Thinking of buying Cat 963 A high hours

Let's go one step at a time. Make sure there are no compression leaks past one (or more) injectors which can be done without removing the head. The installation on those injectors is pretty finicky to get right. I hope the person/company who rebuilt the engine followed the procedure correctly. If they didn't it may tell us something about other corners they may possibly have cut during the rebuild.

While you are there, hand rotate the engine until the bad guide valve is just off the seat and try to wiggle the valve at the top with the spring retainer, it will be stiff but if the guide is bad it will move noticeably. If it does move side to side you have a bad guide and the head will have to come off. I've seen this more times than I ever wanted to and it was always a bad guide on the sooted up cylinder. If this was just rebuilt, they did something wrong, or the guide was damaged when it was pressed in, etc. Do this in conjunction with what Nige posted above.

Know i just remembered, one time i had a injector loosen up and it caused the same soot problem. It also added fuel to the oil. You might do a oil analisis it might shed alot of light on your problem.

I went out there today.

First off, I need to get my dad's full set of SAE tools. All of my tools were stolen a few years ago, and when I stocked up, I decided to buy just metric ... I didn't think I'd be working on anything this old ever again

So I didn't have a small enough SAE socket to get off the injectors. I'll take them off tomorrow.

Anyway, I was able to test the valve guides, and yes, the #3 exhaust valve guide has a 1-2mm of play side to side. One other valve has maybe 0.5-1 mm of play. All the rest are good.

I started taking off stuff to pull the head. It looks like a fairly easy job.

I'll look at see what things look like, but yeah, I'll likely be taking off the belly pan and the oil pan ... I'm still analyzing audio samples, but I think there is some knocking that shouldn't be there.

boy, I sure hope the bottom end is good for you

Head is off and at the machine shop! No more surprises. Everything came right off. Head gasket looked fine. Cylinder walls seem good.

I did drain coolant (using the little valve pictured near cyl #4), but obviously not enough! The coolant on the pistons was just from leaking out as I removed the head.


Got the coolant off and put some oil on top and on walls:


Looks like a 0.040" overbore:



And a few weeks ago between the time my mechanic told me it was OK to run and the time the rebuild guy said not to run it 10 feet, I did a little work. This tree had been stuck deep in the pond for a couple of years. This thing yanked it right out! (broke my chain though after I got greedy and tried to skid it up hill)

no cyl liners in these engines ????

crazyjncsu said:

Head is off and at the machine shop! No more surprises. Everything came right off. Head gasket looked fine. Cylinder walls seem good.

Click to expand...

I would be putting some cap plugs or other cover on those open fuel line fittings on the injector pump before some dirt gets in there and gets expensive!! No cylinder liners in these engines, it's pretty much half of a 3208 "throw away engine"

when you bore them to max then you can sleeve the block back to std.

I got out there today and dropped the oil pan. It took a little more force than I anticipated. I guess there was some silicone sealant or something holding it.

The only thing I had time to do is wiggle everything a bit. My mechanic had said the knocking was likely side-to-side play in the wrist pin. Well, there is side-to-side play in the wrist pins .... and side-to-side play in the rods (video below). But CAT doesn't list a spec for side-to-side play, and wouldn't some be expected anyway? Would excessive play cause knocking?

Another day I'll do some turning of the crank and see if there is any play in the stroke of the pistons (I couldn't create any play from pushing). And I'll remove a rod and main bearing and take some pictures. Any other suggestions?

1 minute video:
https://vimeo.com/134570893

if it was me I,d pull the engine and take it to bare block then see what I had then bring it back up correctly. this way you,ll now what you,ve got plus if you document everything it will mostly come back in resale value. jmo

After seeing your video the fore-and-aft play at the crank and wrist pin end they all look & sound normal to me, although from it's hard to be certain with your hand blocking the view. The key fact is that all 4 cylinders should be pretty much the same. TBH I wouldn't expect problems in that area.

What it didn't seem to me like you tried was to pull down or lift up the rods. That's what would indicate rod bearing wear. I personally would remove all 4 rod end caps and inspect/photo the journal bearings plus also remove the front and rear main bearing caps and do the same inspect/photo procedure. While you have the rod bearings disconnected move each piston up slightly so that the top rod bearing is just clear of the crank then see what up & down play you have between the wrist pin and the rod eye bush. If all that comes out clear IMHO there is no need to go any further than you have right now.

Did you ever get chance to speak to the engine "rebuilder" and find out what parts they put in the engine when they allegedly rebuilt it to zero hours..?

