This is a quick blog to share some inexpensive additional pieces you should think about changing when you rebuild your Cummins N14. The Cummins N14 is a strong, reliable engine that will just keep on going if you treat it right. Depending on how much weight you're pulling, the average rebuild is needed around 800k to 1 million miles. The standard N14 inframe kit will come with nearly everything you need to rebuild the engine. Here's a look at some of the additional pieces that are a good idea to change while preforming the rebuild. The nice thing is they won't break the bank.
1. Engine Brake Gaskets
This one is a gimmie since if your N14 came with engine brakes you're going to need them anyway. The only reason I mention it is because this is the one needed item that all N14 inframe rebuild kits leave out. So, just don't forget to ask for a set when you're ordering parts. Part number: 4920093 x 3
2. Piston Cooling Nozzles
The N14 piston cooling nozzles are located on the right hand side of the block. They are spaced out just enough to hide behind everything that can get in your way such as the oil filter, coolant filter alternator, etc. In most cases you can still wiggle them out without removing these items. The N14 cooling nozzles are made of plastic and can get brittle from the heat of the engine. If one happens to break you will typically have a noticeable drop in oil pressure. A worse case scenario is that the lack of oil to the underside of the piston causes a piston failure or causes the wrist pin to seize in the rod. Either way, this is something you definitely want to avoid. For the small cost of these nozzles it is highly recommended to install a new set after you put the pistons and rods back in the engine. This eliminates the possibility of hitting the nozzle with the rod when dropping the piston & rod assembly back into the liner. Part number: 4058947 x 6
3. Thermostats and Seals
Thermostats are the highest dollar item on this list, but are still a good idea to change when you're only a couple of bolts away. The N14 thermostat seals are one item that I think are often either forgotten about, overlooked, or just plain skipped because they are a pain to change. Cummins make a special installation tool for the job, but if you pay attention to the seal depth prior to removing them it isn't necessary. If the seals are bad they allow coolant to flow around the outside of the thermostat and lessen how effective they are. Changing both the thermostats and seals when rebuilding your engine will help insure against overheats, and slow warm-ups. Part numbers: 4973373 x 2, 186780 x 2
4. Oil Pump Pressure Regulator Plunger & Spring
The N14 Lube Oil Pump is a heavy duty unit. Sure, it's possible for them to go bad, but unlikely. If you want to save some money and not change the entire pump, just change the spring and plunger. The spring and plunger can be accessed with the pump still installed. There is a single bolt that holds a plug on the bottom side of the pump. Removing this plug allows easy access to the spring and plunger. If you note the length of the old spring compared with the new spring, most times you will see a significant length difference. This is because the heat of engine, pressure and time cause the spring to relax. This can cause your oil pressure to go down. The plunger gets scored up from particles in the oil getting caught between it and the body of the pump. If scored bad enough, it may cause the plunger to stick causing the engine oil pressure to jump erratically. Part numbers: 145504 x 2, 3010146 x 1, 3884126 x 1
5. Front Cover Accessory Drive Bushing
Ok, So the front cover or the accessory drive aren't normally taken off during an inframe but I thought I'd mention this anyway. If you've reached a million miles on your N14 and haven't ever had the dreaded giant oil leak caused by the accessory drive bushing spinning in the front cover, count yourself lucky. What happens is that the accessory drive bushing spins in the front cover blocking off the oil feed hole that keeps the accessory drive lubricated. The bushing and drive heat up from the lack of oil and cause the accessory drive seal to fail. This results in any and all remaining oil in the area to run down the front of your engine until the problem is fixed. Unfortunately, the fix is a new front cover, accessory drive, and all the labor needed to change them. A simple solution to this is installing a new bushing when you have the accessory drive out. To better help the bushing stay where it should, a light coating of large diameter sealing Loctite can be used. Part number: 3411389 x 1
6. 90 Degree Fuel Elbows
A trick to help you remove the cylinder head closest to the cab is to take a hammer and break off the 90 degree fuel elbows at the back of the head. The fuel lines can be very difficult to loosen up and many times the line is damaged beyond repair in the process. By simply taking a hammer and breaking the fittings off, it allows for the removal of the cylinder head. With the cylinder head out of the way, the elbows can be taken off the lines. The fittings on the lines can then be worked free to allow for easy installation. The broken part of the elbow will need to be removed from the cylinder head, but a quality bolt extractor (easy out) usually takes it right out. There is also a 90 fuel elbow in the front cylinder head, but this one is usually easier to access. If it's not, just grab your hammer. Part number: 181213 x 2 or 3
These few inexpensive fixes can help keep your N14 engine running trouble free for its second life. If you need to know more about any of the parts mentioned or just have a N14 question in general feel free to call any of the knowledgeable Highway and Heavy Parts staff at 844-215-3406.