long stroke fix?

Your premier source for information on the Turbo KA: KA24E-T and KA24DE-T (KA with aftermarket turbo kit)!
User avatar
lexcrob
Posts: 559
Joined: Mon Sep 22, 2008 7:38 pm
Car: I get a different ride faster than I could update this.
Location: Clarksville, TN
Contact:

long stroke fix?

Postby lexcrob » Mon Oct 24, 2011 9:11 pm

I hate to post this here but this section straight up has more educated experienced people than just about any other forum on the web.

Just had an idea while reviewing countless dyno spreadsheets and set ups for NA ka24de power.


Here goes (very general idea to be taken away here not that it could even work)

ka24de engine seems to have 1 distinct flaw

It does not have a "square engine in that its stroke is longer than is bore. This makes NA power hard to obtain in that with large cams you have to rev higher to get to their efficiency range. Again not helping this NA quest for power is the timing chain limiting decking options (ways around it). Some say this engine has one of the best flowing heads out there and that intake restrictions claim 30% gains to be had...... blaa blaa bahh




Anyways how bout custom pistons with a higher up piston pin creating a shorter stroke. This could even be compensated with say domed pistons increasing compression ratio and slowing piston speed at the same time! Or MILLING the crap out of the block to make it "shorter creating a more square engine with ""slower piston speed allowing you to rev higher!!!!




I have very little engine experience and am in no way an engineer or engine builder. I know there is alot of math in that theory that will probly make it unlikely. Something like angles and con rod to main angle thrust pressure...... i dont know figured id throw it out there


Plus timing chain would have to be shortened (take out a link???

Shur kinda sounds like a honda engine or sr20 if its possible but a 2.4 liter 10k rwd CAN IT BE DONE 200-250hp!!!!!!


User avatar
lexcrob
Posts: 559
Joined: Mon Sep 22, 2008 7:38 pm
Car: I get a different ride faster than I could update this.
Location: Clarksville, TN
Contact:

Re: long stroke fix?

Postby lexcrob » Mon Oct 24, 2011 9:33 pm

http://www.civicforums.com/forums/171-g ... tions.html


^ this guy put it a little better than i did even this seems to be a scarce description of what your actually changing.

User avatar
hannibal
Posts: 9685
Joined: Wed Sep 11, 2002 2:38 am
Car: Red Line to Glenmont
Location: Washington DC
Contact:

Re: long stroke fix?

Postby hannibal » Fri Oct 28, 2011 8:10 am

You can't alter the stroke of an engine by changing the location of the piston pin or length of connecting rods. The only way to shorten the stroke is to shorten the throws on the crankshaft.

User avatar
superDorifto
Posts: 1308
Joined: Mon Jun 13, 2005 1:13 pm
Car: 1997 Eclipse Spyder - AWD/5spd swap in progress
1995 Q45 - 5spd swap in progress
1984 200sx hatch(KA-t swap) - 355WHP
1991/1993/1995/1997 240s - Dead
1982 200sx hatch - fixed/scrapped
Location: CT

Re: long stroke fix?

Postby superDorifto » Fri Oct 28, 2011 5:47 pm

By moving the pin location all you are doing is altering the CR. The rod length and crank throw length are still going to be the same, and you will still have the same top end issues.

To destroke the motor you need custom length rods, a custom crank or both. The ratio that you end up with will most likely need custom pistons to make up for the lost CR....its a vicious cycle.

The is a thread on KA-T.org, a guy wants to potentially use a crank from a L20B, ford modular rods, and custom pistons to end up with a 2.2L fully counter weighted KA that should be able to rev to 8000-8500 without runing into the over square issues that the KA normally faces. check out his thread. I think it is titled "KA Bottom End Upgrades" or something like that.

User avatar
WDRacing
Moderator
Posts: 23888
Joined: Mon Nov 25, 2002 2:00 am
Car: 95 240SX, 99 BMW 540i, 01 Chevy Express, 14 Ford Escape
Location: MFFO
Contact:

Re: long stroke fix?

Postby WDRacing » Sat Oct 29, 2011 4:35 am

Easier to add a few psi then it is to even bother with the internals of the KA. Id never go through the trouble of destroking the KA, simply not worth it. Way to many better engine options as well as methods for making big power with the stock stroke. A high compression boosted engine would be a much better project IMHO.

WD

User avatar
superDorifto
Posts: 1308
Joined: Mon Jun 13, 2005 1:13 pm
Car: 1997 Eclipse Spyder - AWD/5spd swap in progress
1995 Q45 - 5spd swap in progress
1984 200sx hatch(KA-t swap) - 355WHP
1991/1993/1995/1997 240s - Dead
1982 200sx hatch - fixed/scrapped
Location: CT

Re: long stroke fix?

Postby superDorifto » Sat Oct 29, 2011 8:19 am

the reason the guy on KA-T is even bothering is cost.

L20B cranks are relatively cheap if you can find one ~$100. If his calculations are right with a little machining you essentially have a fully counter weighted crank a la BC...for a few hundred dollars. The modular ford rods are just as strong as the BCs and Eagles that everyone uses, but you can get them for MUCH cheaper. a set of eight usually sells for ~$300 new, stalk the ford forums long enough and you should be able to find a set of 4 usable ones for almost free. The pistons will be $500-600, nut needed to get back to a respectable CR. If he finishes the project, I could see this becoming another viable option for people that want to build a cheap fully forged KA that is balanced and revs to 8500.

It should cost about the same as my build, which is spiralling outta control. Hell, I'm looking for a L20B myself to see if I can help the project along.

