Want more power from your NA KA here it is!

[tryiian]

almost everything being said in this thread is lightyears above my head... all I know is that i`m very envious.

Gabe, could you do all of us lesser-intelligent people a favor and do some kind of writeup on a fairly easily accomplished highpower NA KA designed for road racing/drifting use? Particularly one that had compromises for daily drivability. I know that you and the people you know are capable of making NA KA`s in the 300 and up hp range... how about an affordable (i.e. comparable to the cost of turbo) setup that pushes around 250 or so hp using that typical list (i/h/e, hc pistons, fuel upgrades, ecu tuning, cams) and maybe something out of the box that non-engine builders could accomplish, like how to make this infamous destroked KA using another engine`s block.

Not that you`re obligated, but you have a pretty good idea of how famous you are internationally, ne? You could have a huge impact on the NA KA world with just giving away one or two lower level techniques for engine building that must be somewhere in your repetoire.

P.S. Can I move up there and learn how to build/work on engines from you someday?

[Bigvinnie]

Alright tryiianI'm not Gabe but I will describe briefly using pics the method of destroking. The KA deck height is too tall for destroking. The block itself was designed for a much larger crank and stroke hense a larger rod as well. Nissan over the past 30 years really hasn't changed too much design to usdm engines, even the L series cranks are some what similar but are slightly smaller as well as rods and block deck height. L series cranks from the L18/20 came fully counter weighed, basically better balanced for higher rev and stress.The NAPSZ 20 z20s/e came with the EXACT same internals of the L20b, it was just transferred over to block that stood straight up instead of a slant, and had greater improvement to the head such as cross flow design ( although I still dont find 8 valves on a 4 banger optimizing performance, but rather a lack there of). So lets move 10 years down to the production of the KA, same design methods of the z series, which came from the L (30years of production) The KA block is almost the same as the z, same head bolt pattern in the block, same cross flow design. Only difference is that the KA is siamesed which means each cylinder to block was welded together more than likely for reasons that delt with the coolant passages. Only problem with KA is that high rev isn't tha accomodated compared to smaller displacement and smaller stroked z20s/e engines. So now if you want high rev you would need the fully counter weighed crank as well as the shorter rods and displacement. Problem with the KA head is that the valves are to large for 2.0 displacement, which would cause valve shrouding (Lack of atomizing fuel to air, and swirl within the chamber). So usually these z blocks are slightly bumped up to 2.1~2.2 displacement. You can also use the z22s/e but then you are dealing with the same crank as KA which is only half weighted, and will cause more torsional straess at higher RPM's or the lack there of. So in this case it is best to stay fully counter weighed. Although the KA crank does have it's place with knife edging.

Here is the comparison of the blocks.Here is the NAPS-z block.Here is your basic KAEJust by looking at the heads and blocks they are very comparable and similar although deck hiegth and internals are changed.

[deviousKA]

Well, it would take some time to put together something like that. Answering questions is so much easier haha. I could get real in depth all that good stuff, but after a while it all starts sounding like $$$$.

The 240sx being such a large and heavy car, its best to stick with the larger displacement. Starting off with the basic things such as high compression, cams, header, and then moving onto induction modifications is the way to go. Most people do not complete all the steps and quit half way through. Just with those mods I listed above 200+hp can be obtained, properly tuned.

Ill have to take a breather, ill work on something here in my spare time but its not a subject that can easily be tackled in a few large paragraphs.

You could move up to the NW if you would like, haha. Its the datsun capital of the world!

[InsanityInc]

The 240sx being such a large and heavy car, its best to stick with the larger displacement. Starting off with the basic things such as high compression, cams, header, and then moving onto induction modifications is the way to go. Most people do not complete all the steps and quit half way through. Just with those mods I listed above 200+hp can be obtained, properly tuned.

Large and heavy? What's a 300C, then?

[SonyPete]

The intake on that Z-block posted above, is it stock or aftermarket?

If stock has anyone ever tried putting that intake from the Z-Block onto a KA24E??

[Bigvinnie]

The intake on that Z-block posted above, is it stock or aftermarket?

If stock has anyone ever tried putting that intake from the Z-Block onto a KA24E??

The intake was stock on MPI engines that came on the USDM 200sx (1981-83), and the JDM Z18et (79-82).Nope the bolt patern and ports to the intake are different.

