Need advice on CAT engine repair

scott2013

Member
I considering taking on an adventure of repairing an engine in a CAT D8. The dozier belongs to my neighbor and has been sitting for 10+ years. He said it began knocking so he parked it and had a mechanic come out to troubleshoot the knock. The mechanic told him it sounded like #5 cylinder, possibly a wrist pin, but wanted to rebuild the entire engine at a cost of $10-12,000. He didn't have the funds so he covered the exhaust and let it set. I have some work on my property I need done that this dozier could easily do so I'm investigating if a single cylinder repair would be feasible. He will pay for parts and I will do the work. I have rebuilt smaller engines but nothing on this scale. It doesn't look complicated just everything is much larger. The first thing I'll need is an engine service manual (prefer CAT original) for the D342 engine and read through the tear down procedure. Any advice before I start?
Thanks,

Scott
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I guess you would have to determine ahead of time how much work you are willing to do to the engine. In the event that the knock is from a connecting rod bearing you have to
check if the crank journal is acceptable...if it's not the crank would have to come out which means the engine has to come out and then you are into a big job and more expense.
At that point if your neighbour stalls the spending do you leave it in pieces or do you have to put it back together? I guess either way you are gambling with your investment of
time?
 
(quoted from post at 10:27:43 07/22/15) I guess you would have to determine ahead of time how much work you are willing to do to the engine. In the event that the knock is from a connecting rod bearing you have to
check if the crank journal is acceptable...if it's not the crank would have to come out which means the engine has to come out and then you are into a big job and more expense.
At that point if your neighbour stalls the spending do you leave it in pieces or do you have to put it back together? I guess either way you are gambling with your investment of
time?
I had a D8H , Complete engine rebuild back in 1991 was $18,000 - $24,000 back then , I bought a D8K engine for $8,500 , the job of exchanging engine was huge , ran into many problems , the D8 ran fine for a while then started making a ticking noise , No Mechanic could tell me what was wrong , just guess work . I sold the D8H to parts salvage co . Never want to experience that night mare again . Tractor that big is fine when they are NEW .
 
EricB we have already discussed how far we will go with this. If its a crank shaft issue we will button it back up and move along. A reman crank is $7-8000 which puts this into too many $$$. I've looked up parts needed for a single cylinder re-work and I think it can be done for less than $2000. We may need some tools but they can be bought or maybe borrowed. If the engine is toast he can sell it to the scrap man.

Scott
 
Pads look good on it, if its got a decent undercarriage, might be worth fooling with. I'm just wondering, being on the bottom of the engine, would it be prudent to pull the belly pan and oil pan to see whats going on? Going to be a heavy pan for sure, use care if taking it off, don't want that on you for sure.
 
SHE WILL DO ALL U NEED ON 5 CYL...PULL ROD/PISTON OUT, USE HOSE CLAMP ON BEER CAN WRAP ON CRANK JOURNAL...SHE WILL PURR
BE BLESSED, GRATEFUL, PREPARED, NIK
 
Billy NY the pads and under carriage are in the 90% range. The owner told me the machine ran great until the knock started. The belly pan will need to be dropped and yes it would be a b!^*# to get out from under if it fell on ya. Got to figure a way to lower it down with straps.
NIK OWEN you answered a question I was going to wait to ask. I want to see whats wrong inside before I explore other options.

Thanks for the replies,

Scott
 
My first move would be to remove and examine the oil filters for metal,if there is no metal flakes in the filter put it back and consider cranking the engine over on decompression with the pony and see if it brings up the oil pressure up,if it does keep the fuel shut off,remove the oil filler and crank it over on compression watch the filler for blow-back,if you have lots it is possible a piston has an issue,those engines were known to burn holes through the top of the piston,there was also a metal heat shield that that bolted to the piston,I have seen them come undone and make an awful racket,if the guy that looked at it was a competent heavy equipment mechanic and established that the miss was on #5 cylinder the next step would be to remove the back head,if it is piston damage the side plate of the engine comes off and the rod cap removed the piston can removed/replaced,if there is metal in the filter it will more than likely have come from a rod bearing that has picked up,to see what would be wrong the side plates can be removed and the shaft inspected,an inspection of a good bearing shell would tell if its been ground before,measure the bad journal to see if it can be ground again if no its a replacement shaft,question the guy about what happened,did he let it run low in oil,did the pressure drop suddenly,was the pressure up while it was knocking,as Billy said the pads look good if the chains are good as well and the power train in working order it will worth repairing the engine if its only a piston.
AJ
 
Thanks AJ. The owner said he was finishing a pond dam. He said the oil was full, the engine didn't run hot but he was working on a fairly steep angle. Thank you for the troubleshooting procedure. I'll start with your suggestions and work from there.

Thanks,

Scott
 
Dad and I did the engine in a D9G some years back. AJ has given some good advice. The engine will weight around 9000 lbs, with the torque converter attached (the easiest way to pull it). The one on my service truck will do 11,000 lbs, 6 feet out, and I lacked about 6 inches of being able to set it alone. In othr words, you'll need a decent sized crane if you wind up having to pull it.

As far as dropping belly pans, I've done it several times by myself, and I use chains and my crane, but you can use a couple of come-along just as easily, especially if you have help. The way to do it is to hook one end of the chain over the track pad on one side and let the chain drape under the machine. Pick up the live end with a crane, or come-along until it tightens against the pan. Then you can loosen the bolts and lower it to the ground with the chain. it's not quite as easy going back up because bolt holes have to align, etc, but it can be done without a lot of effort.

