KA24E weak rod bearings?

[Florida240sx]

Last night at the car club there was 7 240's. Last year when I went I was the only one. Then about 3 months ago there was 4 of us. The guy I'm buying the engine and transmission from went up there with his finished 240. SR20DET. Got his parts from ENJUKU. Anywayz one guy there was sayiong the ka24e has very weak rod bearing and they are know to be spun. So far I haven't heard this and I though there are a few turboed SOHC that are putting out around 300 on stock internals. Is he right?I haven't heard anything like this yet but just wanting to ask you guys.

[deviousKA]

Ka24e uses standard babbet/copper/steel bearings that had been used for years before, and still used today. The bearings themselves have no special problems.

That said, the ka24e IS prone to premature bearing failure, which is due to lack of oil. The reason for the lack of oil has to do with the faulty OEM timing chain guides. Once damaged, the plastic tension side guide lays improperly on the chain, shredding it to peices. These small plastic peices and shavings travel through the entire engine, lodging themselves inside the crankshaft (centrifugal force). Once enough has built up, the oil passages become completely blocked which causes the obvious problems.

Without the crank being thoroughly cleaned (as in, ball plugs being removed and replaced) the particles will not leave. This can cause further problems even after an engine is rebuilt and/or bearings and timing guides replaced.

On that subject, the ball plugs that close the ends of the oil passages cannot be easily removed and replaced. This is why most machine shops that clean/polish/grind crankshafts skip this step. The absolute best method is to carefully drill out the original plugs, drill and tap again, and install threaded allen plugs. This is common practice at our shop with ka24 crankshafts and everyone should be aware the problem.

[sil80drifter]

Is there NO other way to clean the crank? It seems that this would be a very expensive service to have done. How much do you guys usually charge? I have a crank that has experienced the faulty chain guide, and there is plaastic in the oil pan, so I'm assuming the crank is contaminated... On that note, woudl other part of the engine get contaminated, like the cam shaft oil passages and the rocker arm shafts/rockerarms?How does one clean those?

sil80

[deviousKA]

The price of removing the plugs and fully cleaning varies. Because of the nature of the ka plug design, it becomes more difficult than it needs to be. The plugs cannot be drilled out easily like others. This isnt a huge deal for a skilled machinist, and its not impossible to reinsert the ball plugs. Reason for the allen plugs is to make for easier work in the future, as well as peace of mind for a performance build.

Your not looking at anymore than 70 bucks for the process aside from the other work. It will most likely be cheaper and worth getting done.

We do it here at the shop but shipping will kill you sending a crank two ways. Find a good local engine machine shop and ask them.

edit: If you have the plastic debris in your pan, its everywhere. The entire engine needs to be broken down and cleaned. Get both the block and head hot tanked, crank cleaned, and completely wash out your rocker assembly/rocker arms. The rocker/lifters cannot be easily taken apart and cleaned, these fail easily especially with the plastic debris and lack of oil. Although you might get lucky with them.

[Florida240sx]

Luck hasn't been on my side lately. Which is why I'm ending off the engine. Now to find parts...

[sil80drifter]

I can see how the rocker arms themselves may be hard to clean, but what about the rocker arm shafts? I think worst case scenario, i'll just get new rocker arms. Does it cost much to hot tank and clean all the parts, usually?

I am very new to the whole rings/bearings replacement business, so I woudl appreciate a few tips.Thanks so much for the already given info btw.

So let's say I have a block, it has 70k miles on it, the block itself right now it standing there with plastic in the oil pan (fully assembeld with crank/rods/pistons, nothing else). I don't know for sure, but I think the rings are in ok shape (I will replace them though) and pistons/rods are still ok to reuse, what should my next step be to find out whether the pistons/rods are ok?How do I find out what size rings to get, and whether the old ones were worn out much, or whether the sylinder walls were worn out much? I can't test compression because this block is outside of the car, just sitting there, so is there another way of testing the status of the rings/bearings??

I really want to take it all apart myself, then if nothing else is needed, get new rings/bearings, and put it all back myself as well, re-using the pistons/rods/crank. Is this realistic? Not from the side of me being able to, but whether I could pull it off with just replacing rings/bearings (and having the crank cleaned)? If I have the crank cleaned, will i need to get different size bearings than the ones that were on it originally?

I know my friend took apart his 50k mile block, had it redecked (it was a little warped on top) and then put everythign back together, reusing his rings and everything else. I thought I could do a similar procedure.