[SSS]

Gabe, if you're interested, i've found with the new 102mm stroke, the following will work the best:- Manley forged steel I beam rods to suit the Ford 5.1L mod motor - the Probe Industries forged pistons for the same engine, in 90.2mm bore and 1.098 C/H.

Using the 5.1 rods and the 5.1 comp height pistons means only approx 0.9mm needs to be flycut from the top of the piston to give the required 247mm deck height.

Plus, the stock KA rod/piston combo weighs approx 1250 grams, the new ford combo comes in at approx 950 grams.

This whole ford piston/rod combo is actually cheaper than purchasing KA24E specific pistons from Arias. However, i'm expecting the cost of having the crank modified to be a fair bit, at least $700 AUD.

[s1ndicate]

Would you have to do crank moddifing? Iam not sure what you are doing, Iam assuming modding the crank for a higher rev or modding the crank to fit that stuff.

Will KA24E rods fit the fully countweights L crankshaft? Iam assuming NOT, but if it does, with it being fully counterweighted, you should be able to squeeze alot more RPMs, and will that crank destroke the motor alittle.

You guys can get extremely technical, trying to understand. lol, keep it coming though!

[SSS]

Those Ford 5.1 rods will not fit the KA crank without having the journals enlarged and reground. Without having the crank offset ground to increase the stroke to 102mm, that rod/piston combo only has a deck height of 244mm, whereas the KA block is a 247mm deck height; a 3mm difference. The piston top is supposed to be level with the deck surface on the block.If you tried to run this combo without the increased stroke on the crank, the engine's compression ratio would be down around the 5-6.0:1 mark, which is far, far too low.

[Bigvinnie]

Those Ford 5.1 rods will not fit the KA crank without having the journals enlarged and reground. Without having the crank offset ground to increase the stroke to 102mm, that rod/piston combo only has a deck height of 244mm, whereas the KA block is a 247mm deck height; a 3mm difference. The piston top is supposed to be level with the deck surface on the block.If you tried to run this combo without the increased stroke on the crank, the engine's compression ratio would be down around the 5-6.0:1 mark, which is far, far too low.

Agreed...... NISMO already makes all the parts necessary there are no cutting corners when it comes to the crank.If a NISMO KA built by rebello can rev too 8500RPM at $10,000 I will stick with that option than trying to build something that just won't work.

[deviousKA]

Adam, how are those 5.1l (4.6l stroker) parts going to work? Arent the piston and the rod both shorter? I didnt really find a length on the rod for that engine, but It would have to be longer than 165mm/6.5". EDIT: looked again and its length is 5.9"

Just to clarify, the stroke is the diameter of the "circle" that the center of the rod journal travels, not the radius. The radius is used to calculate the deck height.

5.1l piston c/h = 1.098"/27.89mm

stroke 102mm

rod length required, approx 168mm to bring to exact top deck.

If you were to use the 5.1 piston AND rod, it would require a stroke of 140mm to bring the pistons to deck height of approx 246mm.

But, I might be looking at different parts?

s1ndicate, the longest stroke fully counterweighted datsun crank is 86mm. This is a whole 10mm smaller stroke than the ka24 (96mm). So you can then imagine that if you were to use that crank, with the same length rods and pistons as the ka24, in a ka24 block, the piston will be 5mm below the deck surface of the block.

The ka24 rods are to narrow to use on l/z cranks (the rod journal). The z24 rods are the exact same length (165mm) and can be used with the l/z cranks, no modifications. These z24 rods are equal to ka in strength and design (aside from journal width).

But like I have mentioned a few times before, ka24 blocks (z24 as well for that matter) are to tall to do a significant destroke. The example of 5mm I gave above doesnt seem like a whole lot, but it definately is. Even if the ka block were to be 5mm shorter, it would still be to tall. The 165mm+ rod and 34mm+ piston offer poor rotating assembly characterics in both the ratios and the weight.

This rotating assembly will indeed be under less stress at any given rpm, but it will be very reluctant to rev, and will fall off rpms quickly.

[Bigvinnie]

The 240sx being such a large and heavy car, its best to stick with the larger displacement. Starting off with the basic things such as high compression, cams, header, and then moving onto induction modifications is the way to go. Most people do not complete all the steps and quit half way through. Just with those mods I listed above 200+hp can be obtained, properly tuned.

