My project is a 1969 Dodge D400 slant 6 dump truck. A valve guide broke and while it will run, I want it to be at least as good as it did before the break. While I am dealing with the valve, should be looking for other failures. The vehicle has about 80,000 miles.

What is the average life of rod and main bearings and rings? I will inspect the valves when I pull the head.

I am in Cincinnati and if any have new parts on a shelf because a project failed to materialize. If anyone has anything that I might use, let me know. My project ain't purdy but a dependable engine trumps second guessing some Detroit engineers.

Thanks, Dieter

Age and miles only give the barest of hints as to the condition of the engine at this late date. You'll need to do a compression at a minimum. The pistons rings can be wiped out from detonation or from dust if the air cleaner isn't maintained. Rod and main bearings will wear if the oil is badly contaminated. There's really no way to know without an inspection.

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Joshua

I have never heard of a valve guide breaking, are you sure about that?
I agree with Josh, do a compression test prior to removing the head. That will give you some indication on the condition of the piston rings. Your own experience with oil consumption should also give you a good indication. Something to consider is older engines, even those that had regular oil and filter changes usually have a lot of internal sludge. Because the engine oils available prior to the 90’s just was not very good. You will get an idea of what you are dealing with when you take the valve cover off.
Another check you can do before taking the head off is put a timing light and see how stable the flash is.
If it is moving around a lot, the timing chain / gears are likely worn.
Concerning main and rod bearing wear. If you are running a reasonable weight of motor oil like 10w30 or 15w40 and have acceptable oil pressure when the engine is at operating temps at idle and at road speed, don’t hear the rods knocking,,, more than likely the rod and main bearings are ok.

When you take the head off I would pull the oil pump and service the by pass valve and just to be safe take a look at the oil pump drive gear.

It is always interesting to hear about and see slants that were in HD use.
What kind of tonnage is your dump truck rated at? And do you know the rear axel ratio?
A photo of the truck would be great.

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Let's see a photo of this truck!