240U manifold/exhaust

I am helping my son with his "new" 1959 IH 240U, it currently has the underslung exhaust on it. It has a 369645R manifold on it, which I think is fairly common for that engine, but where on a row-crop tractor a pipe would thread in to poke through the hood, this has a cast 180 degree elbow piece to turn the exhaust downward (held on with two bolts), and then connects onto the remainder of the run of 1.5 inch exhaust pipe down the side and out under the rear axle.

Our questions are:

1) We have been spraying the bolts with PB Blaster but it is in the low teens for temperature here and not much better in the shop. Any hints for unbolting those two bolts without snapping them off in the cast manifold?

2) If we succeed in getting the 180 degree cast piece off, will there be threads inside the manifold to accept a pipe or do we need some type of adapter piece/donut/etc...? We just want to run the exhaust straight up through the hood. (We found a junked hood already so we don't have to cut our good one in the event we do a full restoration at some point).

3) Speaking of cold, we want to plumb an engine heater in. I think the best place would be from the block drain plug under the carb area and then run it up to the tee near the upper radiator hose/temperature sensor on the front/top of the engine. Will that work, or anyone have other ideas?

Thanks in advance!

You're on the right track with the engine heater. It should work good that way. Don't know if the manifold is threaded or not. PB Blaster is pretty good stuff. If it doesn't loosen up those nuts, the only other way is to heat 'em up with a torch.

I agree. ATF or PBBlaster and lots of light tapping to set up vibration and a long wrench handle. If that doesnt work, heat will.
Every older IH manifold I"ve worked on has been threaded to receive the pipe.

im trying to remember on my 240u, i think the bolts go thru the u casting and into the manifold. you can try soaking in penetrating oil with some heat, tapping on the bolts, or an impact set on very low power just to scare the bolts a little before putting the torque to it, try tightening and loosening. or you may want to grind the heads off the bolts and lift the casting off, then work on the rest of the bolt that is sticking out of the manifold. that is a tough call. worst case senario is the bolts break off flush in the manifold and to will have to drill em and retap em.

I took a look at the Parts Catalog, which usually gets you the right answers. Looks like the same manifold is used whichever exhaust is on the tractor. The 180 elbow is held by 2 capscrews that are 3/8 coarse thread. The 2 holes in the manifold are only used with the elbow. The outlet of the manifold itself is threaded for a pipe for the vertical exhaust. The threads will probably be in bad shape due to years of exposure to the exhaust. You will probably be able to clean them up with the correct pipe tap, but be ready for a problem with the threads.

Yes the manifold is threaded. I just bought one from a 240 for my Super C. The company that I bought it from sent me the manifold that was used with the underslung exhaust and it had no manifold pipe. I am now looking for the correct length manifold pipe to thread into it.

On mine I just had some thin wall pipe threaded and then had a Cherry Bomb type muffler welded onto it . It worked great!

Since it is a blizzard here today I spent the morning in the shop with my son and the 240u. After 3 days of PB Blaster treatments and wiggling them the bolts for U-pipe on top of the manifold came right out. A wire brush on a cordless drill cleaned out the carbon build-up from the threads inside the manifold and I threaded in the 1 1/2 inch pipe no problem. To top it off the muffler (which was new) from the underslung system was the same one needed for the vertical configuration! Topped it off with a -flapper- and cut the hole in the hood with the new $25 holesaw blade and all was well, not a single hitch in the plan.

So...we didn't feel right not having any problems so we decided to tackle the engine heater too. Again we were surprised with no hitches. We used a 1,000 watt ZeroStart brand, 5/8 inch heater hose, a couple hose barbs and done. Plumbed it from the block drain on the left side and up over the top to the 1/2 inch tee where the temp sensor is threaded in.

This almost makes up for the loader bracket that broke last night when plowing snow, now need to go fix that and get back after the rest of the yard and get some cornstalk bales moved for the calves.

Thanks again all! Stay warm.