NO BUDGET KA ENGINE BUILD

Your premier source for information on the Turbo KA: KA24E-T and KA24DE-T (KA with aftermarket turbo kit)!
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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

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Here I go again trying to build a car with as little money as possible!

Lets get down to it shall we:
(Keep in mind this information is what ive found read or my general opinion NOT a bible to beginners or a flame war)

RESEARCH 1ST RIGHT!

Quench:
Piston deck hieght for a ka24de is .000 via FSM. I measured it myself and found my engine to be at .005. This number will obviously vary upon cylinder block height as there is casting variation or a acceptable range. This can be continued to point out why some engines make more power than others or run "better". Say you get a block and head at the lower end of the heights so you'll have a slightly higher compression ratio. VERY small difference but it creates a good concept of it. So on to this quench i speek of! Quench essentially is a very close collision between the piston and cylinder head that causes a rush of air or cooling sensation. In some instances I read it can even help engines run higher compression ratios with same octane fuel and or more aggressive timing. This all so can create more turbulence within the combustion chamber creating a more complete burn. You guys get the idea so whats all that mean for our engines! Well down side is for it to really even have a chance and i mean chance of working you definately cant have dished pistons. In fact the effect is almost completely diminished by some opinions! Maybe this leads to point out why everyone says ka engines are annemic. The last note on that is you want flat pistons .035 ballpark for a street/race engine. Keep in mind headgasket thickness varies along with rod length and many other factors measure x2 build once.

Bore/Hone:
As i flipped through the pages of super street and import tuner I kept seeing this thing called a torque plate! I called machine shops to see if they attained such engine building magic and found most machine shops have never even used them! Off to the book store i went to pick up engine blueprinting by SA recommended by a forum member. After browesing through the book and getting jsut about every local machine shops opinion i've come up with a general consensus. If your not going to be making UNGODLY horse power like a rocket ship you really dont need that technology! Engine boreing and honeing is considered an art by many and as ive now realized. Engine building is VERY sloppy from an engineering standpoint. Stright edges are only accurate to .001 every 12". Think about that one for a second esspecially when your going to try and make a piston to wall clearance of .001 and make all the pistons in line of each other and aligned with the axis of the crank. Its really sad how slppy it is i mean obviously there are ranges for everything but as for as a performance aspect there is SO MUCH to it and the best part is nobody really knows. Even if you build and engine blow it up and try to replicate this engine that you blueprinted there is going to be differences you litterally cant measure everything. So waht is the moral to this horrible story. Bring you engine to a shop witha good reputation for import or late model engines drop it off pick it up and hope for the best! Give them an idea of what your going to be doing with it. Of course supply the pistons and tell them what you want ring endgap to be and thats all you can do. Maybe it will be decent maybe it will be perfect maybe it will be horrible but it doesnt really matter. Longevity your talking 60k instead of 100k and power your taliking 5%.


Crankshafts:

The thing that i died trying to find was if a turned" crankshaft was weaker than a mint one.
Furthermore how much weaker is it and how is it done and that kind of stuff. Ill sum it all up with
a quote from the machine shop I ended up using. "we put turned cranks in engines all the time makeing
goobs of power" So in nutshell it does not matter and i came to find out most production
crankshafts are induction hardened which has a hardness depth of .030". This is kind of the
shell around the crank journal.
Everything else is pretty self easy and gets a little to techy for me. .002 is as tight as you can be.
If your crank run out and your straight edge check out you can obviously run a little tighter. FSM
calls for around .004 i believe as the tightest. My aftermarket king bearings put her at .003
with the plastiguage. I did find that plastiguage normally reads on the high side so im probly more like .004.


I will edit this as i go just trying to lay down the foundation tonight!
Last edited by lexcrob on Tue Mar 06, 2012 11:55 am, edited 1 time in total.


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neverlift
Posts: 3700
Joined: Mon Apr 24, 2006 6:26 am

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not sure what this has to do with no budget? Machine work is what drives the cost up in a lot of builds. Don't get me wrong AM rods/pistons are not cheap but that wouldn't be a budget build.

IMO find another crank if yours needs turning. I currently have a budget motor as in it was bad when I spent all my money on it, had to polish crank,new bearings,a piston and re seal the whole deal. It ended up with an ebay hg ,re used rings,some clevites. Been a year now , drifting within the first 150 miles and still going. now on 10psi daily.

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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

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I never thought about it that way about the title. Im building a search base so people can get a good idea what NOT to do and get an idea of exactly how to do it first hand from an average joe. I try to put in all the little stuff that most build threads leave out or assume everyone knows! My last one was called (NO BUDGET KA-T BUILD) *CHECK IT OUT!!

Kind of continuing with that guide but I hope to go a little more in depth.

Agree'd machine work is very expensive and i've got some things that I learned the hard way! I'll put it all up here soon trying to figure out the best way to relay it all. Without it looking like a big typed up mess! I review some of my old posts and it blows my mind how horrible I post. I cant even fig. out what I was trying to get across!

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Caveit77777
Posts: 434
Joined: Sat Nov 07, 2009 7:02 pm
Car: 1996 240sx SE

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NO "PICTURE" KA ENGINE BUILD

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WDRacing
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Joined: Mon Nov 25, 2002 2:00 am
Car: 95 240SX, 99 BMW 540i, 01 Chevy Express, 14 Ford Escape
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Piston shape is going to vary depending on make/model/motor. The piston design itself shouldn't be messed with. Nissan spent 100's of thousands of dollars designing the KA, to include the combustion chamber. Unless you're an engineer, don't over think something like quench and or the very slight difference in compression between motors. IMHO, that would be a complete waste. Something as simple as ring placement can change your whole compression profile.

Quench is basically how the motor avoids detonation. Mess with the quench zone and you're just going to have trouble. Flat top pistons will lead to smashed valves :tisk:

I've rebuilt plenty of motors without using a torque plate. If you're making the kind of power that requires a torque plate, you're not worried about a budget. If you're not worried about a budget then you're using aftermarket everything, so you won't need to worry about having something turned or refurbed in any way.

WD

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quiksilver20004
Posts: 12
Joined: Fri Jul 13, 2007 1:23 pm
Car: 2001 Nissan Maxima Se 20th Anniversary 5spd
96 240sx 5spd

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I personally prefer to run a cut crank over a stock one. yes you are taking a little meat off of the crank but in turn you are reducing weight and the biggest advantage, ie. reason i run a cut crank in my builds, is when you cut the crank you make the journals smaller and bearings larger which reduces bearing speeds which is a big plus!
Also if you are wanting to build and engine correctly then NEVER use plastigauge, it is useless! You need to use micrometers and dial bore gauge to get your clearances set correctly.


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