Not to make a huge debate over this matter, but the N/A sr20de is used in Australia, and with a few bolt on's carries the same 1/4mile times as a stock USDM KA, it also uses the slower 5th gear and the same werner synchros box as the KA.If you ask me a 2.2 litre high rev z/ka frankenstien would whoop some serious *** with a fully counterweighed crank (with the reduction of lowend torque, and higher HP numbers, also using the werner synchros box from the 82-83 napsz, part no. FS5W71B). Of course clover leaf welding would need to be done to the head (no porting, and a polish to the dome) and the fuel injection would have to be worked down to 250~260cc instead of 270cc.But this is basically your cheapest setup, for high rev KA hybrid.I think it would make a good dyno curve from lowend to high end numbers.

[deviousKA]

Yeah that is true.

But for the budget oriented or first time high performance engine builder, its better to keep it simple imho. Excellent results can still be had.

With a "hybrid" type high revving engine, a lot has to go into the transmission and drivetrain as well to make it suit.

In other words, it would be very easy to get poor results with a basic hybrid engine. You cannot leave any stone unturned, you gotta have formula 1 tactics.

Thats my opinion anyways, I dont want any first time builders reading what i say and expecting to get easy results with a hybrid engine, they might be disappointed.

[SSS]

Sorry gabe, it was a typo on my behalf, the actual rods from Manley are the 5.4L rods, which are 6.657" in length C-C (169mm). The 5.1L components are the pistons from probe which have the 1.098" C/H.

So for deck height:102/2+(1.098x25.4)+169=247.9mm ; which means i only need 0.9mm flycut from the piston which will give me just above the 9.0:1 comp ratio i'm after (approx 9.15:1 with stock KA chambers).

[deviousKA]

whoa nm, very cool

I dont think I ever ran across those rods in that length, would definately be the way to go.

You know that when finding a perfect rotating assembly your obligated to complete it

I didnt mention it before, i have designed a 2.6l stroker, but it was toyota (reason no mention). I was able to put a longer rod in this engine than the original, with a very short piston. This engine has been proven to perform excellent (trucks). It only required 94mm stroke.

I might have to look into those manley rods, btw

[SSS]

I'll build it, it's just hinging on how much it's going to cost me to get the journals built up and reground; i've already contacted a metal spraying company that should be able to build up the journals for me.

Only downside is the decrease in rod/stroke ratio, this stroker combo yields approx 1.65:1, with the stock combo coming in around 1.7:1.I guess the decrease is acceptable, since the weight reduction of the rotating assembly is pretty significant.

I have my current rev limit at 6275rpm, which i worked out will be fine with the stroker combo.

[deviousKA]

Considering what your wanting to accomplish with the main parts your using, it would be optimal.

The crank work will be the biggest hitch. I have never heard of successful metal spraying to build up a good amount of material, although the technology gets better all of the time.

It will be some work for a welder, but wouldnt be impossible. Be sure to get all the oil plugs in the crank replaced with allen plugs as well.

[vvaffle]

I'm actually starting to get a slight hang of what you guys are talking about but if you don't mind I would like a few things cleared up.

also using the werner synchros box from the 82-83 napsz, part no. FS5W71B).

This is a transmition we are talking about right? Any reson for this specific one?

Of course clover leaf welding would need to be done to the head (no porting, and a polish to the dome)

Could you explain what clover leaf welding is? I am assuming it is done to reduce the size of the valves because of the smaller displacement.

and the fuel injection would have to be worked down to 250~260cc instead of 270cc.

Couldn't you just tune the ecu so the duty cycle is shorter?

I am guessing you are talking about a ka24/z20 hybrid (because of the 86mm stroke) so if you were trying to up the displacement wouldn't it be best to both stroke and bore out the engine and try to keep the bore and stroke equal? I'm not sure what the stroke would end up but wouldn't this result in a little more torque down low than just boreing it out?

But for the budget oriented or first time high performance engine builder, its better to keep it simple imho. Excellent results can still be had.

Do you mean that excellent results can be had with bolt on upgrades to the KA and upping the compression or by using a piston/rod combo not originaly meant for the KA?

Also, at some point (maybe in another thread) you said it is possible to mount the ka24 lower in the chassis and 1-1.5 inches further back (I think this is what you said, correct me if I'm wrong). Were you refering to a standard KA or a hybrid?

Alright, I think that's all the questions I have for now.

EDIT: reformated so it's a little easier to read.

[Bigvinnie]

This is a transmition we are talking about right? Any reson for this specific one?

Yes it is the transmission from the 1982-1983 200sx. It's just better gearing for the HP curve that the 2.2litre produces and comes with the 2.2litre napsz engines.