I did attempt to pull and lift the rods, I just didn't get any wiggle there. But I was going to get each piston in a position where the crank was pulling it down, then push from the top to see if it moves in at all.

I'll check/photo each rod/main bearing/cap/journal.

I did cover up the fuel injection stuff.

I'm having a bit of a hard time communicating with the rebuilder. For every question I ask I get a response that somehow includes the fact that 3204s are "junk engines", as if that somehow absolves him of needing to do good work. At this point I'm kind of just waiting to see if I find anything egregious enough where I can put any real pressure on him .... not that I need much help at this point, as it's already apart. The engine is out of his one year warranty, but he's a national rebuilder with a reputation (not a great one mind you) that he may want to protect. It seems he clearly botched the value guide ... maybe through negligence. The valves were all mismatched if that matters. There could be something else I find.

There was a bit of inconsistency in the side-to-side play of the rod bearings and wrist pin bearings-- mainly just that #1 cylinder had less than the others. My mechanic could have been right when he said that it was just the wrist pin moving back and forth, and it is a non-threatening knock, but I'm not finding much about this by googling. I've filtered out the audio a bit. It's easy to identify cylinder #2 because of the valve guide (originally I was calling this cylinder #3 because I numbered backwards). So from the 1-3-4-2 firing order I get to hear/see the power stroke on each of the other cylinders. #1 definitely seems like it's a little quieter than the others...

Should a reman engine have new connecting rods? It seems he could have replaced the rod bushing and kept the old rods, keeping any side-to-side play. So I'm thinking new rods could be a fix to the knocking. Would there be much risk in new rods? Anyway, I'll check the bearings first.

That bottom end doesn't seem to have any abnormal side to side play in the rods, did you pull the oil filter off and dissect? Looks like your having fun under there, at least your machine isn't fresh out of the landfill like all the track loaders I work on :throwup

crazyjncsu said:

I did attempt to pull and lift the rods, I just didn't get any wiggle there. But I was going to get each piston in a position where the crank was pulling it down, then push from the top to see if it moves in at all.

I'll check/photo each rod/main bearing/cap/journal.

I'm having a bit of a hard time communicating with the rebuilder. For every question I ask I get a response that somehow includes the fact that 3204s are "junk engines", as if that somehow absolves him of needing to do good work. At this point I'm kind of just waiting to see if I find anything egregious enough where I can put any real pressure on him .... not that I need much help at this point, as it's already apart. The engine is out of his one year warranty, but he's a national rebuilder with a reputation (not a great one mind you) that he may want to protect. It seems he clearly botched the value guide ... maybe through negligence. The valves were all mismatched if that matters. There could be something else I find.

There was a bit of inconsistency in the side-to-side play of the rod bearings and wrist pin bearings-- mainly just that #1 cylinder had less than the others. My mechanic could have been right when he said that it was just the wrist pin moving back and forth, and it is a non-threatening knock, but I'm not finding much about this by googling. I've filtered out the audio a bit. It's easy to identify cylinder #2 because of the valve guide (originally I was calling this cylinder #3 because I numbered backwards). So from the 1-3-4-2 firing order I get to hear/see the power stroke on each of the other cylinders. #1 definitely seems like it's a little quieter than the others...

Should a reman engine have new connecting rods? It seems he could have replaced the rod bushing and kept the old rods, keeping any side-to-side play. So I'm thinking new rods could be a fix to the knocking. Would there be much risk in new rods? Anyway, I'll check the bearings first.

Click to expand...

Answering your last question first. A "reman" rod is simply a used rod that is straight and conforms to all dimensional tolerances that is then fitted with a new wrist pin bush.

Regarding wrist pin side-to-side play. A wrist pin is a maybe a few thousandths of an inch shorter than the distance between the two circlips that retain it in the piston. The fit between the wrist pin and the piston is tight enough that you can push it back and forth with your fingers but it is not slack enough that it will fly backwards and forwards on its own while the engine is running. What can happen though is that if there is a couple of thousandths of play between the O/D of the wrist pin and the I/D of the connecting rod eye bush you can get what I refer to as a "small end knock". I am coming to the conclusion that for peace of mind whatever you find in the crankshaft rod bearings you really ought to whip out the pistons and check the wrist pins, wrist pin bushes, circlips, and most importantly the fit of the wrist pins in the pistons. Also have a look at the pistons and see if they are all the same part number just to be on the safe side, as a last thought check that the piston rings (where it is called for) have been installed the right way up. Some can go either way, often the compression rings have a step in them and must be installed a certain way.

