# Rebuilding A 98 KA24DE Engine?



## Joel4JC (Sep 8, 2005)

Hi Guys,

I have been working on cars for 30 years and have never rebuilt an engine, I have replaced a number of them with used, rebuilt and remanufactured engines depending on the budget at the time. So I guess I am fairly handy with a wrench.

A single mom with a low budget has asked me to fix her 98 Altima with 185k miles before it becomes a major problem and beyond her budget for repair. So, I need some expert advice.

The car makes a loud knocking sound when the engine is cold, it goes away as the engine warms up. Also, the oil light stays on until the engine warms up. I've been told that it is either a bad bearing or too much clearance between the pistons and the cylinder bores.

I'm looking for the best solution in terms of low cost and future longevity of the engine. Buying a rebuilt or a remanufacture engine where I live is going for about $2800. This is way out of her budget. I figured I could rebuild it myself for a lot less.

Questions: What would you recommend? How much of the engine should I rebuild (parts replaced) so I don't have to come back and do this again a year or so from now? I've seen kits with bearings and rings only, would this work? Can I put new rings on the pistons without having the block machined? Is this wise? I was told I should have the crank 10-10 with all new bearings, would this be enough?

I would appreciate all and any advice you guys can give me.

Thanks, 
BTW, should I have posted this in the "Naturally Aspirated, For you All-Motor lovers" forum or is this the right place?


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## ddude2uc (Sep 7, 2005)

*spelling is off a little*



Joel4JC said:


> Hi Guys,
> 
> The car makes a loud knocking sound when the engine is cold, it goes away as the engine warms up. Also, the oil light stays on until the engine warms up. I've been told that it is either a bad bearing or too much clearance between the pistons and the cylinder bores.
> 
> ...


I forgot to say, that replace pistons, rings, oil pump, timing chain/belt, rod & main bearings, gaskets, & get the head rebuilt also. If it is a manual, replace the clutch also.


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## Joel4JC (Sep 8, 2005)

It is all good advice but, I was trying to avoid a complete rebuild because of the cost and the budget of the owner (a single mom on very tight budget).

If I buy a complete rebuild kit, have the block hot tanked, crank turned, cylinders rebored and the head redone, we are talking about $1500+.

The question is, does it really need all this? The question is, what is the minimum I can get by with and still have a quality car (engine wise) when it is all done.


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## ddude2uc (Sep 7, 2005)

Well, if you want to see what kind of shape the rings are in, do a compression check on all the cylinders with a compression tester. If the readings are less than specs., then you have worn rings. Also if the readings vary more than 20-25%, you have excessive blowby. Sometimes the valves need adjusted, depends on if you hydraulic ones, which are self adjusting. 

If your compression readings are all good, you should be able to just buy a Re-ring kit, wich has the rod & main bearings, complete gasket set, & rings.
To see if you need the block bored, would require you to take the pistons out & measure the inside bores with a telescoping gauge & measure it with a outside micrometer. Another good way to see if you block needs bored out, is look at the top of the bore, if there is a ridge, then more than likely needs bored out. When you bore a cylinder out, it requires over-sized pistons & rings. 

The main & rod bearins need to be plastiguaged in order to see what size bearings you need. As you mentioned, if it is making a loud noise, you might need to have the crank turned. Most machine shops will take measurements & tell you what needs to happen, whether it can be polished or turned.

I beleive you can get away with a Re-ring kit, only if everything is within specs., (bore size, crank is ok)


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## Joel4JC (Sep 8, 2005)

Will do. Thanks for all the info. I'm hoping for the minimum, for her sake.

Thanks Again,
Joel


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## ddude2uc (Sep 7, 2005)

I will say that I didn't mention, is sometimes it is worth buying a used motor. 

Here is one on ebay. http://cgi.ebay.com/ebaymotors/91-K...33615QQitemZ7999689852QQrdZ1QQsspagenameZWD9V

Here is some more info. on engine rebuilding. 

Once your parts are at the machine shop, the first step will be to hot-tank everything for cleanliness. This should be followed up with what is referred to as Magna-fluxing for the block and head castings. The process uses colored iron powder that is sprinkled on the parts and then magnetized, causing the powder to collect along cracks, making them more obvious. If your parts pass the test, the critical measurements will be taken to determine what must be done to recondition them, and what size replacement pieces are needed. Our 302 was standard bore at an even 4 inches. We'll take it 0.030 inch over for the rebuild.
Once you have your new pistons, don't be tempted to install them on the rods yourself if you have access to a press. The machine shop has a jig that heats the small-end of the rods using electric coils, which expands the bore, allowing a press-fit pin to drop right in. Pressing them together cold can easily damage the pistons. Whoever mates the rods and pistons needs to pay attention to their orientation--some rods must face a certain way, and most pistons must face front. Some pistons also have offset pin bores, requiring them to be used in a particular bank of the engine. We're using Speed-Pro forged pistons (L2482F-030) with press-fit pins, though some high- performance applications use full-floating pins. These slip right into place, but must be retained with clips in the ends of the piston's pin bores. If you haven't installed the clips before, have someone with experience help, or at least check your work.