What do you think?

sil80

[deviousKA]

The rocker shafts are simple to clean, you just need to disassemble the assembly and flush them out with gasoline or carb cleaner. Hot tanking of these parts is really unnessary, you can get them clean yourself. Rocker arm/lifters are very expensive for new oem type. I have heard of places being able to get them as cheap as 20 per rocker, but prices i have found are more like 30 per, my price before markup. This is another advantage of the solid adjustable lifter conversion, i sell the full set converted for $220. Conversion can be done on rockers with bad lifters no problem and gives you many various advantages.

A simple inspection of the journal surface will tell you a lot about what your going to do as far as bearings. If you disassemble, inspect, and they are very good shape (no scarring or galling) you can assume the same size bearing can be ordered (bearing size is marked on back of bearing shell). You will always want to plastiguage on install to make certain of your tolerance. If the engine had no apparent major rotating assembly issues (ie, spun/seized bearing) and the rods look to be in good condition, they are. Look for overheating (bluish purple) haze near all the rod big ends.

In order to truly check your pistons and bore, you should have internal and external 4" mic's and compare specs with fsm to see if they fall in tolerance. If you have done a lot, you can inspect the fit with feel/eye but i wouldnt recommend it unless youve built a lot. You will want new rings and a good hone (proper crosshatch) minimum for the piston/cylinder.

You can get away with your plan, it all depends on what you find once you take it apart. With a crank cleaning, you dont need different bearings. That is unless the machinist says otherwise. Have them give it a thorough look over/cleaning and a simple polish of the journals (larger bearings not needed with a polish, depending).

new bearings and rings, with a good cylinder honing is a minimum, you will thank yourself later.

Oh btw. If you got the plastic chip mess, 90% chance your oil pump needs replacing as well. Id suggest a high volume option. I sell these brand new for $70 ka24e.

If you dont have it already, get a fsm, even the pdf online versions. They list all basic rebuild procedure and needed specs for bearings, pistons etc... They will list the bearing tolerance a bit tighter than i like to run, go for a .002-.003" fit.

[sil80drifter]

Thanks so much for the advice and explanations. If you don't mind elaborating on the advantages of solid adjustable lifter conversion, and/or perhaps showing me a link to an explanation, if you don't feel like going into it yourself. I actually just got a new Z24 high flow oil pump right after replacing my timing chain, because my oil pressure dropped significantly. Too bad I paid $100 for it, I wish I knew you had those for sale.

sil80

[sil80drifter]

I can see how the rocker arms themselves may be hard to clean, but what about the rocker arm shafts? I think worst case scenario, i'll just get new rocker arms. Does it cost much to hot tank and clean all the parts, usually?

I am very new to the whole rings/bearings replacement business, so I woudl appreciate a few tips.Thanks so much for the already given info btw.

So let's say I have a block, it has 70k miles on it, the block itself right now it standing there with plastic in the oil pan (fully assembeld with crank/rods/pistons, nothing else). I don't know for sure, but I think the rings are in ok shape (I will replace them though) and pistons/rods are still ok to reuse, what should my next step be to find out whether the pistons/rods are ok?How do I find out what size rings to get, and whether the old ones were worn out much, or whether the sylinder walls were worn out much? I can't test compression because this block is outside of the car, just sitting there, so is there another way of testing the status of the rings/bearings??

I really want to take it all apart myself, then if nothing else is needed, get new rings/bearings, and put it all back myself as well, re-using the pistons/rods/crank. Is this realistic? Not from the side of me being able to, but whether I could pull it off with just replacing rings/bearings (and having the crank cleaned)? If I have the crank cleaned, will i need to get different size bearings than the ones that were on it originally?

I know my friend took apart his 50k mile block, had it redecked (it was a little warped on top) and then put everythign back together, reusing his rings and everything else. I thought I could do a similar procedure.

What do you think?

sil80

[Newcastle82]

A question for DeviousKA since we're on the subject of plastic tensioner shavings infiltrating and making your KA a sad little beast.

Can't those upper guides just be removed? And if so, how does one go about doing that without harming the chain itself or its housing?

Thanks a bunch.

[sil80drifter]

The SOHC only has two guides, both are necessary to the chain's operation. The stock ones are plastic, the replacement ones are metal and plastic (plastic backed by metal). The most common cause of the stock ones going is not just their plastic consistency, but the slack in the chain that is caused by a clogged chain tensioner. This results in chain lash which quickly destroys the plastic chain guides. If you properly maintain your car, change oil often, and warm it up, the stock guides may (and have in some cases) last way over 100k miles. But for peace of mind, even if nothing is wrong with the car around 100k, you'd be best off replacing the chain/tensioner/guides (and maybe even crank/cam sprockets).

sil80
Modified by sil80drifter at 10:31 PM 12/1/2004