Jump to content

Exhaust Manifold Replacement


Recommended Posts

I have been noticing a tiny ticking noise from my 265 in my PU lately going up hills and at first startup. I rebuilt this 1954 Chrysler engine as a H-Duty truck engine with sodium valves, heavy duty forged pistons ect back in 1974. Well I decided to replace the gaskets and manifold this past weekend. I have done many over the years.

Of course the two exhaust center bolts broke off. The rear six point head rounded off. Tried a 14MM six point socket. Nope-it too slipped! Got the Oxy/Acetylene torches and heated the hex head red hot and flattened the head and used valve grinding compount for a good grip. It worked and of course the bolt snapped off. Kinda knew it would. The other bolt just broke off. I got the manifolds off in about 1-1/2 hours. I drilled out the first front bolt. Centered the bit and drilled it all the way dead center and came to the dangerous ending of the bolt. I slowed down and started to pull the 1/8" bit back ... The drill bit broke off 1/2" down in the broken off stud. Now I was really ready to swear in some strange foreign language! :angry:

I had some stiff stainless wire and slipped it along side the bit in one of the flutes and was able to hook the bit just enough to pull it out. Lucky on that one. The other stud had two inches sticking out and was very eroded next to the block. It would have snapped at this rusty thin area. It was late and I decided to heat the stud red hot a couple times away from the rusty area and let it sit over night thinking it might break the bond of the rusted threads in the block but also thinking it would still snap off and I would have to mig weld a thick washer and nut to the nub sticking out.

Next morning I vice gripped the stud and it came out! YES!

I have been through this type of exhaust work many times as this is part of what I do. I just thought for my truck it would be a quick and easy. OoooHHH NO. It had to be a pain in the you know what.  All the studs and correct hardware are all lubed/sealed up with anti-seize and or sealer for a leak free job as all the studs go into the water jacket area. Boy oh Boy sometimes these MoPar flatties can have a seemingly simple repair turn into a nearly endless repair!

Well the job is all done and good for the next 35-40 years!

Bob

Edited by Dodgeb4ya
  • Like 4
Link to comment
Share on other sites

Another one of those jobs and it will be the end.... of me! :lol:

Link to comment
Share on other sites

:) I went through a eerily similar process when bring my old engine back to life. Far more work than I was expecting......but then this is my first old Mopar flathead. Applying localized heat helped prevent a few from breaking off. My engine had sat for a long time with water in the radiator. Sure wished the PO had drained the radiator and block. :mad:

 

Jeff

Link to comment
Share on other sites

So the brass manifold nuts on my 218 are not factory then? Most of them came right off, and the studs are still in fair condition... The 230 on the other hand... already broke a breaker bar trying to get them loose. AND the exhaust manifold has several cracked ears.

 

The grill bars are stainless steel, I guess using that same material for critical engine component assemblies would have been "too much like right"...? IF I can get the 230 studs loose, they'll be replaced wih marine grade hardened stainless steel or high tensile silicon bronze. I really only want to fight with any given fastener once at the most.

Link to comment
Share on other sites

I think the Chrysler eights were the only manifolds that used brass nuts to bolt the manifolds to the engine block from the factory-could be wrong though. All my eights use them. The 23" and 25" engines do use two cone nuts and brass countersunk spacer washers with these cone nuts-two used on each end of the exhaust manifold to let it expand and contract. These special brass washers and cone nuts will prevent the exhaust manifold ends from breaking.

Some pics of the original nuts and washers used on all 218/230/236/251 and 265 engines.

Edited by Dodgeb4ya
Link to comment
Share on other sites

I think this changed over the years: The parts book for my '33 engine lists brass nuts for the manifold studs. Cone washers also came later. Maybe when they started using the coned washers they also changed to using a different material for the nuts but I am away from my parts books so I can't look that up.

  • Like 1
Link to comment
Share on other sites

I don't really know much at all about the pre 1941 Mopar engines just 1946-54 models. I know the brass nuts can strip out pretty easily as I have had to replace a few of them on my chryslers but they do come off nicely.

I think this changed over the years: The parts book for my '33 engine lists brass nuts for the manifold studs. Cone washers also came later. Maybe when they started using the coned washers they also changed to using a different material for the nuts but I am away from my parts books so I can't look that up.

Link to comment
Share on other sites

I don't really know much at all about the pre 1941 Mopar engines just 1946-54 models. I know the brass nuts can strip out pretty easily as I have had to replace a few of them on my chryslers but they do come off nicely.

Just looked in the 36-48 Plymouth parts book: The intake studs intake 9 of part number 114547 and the exhaust takes 4 of part number 623370.

 

114547 is listed in group 18 as a "3⁄8-24 (21⁄64 thick) Plain brass, free fit, regular hexagon nut". Parts book image of the exhaust stud nut shows a cone nut to work with the special washer. So all the intake stud nuts should be brass on all Plymouths '36 through '48. Don't know the material of the special cone nut as that is not in my group 18 copy.

 

Not sure of the material

Link to comment
Share on other sites

The cone nuts are steel for sure. The 1946-8 Chrysler six cylinder cars also use (9) of the part# 114547 brass? nuts same as the 1948 and back Plymouths.  Later 1949 and up parts books list 114547 as now just a plain nut. Learn sumthin every day here!

Bob

Edited by Dodgeb4ya
Link to comment
Share on other sites

The cone nuts are steel for sure. The 1946-8 Chrysler six cylinder cars also use (9) of the part# 114547 brass? nuts same as the 1948 and back Plymouths.  Later 1949 and up parts books list 114547 as now just a plain nut. Learn sumthin every day here!

Bob

 

Interesting that none of those entries on your scan show material. All the ones in the couple of different group 18 books I have always list material and finish, for example "Cad plated steel".

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use