Most machine shops offer the option of balancing your rotating assembly. For stock rebuilds using pistons that are similar to the originals mounted to stock rods, this could be considered unnecessary, although factory balance jobs of production V-8s are usually not nearly as precise as custom balancing. If pistons are being changed to high-performance slugs of significantly different weight, and/or if aftermarket rods are being used, custom balancing should be considered mandatory.

Once the guys at the shop have verified that your parts are good and taken the initial measurements, have them alert you so you can order parts, unless you want them to do it for you. The machinist will want the pistons prior to performing the final hone, so order the stuff promptly. When you receive the parts after the work is done, the shop should give you a rundown of everything that was done, along with the specs for the areas that were resized.

Once your parts are back in your possession, and you're preparing to start assembling, make sure that you first clean all the parts thoroughly since the machining process will leave metal shavings behind. We've outlined the reassembly steps in detail in the photo captions, but remember that this is general information, so you really should have some good printed reference material on hand that is specific for your application to provide specifications and procedural guidance. Take your time, and seek advice when you have questions or doubts. When it's all together, make sure to pre-lube, follow the cam break-in specs (for flat-tappet cams), and resist the urge to wring the new engine out until you get a few miles on it. If you did it right, you should be set for many miles to come.
One of the most critical aspects of building an engine is attaining the proper bearing clearances. Of course, this will be the work of the machine shop, but it's up to you to verify that everything is right before you bolt it all together. Many novice builders will rely on Plasti-gauge for this, though a far more accurate means of determining clearances involves using micrometers. However, these are expensive, and using them properly requires some instruction. If you don't know anyone with a set, see if the machinist will measure your critical dimensions when everything is done.

The first step of actually assembling the engine is installing the bearings and dropping in the crank. Set the bearing shells in the block, making sure to place the thrust bearing in the right place--in our case, the middle journal. Some form of lubrication should be used, and while engine oil would work, most builders prefer dedicated assembly lube. The special lube is sticky, so it stays put, whereas oil can run out of the bearings and into the pan before the engine is started. Place the remaining bearing shells into the main caps and torque the bolts to factory specs. We used ARP fasteners for this step.


Before proceeding, check the thrust clearance. Use a dial indicator in line with the crank. There are different methods, but you're checking the amount of endplay in the crank. Some guys like to beat on the ends of the crank to shift it back and forth, but Taylor prefers to nudge it back and forth by prying with a screwdriver. Again, the spec is determined by the factory. Our Ford showed 0.0065 against the factory 0.0040-0.0080 spec: perfect.

Now it's time to install the rings. Stock-type cast rings are very brittle, and bending them just a little too much can break them. Performance rings are often more malleable, but they too can be damaged by over-flexing, though they will often bend rather than break. You'll see lots of pro engine builders spiraling rings on by hand, but for the novice, a ring spreader tool and patience are best. Expand the ring just enough to get it around the piston. The rings will be labeled for position, and often have a top side, which should be marked. Professional performance engine-builders often use file-fit rings so they can set the gaps right where they want them, but pre-gapped rings are sufficient for the novice's first effort. Still, the gaps must be positioned properly. Usually, the two top rings are positioned so the gaps are 180 degrees apart. The oil rings are often set 90 degrees apart, but away from the compression ring gaps.
A ring compressor is required to get the pistons below the deck, and while there are several types, the best is the tapered ring compressor. These are made for a specific size bore. Our 4.030-inch bore is super common, and the tool can be had for around $30. Lube the rings with a coating of assembly oil, and do the same for the cylinder bore. There are many opinions on the best lube to use. Total Seal offers a dry-film lubricant especially for the job. Before inserting the piston and rod combo, cover the rod bolts with something to keep them from scratching the crank; short lengths of rubber hose work well. When the time comes to drive the piston in, use something soft, like a hammer handle, and don't force it. If everything is right, the piston should slip right it--if not, start over.


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## Joel4JC (Sep 8, 2005)

ddude2uc said:


> Here is some more info. on engine rebuilding.


Can you give me the source of your information, I would like to read the rest of the article or book.

Thanks


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## ddude2uc (Sep 7, 2005)

Joel4JC said:


> Can you give me the source of your information, I would like to read the rest of the article or book.
> Thanks


No problem. It is a article out of Car Craft. They have some interesting stuff on there. 

http://www.carcraft.com/techarticles/116_0407_first/index.html


Also, here is price (link) for your rebuild kit if you decide to do it.

http://www.rpmmachine.com/enginerebuildkitsnissantop.html


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## Joel4JC (Sep 8, 2005)

Thanks for the links. I found these three articles really helpful at the carcraft site: "How To Build Your First Engine", "Build Your Fist Engine: Doing it Right the First Time" and "Build Your First Engine". Even though they are geared towards Chevy, Ford and other V8 and Small Block engines, the principals, tips and guidelines apply to all engines.

I also checked out the rebuild kit. thanks again.

My problem now will be find a good reliable quality machine shop. I don't know anyone in my area who rebuilds engine so I have no recommendations.


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