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Exhaust Mani removal


boxboy

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So I finally pulled the 520 into the garage to tear to replace some badly leaking tappet gaskets as well as a messy looking carb and front cover/crank seal. I have been putting generous doses of knock 'er loose on the nuts for a few weeks now, but I managed to twist off the first stud with very little effort. The rest were almost loose enough to remove with my fingers. The problem I am having is that I can't get the manifold to break loose from the exhaust pipe. I have the flange removed, but I am assuming I just have a rusted joint. It is soaking in Knock 'er loose again tonight. Any suggestions?

 

Anyone have a spare exhaust stud. Its the one at the very front? I think I can work the stud out if I manage to get the manifold off. There is about 3/4 inch of it sticking out and it is soaking again.

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So I finally pulled the 520 into the garage to tear to replace some badly leaking tappet gaskets as well as a messy looking carb and front cover/crank seal. I have been putting generous doses of knock 'er loose on the nuts for a few weeks now, but I managed to twist off the first stud with very little effort. The rest were almost loose enough to remove with my fingers. The problem I am having is that I can't get the manifold to break loose from the exhaust pipe. I have the flange removed, but I am assuming I just have a rusted joint. It is soaking in Knock 'er loose again tonight. Any suggestions?

 

Anyone have a spare exhaust stud. Its the one at the very front? I think I can work the stud out if I manage to get the manifold off. There is about 3/4 inch of it sticking out and it is soaking again.

Once you get the manifold off, you need to heat the stud area of the manifold till it starts to glow red without heating the stud itself, then hit the manifold area near(not the stud itself) the stud with a hammer and then turn the broken stud out. If you break the stud off level with the manifold trying to get it out without heat, then it will have to be drilled and rethreaded. wayno

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Maybe I wasn't clear. The stud is still in the head. The end of it just broke off with the nut. So I can slip the manifold off like normal. I just have to figure out how to get the stud out of the head. I would assume that the stud is just screwed in with normal right hand threads. Please correct me if I am wrong!

 

More pressing now is that the exhaust pipe is somehow fused to the manifold down at the connection. I can't pull the manifold out without getting that joint loose. I don't know if it makes any difference, but I have left the intake mani attached to the exhaust mani. I don't want to take things apart that I don't have to. :)

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How hard can I hit it without braking something? Not much room to get a swing in. Just soaking and wiggling at this point. Hope something breaks loose.

 

Any advice on getting the stud out? Monkey wrench? Vise grip? Lefty loosy?

 

No sweat Mike. I knew there were only two bolts.

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grinder ? just a touch ?

 

 

^^^ What he said

 

Grind that nub down to the manifold, pull manifold. You can then add some PB blaster to that bolt, then remove. I had to use a 5lb sledge and lightly tap one a few times before. It actually took me a whole week of spraying it with PB blaster, tapping it, and using vise grips to get it out. Good luck man!

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Heat manifold with torch. Don't worry it's used to being hot. Hit around from all sides with regular hammer to shake loose. Heat will expand the hole. The stud has likely frozen to the manifold as well as torqued to the head and that was enough to snap it off.

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I have the manifold loose. I just can't get it off because the lead pipe is rusted to the manifold at the joint. Once that is loose the manifold will come right off. I think I will not mess with the stud until I spend a week soaking it with PB. Funny that it didn't take much to snap it, and all the others were almost loose enough to turn with my fingers. Any J13 guys know where I can find a new stud? Metric, or standard?

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Well, its official. I just can't get my Datsun to fall apart right. :angry: :P Manifold to lead pipe is still frozen fast. Wiggling, banging soaking and the like has not produced any progress. I many have to just remove the entire exhaust system. :o

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In order to get to the tappet gaskets I want to change I just unbolted the whole exhaust system and now I can tip the manifold to the side and give me enough room. Makes it difficult to clean old gasket off without getting bits into the manifolds though. Hopefully I don't get anything in the intake ports. I have the block taped. I have to get a lot of grease and grime off before I pull the covers and replace the gaskets.

 

Found out that my new torque wrench I got for Christmas is crap in this process. Click type, but I got no click. :angry: I hate it when new stuff doesn't work.

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So, anyone got an idea where to get a new exhaust stud for this 520. Its the one on the head, not the flange. Napa? Dealer? Do I need a special hardened stud?

Just remove one of the good ones if possible and go to the hardware store and get another one. Thats what I do, the only vehicle that i can't is my 1953 MGTD, it has a whitworth thread, one bucket SAE, another bucket metric, and now another bucket whitworth. :wacko: :wacko:

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Okay, I managed to get the old stud out without further breakage. But when I went to the hardware store (Parkrose Hardware) the only one they had that was close was a 5/16 stud with fine threads on one end and coarse on the other. So, I got it thinking I can use the fine in the block as original, but had to buy new coarse nuts for the manifold side. Hopefully this is not a problem. Can anyone confirm for me that the 5/16 fine is what I need for the block? I don't want to monkey it up now that I have gotten it out without drilling and tapping.

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Just remove one of the good ones if possible and go to the hardware store and get another one. Thats what I do, the only vehicle that i can't is my 1953 MGTD, it has a whitworth thread, one bucket SAE, another bucket metric, and now another bucket whitworth. :wacko: :wacko:

 

Supposedly these guys can get whitworth stuff: Metric & Multistandard Components Corp. Hawthorne, NY, 914-769-5020

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