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About to do Exhaust manifolds on a Chrysler 340 any tips?

stevemiller333

stevemiller333

Contributing Member
Hello Everybody.

I am about to replace the exhaust manifolds on my 75' Century Resorter with the Chrysler 340 V8. It has the log type manifolds with 20 degree elbows. I ordered all new manifolds, risers, end caps, and end cap installation kits. I thought I got a pretty good deal at $706 shipped for everything.

I was wondering if anyone has any tips or things to look out for when I do the job? The original manifold bolts have been replaced along the way with cadmium studs which I am going to use as they are in great shape. It looks like the previous owner had the gaskets done recently and either kept the old manifolds, or replaced them with leaky used ones because they both leak a little water from cracks in the cast iron visible from the outside.

Any advice would be very much appreciated, I will have my father there to help I hear they are pretty heavy.
 
Yeah. FIrst of all, get a set of exhaust gaskets that are ONE piece or you'll go nuts trying to get the end pieces the right way--they can go at least 1,267,334 ways!

Next--if you're performance oriented--port the manifolds similar to the ports on the heads. The manifold port openings tend to be much smaller.

Make up a couple of studs with a screw driver slot in the end. Put one on each end of the head, slip the ONE piece gasket on, then the head. Add a few bolts, unscrew the studs, and finish the job.

Finally, don't even think of using anything less than grade 5 steel (NOT stainless) bolts, and put anti-seize on the threads (which you cleaned with a tap).

Jeff

PS: Retighten the bolts a few times as the works warms up. Have fun!
 
Jeff, Where do you get the one piece gasket? My head surfaces are pretty rough also so looking for s nice thick one!

Will
 
I did my manifolds recently and they gave me the cheap multiple piece ones. I used them, but I ended up with a couple leaks. I will try some thicker header gasket ones.
 
DRAIN the manifolds, risers/ elboes and the block BEFORE taking them off or you'll end up with water entering the cylinders (through the exhaust ports).

Jeff
 
Thanks Jeff,

I can see the drains for the manifolds and elbows but I am unsure where the drains are for the block. I don't want to go unbolting stuff.
Are there multiple drains for the block?
 
The photo is of my 440, your 340 should be the same. The drain is a small plug on each side of the block. Many people remove the plug and install a petcock. Since this is the lowest part of the cooling system you may find some crud has built up or some left over casting sand from Chrysler. It normally only takes a small piece of stiff wire to clean out any build up.

Petcock:
Fgallery7-5.jpg
 

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Going well so far, thanks for the drain location on the block, I figured I'd give it a try. The drains on the manifolds themselves were cracked from someone in the past so I drilled holes in them to drain them. This old motor needs some paint! Let the weekend begin.
engine.jpg
 
fastjeff said:
.

Finally, don't even think of using anything less than grade 5 steel (NOT stainless) bolts, and put anti-seize on the threads (which you cleaned with a tap).
Click to expand...
Excellent advice.

As for a petcocks, steer clear of any that cannot be probed easily with a wire.
You'll want to probe these openings when you winterize as to remove any rust scale that may prevent water from draining completely.

These seem to work well, and the stop is completely removable.

9-41201.jpg
 
I noticed there was plumbers tape on some of the drains, is this common?

And do you really just need to drain everything as it says in the manual for winter? No anti-freeze?
 
stevemiller333 said:
  1. I noticed there was plumbers tape on some of the drains, is this common?
  2. And do you really just need to drain everything as it says in the manual for winter? No anti-freeze?
Click to expand...

  1. Many will just use a thread sealant.
  2. Plain 'ole Air will not freeze, expand, and crack your expensive cast iron components. If you add anti-freeze, IMO, it's best to drain this again afterwards. If the anti-freeze was to become diluted by any residual water, it may not give the protection otherwise thought to give. Your call!

On a side note, each spring we'll occasionally read about someone who used anti-freeze being drawn up and into the engine and exhaust via the sea water pump, in lieu of proper draining. Often this costs them freeze damage.
The Anti-Freeze does offer some corrosion protection, but unless you know that it has not become diluted, I'd sure drain it again afterwards.

.
 
what is the other drain looking bolt next to the block drain. If has a big washer and rubber washer as well, says something about read instructions before removing.



engine2.jpg
 
stevemiller333 said:
what is the other drain looking bolt next to the block drain. If has a big washer and rubber washer as well, says something about read instructions before removing.



View attachment 5071
Click to expand...
That was a core plug or many people call them freeze plugs. The plug should of been brass and when they fail it's common to use a rubber expansion. style. It's kind of a poor patch for a brass plug that should be there.
 
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