Diesel Engine Inframe Rebuild Part 1

       Hello again and welcome to an overview of an engine inframe service. This is not meant to be a repair guide, just an outline of what’s involved in the job.
       For a complete guide on rebuilding the DT466, click on the book sales tab above this post.
       One of the biggest complaints customers have about an inframe rebuild is the high cost involved, especially the labor quote. This work requires more hand work, fitting, and cleaning than any other type of job, by far. It is work that can’t really be handed off to a lower paid apprentice or helper because an experienced tech will be looking for problems and inspecting parts for flaws as all the work is done. The engine in this example is an International 466E, a very robust medium duty engine. Although it is one of the simplest engines in terms of numbers of parts and assembly, the job still requires about 30 hours of work, not including removing cab parts to get the doghouse off or test driving.
Before we get started we need to review heavy duty engine construction. The 466 is a wet liner engine, as are most modern diesel truck powerplants. The liners provide a cylinder wall that is replaceable for rebuilding, and when installed its outer surface is in contact with the engine coolant. The head gasket seals the top of the cylinder, and O-rings seal the bottom from the crankcase. The typical inframe kit includes bearing shells for the rods and mains, liners, pistons, and rings, and all gaskets needed. The result is basically a new engine except for the oil pump, cam and bearings, injectors, and head(s). Everything can be done without machine work (usually), and with a minimum of special tools. An engine can be rebuilt multiple times for a very long service life, and many inframe kits are still being sold for engines 40 or 50 years old.
The object of this rebuild came into the shop leaking massive amounts of coolant into the crankcase and had an audible knock in one cylinder. Removal of the oil pan revealed coolant leaking down the outside of the liner for cylinder #3. Often the cooling system must be slightly pressurized to reveal a leak, but this one leaked so bad that just pouring water in the radiator was enough to find it. It is important to pinpoint the leak exactly, as there are several was coolant can get into the crankcase, including from the front cover seals, pinholes in a liner, or a damaged block.

466E in a 4300 chassis

The first order of business is usually to drain the oil and water. If the truck had been running lately, oil will continue dripping off the block for days, so I usually leave the pan on with a container under the drain, while I take the top of the engine apart. Working under an engine dripping both coolant and oil is one of my least favorite things, so I let it drain as long as possible before the oil pan is removed.

Some preliminary work had to be done to gain access to the engine itself. Most modern chassis have the engine pushed back as far as possible, and in the 4300 International, about the rear 1/3 of the engine is back of the firewall. In order to remove the doghouse over the rear of the engine, the passenger seat was taken out and the threshold plates holding the outer edges of the floor mat were removed so the floormat could be rolled back. The doghouse edge is under the floormat, and removing it with the mat in place will tear the mat at the corners of the opening. The automatic shift selector and the parking brake handle were also taken loose but left connected to their cables. Under the hood, the air cleaner assembly was taken off and then the windshield wiper and linkage assembly and the panel at the bottom of the windshield removed. The modular component assemblies on this model make it one of the easiest brands to work on, once you have a little experience with it. 

Now that we have access to the engine, components attached to the head can be taken off and the head removed. The valve cover and intake manifold are integrated in one casting as is the thermostat housing and A/C compressor mount in front of the valve cover. I usually leave the turbo attached to the exhaust manifold and remove/install as a unit. This is heavier than dealing with each component separately, but dealing with turbo mounting nuts can eat up a lot of time. As long as the gasket doesn’t leak and none of the studs are broken, I leave it alone. If you do choose to renew the gasket, it is much easier with the manifold off the engine. Unusual on this job was that the head of one exhaust manifold bolt was broke off, and its mate broke when I tried to remove it. It is unusual to find this problem on the 466; normally the bolts come right out. Luckily, they broke off right under the head and were extracted by welding a nut to them and twisting them out. Always remove the injectors before pulling the head; if an injector tip is bumped while swinging the head out or putting it on the bench, the injector will likely be ruined. You need to check the injector bores and cups for damage or leaking, anyway. 

When removing the head, I try to back the headbolts out a turn or so at a time until they turn freely, especially the long ones holding the rocker shaft in place. This may be more cautious than necessary, but it doesn’t really cost anything in terms of time. When the rocker shaft is removed, I make a point to carefully inspect the ends of the valves and the rocker arms for damage. Quite often one or two will be damaged and need replacement. I think when the valve adjustment is not done for a while, the arm hammers the end of the valve, mushrooming its end and the contact pad of the arm. The turned over edge of the valve stem needs to be removed with a die grinder so it will pass through the valve keeper when the valve is removed. Use a little valve grinding compound to lap the new valve to the seat. 

Once the head is off, it is inspected closely for cracks in the combustion chamber. This is seldom a problem in this engine, but they can crack from the injector hole to a valve seat. If all is well, I turn the head with the exhaust ports up and fill the ports with Stoddard solvent and let it sit a few minutes. Any leaking valve will let solvent out the bottom of the head. If the exhaust valves pass the test, do the same with the intakes. 

The head is off, the pistons
and liners removed.

Note the large gap in the
coolant seal of liner #3

        Removing pistons and rods is straightforward, just unbolt them and push them out with the handle of a hammer. Unfortunately, in order to remove the oil pump pickup, the vibration dampener must be removed, there is never much room to get a puller in, and they often pull off pretty hard. This one actually needed to be warmed a little with a torch to get a pull started. You can bend up a 10mm box wrench and loosen the bolts from behind the crossmember without pulling the dampener, but that isn’t too easy, either. 

