258 exhaust manifold heat riser removal

258 exhaust manifold heat riser removal

elwood blues

Always Off-Roading Jeeper
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Location
Export, PA
Vehicle(s)
1978 CJ7 4.2L Comp Cam & valve train, MC2100 carb, MSD ignition, Dana 30 front, T18 trans, Dana 20 txfr, AMC 20 rear.
Inside of the '79 and older style exhaust manifold is a heat riser. Has anyone else ever tried to remove this? If you did, what did you do to plug the holes that were left behind?

In case you're wondering, here's what I'm talking about.

HeatRiserCLOSED.jpg



Here's the back story. For the last almost year, my CJ has been torn apart, but I've been gone so much getting it back together was really slow. The spring had been gone from my exhaust manifold for a while, and I was really tired of hearing that flap slap open and closed when I got on and off the accelerator. So, while I had everything apart I took it upon myself to remove said flap. I don't have a welder, and didn't find anyone locally that wanted to weld cast iron. So, I tried this stuff called castaloy (they also make alumaloy). The idea is, it's kind of like solder, but once it hardens it's GTG. Well, that claim is straight BS, once the engine was up to operating temp the plugs that I soldered into place with the castaloy melted out on to the driveway.

So, now everything is back together again and I have two less than 1/2" diameter holes in my exhaust manifold. My next plan is to get some high temp JB Weld and a couple of 3/8" stubby bolts, coat the bolts in JB Weld, and hammer them home. Let it cure overnight and see if it holds. Anyone else have any ideas?
 
You can always tap threads into the holes, then insert plugs. Contrary to what some people might think, cast iron is actually fairly easy to drill and thread.....just use a high-quality tool and a good amount of tap oil.
 
I would leave it, it helps reduce warmup times and cold weather performance.

In the "open" position it provides little restriction.
 
I would leave it, it helps reduce warmup times and cold weather performance.

In the "open" position it provides little restriction.


That's not an option, its already gone.
 
i agree with les.. since its gone and your at a point of no return.. drill and tap it.. :chug:
 
what if you just put a bolt all the thru and then put a nut and washer on it
I know its a little late but I just stumbled on it
 
I know this is almost a month late, but I did end up simply tapping the holes. 1/2" 24 with header plugs, no big deal, no leaks, thanks guys :chug:
 

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