ka24e pistons in a ka24de

[TRUSE-R]

I was wondering if you guys can help me out? I currently own a '91 240sx (KA24DE). I would like to keep the car N/A for daily use while upgrading it to get respectable numbers out of it. I have heard that JWT has a KA ECU available. I was wondering what the program consists of? Are there cheaper alternatives than JWT? Also, I am planning on putting the SOHC pistons (ka24e) in the ka24de block, raising the CR to 11:1? I have heard of others doing this, but I am doing some research on it. I was wondering if anyone has a complete listing of parts needed and a how-to? Are the pistons a direct drop in? BTW, my current mods are as follows:1. Hotshot Intake2. Hotshot header3. Walbro fuel pump4. UR crank pulley5. High flow cat6. 2.5 in cat-back exhaust system7. Upgraded ignition wires and MSD coil8. ACT clutchI was planning on running a NX single fogger kit (75 hp shot) too, if possible. I hope you guys can help me out on this. Please e-mail me back @ [email protected] or post replys here.

Thanks in advance.

[InsanityInc]

bikirom.com, so long as you can solder.

[JesusLikesKFC]

also still lookin into the sohc piston swap but reading up on valve clearing isssues and streetability along with assloads of tunning, and as for the other ideas go for a 3 inch cat-back and deletepipe or straitpipe, for intake.... u dont need to blow 400 on a lame CAI, better off buying a k and n cone filter. if you find any usefull info on a sohc piston swap feel free to post info on it.

[JesusLikesKFC]

oh btw u might wanna add a resonatted pipe cause the header/ exhaust combo wil be LOUD. also the sohc are supossed to drop in but they wont clear intake and exhaust valves so PLEASE sombody who has a high CR motor post this shizz and help anotha brotha

[3blackbirds]

i droped the flat top e pistons in the de motor and swaped the DE into my 89 coupe. your CR will actually be 11.7:1. but that can depend on the manufacturing year, mine is 11/88. i think that earlier manufacturing dates have less of a CR of about 11.5? not too sure on that one. the pistons are a direct drop in with the 91-94 crank. make sure you hone your cylinders out before you drop those pistons in or the new rings wont set up and make a seal!! you can have a shop do it (highly suggest) or get a cylinder honer from the auto parts shop of your choice and attach it to your electric drill.

i dont have valve clearing issues at all. even with PDM racing's cams. i have a cheap exhaust system of OBX headers, stock cat, and a pacesetter exhaust. which the pacesetter is being replaced by something else very soon, btw. the motor sounds very mean. not an import sound at all, a deep note big ballsy sound that isnt loud and obnoxious. it is very nice, very different.

i have a jwt ecu and an SafcII for it. havent had a chance to play with it too much. as soon as i got it built and running, i got sent overseas, which is where i am right now. your not going to see a whole lot of performance gains from the E piston install. you'll maybe get a 10% increase in power from these alone.

with your mods right now plus the E piston install, id say you'll be looking at around 180hp.

let me know if you have any more questions, ill be happy to answer.

[Chezedik]

How bad do you think compression would be if you didn't hone, would it fix itself?

[tonynalli]

good luck on turboing it down the road....that compression is way to high to be safe

[yellow_jacket]

How bad do you think compression would be if you didn't hone, would it fix itself?

If the rings don't seat properly, you can easily get less compression than your current setup. And no, it will not fix itself.

[elgarvo616]

who said hes gonna turbo it?

[nuts510]

there are two different piston compression ratios in the single cam car. If you use the piston from the 90 model your compression ratio will be around 10 1/2 may be a touch more this is much more reasonable if you want to drive it daily it'll run great offer premium gas you can even bump the timing up one or 2° and that'll help that is untill you start the shot you want to retarded the timing a little for that or it could get ugly.amazingly enough to Stock computer will manage everything good I have found the computer out of the 94 to be the best running one and of course there the hardest to find one. Even with the Jim Wolf cams there was no issues with valve clearance with the 90 pistons.though I would not even consider raising the Redline much because the valves are so hard they'll break if you float them and a piston makes contact with them!!At this particular time I have two cars running on this combination if your cylinders walls in good shape the Pistons drop right in there even free-floating wrist pen so you can change in yourself don't put the rods backwards to the Pistons also replace the rod bolts if you're going to be hard on it I have seen them break

[DjPantsSpecR]

if you use the 90 piston, you'll get 11.1

the 89 piston is 11.6-11.7

[GnarKiller]

Are you sure those are the right compression ratios?

How do you know...

[DjPantsSpecR]

i thought that was a well known fact?

however ive read alot of stuff here saying that the 89s give 11.3 to 1, but from what ive read alot more of on fresh alloy, it is infact 11.6-11.7

i know for a fact that it shouldnt be 10.5, adn im not questioning he has this setup, im just sayin his math is a little off

[:: orion ::]

there are two different piston compression ratios in the single cam car. If you use the piston from the 90 model your compression ratio will be around 10 1/2 may be a touch more...

Not so...the correct #s are 11.1 for the 8.6: SOHC pistons, and ~11.6:1 for the 9.1:1 SOHC pistons - See below.

Are you sure those are the right compression ratios?

How do you know...

Do the math...

http://www.ariaspistons.com/sportnissan.htm - Lists Head cc (46cc), deck height (0.0001, since 0.0 does not work in the calulators), bore and stroke, and head gasket thickness (~0.045, or ~1.2mm...standard for the KA).

9.1:1 SOHC pistons are known to have a 2.8cc dish, so use "-2.8"

8.6:1 SOHC piston have a 6cc dish.

Plug those #s into here:

http://www.campbellenterprises...s.htm

And you'll get ~11.1 and ~11.6

Easy stuff.

- Brian

[Chezedik]

So, here is a good question. If you buy new aftermarket pistons for the 89-90, they have the same part number (and are therefore the same), so do you think they are modeled after the 89 or 90's pistons?

[irax]

generaly it will be the higher compression... because with the DE block the aftermarket pistons are pritty much all 9.5:1 (OBD2KA)

[Southeast240]

ok, which rods do you use? is the E or the De rods?

[SimpleEnigma]

you can use the stock DE rods and wrist pins.

The '90 E pistons are the ones you are looking for if you still want to be able to run pump gas.

I dont think you can run nitrous with those though (you say something about nitrous?)

[deviousKA]

eh, this is an old post but hopefully this clears everything up.

Here is a ka24de piston chart, stock combustion chamber.

early 89 ka24e piston = 2cc dome, 34mm compression ht.late 89-90 (also 91-97 truck and 90-92 stanza) = 2cc DISH, 34mm compression ht.

And yes this is all 100% correct, as you can see compression ratio varies with bore and the 11.1/11.7 assumes 89mm std. All CC measurements done by myself with proper equipment and multiple subjects.



My chart btw, didnt come from fresh alloy or anywhere else

[DjPantsSpecR]

so, you can go to your local nissan dealership, purchase early 89 pistons 1mm over and have compression ratios in the 12.1:1 range? I'm just wondering if im reading it correctly

i had gone to nissan months ago about this, and i was priced at 347 bones for these pistons and rings. I couldnt afford this and the machine work, but its still a pretty impressive deal.