If you need any info regarding specifications please drop me a PM with the info required and your email address.

Regarding the "rebuilt/reman" engine. The work was done for the previous owner of the tractor, correct..? If so surely he has some paperwork, an invoice, etc, etc, that details what work was done to the engine during its alleged rebuild.

Thanks for the advice! I'm working through this stuff:

I removed a couple connecting rod caps. Then I removed the #4 piston (which seemed from the audio to be the loudest knock).

The wrist pin is loose. I took it into the machine shop (as I was picking up the head from there), and I showed it to the guy there. He thought it was loose, estimating about 7 thousandths of clearance. It's supposed to be about 1.5 thousandths with 3 thousandths the max allowable. He obviously couldn't say for sure that this was the source of my knock, but with the other mechanic initially diagnosing the knock as a wrist pin, I'm getting more confident this is the source.

When you buy new connecting rods, do they usually come with bushings in them? The machine shop guy said new rods may be my best bet if they include the bushings.

The bottom part of the rod bearing (on the cap) seemed to be in good shape. The top part was a little more worn (less white, more metallic) with specifically a teeny bit of discoloration where the force from the power stroke would be applied. The machine shop guy said everything is probably OK, but to plastigage it before reassembly. I'll try to do that this weekend.

The crank rod journals appeared fine.

The main bearings look like a real PITA to deal with. They require 120 ft-lbs of torque, and my wrench only measures to 100 ft-lbs. And the service manual says I can't rely on plastigage with the weight of the crank on the bearing, so I'm not sure what that means. I'm thinking about leaving the main bearings alone unless something turns up with the clearance of the rod bearings. Bad idea?

Oh, and the head is trash. The rebuilder apparently put in a new valve guide, but the machine shop guy said the head should have been thrown out before the rebuild. The piece of the block that the valve guide went into was already way too stretched out (if you look real hard at the picture you can see it, but I need another picture). I talked with the rebuilder again, and he may be willing to make good on some of this stuff.

1:40 video where you can hear the looseness of the wrist pin bushing fit:
https://vimeo.com/135104055

Some pics:

Lower rod shells should never ever show wear, if they do you have big issues internally, as to the upper shells, almost appear as if installed dirty, oil was left dirty too long or they did not adequately prelube after build last time, more than likely +.001-.002 additional clearance to stock new. As to wrist pin play, piston slap is still piston slap whether it taps the head or carbon ridge or rattles in a spreading liner bore or slops up and down on a pin, will knock noticeably and usually under low load conditions.

Hope the rebuilder does stand behind it, many today slap these things together with a get it out the door warrantee, too many do not any longer put out a quality job.

I don't see anything in those rod bearings to worry about. As DM says dirty oil or not prelubing enough before the first start could have done that could produce those symptoms.

Reman or new the replacement rods will come with bushes already installed. As your rods appear to be prefectly OK to the naked eye then they would definitely be acceptable as cores to turn in for the set of Reman rods. That would be cheaper than going new and would get you to effectively the same place. The rod is an 8N-1721. Reman is 0R-0914 and lists around $180 each. New rods are $335 each and the Classic option 269-5291 lists at just under $100 each.


Regarding the cylinder head you also have a Reman option because despite the wear in the bores where the valve guides are installed your existing head will still qualify as a Core. Your existing head will be either a 1N-4304 or a 7N-6544. Both service to 1N-4304. The Reman number for that is a 0R-2672 that I'm showing at around $1150. There is a Classic option of a 269-8761 @ around $1000. A new 1N-4304 is around $1700.

In the case of both the connecting rods and cylinder head you should order them based on your engine Serial Number just to make sure they are the correct ones.

You really need to be at the rebuilder for the cost of the Reman head plus at least one rod to replace the rod with the dodgy bearing plus a set of gaskets if nothing else. I would go for genuine Cat ones rather than will fit TBH. Better still go at him for 4 rods. Why not..? The worst he can say is no ........

Having built a number of engines in my career I have to agree with Nige here, go o the rebuilder, offer to subsidize or share cost to see if can swing a full set of rods, and the head, insurance is a handy item if well placed.

I would also comment that I would not use Cat Classic Parts in an engine, however cheap they are. Things like mufflers, fine - internal engine parts no. Although I guess a lot depends on how many hours/year you plan on putting on the machine.