01 AM
My understanding is the factory installed conical washers to allow the manifolds to expand and contract and not crack doing it. No gaskets needed iron to iron. I had a hemi exhaust manifold welded that was broken like that and it never broke again but the welder really knew what he was doing. If you can find a good manifold easily that will be your easier route though.
Get another manifold... I've had one welded, it worked but it looked like crap...
:iagree:
WHile anything can be fixed the process in not easy , the casting has to be preheated to over 500* then welded with a special high nickle rod , in most cases the cracks has to be drilled at both ends to prevent the crack fo=rom spreading , but this doesn't apply where the crack is in this case then the casting has to be cooled slowly & the surface milled flat again , the cost would outweight the cost of replacing it .
I've had manifold ears cast iron welded before.
$50... 20 years ago.
You will need to go back and make it look pretty. Die grinder and such.
They are just going to weld for function.
Quote from: RUNCHARGER on July 25, 2020, 08:08:01 AM
My understanding is the factory installed conical washers to allow the manifolds to expand and contract and not crack doing it. No gaskets needed iron to iron. I had a hemi exhaust manifold welded that was broken like that and it never broke again but the welder really knew what he was doing. If you can find a good manifold easily that will be your easier route though.
That is what they are for and this crack is on the front driver side stud and did have a conical washer. I was having problems with the center ports bolts loosening too and removed the washers per service manual. The bolt kit comes with 10 yet per the service manual, only 6 are used.
Very common issue. I had set of original L-36, 427 chevy exh manifolds where one cracked just like yours. I had them brazed, which is supposedly the way cast iron is supposed to be repaired. The key to keep them from breaking after the repair is to have them resurfaced so the head side is perfectly flat. Along with the proper washers, etc,
The repair site can be a little ugly, but can be finnessed easily so the repair is minimally seen. One way is to finese the site with a little fine grinding and then sandblast the exh manifold for a uniform appearence, then paint it with whatever you are using
I had an exhaust leak on a manifold on one of my SUV's.The shop said I needed a new manifold because it was warped.Dealer wanted over 400 bucks just for the manifold.I took the manifold to a machine shop that did some engine work for me.He grab the manifold with both hands put it on a long sander and flattened the manifold perfectly flat in less then 5 minutes.Cost me 20.
What manifold do you have?
Quote from: B5fourspeed on November 21, 2020, 06:50:32 PM
I had an exhaust leak on a manifold on one of my SUV's.The shop said I needed a new manifold because it was warped.Dealer wanted over 400 bucks just for the manifold.I took the manifold to a machine shop that did some engine work for me.He grab the manifold with both hands put it on a long sander and flattened the manifold perfectly flat in less then 5 minutes.Cost me 20.
I have done that before too !