706 C263 Exhaust Valve

when the 706 C263 gas came out they had a lot of exhaust valve problems. there was an IH mechanic in olwein, ia. that solved the problem by using an oversized exhaust valve. i am sure that pullers used larger valves also. does any one know a source, brand or part# for a larger exhaust valve? my dad, a 45 year ih mechanic tried using the older cylinder head and several other methods to no availe. I would like to try a larger valve.

If you use low-ash oil, there shouldn't be a problem.

use the low ash oil

well i may not have 45 years on I H tractors bot do hnow the 706's inside and out far better then anybody on here . Ya want to stop exhaust valve torching then all ya need to do is CHANE the type of oil you are using . After you do your valve job use nothing but Case I H LOW ASH 30 weight and nothing else. Since i have switched to usen this oil and all my old customers switched i have not had to do a valve job on any C seires engines due to valve torching. And by doing this i shot myself in the foot for loosen the work as valve jobs were a vary big part of my work. The next thing in C seires engine health so to speak is the use of the propper gas and here you need to run the 93 octane . Correct engine ing. timing is most important also . I just looked at our one 706 last week and it has over 4700 hrs since it;s last major overhauland is still running good . Now i did replace the oil pump and we did pull the head to replace the valve giudes last year and i have had to replace two pistons due to the fuel supplier bring in the wrong octane gas as a new driver brought in a load of 300 gallon of 87 octane by mistake and the fuel supplier ate the cost both times . Around here there are still a lot of I H gassers still in use working on dairy farms and i am the one that keeps them running .

Low ash oil, correct octane gasoline, correct ign timing and do not over look the valve seats. Most of them get loose in the head. A valve transfers most of it's heat to the head through the valve seat. If that seat does not not transfer heat as well as it should, the valve stem carries more heat. This in turn can cause that valve to stick for an instant and torch out. I put in a lot of over size valve seats in the 263 engine, even before IH introduced LOW ASH oil to get me out of the woods on valve burning. This was when we had so called good gasoline also, like 1964, 65. We had the same problems with that very similar engine used in trucks. They used to cup the valves so there was no clearance, reset them and in a couple trips, same old thing. Then IH came with a plate to block off the heat riser in manifold. That helped but was not really a cure. In a truck, drivers just held the pedal to the metal and they melted down. Had the same problem with my inlaws old chev powerglide. Local shop had installed valve seats and they were not tight. It would burn the valve in a couple thousand miles. I was young and learning and didn't recognize the seat problem for a couple of valve job. Cured it though.

Question: Regarding the low ash oil, do you know what it is about the oil that protects the exhaust valve? Just curious - thanks

Ash in oil is composed of non-combustible additives and metals that are present in oils (even the newer diesel oils do not meet the IH spec of .5% ash.
The non combustible materials fuse to the valve stem. and create a buildup that can and does migrate into the tip of the guide just as the valve closes, thus allowing the valve to get hung up and a tiny bit open. This prevents cooling, and allows the valve to get so hot that it changes shape and fails as exhaust screams past under combustion pressure. It is like cokeing, but is more like ceramic, and less like a briquette, Jim