Two winters ago, we went through the back half of the machine (steering booster re-seal, new bearings and seals on the cross shaft, rebuilt steering clutches, relined steering brakes, and rebuilt the dry master clutch with the last "new" flywheel pretty much in existence).  In doing the clutch work, it was easy to throw a dial indicator on and check the end play of the crankshaft, which of no surprise to me, was way out of spec.  We also serviced the fuel system, had the fuel tank cleaned, and changed the timing of the injection pumps.  When I went to use the machine this past January to dig up the nursery trees, it ran good initially.  Then it kind of started to struggle a little.  In between pulls, I'd shut the machine down.  Normally with an already warm engine, it would fire with ease with a quick bump of the starter.  But now I had to shoot it with ether to fire the warm engine....luckily I only had two rows of trees to pull, so we just squeaked by.....

Upon further investigation, I noticed a ton of rust inside the fuel tank.  Probably mostly my fault, I forgot to fill the tank with diesel all the way to the top after the fly-by-nighter radiator shop cleaned the tank with oven cleaner and water .  I'm sure the fuel filters have all kinds of rusty crud in them.  I will re-address that and the fuel tank here very soon.  In any event, we decided to just overhaul the engine.

At the end of last week, we got right into it and pulled the head........
 
 
 
 

The exhaust ports on holes 3 and 4 were kind of wet looking.  Everything else looked pretty good.  When the head came off, piston 3 was in the worst shape, as can be seen in the pics.  We think the gouges burned into it are probably from a bad injector capsule dripping fuel instead of atomizing it.  The underside of the head looks to be surprisingly very good.  No sealing issues with the head gasket.  I will say, the liners are sitting deep, with minimal protrusion, not leaving a whole lot of crush for the head gasket, but apparently just enough to have gotten us by.

We haven't dropped the oil pan just yet.  As you can see in the first pic, this machine is kind of one-off.  It was built up on a special frame that makes it high-clearance.  To attempt to inframe this engine, we need to jack up the front end of the tractor so the oil pan will have room to drop down and slide out past the leaf springs.  We are in the process of fabbing up a framework to safely support and jack up the front end.  Photos to follow when that's all done and in place.  In the meantime, the radiator came out today and got dropped off to the good radiator shop that my family has gone to for years (no more fly-by-nighters for this boy!)

In removing the radiator, the water pump and fan also came off the machine.  While we are into it, we want to replace the water regulators.  I couldn't find them anywhere in the appropriate 8U parts book that we have.  I searched past posts, but was inconclusive as to which part number I am in need of.  It sounds like there are different iterations of regulators according to serial number.  Mine has some chamfered brass rings that need to be pried out before the regulators can come out.  I was looking for some guidance/input here form someone in the know as to what part number(s) I will be needing.....

Also, I started researching overhaul gasket kits.  I remembered and referenced a previous post where Old Magnet posted a chart of engine gasket kits with their corresponding Cat part numbers according to the model and series of tractor.  The "Basic Overhaul Group" gasket set from said chart for an 8U/9U D6 is listed as part number 9M4740.  I went to my local Cat dealer this afternoon and had them look this part number up......discontinued!!  Not to panic, I think you can still order all the pieces individually.  But I really didn't want to endure the pain of dissecting my entire parts book for all those part numbers.  Just for fun, I asked my parts man if there was any way for him to generate a list of all the individual part numbers that went into gasket set 9M4740.  He went into a separate parts program/database on his computer that is called "TMI" and came up with the list of part numbers that he printed out for me here:
 
 

Having a good competent parts man at the dealership you go to is half the battle.  If anyone else references any of those engine gasket kit numbers from the chart that OM shared in that old post (the chart is uploaded and available in the database here on the website) for a different machine, and the part number comes up as discontinued, ask your parts man the same questions I did, and if you get a parts person that suffers from any level of ineptitude, more specifically, ask them to look the gasket kit part number up in "TMI"

That's all I have for now.
Thanks!
-Nick
 

Thanks for the update Nick! Hope you get things buttoned up before the “big dig” begins.
I have always been intrigued by tree diggers. JM

You need to get acquainted with www.machinerytrader.com
There still may be some 9M4740 kits around.
www.machinerytrader.com/parts/search?Par...740&SearchType=Start
 

OM-
You are probably the one that would know best….would you happen to know what the part number is for the water regulators for this machine? I can’t find them anywhere in the parts book. 

Thanks!
-Nick

Hi,
You will find the regulators in the water pump section of the parts book.

 

Regards 

Thank you, Rax !!! ....I totally missed that in the "water pump" section of the manual. That definitely threw me bigtime. I was looking for them to be in the "water lines" section, since the housing and lid for the water regulators is actually shown in the drawing there and it would have made a lot more sense (at least to me) for them to have been listed there.  I will have to remember this detail for future repairs on other models.

OM-  Machinery Trader is a great resource.  I am leery of buying older gasket sets that have been sitting around in hot warehouses for many years.  We have had a few bad experiences where the NOS gaskets (mostly the ones made of cork, but some were paper too) shrank down.  When we went to try and stretch them out a little to get the bolt holes to line up, they always bust apart.  Then you're out twice the money when you have to turn around and buy a brand new and fresh gasket from the dealer.  We've found that you're always money ahead just getting fresh gaskets from the start.

We made a lot of progress today. My shop foreman finished up fabricating the jack frame and we got it in place, removed the bolts connecting the frame of the tractor to the crossmember that sits on the leaf springs, and got the front end of the tractor jacked up enough to clear the oil pan.  That oil pan was a bugger and didn't want to break loose from the engine even with all the bolts out.  We had to heat all along the boltline of the oil pan with the torch and rap on the pan with a hammer to finally get it to break free and come down. 

 

 

 

 


That's all for now.  As always, thank you for your inputs.  More to come as we get there....

-Nick

That screen.........

Lots of material/debris on front and rear oil pickup screens!

Congestive heart failure!

Just to prepare you, 10 years ago the Cat thermostat for the Cat 318 was made in China. The person buying them said defective as the engine still pushed water out. But I believe it is the seals in pre combustion chambers leaking. The D6 has been sitting and the owner dead. So the issue was never addressed. So I think the thermostat worked, but if you don't want China parts I would check you old ones. Put them in a pan of water and heat on the stove and watch if they open.

What a good piece of safety gear you have in the stands to hold the engine up, for pan removal.

There is modern teck equipment to cut gaskets (terrible to be old and forgetful, as to what industry it can from, maybe cutting cloth for clothes) way expensive for just a handful of jobs. But a good opportunity for the right person. I cannot come up with what color iron was being discussed. Someone stumbled across a used machine and cut some very thin gaskets like would be in a carburetor very successfully. But a small ball peen hammer does alright on a lot of flat gaskets if you cannot buy sets anymore.