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The scenario and a few questions on my 39 Plymouth.

I'm removing the split manifold and going back to single exhaust manifold, but will use at least 2" pipe. It needed new manifold gaskets anyway.  I'll probably use a single glasspack muffler. Any muffler recommendations?

The nightmare is the bolts snapping off. Before turning any bolts or nuts, I soaked them with Buster for several days with little results. Three of the four bolts that hold the two manifolds together snapped off. One of the two bolts that goes through the exhaust manifold into the block snapped off. All of the nuts were rusted onto the

studs, but fortunately the studs came out with the nuts still on them. However, I'm still looking at the lower bolt hidden behind the intake manifold. It's a tight space and looks like it will require an end wrench? I'm hoping it will ease out. Probably two chances of that happening, slim chance and fat chance.

The heat riser is shot and no spring. It was held in position with wire. I'll be making a stainless steel plate to seal the exhaust flow from the intake. The heaviest stainless I can find locally is .018. Will that be thick enough? It looks like a gasket will only be needed between the stainless steel plate and the exhaust manifold?

What is the best sealer to use when installing the new studs? I have a can of Aviation sealer.

 

Edited by Dennis Detweiler
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Watched a youtube vid recently on removing exhaust manifold bolts. What I took away from it..

Naturally spray them and soak

Loosen the bolt a smidge and then tighten, back and forth going a little further each time.

 

Key point, if they do not want to turn at all. Reason is the shoulder of the bolt is rusted to the exhaust manifold. Here you need to apply heat with your torch, you can hear a click when the stud breaks free, then repeat the 2 steps above.

 

This was a mechanic working on modern engines with the head out on the work bench. Principle is the same. One that would not move, he heated with his map gas torch, then zoomed in the camera as he removed it and loads of rust was coming out as soon as the head of bolt backed out.

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Tricks on removing stuck hardware after spending time in the Navy removing corroded hardware from antennas.

 

Tighten before you loosen.

 

Heat it up, get a torch in there and get the nut red, Mapp gas torch is sufficient, then let is cool.

 

Impact, use a brass drift or similar soft metal and whack it with a hammer.  Impact shock can loosen it up.

 

Never, ever try to force it.  Things break, stuff rounds off and then you just made it worse.

 

Some times, no matter what, it breaks off.

 

EZ Outs can be your best friend or your worst enemy.  If it takes it out, yay, if the EZ Out breaks you have just made the problem 1000% worse.

 

Time is your friend, walk away and leave it for tomorrow if you get frustrated. 

 

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The issue we face when removing a manifold is compounded by the stud extending into the water jacket. When the nut refuses to budge torque is transferred to the stud which cannot turn because the end that protrudes into the water jacket has enlarged due to corrosion and is now wedged against the crankcase. So we apply some more torque and the stud breaks. Now we get to drill out the stud, clean up the threads and install a new stud. If we are really sharp, we will carefully install the new stud only far enough to prevent the end from extending into the water jacket and the corrosion problem rearing its ugly head for the next guy who removes the manifold.

 

The bolts securing the two manifolds together on my car were so degraded that just the slightest torque snapped them. Fortunately there was enough of a stub sticking out of the intake manifold to allow grabbing the stub with a stud extractor and the stub could be unscrewed without damaging the threads. The stud extractor also made short work of removing a couple of studs in the crankcase that needed replacing.

 

712Z6RTqTeL._AC_UL115_.jpg

 

https://www.amazon.com/Shop-Iron-16023-Drive-Extractor/dp/B00265M8N4

 

 

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I always use heat from a propane bottle, penetrating oil, and some light hammer taps on the bolt head to get them off. Work them back and forth a little at a time instead of just going in the loosen direction only. Takes time but I’ve gotten a lot of them out without breaking them this way.

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I tried the back and forth method for a while, but it didn't seem to make any difference. It felt like the bolt shank was just twisting in both directions. Looks like they broke off at the threads.  Likely flush? So a center punch, drill bits and eventually a tap to clean the threads will be the procedure? Looks like the only method for the lower bolt is a box wrench. The manifolds and bolts must have been on there for decades. The 3 broken manifold to manifold bolts were nearly rusting in half. The gasket is mostly gone. I won't know more until I can get the manifolds off of the block and onto the bench.

One problem I can see with the added exhaust outlet on the original stock manifold is, it's nearly impossible to adjust the front six valves without removing the exhaust manifold.

