D69U Head removal procedure.

Only way I have ever had the rockers off is to take both boxes off as a unit. I needed to harvest a single rocker arm off an engine sitting on the ground with no pony in the way. Its not easy, but you can remove the decompression shaft by loosening the clamp bolts on the cams that ride on the detent ball in each box. Be careful to catch both detent ball and spring as well as the tiny woodruff key that keys the cam to the decompression shaft.

I would just take loose the two small oil feed lines and the decompression lever linkage and lift the whole kit and caboodle off as a unit.

There would be lots of things that you had to modify to drop a 3306 into a 9U. I would find a good runner or overhaul the engine you have. If you have a good head, block, crank and connecting rods you can have a good engine of known quality.

An impact gun will sometimes rattle things like that loose, I would try soaking it and applying heat to the nut and letting it cool. Have seen the whole PC chamber break loose on one before the hold down nut came loose when using a breaker bar.

Thanks for the detailed reply ccjersey.

I will try applying some heat to the nut next, then impact. I already sprayed a liberal amount of fluid film on it yesterday. Also, I was using an impact gun and that's what got the other 5 out, but it is just a 3/8" milwaukee battery operated unit I had in the field, so not a whole lot of oomph. I'm leery about a big breaker bar also because that nut is pretty narrow and I can tell the socket wants to slip off, so I have to hold it with one hand. Would be easier with a helper I guess. Is that a bad thing if the P/C turns instead?

Your comment about removing rockers and both boxes as a unit makes sense. I'll give that a go. Mostly I just wanted to find out which if any valves are stuck. Though the heads will most likely need to come off eventually also.

Also I ordered the engine service manual off amazon. sure would be nice if the old manuals were in the public domain and hosted online by now.

related question: besides the piston rings, what else might be rusted and preventing turning?

Here's my short list:
+ valves, stuck shut.
+ injection pump. ( doesn't seem likely, full of diesel. )
+ water pump.

what am i missing?


my plan is to soak first with marvel mystery oil for a few days. Then siphon it out, and replace with vinegar, which has a mild acid to remove the rust and is mainly water which is heavier than oil, so it should reach the metal past the marvel/diesel and even past any water still in there from the rain. might also try a little diet coca cola also as I hear good things about the phosphoric acid. A final trick will be to siphon again and then pour in some boiling oil; the heat is supposed to expand the cylinder and let the oil seep in through cracks.

D318 does not have heads. It is one long heavy brute to manage on your own without lifting gear. Also needs a lot of care to refit as there are a lot of seperate sealing rings in the gasket to keep in place.
Chances are you will end up pulling the head to get it cleaned out properly. A lot of crud can fall into the innards via those pre combustion chamber holes. depends how clean he water space is. If it is a bit blocked up there will be a heap at the bottom of the liners and the bottom pilot motor passage behind no 6 will be very likely be completly blocked. Then you can pull the pilot motor to clean that all out. Believe me it can be a long journey.
good luck WF

9This process of getting one going is a slippery slope! Before you know it you will be doing a complete overhaul!

I was about to suggest that you would want to go ahead and break the precombustion chambers loose while the head is still on the engine as that can take some serious torque. But on the other hand if they aren't leaking I would probably leave well enough alone. If the head needs milling later, they will have to come out, but probably best to try to rattle them out with a good impact gun. I have seen them take the threads out of the head.

Really the only thing that will be holding the engine is the rings. I think you are going about it right. You may wind up overhauling it in the end, but that process is much easier if the engine will turn over.

I would delay taking the rocker boxes off until you know you are going to take the head off. I would just pour motor oil over the rockers and down the pushrods to lube the lifters and camshaft. Then if you want to check the valves simply bump on each rocker with a hammer handle etc.