About rebuilding the Engine? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Drift Style S14 · 04-09-2002, 12:39 AM

Hey everyone i was wondering, what are the max hp the components of our ka's can handle? for example the pistons, connecting rods, crackshaft, etc. etc.

DuffMan · 04-09-2002, 04:03 AM

Pistons : 250 flywheel
Rods: forged but their durability varies. 300-400 depending on other factors.
Crank 400+

These are pretty safe numbers that I'm just pulling out of my ass to give you a general idea though. Some people put down over 300 hp at the wheels on all stock internals and have no problems. It's like a long expensive game of russian roulette.

*sykikchimp* · 04-09-2002, 10:19 AM

There are a couple guys around now with b/w 300-350 hp on stock internals.  I would say the pistons can hold to about 300hp max before I personally would change them.  I think 250 is a fairly conservative estimate.

The pistons are definately the weak point though.

geeaj · 04-09-2002, 10:40 AM

Rods and crank are forged from the factory. For anything over 250hp, I would suggest you shotpeen, polish, and balance the rods to overcome any manufacturing flaws or imbalances. Stock nissan rods are used successfuly in racing when prepped accordingly. No need to spend on aftermarket rods such as Carillo and such unless your building an all out race or drag car.

As for the crankshaft, you should have it magnafluxed, lightly polished, and magnafluxed. This doesn't cost much maybe $200. What you get in return is the some measure of security when you start cranking up the boost. The stock bottom ends are very stout IMHO, iron block, big mains, girdles...etc. Since your doing this, you might as well have the crank oil holes drilled a bit larger for increased lubrication.

Pistons are the weak link, I will agree. Enough said. You can go aftermarket as far as piston rings, something like total seal. But if your ring lands are of good design on the pistons, then OEM Nissan chromoly would be fine. Just make sure the engine builder has EXPERIANCE putting together engines. You can use the best parts in the world, have the best machinist, but if you skimp on assembly, your reliability will go downhill.

For extra protection, I would look into an aftermarket oil pan. One that provides increased capacity and preferably baffled to decrease oil "sloshing" during hard cornering or acceleration. Running higher oil pressure maybe a good idea too. Nissan motorsports sells a high pressure oil pump spring/washer set for the 280zx turbo, which can be modified to work on the ka oil pump.

Drift Style S14 · 04-10-2002, 11:51 AM

So this brings up another question, what level of boost would i be able to run after work like that done to the motor? Also, roughly, how much would all this cost to build up the motor? thanks for the great info peps.

guy · 04-10-2002, 09:44 PM

I am seriously thinking about the same thing.  I also was wondering roughly how much to spend on the engine work.

whateverjames · 04-10-2002, 10:00 PM

i talked to a fellow 240sx owner who rebuilt his engine. he said with aftermarket piston heads and connecting rods, all machine work, and labor it came out to be $2,500.

you could probably run 25 psi on a properly tuned engine.

04-09-2002, 10:19 AM	#3
sykikchimp WOW addicted Join Date: Dec 2001 Location: the moon Age: 44 Posts: 6,525 Trader Rating: (0) Feedback Score: 0 reviews	There are a couple guys around now with b/w 300-350 hp on stock internals.  I would say the pistons can hold to about 300hp max before I personally would change them.  I think 250 is a fairly conservative estimate. The pistons are definately the weak point though. __________________

04-09-2002, 10:40 AM	#4
geeaj Zilvia Junkie Join Date: Dec 2001 Posts: 357 Trader Rating: (0) Feedback Score: 0 reviews	Rods and crank are forged from the factory. For anything over 250hp, I would suggest you shotpeen, polish, and balance the rods to overcome any manufacturing flaws or imbalances. Stock nissan rods are used successfuly in racing when prepped accordingly. No need to spend on aftermarket rods such as Carillo and such unless your building an all out race or drag car. As for the crankshaft, you should have it magnafluxed, lightly polished, and magnafluxed. This doesn't cost much maybe $200. What you get in return is the some measure of security when you start cranking up the boost. The stock bottom ends are very stout IMHO, iron block, big mains, girdles...etc. Since your doing this, you might as well have the crank oil holes drilled a bit larger for increased lubrication. Pistons are the weak link, I will agree. Enough said. You can go aftermarket as far as piston rings, something like total seal. But if your ring lands are of good design on the pistons, then OEM Nissan chromoly would be fine. Just make sure the engine builder has EXPERIANCE putting together engines. You can use the best parts in the world, have the best machinist, but if you skimp on assembly, your reliability will go downhill. For extra protection, I would look into an aftermarket oil pan. One that provides increased capacity and preferably baffled to decrease oil "sloshing" during hard cornering or acceleration. Running higher oil pressure maybe a good idea too. Nissan motorsports sells a high pressure oil pump spring/washer set for the 280zx turbo, which can be modified to work on the ka oil pump. __________________ Beware the fury of a silent man, be more cautious of his silent farts....

04-10-2002, 10:00 PM	#7
whateverjames Nissanaholic! Join Date: Jul 2001 Location: St. Louis Age: 45 Posts: 2,263 Trader Rating: (0) Feedback Score: 0 reviews	i talked to a fellow 240sx owner who rebuilt his engine. he said with aftermarket piston heads and connecting rods, all machine work, and labor it came out to be $2,500. you could probably run 25 psi on a properly tuned engine. __________________ 02 Blazer X - 90 240SX w/SR oh noes

04-09-2002, 12:39 AM	#1
Drift Style S14 Zilvia Addict Join Date: Sep 2001 Location: ............ Age: 42 Posts: 602 Trader Rating: (0) Feedback Score: 0 reviews	Hey everyone i was wondering, what are the max hp the components of our ka's can handle? for example the pistons, connecting rods, crackshaft, etc. etc.

04-09-2002, 04:03 AM	#2
DuffMan Post Whore! Join Date: Oct 2001 Location: in a cardboard box Posts: 2,517 Trader Rating: (0) Feedback Score: 0 reviews	Pistons : 250 flywheel Rods: forged but their durability varies. 300-400 depending on other factors. Crank 400+ These are pretty safe numbers that I'm just pulling out of my ass to give you a general idea though. Some people put down over 300 hp at the wheels on all stock internals and have no problems. It's like a long expensive game of russian roulette.

04-10-2002, 11:51 AM	#5
Drift Style S14 Zilvia Addict Join Date: Sep 2001 Location: ............ Age: 42 Posts: 602 Trader Rating: (0) Feedback Score: 0 reviews	So this brings up another question, what level of boost would i be able to run after work like that done to the motor? Also, roughly, how much would all this cost to build up the motor? thanks for the great info peps.

04-10-2002, 09:44 PM	#6
guy Join Date: Apr 2002 Location: Madison, WI Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	I am seriously thinking about the same thing.  I also was wondering roughly how much to spend on the engine work.