S13/S14 Head & Block differences?

[djsilver]

I've been reading/searching/researching and would like to verify what I think I've figured out about the KA24DE long block variations;Best I can figure, the only difference between S13/S14 heads is the cams (240/248 vs 232/232?) I've read references to higher compression and a more aggressive cam in the '91 DE motor but the references mentioned the same 9.5:1 and 240/248 numbers that are in my '93 FSM. I haven't read anything to indicate any differences in the S13/S14 blocks. All the other differences in intake/exhaust plumbing, ecu's, distributors etc. are external to the long block. I'm checking because I'll be autocrossing a '93 240sx base hatchback in SCCA's street prepared class and, while they allow some updating/backdating of components, the rules are very specific and I need to have my ducks in a row and be prepared to prove legality.

[TheOne]

i believe the difference between ~91-94 ka's and 95-98 ka's are the older has better cams, but the 95 to make same(bit more) power is because the ecu is tuned better for that, the 95+ have internal coil, the 91-94 has external coil. 96-98 have other sensors on the intake manifold and some stuff for emissions(OBDII, which some late 95's have also).

[:: orion ::]

The head casting IS different....as you can tell by the valve covers (different bolt patterns, they are NOT interchangable). Same goes for the front upper cover...it's *almost* identical, but there is one bolt different.

EVERY KA24DE that came in the S13 or S14 is 9.5:1...no exceptions.

The '91-93 motors had better cams, so it's in your best interest to retain/reuse your '93 cams.

Other than that...the intake manifold is different (secondary butterflies for S13, none for S14), but your S13 mani will bolt right up to a S14 head.

Exhast manifolds are also different...S13 is better.

The key is...use ONLY the S14 head and block, keep everything else from your car (manifolds, ECU, harness, sensors, etc....) and it *should* be legal at anything other than nationals...where someone would have to pay $50 to challenge you in your class...and you'd lose the challenge. Thing is...with a stock-ish KA in your car (stock class), you won't be in any nationals running anyway. Maybe DSP or SM if you turbo'd it, you'd stand a chance...but any class where the motor HAS to be original or same year...it'll never make a difference.

- Brian

[1991S13]

I read somewhere that S13's with automatic transmissions do not have secondary butterflies...

Is this true?

[Dattebayo]

I wouldnt believe it, the FSM says nothing about the "SCV" missing from automatic cars.

SCV is the Nissan name for the device, coined from the phrase "Swirl Control Valves". And they really cant be defined as secondary butterflies, because they do not function as butterfly valves do...