Dropped Valves

[Dirtleg]

No I haven't dropped a valve or anything but it just seems to me it is a far to common occurance with these motors. I am curious if anyone has attempted to or been successful retrofitting different valves and better keepers on an IDI.

Also, since I don't really know much about the stock components what is it that causes the failure?

I am just asking at this point but who knows about the future. I am not one to let an obvious and highly likely, potential problem go unaddressed if I have the means to correct it.

Thanks for any input you may have.

 

[160k87F250]

I might be wrong, but I think the problem is worn guides or valve seats. Then the valve gets loose and the keepers can work free. Just guessing, don't know for sure, but I did see Pafixitman's worn heads, and the valve and spring would wiggle around in the head. Not very good.
John

 

[FordGuy100]

I dont really know it all, but I'm pretty sure I know some of it. The 6.9's had something wrong with there deseign of some valve component and that caused them to burn oil. To fix that international changed that flaw, but caused a higher valve failing rate. So they fixed the burning oil deal, but the trade off was that sometimes they would drop a valve. At least thats what I've taken in over the years.

 

[82F100SWB]

There was nothing wrong with the 6.9's valve seals that let them use oil, that's how old diesels were, oil useage was normal... The problem with the 7.3 is they fixed the seals, but, didn't change the valves/guides any, and they were designed to be oil lubed.

 

[typ4]

Here is my 10 cents worth. I have seen a bunch of these in wrecking yards with dropped valves, 2 things, the rockers were really worn bad on the tip, shoving the valve thru the guide ,then the exhaust heats up the valve spring and it fails. The rockers were really galled on these and 2 of them had the service records in the truck and they didnt show oil changes but for every 10k or more miles. My core engine had 200k on it ,was owned by a farmer that changed the oil every 4k and it looked like new inside, except for the hole in one cylinder from the worm. I knew him and he never heard of changing or checking coolant, so I clued him in.
The valves IH uses are better than anything afterrmarket so I am pretty sure it isnt the valves fault.

 

[f-two-fiddy]

I think Russ hit it on the head. Maintainence is the key.
There are different guides available thru DAS that address the oiling problem. I suspect they're high in lead content?

 

[Jaybee]

Dirtleg - I have the perfect opportunity for you! I have for sale right now an idi truck with one worn valve guide that hasn't yet proceded to the "drop" phase. You could buy the truck and do an in depth study on it. If you drove it home to VA from GA it might even decide to drop the valve on your way home - saving you the fuel costs of further test driving to reach the failure point.

Mine started as a slightly odd note to the exhaust that I chalked up as me worrying too much and hearing problems that weren't really there. This was as I left on a 2200 mile trip towing a 9000lb trailer up to PA and back with a bunch of driving around in PA while up there. Throughout the trip the noise got louder developming into a chuff noise that started to concern me. Power never dropped off a bit. When I got home I hit the forums and realized what the problem was much to my dismay! The engine has about 120,000 miles on it since it was new in '91.

Now, as long as I've owned the truck there has always been a bit of a tick under the valve cover on the side that this guide is failing on. I never could find what it was, though, and everyone I asked to listen to it said I was hearing things. I'm wondering if there was something else slightly off in the geometry of that rockers, etc that might have made this guide wear faster since none of the others seem to have this problem.

Oh, and one other thing I haven't noticed mentioned on this thread. Does the de-sulferization of the fuel since this truks were new play into things? In other words would these guides have held up if the fuel still had the sulfer in it that it had in the early 90's? Seems like that would have provided some lubrication qualities...

 

[Agnem]

I'd have to agree. I think infrequent oil changes is the root cause, especially for the 6.9's which had a rocker design that was later changed for the 7.3's. Be that as it may, every time I've had the rockers out of my 83' (not often) they looked like new and had no wear. That's the way things go when you change your oil every 2000 miles.

 

[Diesel JD]

My strap type rockers looked pretty new when they were out last at 153,000 miles. Have no idea how they are now. The P/O said he changed the oil every 2500-3500 miles with Rotella, and that the owner before him maintained it well too. I have changed the oil anytime I suspected contamination or every 2500-3500 miles or so as well. Aside from the scary high lead reports after my WVO experiement I have always had good oil sampling results. I don't want to brag assuming that poor maintenace is the cause, but it seems like it might be part of it at least.