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Manifold Project


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I want to restore this manifold set. Any suggestions on breaking loose those bolts, etc. I will soak them for several weeks then possilbly with heat they may come loose. (2) Does one have to take the wing off the air control or does one just replace the bushings?

This is a good set, so I'm going to restore them, hone out the inside and possilby add a second exhaust exit. The set on the engine now is a good set also.

Any help will be appreciated.

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That's about how my manifolds looked when I got my truck. The engine had been partialy disassembled and the manifolds were just like that with the broken off bolts in the intake. There was just enough bolt sticking out that I could either get a Vice Grip on it, or weld a nut to it. Then I heated the corners cherry red with a torch and they screwed right out. The heat riser was also seized, but after heating the manifold just above the pin it freed right up and works fine now. I did replace the spring though.

Merle

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My set we took a grinder and cut a screw driver slot into the remaining bolt. Then heated the corner cherry red as Merle said and out they came. If the bushings are bad in the heat risor you have to remove the wing and shaft to replace the bushings. I couldn't get mine to push through until I drilled them most of the way. Once they were very thin they pushed out with a punch.

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This last weekend I also got very deep into a exhaust manifold project on one of my Chrysler straight "8" cars. The exhaust manifold cracked-I heard a snap 1/2 hour after I driven and then parked the car. A very expensive and difficult repair on the 1946-1950 Chrysler straight eight cars. A very tight access job to say the least!

It requires the same repair/rebuild methods as for Pauls six cylinder manifolds. The eights are just a lot more complicated ( 3 Piece Manifold) and bigger design.

A lot of penetrant and a hot wrench is a must to free up frozen nuts and bolts on exhaust manifold repairs. Speeds up the removal of frozen manifold bolts and nuts to just seconds instead of hours or days of waiting. As mentioned above heat to cherry red once or twice and off come the nuts or bolts- almost always! A propane torch doesn't work well or fast enough on these bigger car projects.

The heat risers usually can be freed up with a torch and and lubricant and by carefully tapping on each end of the shaft-back and forth and trying to rotate it.

If the heat riser is beyond freeing up a NOS MoPar heat riser kit is the answer if another good manifold is not available. MoPar six cylinder heat riser kits are kinda hard to find anymore. Straight eight kits are not available-anywhere! I have been looking for years! I had to cut apart another damaged 8 cylinder manifold for good heat riser pieces for my manifold repairs.Welding is required to do the heat riser replacements.

When mounting the manifolds on the sixes it is a must to use the proper four tapered cone nuts and matching special 3/8" thick brass washers at each end of the exhaust manifolds. These will let the manifolds expand and contract without breaking at the ends. See pics.

Also make sure the header pipe and muffler are installed properly with no stress, otherwise after time the exhaust manifolds can break at the rear outlet. Some pics....

Bob

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Also make sure the header pipe and muffler are installed properly with no stress, otherwise after time the exhaust manifolds can break at the rear outlet.

WOW, that line was worth this thread. I just finished loosely installing my exhaust system. Now I understand all the hangers. I picked up a muffler this morning. To twist and turn those pipes to get a clean route is 'fun'. My source said to put it back of the cab to keep the heat out of the cab, so I figured I'd keep it as far away from the fuel tank as well. It's a Flowmaster, aluminized steel. Now I'll mark it and then weld it as one. Did this waiting for more brake line tubing. Fixing an old truck is a good exercize in multi-tasking.

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Edited by pflaming
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Where can the special washers and cone nuts be found?

I just used plain flat washers, split lock washers, and brass nuts on mine, not knowing these were originally a special design.

I never had any problems but would like to do it right this time around.

Thanks,

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When mounting the manifolds on the sixes it is a must to use the proper four tapered cone nuts and matching special 3/8" thick brass washers at each end of the exhaust manifolds. These will let the manifolds expand and contract without breaking at the ends. See pics.

bob,

i assume the lower, outer attachments for the intake manifold also use the cone/slotted nut? your picture/arrows don't show these, and the other picture only lists 4 of each. should there be 6 cone/slotted nuts, ie, used where the nut is only attached to either the intake or exhaust, rather than both?

wally

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nope just 4 at the outer ends on a 6cyl. Then across the top there's 4 nuts with thick washers to bridge the cap between the two manifolds. The rest are plain nuts on studs. Some do have bolts instead of the 2 long studs.

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nope just 4 at the outer ends on a 6cyl. Then across the top there's 4 nuts with thick washers to bridge the cap between the two manifolds. The rest are plain nuts on studs. Some do have bolts instead of the 2 long studs.

Exactly as Ed stated.

Bob

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Paul;

I got the stud set from VPW recently. It had everything you need except the 4 bolts that hold the manifolds together at the heat riser. They have been very good to deal with. Also got the heat shield from them.

When I removed the old studs I had 3 that would not respond to the wrench treatment alone. But heat them and hit it with some PB Blaster and out they come. This is an area you definitely want to chase all the threads on. Also I think it is wise to apply a thread compound like Permatex on all the new studs when you put them in. All but 3 go into the water jacket.

I trued the surfaces that mate to the engine on a large piece of tempered glass covered with silicon carbide sandpaper. It took a while but I think it is probably worth the effort as you don't want air leaks here. I did a tiny bit of cleanup on the ports of the intake manifold. There were a couple of pronounced ridges inside the manifold just before the mating surface that I worked slightly with the die grinder. I doubt if any more than this small cleanup would actually be worth the effort on a stock engine.

Hope this helps.

Jeff

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Jeff, I took the manifold that is on the engine to a machine shop and had it trued, and I used all new studs as well. Someone else was inquiring about them but that's ok.

I know these manifolds are expensive so I'm going to restore it either for a second or to sell. I'm not in any hurry now to take anything more off until this truck see's 60mph and I am getting close.

Yet thank you, I've purchased from VPW and have no complaints either.

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Jeff, I took the manifold that is on the engine to a machine shop and had it trued, ...

I had a devil of a time with either back firing on down grades or burning out exhaust manifold to block gaskets, etc. Cured that by having a machine shop true up the combined intake/exhaust manifold assembly. Mine was something like 0.080 off true and there was no way a gasket would have a chance of doing its job.

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