KA Head Z24 Block Once more for giggles

[frankendat]

I have acquired a Z24 in need of rebuild. It is missing the exhaust manifold and distributor and will need pistons/rings. I like to keep things simple, but am warming up to computers. Reading the many threads, on this and other Nissan sites, on the application of a KA24E (Not DE) head and pistons to a Z24 block has me confused.  So, using a scale based on simplicity (tweaked a little for my simplicity) please check my understanding.

Simple = Buy the correct size K24E (truck) pistons instead of the correct size Z24 pistons, increase compression and with some ignition tweaking, increase efficiency a bit. Added gains small, no added cost, no added complexity.

Simple = “port” and gasket match the Z24 head, following DatzenMike’s lead. Added gains small, no added cost, no added complexity.

Simple = Install a weber 32/36. Added gains medium, added cost $300+, no added complexity

In the never ending pursuit of “a little bit more” (in my case engine efficiency) less simple modifications might be entertained. The first less simple modification has a ton of information spanning multiple sites. From what I have been able to gather, application of a single cam KA24 head to a Z24 block, requires some modifications to the coolant/oil passages and the custom machining of a gear. I could not find a step by step of this process, however it appears straightforward, so long as then end product will be a carb fed KA24 single cam head.

Less Simple = Install single cam (12 valve) KA24 head onto a carb fed Z24 block. Added gains small/medium, added cost $200+, added complexity medium

BUT, a carb fed KA head is missing a big potential benefit of the KA head…EFI.  The threads outlining the different methods and different builds attempting (some successfully) an injected KA head are long and bursting with information. Reading the threads one thing was clear, it’s not easy.

Difficult = KA head Z24 block fuel injected, TBI, MPFI, EFI. Added gains medium, added cost $500+, added complexity XL

That is what I have been able to gather from the many threads regarding the KA head and the Z24. My goal is to bridge the gap between threads that say it is a bolt on swap and other threads that go on for months cataloging the many problems encountered.  The only way I can rationalize the discrepancy in thread difficulty is that the authors were working towards different goals. The additional goal of fuel injection seemed to be the tipping point.  It appears that adding KA24 pistons and head can be accomplished fairly easily if you forgo fuel injection, but without the benefits of computer controlled injection is the head swap a good cost/effort/benefit? What have I missed/screwed up?

[datzenmike]

8 hours ago, frankendat said:

 

Simple = Buy the correct size K24E (truck) pistons instead of the correct size Z24 pistons, increase compression and with some ignition tweaking, increase efficiency a bit. Added gains small, no added cost, no added complexity.

 

KA-E  head with KA-E pistons in a Z24 block will equal a KA-E engine. There will be no compression increase except that a Z24 is 8.25 and a KA-E is 8.64..

 

 

8 hours ago, frankendat said:

Simple = “port” and gasket match the Z24 head, following DatzenMike’s lead. Added gains small, no added cost, no added complexity.

 

Very little gain but increases with every performance increase added.

 

 

8 hours ago, frankendat said:

Simple = Install a weber 32/36. Added gains medium, added cost $300+, no added complexity

 

You could use a 38/38 with 2.4 liter engine but I'm not a fan of them.

 

8 hours ago, frankendat said:

 

In the never ending pursuit of “a little bit more” (in my case engine efficiency) less simple modifications might be entertained. The first less simple modification has a ton of information spanning multiple sites. From what I have been able to gather, application of a single cam KA24 head to a Z24 block, requires some modifications to the coolant/oil passages and the custom machining of a gear. I could not find a step by step of this process, however it appears straightforward, so long as then end product will be a carb fed KA24 single cam head.

 

What gear? This is a Z24 first.... with a KA head. All that's needed is a Z24 cam sprocket fitted to the KA cam and all the other Z24 timing gear should fit. Yes there is an oil drain back hole that needs to be plugged because it would join to the cooling system otherwise.

 

 

8 hours ago, frankendat said:

Less Simple = Install single cam (12 valve) KA24 head onto a carb fed Z24 block. Added gains small/medium, added cost $200+, added complexity medium

 

Use the truck KA-E intake with the EFI throttle body removed. It looks like a 4bbl intake. Make an adapter plate for a Weber and use a 4 plug L20B distributor.