User avatar
lexcrob
Posts: 559
Joined: Mon Sep 22, 2008 7:38 pm
Car: I get a different ride faster than I could update this.
Location: Clarksville, TN
Contact:

Re: long stroke fix?

Postby lexcrob » Mon Oct 31, 2011 7:10 pm

Well checked out my block last night with my new straight edge. Good to go i guess couldnt get .002 feeler under it anywhere on deck or main bores. I guess its good to go. I dont know for shur straight edge stuff is sketchy since their only accurate to .001-.002 every 12" so if your trying to measure .004 ............

Trying to source a crank now dont really wanna get a reman since they only offer bearings .025 and surface hardness of induction hardened crank only .030 tops. So yea we'll see what i can find maybe another supplier or maybe ill call tomarrow see if they got "tighter ones.

Bore 60 over/deck it just a touch (i plan to do the degree wheel thing and do some cam timing options) 248/248 /i guess stock pistons for now/ godspeed intake*/Q45 throttle body(half shafted eh<< ford guys lol) gasket match everything port/ de shroud a tiny bit/ CC'ing cumbustion chambers all even/balance rods and pistons tiny bit/index spark plugs/walbro/maybe send off injectors to get RC treatment.......tune im torn between emanage ultimate **NO MAF or SAFC and msd or NISTUNE <<<<probly that but still testing waters


anyways i figure MAYBE 180 for pretty cheap eh not really done figured it be different and cheap


im on the wrong section LOL

User avatar
lexcrob
Posts: 559
Joined: Mon Sep 22, 2008 7:38 pm
Car: I get a different ride faster than I could update this.
Location: Clarksville, TN
Contact:

Re: long stroke fix?

Postby lexcrob » Tue Nov 01, 2011 9:25 am

Well i guess there is a guy that put mazda b2600 pistons into a ka24e! Said he ran it for 2 yrs like this no problems and it ran great. 51$ for pistons sounds like this may be an option! Piston pin is 22mm not 21(ka24e?) and he had to grind down the pistons tops flat to clear deck. He did piston to valve clearance and was at .008. I have no idea of all diff. between ka24de and ka24e i guess ill start searching. I know there is def. BIG differences. Maybe it could work!!!! :ohno:

User avatar
SX APPEAL
Posts: 1345
Joined: Tue Oct 05, 2004 10:26 am
Car: 06 G35 Coupe 6MT
95 Maxima SE 5MT
Location: Springfield, MO

Re: long stroke fix?

Postby SX APPEAL » Tue Nov 01, 2011 4:48 pm

WDRacing wrote:Easier to add a few psi then it is to even bother with the internals of the KA. Id never go through the trouble of destroking the KA, simply not worth it. Way to many better engine options as well as methods for making big power with the stock stroke. A high compression boosted engine would be a much better project IMHO.

WD
Stay tuned ;)

User avatar
lexcrob
Posts: 559
Joined: Mon Sep 22, 2008 7:38 pm
Car: I get a different ride faster than I could update this.
Location: Clarksville, TN
Contact:

Re: long stroke fix?

Postby lexcrob » Wed Nov 02, 2011 10:13 pm

Well just bought a running 240sx for 300$ 5spd. and all...... guess im gonna try kat again this time rebuild first for shur! I really cant get away from these things maybe ill go holset this time! Buying a friken welder first tho!!!!!!!!!!!!!!!!!

User avatar
lexcrob
Posts: 559
Joined: Mon Sep 22, 2008 7:38 pm
Car: I get a different ride faster than I could update this.
Location: Clarksville, TN
Contact:

Re: long stroke fix?

Postby lexcrob » Sun Nov 06, 2011 7:00 pm

Picked up a i think 300zx turbo 75$ no shaft play make grindy noise and has rust on spring thing looking in oil drain??? Figure ill send it in for a freashin up or maybe try myself.
Did a compression test on my car i drove home other day. (1-4) 180/170/160/150

Weirdest compression test ive ever done! Figured it was battery slowly dying so rechecked #1 180.......


Added oil to (2-4) and blew 180 on the nutz so i got my winter project! Might try to bandaid it for a while but due to very poor test dont know if that would be a good idea.

wa-chiss
Posts: 2568
Joined: Mon Feb 20, 2006 10:23 pm
Car: 1990 S13 H/C KA24E
2005 Toyota Sequoia
1976 Honda CB750F Super Sport
Location: San Angelo, TX

Re: long stroke fix?

Postby wa-chiss » Tue Nov 22, 2011 8:28 pm

SX APPEAL wrote:
Stay tuned ;)

You too huh? E or DE? I'm in the works of a SOHC High Compression with boost project.

User avatar
SX APPEAL
Posts: 1345
Joined: Tue Oct 05, 2004 10:26 am
Car: 06 G35 Coupe 6MT
95 Maxima SE 5MT
Location: Springfield, MO

Re: long stroke fix?

Postby SX APPEAL » Wed Nov 23, 2011 12:46 am

Dual cam bra... a-new-way-of-thinking-t2-low-boost-high ... 17764.html

my planned setup is near the bottom

wa-chiss
Posts: 2568
Joined: Mon Feb 20, 2006 10:23 pm
Car: 1990 S13 H/C KA24E
2005 Toyota Sequoia
1976 Honda CB750F Super Sport
Location: San Angelo, TX

Re: long stroke fix?

Postby wa-chiss » Wed Nov 23, 2011 9:55 pm

Hmm. Lots of good info in that thread. We must compare setups and numbers after we're both done. I'm glad to see that there are at least some people that know what they're talking about and that I'm not the only one with this idea. Should be fun to see how the SOHC and DOHC compare with the same punishment.


Return to “KA24ET / KA24DET Forum”