Reo OA-331 intake/exhaust questions

[Kaiser67M715]

I took apart my exhaust to fix a couple leaks(both end gaskets were completely blown out, center intake/exhaust gasket looked much newer, but also looked like it was on the verge of failing) and discovered that the heat valve for the bottom of the intake is gone, which makes me wonder if this has caused some of my hard starts after running, normally letting it sit a couple minutes, or running the throttle wide open could get her started. Anyways, I would like to block this off some how, with maybe some thin steel? or part of an aluminum can? I could just make another valve and weld it, but I wouldn't mind something that would completely seal it off.

I'm pretty sure I read that the civilian versions did away with the heat riser/valve system, but I'm sure the head design changed some too. but any input would be nice.

Thanks.

 

[Barrman]

I have my valve closed and it is still hard to start with a hot engine on a hot day. One of our members from Spain put up some pictures of Gasser trucks in service with his country. All of the hood side panels were removed to help underhood heat and he claimed they still had issues getting them started hot.

The next size up engine after the OA331 was I believe the 400. It had the different design intake and exhaust manifolds. They will bolt on to our engines though.

 

[Kaiser67M715]

Thanks, its good to hear the different design manifolds would bolt up,

I did talk to my dad about it, he thinks a piece of thin gauge stainless(for the heat) a full size piece of exhaust gasket, and stuff the void with fire braid(the rope stuff you put around a wood stove door to seal it), he thinks that will help quite a bit, oh, and make sure there is a small hole for the gas to escape so we don't crack the intake.

I'll try and keep my eye out for the different manifold though, some stuff I don't mind "upgrading" but I definitely want to keep with its roots and be "more" correct, while still being reliable.

currently I will be sending out the manifolds to get resurfaced, just to make sure they are flat for when I put it back on, and I am looking to rebuild the carburetor as well; it was starting to "pop" out the exhaust, which is when I noticed the exhaust leak, but the gaskets didn't reveal an intake leak

 

[rustystud]

My old journeyman I learned gears from was in the Korean War. He said the old M35 gassers would overheat so bad they made a standing order that they could only be driven for 1 hour at a time then they must have a cool down period. This was driving through rough hilling terrain. At least the multifuel solved the overheating problem ! I'm sure that if someone took the time to map out the cooling system they would find all the bottle-necks and other areas that could use some improvement and come up with a plan to fix it. This engine is not much different then the IHC Diamond series. Those engines never had a cooling problem.

 

[ReoRider]

Replacement parts for the heat valve in the manifold or a complete used one should be available from the regular suppliers. Is a handy feature to have on the truck for cold climate locations to speed up the fuel/air system warm up. Is a similar unit, also with manual adjustment, on the Dodge 3/4 tons. The "advanced" version was found on the Jeep series with a bi-metallic spring control to respond to temperature changes.

Hard starting when hot, that responds to a wide open accelerator pedal, is usually more likely fuel related, with the usual suspects of needle valve, float level, fuel pump pressure and so on. Have not experienced a pattern of overheating with the Gold Comet Series of Reo engines. It was an excellent OTR truck engine for many years with a great reputation. I enjoyed many cross country trips in my loaded M35 with enough heat crossing the Midwest to run with the front windows way open into the evening. Naturally, a clean radiator and good PM are necessary for all our beasts.

 

[Barrman]

Mine has a "happy speed" of 48-52 mph when it is over 100° out. Several years ago I drove 130 miles to Houston, hooked up to a motor home and flat towed that thing home. 38-42 was the "happy speed" for that trip based on keeping the temp gauge below 200°. It would run as fast as I wanted though and the hills were none issues if I attacked them before I got to them.

4.9 mpg going down empty and 4.5 mpg coming home.

 

[ReoRider]

Not surprised at the performance, the Reo is quiet, has a good torque point and lots of high revs available. For one of the long hauls out to visit Jack Tomlin in Utah, back in the day, I added a second fuel tank and swapped the Spicer to the 5th overdrive configuration. It lived in top gear on the flats and had direct available anytime the road moved up too much.

 

[Kaiser67M715]

I am getting a carb rebuild kit, hopefully by next week, as I always thought the carb as a whole was a little off- I never really rebuilt it, just cleaned it when I first got the truck going, and I didn't really get into the wealth of information that was available on here, till later.

Anyways, got the manifolds resurfaced, and picked up a piece of 22g stainless, drilled out the stud holes and rolled a 1/8" bead around the outside edge to help seal, I only have one gasket for the intake to exhaust mount, so figured gasket on bottom and stainless on top, couldn't find the fire braid, or rather no one had some in stock, some came in kits of 5 ft, but I would have no use for the 4.5 I wouldn't use.

I never really plan to use the truck in the cold(40's maybe) so the lack of a heat riser isn't too concerning right now. At least everything I am doing is completely reversible.


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[Kaiser67M715]

got it all back together, I did a quick carb clean-but still waiting for the rebuild kit-the truck started much faster, and warmed up almost 10 times faster- I literally started the truck went to check for exhaust leaks, tightened a couple bolts, then got back in the cab(less then 5 minutes total) and the truck was sitting at 160, normally that is a 20-25 minute process, didn't even need to use choke to take off, seems a little better power wise as well. I could tell it was warming up faster, because the exhaust was getting very warm very fast as well, sounds much better-quiet better, I think the exhaust ha been leaking for a while(intake too) but it was past the "tick" noise, which is why i probably never really caught it, and why it sounds much quieter now.

I took a short video, run down to the corner store, then back, once I get it downloaded, I'll link that up.

 

[REO 54]

Thanks for the thread/info. I haven't experienced the issue yet, but I don't drive my REO as much as it deserves to be.

Im into the brake pack right and trans brake right now.

 

[Kaiser67M715]

here is the video, going to pick up some hay bales with her now, probably be an 80 bale crop this year, we'll see how she does.

https://youtu.be/JXj9PcYlZ08

 

[rustystud]

here is the video, going to pick up some hay bales with her now, probably be an 80 bale crop this year, we'll see how she does.

https://youtu.be/JXj9PcYlZ08

And I thought our roads where bad ! Your roads take the main prize for being the worst !