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I'll be measuring the distance of the block threads and make sure the new studs don't go into the water jacket. After removing the old studs, it's plain that they were more than 1/4 inch into the jacket. Maybe the next owner won't have this problem. I'm figuring lots of sludge to remove after I get the valve cover plates off.

When I bought the car, the owner said it had an overhaul 10,000 miles ago. When I had the pan off, the cylinders looked new and the cylinder walls had vivid cross hatching. However, since I'm in the middle of removing the manifolds, I don't see how they could have done anything with the valves. It was likely a head and pan removal and only honed and installed new pistons and rings.

Thanks for the input so far.

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3 hours ago, Sam Buchanan said:

The stud extractor also made short work of removing a couple of studs in the crankcase that needed replacing.

 

712Z6RTqTeL._AC_UL115_.jpg

 

https://www.amazon.com/Shop-Iron-16023-Drive-Extractor/dp/B00265M8N4

As was stated by Sam this is a great tool and Advance Auto Parts stocks these and usually has a code to get you 20% off if you reserve it on line.

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5 hours ago, Sniper said:

Tricks on removing stuck hardware after spending time in the Navy removing corroded hardware from antennas.

 

Tighten before you loosen.

 

Heat it up, get a torch in there and get the nut red, Mapp gas torch is sufficient, then let is cool.

 

Impact, use a brass drift or similar soft metal and whack it with a hammer.  Impact shock can loosen it up.

 

Never, ever try to force it.  Things break, stuff rounds off and then you just made it worse.

 

Some times, no matter what, it breaks off.

 

EZ Outs can be your best friend or your worst enemy.  If it takes it out, yay, if the EZ Out breaks you have just made the problem 1000% worse.

 

Time is your friend, walk away and leave it for tomorrow if you get frustrated. 

 

 

This is great advice. I've been there with a broken manifold bolt. I tried all of the above but one did break off but fortunately with enough of it showing out of the block that I could get it super hot and put a pair of vice grips on it and slowly work it out using the old tighten/loosen method mentioned. I am not normally a big fan of vice grips but it really worked well for this application.

 

I got a new bolt and a brass nut from a local auto supply store. I just cut the bolt to the desired length.

 

Manifold2.jpg.55c122618ccccdb74b8ca05e6a8968cd.jpg

 

Manifold.jpg.82ad2acb65779d8afd53059e71337b42.jpg

 

1804079529_manifoldbolts.jpg.d977776193a34cb52867cab0d3867c2a.jpg

 

Edited by RobertKB
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2 hours ago, Dennis Detweiler said:

I'll be measuring the distance of the block threads and make sure the new studs don't go into the water jacket. After removing the old studs, it's plain that they were more than 1/4 inch into the jacket. Maybe the next owner won't have this problem. I'm figuring lots of sludge to remove after I get the valve cover plates off.

When I bought the car, the owner said it had an overhaul 10,000 miles ago. When I had the pan off, the cylinders looked new and the cylinder walls had vivid cross hatching. However, since I'm in the middle of removing the manifolds, I don't see how they could have done anything with the valves. It was likely a head and pan removal and only honed and installed new pistons and rings.

Thanks for the input so far.

The valves can be removed with the manifolds on, IF one has the correct spring compressor.  Kind of a pain to work around the manifolds, but in your case they probably tried to remove them, found the same issues you did and just worked around them.

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1 hour ago, RobertKB said:

 

I got a new bolt and a brass nut from a local auto supply store. I just cut the bolt to the desired length.

 

 

BRASS nut is key for these manifolds.  If you use steel you will be revisiting this problem.

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If the stud breaks off flush with the block and you have to drill, Start small and work your way up to just shy of the hole size. Make sure to center and drill straight. Also use oil or drill bit lube to cool the bit so it won't break off. If it is the number six exhaust, use a 90 degree drill. I had to do that on mine when the number six back bolt broke flush. I think I started with an 1/16 inch then a 1/8th, then 1/4 and I think I used a 5/16 last (maybe a 3/8) but only for the length of the shank. Then used a tap to clean the threads. It was a slow process but it needs to be.

 

Joe Lee 

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I took an old box end 6 point wrench I picked up some where and ground it slowly down so it would fit through the tight spots, bent at a angle so I could whack the open end with a brass head hammer.  That worked on all but two that needed the flame wrench.  Been using atf and acetone 50 50 applied with an old syringe for penetrant.  Would better than most of the aerosols. Most of the ones these days you can only get half a can out before the propellant runs out.

