240sx ka24de main crank bearings

j ai entendu que les main bearing du crank du ka24de vont tourner ou quellque chose comme ca si tu boost le moteur a 300-350hp c est tu vrai...

Ask the resident 240Sx God Ssspikey

If memory serves me right (now's your change to flame me to hell Ssspikey)

Booster le KA24DE pour avoir plus que +- 350hp sur les internal stock t'es garanti que ca lache... mais c'est quand meme bon.. c'est plus que 2 fois son potentiel stock...

Puis hum... Google.com has the answer just ask

I know that making 350hp on stock internals is not realistic but I wanted to know if the main crank bearing are a weak point of the ka24de if it has a properly built bottom end, and if it is a weak point are upgrades available. thanks for your reply

ka24de does not have a forged crank like the sr20det does.even though it has an iron block, the engine is stroked to the max, it has an under-square layout which hurts it in the capability to rev higher.unless your building a fully built engine for drag racing or just for fun, reliable hp without sacrificing the engine's normal life expenctancy would be around 275hp.beyond that is looking for trouble, even though ive seen people running 315hp on a stock block and head.it IS possible to attain that mark and even go further, but i dont like taking chances, i like my stuff rock solid.as for the engines weak points, ill let the little genius tell them.

edit:if i remember correctly, a while back in SCC there was a turbo ka that was making 43X hp, but i dont remember if his internals were stock or not.

please explaine under-square layout and how long is life expentancy and what parts whould go bad after a while.

under-square is when your stroke is bigger than the bore of the engine.In the case of the ka, if i remember, the bore is 89mm and stroke is 96mm.It affects the revability of the engine, as well as the torque production.Under-square engines are frenquently found in trucks, because they produce more torque.They also rev slower and have a lower rev capacity.Big bore engines, over-square, rev higher and smoother but have trouble igniting fuel envenly inside the cylinder.They also have trouble with strenght because the cylinder walls are too far from the others.Typically large bore engines(wrx engine, porshes and the honda B16, as well as F1) rev higher, its more "fun".More torque is for the big stroke engines, think ka or honda b18 series , rev lower(honda is an exception though, b18c ) Square engines, sr20det, have the best of both worlds.Hope i didnt make any mistakes. Life expectancy, well, how long your engine is capable of running.How many km u got on your speedo?As for the typical failures, i dont know them, ask sspikey for that.

thanks for the info

I always thought the "revability" of an engine was related to the stroke not the bore...

Anyway howstuffworks.com has info about engine basics.

The Purple 240Sx in SCC blew its engine 3 times before making 4xx HP. It now has forged internals shotpenned stuff and all (that was a loooooooooong time ago)

Bore=surface of the cylinder
Stroke=How far the piston goes into the cylinder.
Ill give you an example, if you do benchpress, lets say 145pounds.What is the easiest and the fastest way to make more reps?Large grip with 1 foot of going up and down or narrower grip with 3 feet of going up and down, i dont know for you, but id take number one option any time.It is more difficult to make more reps when you go further in the up and down motion .Another example, try to punch something, lets say air.Now punch the fastest you can go with 10 centimeters of margin and 50 centimeters of margin.If you can throw punches faster with a longer distance than with the short one, ill present you to the Inter-box group, they need your help.As you can see, doing quick small punches makes you go fast but the torque is missing, while punching slower but with a greater distance packs quite a "punch"(cheap joke).

so if the ka24de has a longer stroke than bore what is a reliable top rpm for it and will over boring the cylinders help, why honda engine like mine ( b18c1 GSR ) can rew to 8000rpm just like the b16 with no broblemes so what is diffrents with the ka24de.

dont rev the KA high
it will be mad at you
nissan engines dont like to go over oem redline without decent amount of work done to them.
t3/t04E work AMAZING on KAs
i dont care what some sr guys say. overlayed graphs on same peak power shows the ka has way flatter power when the SR just peaks.

I second Sspikey !

BTW very interesting topic guys !

thanks sspikey for your advise but what would be the decent amount of work that you are talking about.

where to start.......
camshafts gotta go for JWT S4. next up valve guides and valve springs while your ar it new valves and new shims. jwt cam gears help and of course proper tuning.