As far as the oil pan, it should be a two piece unit, if I remember right. Again it's not light, but it can be lowered either with chains or with a jack. Too, having help makes things a lot easier.

As far as the crank, unless it's really screwed up it can be ground under sized without a lot of problem. Your biggest issue is most engine machine shops aren't going to be able to handle the block.

For parts, try Offroad Equipment Parts in Tennessee. They carry NOS OEM parts, as well as aftermarket parts, for CAT equipment. I've ordered stuff from them for maybe a quarter of what the same part would cost from CAT, and in some instances it was a true CAT part, but was an NOS piece they had bought from an auction, etc, etc.

As far as cost, I usually figure a rebuild now days at somewhere around $2000 per cylinder. That includes my labor in and out, my labor to build it, machine shop charges to get the block, head, and crank done, a rebuilt turbo, and a rebuild injection pump. A larger engine like this would add a little bit to that total due to the shear size of the parts, and the difficulty handling everything, but not that much. I would figure on doing all of the above if you decide on a rebuild, as not doing it all is just asking for problems. If you cut off the labor cost, and did it yourself, I see no reason you can't do it for less than $10,000.

As far as a single cylinder repair, that is an option. Unfortunately, you already know, you'll have to tear into it far enough to verify the problem before you do anything else. This alone will be pretty involved. I've got the heads off a D9G right now, and I can tell you for a fact that's no easy task in itself.

Whatever you wind up doing, good luck. If you run into any problems, or need parts, as you can see there are plenty of us on here with the knowledge and resources to find pretty much anything you need to know, or anything you might need parts wise.
 
Before you tear into it check the #5 fuel injector. A bad injector will generator a knock like a rod bearing going out. Move the suspect injector to another cylinder and see if the noise follows it. As stated check the filter for metal. It's usually #3 rod bearing that goes out on these. The thrust main bearing is not pinned like the rest and if the bearing moves it blocks off the oil flow to #3.
 
NCWayne and Old Magnet excellent suggestions. I have a starting point and several things to try before I start tearing into the engine. We are going to get some batteries this weekend and turn it over. I'll report back with our findings.

Thanks for the replies!

Scott
 
Be interesting as to what turns up on this engine, was thinking, (on the back burner LOL) what Old Magnet said regarding the knock, and any other preliminary work before you can do to make a determination before you have to tear into it, good advice here for sure. H's were a good series, with an undercarriage that is like you say, definitely worth repairing the engine if you can do it.
 
I would have thought that the mechanic that checked it would have established that it was not fuel related,the machine standing for 10 years because of a bad nozzle takes some believing,if a nozzle fails the neat fuel gets blown out the stack making a bit of a mess and he surely would have noticed but.
AJ
 
I'm with you on this AJ. I asked the owner about the injector issue and he told me the mechanic told him it was a possibility but they never checked it out! The mechanic wanted to "freshen" the engine for $10k. The owner didn't have the funds for that kind of repair so it has set for 10+ years and the only thing wrong could be a single injector. I'm going to remove the filters tomorrow and check them first then we need to get batteries in it and turn it over.

Scott
 
Checked the oil filter for metal and didn't find any. I emptied the filter into a clean can and swirled a strong magnet around and didn't pick up any metal. I guess there could be aluminum from a piston but I don't know how to check for that. Next is to get some batteries and turn it over.

Scott
 
Try baring the engine over first. You can insert a pry bar in to the flywheel teeth after removing the timing mark cover and pointer at the top of the flywheel housing.
 
(quoted from post at 18:47:17 07/26/15) Try baring the engine over first. You can insert a pry bar in to the flywheel teeth after removing the timing mark cover and pointer at the top of the flywheel housing.
Got this done. Thanks for the suggestion. The engine moved easily and didn't feel stuck at all. Next we're going to change the oil & filter and drain the fuel to check for water. I was underneath the engine looking for a drain plug for the oil and didn't see anything but the belly pan. Surely there is a way to drain the oil without dropping that heavy pan?

Scott
 
I finding it a problem to remember where like things drain plugs are located I see so many different makes and models,look at where the dipstick fits to the oil pan,you will notice a raised hump,down near the bottom is the drain plug looking at the frame,there should be an access plate there on the outside of the belly pan,scrape around as it is recessed so it will not get knocked off,some of those engines had what they called speed oil change kit fitted,it was no more than a hose that screwed into where the drain plug went and the other end was held in a bracket higher up,the service truck would come along and siphon the oil out,fill the filter before putting it on it will save the pump having to do it.
AJ
 
We took the oil filter back off this morning and cut it open to check for metal again and we found lots of it. We're going to drop the belly pan and the oil pan to see what is damaged and how bad. No longer in a rush. Gonna wait until it cools off before moving ahead. Thanks for all the replies and advice.

Scott
 
She's probably knocked out a big end,avoid starting it now to prevent further damage as they have been known to put a leg out of bed,if you do tear it apart and the crank needs a grind care is needed in handling it,cut some vee blocks of wood so it can be supported evenly when its out of the block and been transported to the machine shop.
AJ
 
I worked on one many years ago that had a knock. It was a rod bearing. Since it had aluminum bearings there was bearing material stuck on a crank journal but after polishing the aluminum of the crank it was still in good shape. I just installed new bearings and all was well. This was a farmer owned machine so it didn't get a lot of hours on it but it was still running fine 10 years later when I lost track of what happened to it when it was sold.
 

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