Could you explain what clover leaf welding is? I am assuming it is done to reduce the size of the valves because of the smaller displacement.

It reduces chamber size to bring the engines compression up. It doesn't reduce the size of the valves though.

Couldn't you just tune the ecu so the duty cycle is shorter?

I guess you could, but more than likely the engine will still run a little bit richer than leaner. Using the correct injection size is a good way to regulate fuel, and fuel economy as well as performance. Decreasing the tip size will allow for better atomizing of air to fuel the spray will be much better. The point is to optimize the spray pattern to mix with the amout of air that each cylinder consumes.

I am guessing you are talking about a ka24/z20 hybrid (because of the 86mm stroke) so if you were trying to up the displacement wouldn't it be best to both stroke and bore out the engine and try to keep the bore and stroke equal? I'm not sure what the stroke would end up but wouldn't this result in a little more torque down low than just boreing it out?

Why would you want to stroke a fully counterweighed crank? You would just lose your high rev. Thats kind of like saying, lets stroke the KA even more than it needs to be stroked for a 4 banger. Increasing the displacement will increase torque, but in the HP gained by increasing the displacement it is more of a better balanced engine than a torquey stroker like the KA, with a much better and higher redline than the KA.
Modified by Bigvinnie at 10:13 PM 10/1/2005

[SSS]

It will be some work for a welder, but wouldnt be impossible. Be sure to get all the oil plugs in the crank replaced with allen plugs as well.

Absolutely. Along with that, the cranks mods will extend to:- Cryo treatment after journal enlargment- Offset grind to correct journal size for 5.4 rods, - Miropolish all journals- Cross drill oil galleries in journals- Knife-edge/lighten crank to reduce rotational inertia- full balance

Anything else i might be missing? I don't really see the point in shot peening an already shot-peen'd crank.

Although i had my current SOHC head welded to decrease chamber size and the filling work was good, i'm hesistant to let some loose on the journals with a TIG by hand. Ideally somewhere that can build them up using a submerged arc process would be absolutely ideal.

It's going to be a killer bottom end, and i can't wait! In fact, i would love to build the same bottom end for a killer NA version....

[vvaffle]

thanks alot for the clarification vinnie.

[Type X(J)]

hey guys - just read thru the post and I have a question for deviousKA, you mentioned that one can move the KA engine a bit more towards the rear a bit more. How can I do this.

[s13satch]

I've been tempted by the turbo's but I'm gonna stay with NA for 3 reasons. One is that a swap is illegal here in my home state of MD. Two, is that my motor currently has 112,000 miles and a compression of 150 psi on each cylinder. I have not done a leakdown test, but I suspect the loss is due to the piston rings. I don't have near the budget for a rebuild and a turbo kit. Third, like most 240sx owners, I started out with some bolt-ons. They have added up overtime and I can't see the sense in a turbo or swap b/c of all the money I already put in the NA KA.

I already have an I/H/E combo, ASP crank pulley, and a MSD ignition. My plan is to do a simple performance rebuild. I'm looking at running SOHC pistons, having my intake ports matched to the manifold and the exhaust ports polished, and using ARP head studs. I'm guessing I could get 170 whp with this setup. So about $1600 for the parts I already have + $3000 for the rebuild = $4600. I end up with around the same whp as a stock sr20det for around the same price as a swap, but I get more torque and essentially a new motor. The only down side is the need to always run 93 octane with the 11.1:1 compression.

Further down the road I may finish off with an electric fan, JWT cams, JWT ecu, and a larger MAF sensor. I'm sure there is a lot more power to be gained with these parts, but they will run another $1500. At that point, I may as well have stuck with stock compression and going to a basic turbo setup. I don't think those remaining parts would get me anywhere near the 240 whp a KA with a small turbo running 8psi would produce.

[dfw240_EE]

The 240sx being such a large and heavy car,

Funny statement these days, seeing how sports cars have porked up a little bit. Aside from a small handful of exceptions (Lotus Elise ~2000lbs Mazda Miata ~2400lbs), most sports cars weigh around the 240SX. Honda S2000, Pontiac Solstice, Saturn Sky, Civic Si (all ~2800lbs give or take), Scion tC, Hyundai Tiburon (3000lb+ porkers), and the Sentra SE-R (~2700lbs), the 240SX seems trim in comparison.

Sorry, off topic. Still trying to digest this thread