ISX Valve Issues

[8TiresRollin]

Originally Posted by jad300

My question is: Is it always number 6 cylinder on these engines that drop the valve? If so why? In my thinking there must be a bad cam profile or there must be a heat related issue in that cylinder. Mike

Wonder if there is something like a restriction in the water jacket or head gasket that disrupts cooling water flow and causes #6 to get hot? After all some members have had this happen twice always #6 so something is up there. Anyone tried that water wetter compound in the cooling system? That ensures all air bubbles are removed. Just firing out ideas here. What about aftermarket exhaust valves such as sodium filled ones like used on racing cars. For the money that are being spent on repairs a custom valve manufacturer could make really high quality ones. After all, the valves that are in the engines now were produced by the cheapest bidder!!

[Dutch Star David]

Originally Posted by 8TiresRollin

Wonder if there is something like a restriction in the water jacket or head gasket that disrupts cooling water flow and causes #6 to get hot? After all some members have had this happen twice always #6 so something is up there. Anyone tried that water wetter compound in the cooling system? That ensures all air bubbles are removed. Just firing out ideas here. What about aftermarket exhaust valves such as sodium filled ones like used on racing cars. For the money that are being spent on repairs a custom valve manufacturer could make really high quality ones. After all, the valves that are in the engines now were produced by the cheapest bidder!!

Most-if not all-of the issues with the ISX have been on the ones "juiced" to 650HP. Hopefully my 600 will be OK.

[hrw]

nothing "juiced" about the 650hp. I'm not sure what you mean by that comment but the 650 came from the factory with that horsepower. When ours dropped a valve, the guys at Cummins Coach Care in Coburg told me the material used in the new construction was not standing up. When the overhaul was authorized they went back to a material that was used in previous models. True or false who knows for sure? I will say no one can beat me on the hills and the unit runs like a top.

[hrw]

Originally Posted by dlovitt

Most-if not all-of the issues with the ISX have been on the ones "juiced" to 650HP. Hopefully my 600 will be OK.

yes, I believe the 600 hp is a better from the factory engine than the 650. Mine has been overhauled and I'm betting I'll make plenty of trouble free miles now. All the best

[Dutch Star David]

Originally Posted by hrw

nothing "juiced" about the 650hp. I'm not sure what you mean by that comment but the 650 came from the factory with that horsepower. When ours dropped a valve, the guys at Cummins Coach Care in Coburg told me the material used in the new construction was not standing up. When the overhaul was authorized they went back to a material that was used in previous models. True or false who knows for sure? I will say no one can beat me on the hills and the unit runs like a top.

"juiced" probably a bad term but Cummins must have done something to that engine to get the additional 50 HP. Whatever that was may have been why the 650's seem to have the valve problem.

[Steve Ownby]

Originally Posted by dlovitt

"juiced" probably a bad term but Cummins must have done something to that engine to get the additional 50 HP. Whatever that was may have been why the 650's seem to have the valve problem.

I've been watching the ISX valve problems on these forums for a number of years. It appears that all the ISX rebuilds involved the Double overhead cam version that was redesigned for the '10 EPA engine to a single overhead cam version. The '10 version doesn't seem to have been offer above 600 hp. The older twin cam version that was used for several years at525 hp didn't seem to be prone to this failure.

[koole]

Anyone who had to do a fix on their ISX for the valve on Number six, was it the exhaust valve or the intake? Did the valve break off or did a piece of the valve break?

[vito.a]

We are seeing similar exhaust valve problems in other high performance engines like the LS7 Corvette engine. Valve manufacturing shifted from the US to South America and quality control is not as good. In the case of the LS7, they are sodium filled stainless steel valves and the hollow stem is not concentric. In some places the stem is only .017" thick. These valves are manufactured using an electric welding process to attach the stem to the head. The result is the valve heads are breaking off. Just like the ISX 650, the results are catastrophic.

[koole]

Just wondering why the only cylinder that seems to have trouble is number six.
My friend's engine a ISX 525HP had number six give trouble but the intake valve broke a piece out of it, leaving me to believe that heat had nothing to do with it.
I have a 650HP and I am thinking of changing the valves or the complete head to avoid future problems. Any thoughts or comments would be appreciated.

[vito.a]

Dropping a valve can be caused by broken/bad keepers, broken/bad retainer, broken spring, piston to valve contact, or the valve head breaking off.

A replacement ISX cylinder head will be expensive in both parts and labor, but cheaper than replacing a cylinder liner, piston, rod, and cylinder head. The problem is how do you know you have one with redesigned/updated parts.

[WILDEBILL308]

I am inclined to think it is pore material in the valves. I have abused gas engines with valves that were a lot thinner with undercut stems, double valve springs and no problem.
I have heard of a valve seat coming out and starting the problem.
I would bet you could buy different valves as a replacement.
Racing Engine Valves | Ferrea.com
If I had a ISX and was worried I would see what they say.
Happy New Year
Bill

[koole]

I would still like to know why it seems to be only number 6 cylinder that has the trouble. If it was faulty valves why no other cylinders have had trouble?

[MnTom]

Originally Posted by koole

I would still like to know why it seems to be only number 6 cylinder that has the trouble. If it was faulty valves why no other cylinders have had trouble?

Good possibility if you had a pyrometer in each cylinder you would most likely see #6 is hotter than the others. On the 5.9 #6 is the hottest also due to a bit of an air flow restriction so it gets less air than the rest and with a diesel the more fuel the hotter the temperature. If you remade the intake, ported the head, and put a 'performance' exhaust on you would see cooler temps on the pyrometer.

[koole]

Originally Posted by MnTom

Good possibility if you had a pyrometer in each cylinder you would most likely see #6 is hotter than the others. On the 5.9 #6 is the hottest also due to a bit of an air flow restriction so it gets less air than the rest and with a diesel the more fuel the hotter the temperature. If you remade the intake, ported the head, and put a 'performance' exhaust on you would see cooler temps on the pyrometer.

If heat was the problem,why would the Intake valve break?
I am only asking because the Intake valve should be quite bait cooler.