 

 

8 hours ago, frankendat said:

BUT, a carb fed KA head is missing a big potential benefit of the KA head…EFI.  The threads outlining the different methods and different builds attempting (some successfully) an injected KA head are long and bursting with information. Reading the threads one thing was clear, it’s not easy.

 

 

For EFI you would need a KA-E crank angle sensor (CAS). The Z24i uses them, I don't know if a KA-E CAS will fit the Z24 of it the Z24 CAS will work with the EFI or not.. To use a CAS the distributor spindle has to be changed also.

[frankendat]

Thank you for sharing your insight Datzenmike, it is valued. The Z24, in stock form, has all the power I would need. My only rationale for entertaining modification is not to miss technological advancements that are easily applied. To put it simply, I don't want to leave money on the table. And, I currently have access to a small machine shop, unfortunately it is set up for guns not automotive, but there is a mill and lathe nonetheless. <BR>

<BR>

I understand that miles per gallon is subject to many variables, only one of which is engine efficiency. But, I want to increase engine efficiency as much as "simply" possible, with the understanding that as the complexity of an engine increases, the reliability decreases.Reliability and serviceability are the primary reasons that I have abstained from EFI,  but I am forced to admit that fuel injection is now pretty well sorted and pretty reliable. Where I still remain skeptical is whether the cost and assache of converting an engine to EFI is sensible from a "saving money and problems in the future" perspective.<BR>

<BR>

In your opinion, where is the cutoff on the list of KA modifications to a Z24 block, where  the added complexity either undermines the reliability of the  motor or for the minimal gains enjoyed is not worth the effort? (bearing in mind my time is free and parts will be primarily salvage yard sourced)                                                                                                                                                                                                                                                                      

[datzenmike]

If you can buy an after market EFI that tunes itself and that you can put on the Z24 I would do that. The KA head swap is a lot of work just to get 30 year old EFI technology. The KA 3 valve  head will breath better for increased power over a Z24, but not really contribute much to mileage. As for compression you could mill the Z head and raise it. Very generally a higher compression is more efficient. It gets more bang out of the gas used but brings it's own problems along with it. If the Z24 has a compression of 8.25 and you went to 9.25 you might gain 4-6% power increase.... on a good day.   

 

KA pistons in an otherwise stock Z24 would give you 9.52 compression.

 

You may want to mill the head level anyway so no extra to remove more...

Milling 1mm off the Z24 head will give 8.8 compression

If you deck the block 0.5mm plus the 1mm off the head you get 9.18 compression

 

[frankendat]

I might be confused on an obvious point. To achieve EFI on a Z24, I thought the options were either find a Z24i head and throttle body to achieve a  Z24 TBI or swap manifolds with, I think it was a Geo Storm, again to achieve a Z24 TBI. But to achieve EFI, both the head and manifold must be exchanged, to use cylinder injectors. In my original post, this is where the complexity of the build threads became intense.

 

Am I understanding correctly that your recommendations are to install new Z24 pistons and rings instead of K24E pistons and rings and mill the deck and block to achieve the raise in compression. Additionally, finding a Z24 TBI manifold and computer tuner (Ford EDIS  with crank trigger perhaps?) would be more "bang for the buck"  then attempting a KA head swap. Even though with the KA swap a KA computer and CAS are available. Correct?

 

Thank you for your time
 

[datzenmike]

The Z24 and the Z24i use the same heads. The intake might be the only difference for mounting the throttle body injection. Technically it's EFI but now 35 year old technology.

 

The Z24i uses a crank angle sensor already so no need for EDIS

 

The '80-'83 Z20E or Z22E 200sx have an intake with multi port injection but again this is a batch fire system and close to 40 year old technology. Maybe something like this with a newer EFI controller? Even the KA-E fuel injection would be better if used on a Z24. This has been done putting the KA sensors and MAP/MAF on the earlier 200sx manifold.

