Farmall 656 motor issues

got farmall 656 gas that don't run properly. it has almost 8500 hours and has only been overhauled once. the symptoms are it does not run smooth as i refer to it as "the hit and miss" meaning it sounds like it does not hit on all cylinders. it also starts really hard and when you idle up it pops and sometimes shoots a flame. it also leaks exhaust around the manifold. does anyone have any ideas on what could be the problem? thank you

Leaking exhaust at the manifold is a clear indication that the intake and exhaust need to come off. Probable intake leak as well as exhaust. Remove the carb and attachments (take pictures to remember the way it was). then remove the manifolds as a unit. Have the castings checked for internal and external leaks. (between the manifolds is a heat box that can leak exhaust into the intake) Have the mating flanges that bolt to the block surfaced (with it together) such that flat bright shiny metal is now interfacing with a new gasket on a well cleaned (shiny) head mating surface. Use new studs if at all possible, and new nuts for sure. use a torque wrench to reassemble the casting to head. If it still runs poorly we will help from a position of good intake and exhaust. Jim

Intake and exhaust leaks will do funny things to an engine.

It's a couple hours' work to pull the manifolds, clean things up, and put new gaskets on.

Fix the glaringly obvious problem first. See if that helps.

I think i would do a compresson test first,then when running shoot a slight amount of starting fluid around the intake manifold! If the speed increases you have found your leak? Any way to hook a vacume gauge to the intake? a flucuating reading usually points the finger at your valves.What about a wobbly dist shaft?? Lots of simple things to check before you pull it apart? Bud.

Hello guys. I'd kinda like to pull the manifolds on my C-263 since I have to use a lot of choke to start it. Spraying fluid and propane around the intake doesn't do anything. I'm not sure the flapper in the box is still there.

Anyway, I'm just wondering what the price of gaskets and new studs is approximately and how hard is it to pull the studs? It just seems like every time I work around an exhaust system, the nuts are rusted tight and strip out, or they break off, and they are in a place where you can't get to them with any leverage. I'm just always afraid I'm going to start wrenching on that 2606 and be shut down when I've got hay to move. I may go hit them with some wd this evening and start wrenching and hope the ih dealer has stuff in stock. If nothing else, I'd like to see the inside of that box. Thanks for any help.

(quoted from post at 08:31:24 03/04/11) Hello guys. I'd kinda like to pull the manifolds on my C-263 since I have to use a lot of choke to start it. Spraying fluid and propane around the intake doesn't do anything. I'm not sure the flapper in the box is still there.

Anyway, I'm just wondering what the price of gaskets and new studs is approximately and how hard is it to pull the studs? It just seems like every time I work around an exhaust system, the nuts are rusted tight and strip out, or they break off, and they are in a place where you can't get to them with any leverage. I'm just always afraid I'm going to start wrenching on that 2606 and be shut down when I've got hay to move. I may go hit them with some wd this evening and start wrenching and hope the ih dealer has stuff in stock. If nothing else, I'd like to see the inside of that box. Thanks for any help.

Click to expand...

Use you oxy-acetylene torch and heat those nuts red hot, let them cool down to room temperature and they will come off easily. If you don't have a torch, it might be time to get one. A torch is almost a necessity when working on old iron.

Use an acetylene torch to heat them. Hal

PS: Check with Fastenal to see if they have the nuts and studs.

Getting the manifold off is no problem normally as they use plated cap screws to hold it on. The problem comes in if you want to do it right , that is take the manifold apart to clean and repair the heat riser. Also, note, two different types of gaskets were used. IH went to steel raised beads gasket with composite on both sides of intake sections. That made a good sealing gasket but requires proper tightening procedure with manifold loosly bolted together to properly align itself onto head. Other gasket that most suppliers use is same thickness all the way.I'm not sure if CASEIH still uses embossed composite or not but I actually have a head gasket set laying out at the shop I am working in so will know when I go back out there Monday, weather permitting.

well i am not sure what all the things you have mentioned are. i talked to a guy today that said try taking a spark plug wire off the distributer to see if you can narrow down which cylinder may be missing. i really don't know a whole lot about engines so i really dont want to get in too deep so i am trying to get ideas of simple things to narrow down the issue thank you

We can help best if we know what capability you have for diagnostics and repair. Your lead statement in this response is very helpful.
If you have a cylinder miss firing, and the tractor backfires and is not smooth, there are 50 things that could be direct cause.
Starting with which cylinder is not firing, or not firing all the time is a good starting point. Pulling off plug wires is hard on the components unless done safely.
With a used sparkplug (even from a lawn mower)the test can be done. With it not running, pull the #1 plug wire off of its plug (closest to radiator). Be careful to twist on it to break the seal of the rubber insulator before just pulling. Use the spare plug to control the pulled off plug wire. Insert the plug into the wire and place the body of the plug against the metal of the tractor engine, or use a jumper from the plug threads to the engine metal. This provides a path for high voltage, as much as 20,000 volts. Do not hold the plug, tape it to the tractor engine if needed.
Now start the tractor and note if it sounds different. it will now be missing on two cylinders and be much worse. If it is worse, do the same thing to each cylinder, putting the wires back on the tested cylinder before removing the next wire. One of the cylinders will cause no major change in the running. This cylinder is the suspect cylinder. Now check the plug wires for correct connection. The #1 plug wire is a starting point. The distributor (where the plug wires go to be fed electricity) turns Clockwise. The firing order is 153624. Thus clockwise from the #1 plug wire hole in the cap is #5 plug wire. proceed around as in the order above. If they are correct, that is good. If they are wrong Recheck your self before making changes.
If changes make it worse put it back the way it was.
The reason we all zoned in on the manifold is that a loose manifold will make every symptom you listed. And a leaky exhaust will indicate that the manifold may be leaking on the vacuum (intake) side as well. It is a common issue.
Do these tests, then start a new posting with the results. We can do this. Jim