 

 

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1 hour ago, Sniper said:

 

BRASS nut is key for these manifolds.  If you use steel you will be revisiting this problem.

 

 

Totally agree. They used brass nuts at the factory for a reason. 

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24 minutes ago, greg g said:

Been using atf and acetone 50 50 applied with an old syringe for penetrant.  Would better than most of the aerosols.

 

Going to agree with you on acetone/atf. If going to be applying heat ... this combo is pretty flammable. I would want to keep a fire extinguisher  close by. Especially if the engine is in the car.

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The lower center intake manifold bolt was only finger tight. Both manifolds are off. The split manifold is not a true split. It's just has two outlets. The weld has a crack on one side, but I'll be installing a stock single exhaust manifold. I drilled out the 3 broken bolts that connect the two manifolds together and have them re-tapped. One of the two center exhaust manifold bolts broke off and has about a 1/2 inch stub. I have it soaking and will try to move it back and forth tomorrow.

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3 hours ago, Dennis Detweiler said:

The lower center intake manifold bolt was only finger tight. Both manifolds are off. The split manifold is not a true split. It's just has two outlets. The weld has a crack on one side, but I'll be installing a stock single exhaust manifold. I drilled out the 3 broken bolts that connect the two manifolds together and have them re-tapped. One of the two center exhaust manifold bolts broke off and has about a 1/2 inch stub. I have it soaking and will try to move it back and forth tomorrow.


Go head and buy the stud extractor.......don’t mangle the stud with vice grips to where the extractor can’t get a good grip.

 

image.jpeg.b1e7328da565e99bfb8b2009a03a3346.jpeg

Edited by Sam Buchanan
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"Used brass nuts in the factory for a reason".  Does anybody have a guess as to "why"  they used brass nuts at the factory.  Not only that but why there are two configurations of brass nuts...standard shaped nuts with standard shaped washers and "conical" shaped nuts with "conical" shaped washers and then in specific locations?  I asked this question awhile back and a gentleman from Germany offered his thoughts on the subject and they all sound reasonable.  If you do a search on "brass manifold nuts" you can see them. Just wondering if anybody might have anything more definitive.  Regards to all.

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Brass won't lock up to the stud with corrosion.

 

As for the shape, it's to allow the ends of the exhaust manifold to move as it expands and contracts with heat.  Otherwise it would crack. 

 

 

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As mentioned the manifold moves with heat cycles. The assembly should only be tightened enough to clamp it together and as necessary to seal joining surfaces from leaking.  I believe the torquespecs are in inch pounds.  Overtightening will cause problems between the manifolds and to the block.

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brass by design is used as a sacrificial metal...one that will clamp with sufficient force but also one that normally will not seize to the stud...and if it does seize due to corrosion on the stud...being soft material it yields its internal threads and saves the stud....quick clean up, new brass nuts and away you go...manifolds are not by design to get an extreme amount of torque applied....brass nuts are not uncommon and should be easy to acquire at the big box store or on  e-bay...I scored a set of 6 metric for a small engine I just put together for a very reasonable price and was hanging on a HELP card at the local chain store....surprised to find the metric...

Edited by Plymouthy Adams
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I bought a stud remover tool, tapped on the stub several times and heated the block around it. I've been giving it shots of blaster for 2 days. The stud remover managed to twist off the remaining stub. So, I filed the little remaining stub flush with the block and punched the center of the bolt in prep for drilling. Looks like I have it punched accurately on center. This is a "bolt" that twisted off.

 

Three exhaust studs came out with the conical steel nuts rusted onto them. I'm just going to dress the studs that remained in the block with a die. I'm not going to risk twisting any of those off too. They seem to be in good shape other than threads needing cleaned up. I will probably have to make a bullet shaped washer to fit between the factory expansion washers and brass nuts to make the original brass expansion washers function properly. I'm looking at making them out of large cap nuts. A cap nut seems to fit perfectly into the cone expansion washers. The original steel conical nuts are rusted into the stud bolts. I'd rather use brass nuts on the exhaust manifold anyway. The next guy won't have to deal with this.

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Or VPW-vintagepowerwagons.com

 

 

Screenshot (33).png

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