Caution should be used when pushing the pistons out. The liners in this engine are not as tight to the block as some other makes; occasionally the liner will push out when a piston hits the wear ridge. It’s no fun to take a coolant shower when you are under an engine. I have very seldom needed to use a liner puller on this engine; just drive the liner up about ½” with a big punch, then pry them up from the top with a big bar. The engine in this case had a large gap in the coolant seal in cylinder #3. The lack of coolant around that cylinder overheated that piston, which expanded and was very severely scored. The slap from this damaged piston would account for the knock we heard when we pulled the truck into the shop. 

With some parts cleanup, that usually concludes the first day of work. Check soon for part 2 of this survey, where we clean everything up and start assembly.

All parts for 466 inframe removed for inspection and reassembly.

How to Find Your First Mechanic Job, Part 2

      Hi, everybody. Welcome to part two of finding your first mechanic job. Last time we talked about the different kinds of jobs you may encounter in your search. Now it is time to narrow the options and choose a few of the most likely and attractive possibilities. Deciding going in what you are looking for will focus your search and make you perform better in an interview. Interviewers look for candidates who seem to have direction and who know what they are looking for. Your geographical area may influence the types or number of jobs available, but even in non-metropolitan areas there are probably more possibilities than you would at first think. Within larger cities, specific areas often have clusters of similar types of industry; hence an area shop might specialize to serve them. Often several shops will be grouped in a given area where truck traffic is heavy.

Writing a good resume will help to focus your search. I feel the most important things to think about when writing are as follows:

• The only reason for a resume is to get an interview. Make sure it is easy to read and includes the most important information first.

• The best things you can show are punctuality and attendance, a good attitude towards working with others, and an ability to learn.

• Do your work on a computer. You should write a generic version that can be adjusted for each prospect.  If you can, include the name of the interviewer in the header. At least use the service manager’s name. Including a name will show that you have done some research on the organization.

• USE SPELLCHECK. Also make sure you use proper grammar, and have a Writing or English teacher read it, if you are at all unsure. We may be mechanics, but we can still be literate. 

• This is an extension of the above, but the resume is the first contact you will have with the business to which you are applying. Don’t give anyone a reason to reject your application. Remember that the first person who sees what you write, especially at a larger shop, might be a secretary or other office person. 

• Be brief and stress your strengths. One good page is much better than three pages documenting every bicycle and toy you ever fixed.

        Finding the right place to work is probably the hardest thing about the process. If you can, talk to someone, preferably a mechanic, who works at a shop you are interested in. Talking to him will give you an idea of what it is like to work there, and can give you the names of supervisors or managers. You may also get some of that information at the company’s website.  A big problem is that a shop won’t necessarily advertise a job opening. Sometimes positions are filled by word of mouth, when one mechanic knows another who is looking to change. Make sure you give your phone number or Email address to tool truck guys, as they often know of openings and they cover a lot of territory. 

Finding that first job can be a challenge for a student without experience, so if you find somewhere you really want to work, maybe you could get a position as a parts runner, mechanics helper, or utility person. You can prove yourself by doing good work, and gradually start doing mechanic work to prove yourself. This is a traditional path many of us took to become mechanics. My first job was pumping gas (this was before self service!) and I gradually learned to repair tires and do simple repairs. After a couple of years, I was a fairly capable mechanic. Of course, dealers that offer apprenticeships will take new graduates, but the competition for these positions will likely be stiff. 

Recognizing a shop as a good place to work can begin by talking to someone working there and doing online research, but you need to visit in person before seriously considering it as a possibility. Actually, driving by the location a few times in a couple of weeks might give you a good idea of the kind of vehicles the shop works on and how busy it is. Usually if you are being considered for a job you will be given a tour of the facility, and you need to keep your eyes open for clues.

       Several things will be clues as to the culture of the shop and the way it is run. First, what does the shop floor look like? Can you easily walk around without stepping over old parts and equipment? Naturally there will be things lying around in a busy shop, but there shouldn’t be a bunch of stuff that looks like it hasn’t moved for months. The floor may not be as clean as the one in your garage, but again, it should look like it has been swept within a week or so. I personally think there is such a thing as trying to keep a shop too clean. It is hard for me to work efficiently if I am too concerned with spilling on or marking the floor. Time spent in fastidious cleaning is better spent generating revenue. On the other hand, care must be taken that dirt or grease is not transferred to customer vehicles, so sometimes there is a fine line to cleanliness.

Another thing to look for is the general feel of the shop. Do the mechanics seem to like being there and interested in work? What happens to the atmosphere when the boss or someone from the office steps onto the floor?  It is difficult to gauge how the shop is run or what it would be like to work there from a single brief visit, but it is probably the only chance you will get. This is why it’s important to have more than one possibility, if possible. One place will likely be more attractive than the others. Also, remember that you don’t have to work there forever. You should not jump from one job to another every few years, but there is something to be said for having experience in several places before finding exactly what you want. Varied jobs give a broad variety of skills that would be impossible to learn from just one. 

That is really all I have to say on the job search. Unfortunately, this is one area where no one can really offer much more than general advice. Your first job will teach you most of what you need to know about finding what you really want. If you are really lucky, the first one you find will be the perfect job, if such a thing exists.