So I took the top of the head apart this morning to fix the broken valve spring. And found another worn valve guide on this D8K I talked to the machine shop where I got the engine rebuilt and purchased these new heads from, they say this is an on going problem world wide with old D8s D9s and older 3406s. He said going to a 3/8s valve stem has seemed to slow the problem up some but no one has really solved it altogether. Seems to me that maybe its just cheap after market junk. 2 burnt valve guides and a broken spring in less then 400 hours of run time. What do you guys think? Anyone else having these issues?
Been around D342's since 74' never known of your problem. We always used Cat parts though.
Could the latest generation of low sulphur fuel have anything to do with it..? These engines weren't designed to run on 50ppm of sulphur, more like 5000 .............. I'd ask the same question as Dan. Genuine parts failing, or "will fit"..? There could lie your answer.
I don't know that you can get new heads anymore from inside the US. Broken springs and worn out valve guides in 400 hours is a bunch of crap also. You might ask your supplier which brand of beer cans their aftermarket suppliers are using. I hope they are treating this as a warranty issue?
I can't see where low sulfur fuel would cause valve guides a problem. No way these things should fail in 400 hours, the shop that did the work is full of crap. Tell them to fix it or you will take out a full page ad in the Sunday addition of the local paper telling what kind of work they do and how they stand behind it. At 400 hours a 342 should not even be broken in yet
I would check the zinc content of the oil used. Alot of the new oils have very little zinc for lubrication.
On the spacer plate 342 motor I like to have the 1/2" valve stems poking up and down, I have never had any trouble like this spring breaking worn out performance, it sounds like the oil feed is suspect? I would be squirting an oil can up the oil feed pipe and following the flow through the rocker shaft, if the tractor is cooling correctly and shut down correctly, valves and springs often last longer than the heads, also check the rotocoils to make sure they are good, on the fuel side these D8K's are the last of the beasts that will also run on near any old crap. parafin, Diesel, Kera, the cylinder head and parts should stand 6'000 hrs easily, if there was an issue with the engine oil, I tend to think you would know fast, the fact that you are running a K, makes me think you should know a bit about what oil to fill the old girl with?
I have heard of this problem in D8k's before. My friend had a valve drop in his D8k with only 800 hours on it. I think he was using CAT reman heads. I run Lucas upper cylinder lubricant in all my diesel and I now have about 2500 hours on a set of aftermarket heads. I heard its not much of a problem with the 1/2" valves and was a big problem with the 3/8" valves. We have had several valves drop with CAT Reman heads so be weary of them as well.