 

 

[frankendat]

Happy Sunday, I spent most of last night researching these questions and kept running across the posts and threads of three, no longer active, individuals: Sealick, HRH, and mobile joe. I found specifics on the HRH build and on mobile joe's build. Sealick's build details I could not find, even after going through his individual posts. Is a link to his build information available? Even if the website is no more, it might be on the Wayback Machine.

 

The MPFI information that I seek was referenced a couple of times in different threads; once by Datzenmike,

 

"Sealick has done this with an early 200sx EFI onto a Z24. The AFM needs adjusting for the larger displacement."

 

"Another guy I know has used the 200sx EFI manifold but swapped KA sensors/injectors and ECU over to it."

 

I am assuming that the above referenced builds are not TBI, but rather MPFI and I would love the details of what was used, what was made, and how it worked out for both of the above mentioned builds.

 

Thank you for guidance,

[datzenmike]

http://720world.com/forum/topics/2016119:Topic:686?commentId=2016119%3AComment%3A1158

 

Patric Smith from Las Vegas has a Z24E using a 200sx intake and I think 240 sx parts.

[frankendat]

Datzenmike that is fantastic information! Did you ever install that Z24 head you ported and injector notched? Also, any leads on Sealick's build info?

 

[frankendat]

Found some additional Sealick build info, search the site in the link provided, thank you. I am very  interested in how far you progressed on this endeavor

[datzenmike]

Like a lot of stuff I try I often go in another direction. 

 

Haven't heard from Doug (Sealick) in almost 10 years.

[frankendat]

For better or for worse we are much the same. Would you be interested in selling some of the items created for that venture?  Send me a PM, might be a way to save me time at the pick and pull and fund your next conquest

[datzenmike]

HRH got one of those 200sx intakes. I don't know what he did with it but that was 15 years ago? He's in Spokane and most active on this forum....

 

https://nwdatsuns.com/

 

https://nwdatsuns.com/memberlist.php?mode=viewprofile&u=388

[frankendat]

15 years ago, that's far too long. I was hopeful that you still had the KA fuel injection from an '89 240sx with the engine wiring harness and  ECU from Patrick Smith acquired around 2008, a mere 12 years ago. Or if you still had that injector notched Z24 head and Z24i distributor to complete the package. Or basically anything from this list:

PARTS NEEDED: (ALL FROM 240SX KA24E UNLESS SPECIFICALLY MENTIONED OTHERWISE)

Coolant temp sensor

Throttle position sensor/ throttle switch

AAC (auxilary air valve) FICD and IAS (idle air screw) combo and mount portion removed from upper plenum

4 fuel injectors

Aluminum Fuel rail blank (available from aeromotive. can be machined and drilled to fit your injectors to the NAPS-Z manifold. If you are food you can make the rail from square steel tubing and bastardize a KA24E rail

Fuel pressure regulator (adjustable is preferred, oem good if it will fit your fuel rail.)

Throttle body (KA24E is best fit)

Oxygen sensor

MAF (Mass Air Flow Meter)

IAT (intake air temp sensor)

Distributor (Hardbody Z24i)

Ignition coils and power transistor assemblies (Hardbody Z24i)

Appropriate tubing for intake duct to MAF

A Thousand feet of electrical tape

wire loom (preferred)

Mostly complete KA24E engine wiring harness

KA24E Computer (Manual or Automatic does not matter. Automatic is preferred.)

[bottomwatcher]

This doesn't make any sense. I did the ka 24e swap. 240sx intake on truck block. It will cost a couple grand if you do all the work yourself and is not a drop in, but man it makes the truck a pleasure to drive. To go through all that effort maintaining a z24 is a waste of time and money. That being said the z24 with a tuned weber and doing the maintainence schedule including headbolt retorquirng is will leave you with a dead nuts reliable rig. The amount of single digit solutes you get from todays roads and drivers will have you wishing for more power. The ka e running with a manual ecu and no vss input will cut out at 3500 rpms. Need auto ecu or vss sensor input.

[datzenmike]

I don't even remember where I left my slippers two days ago..

[frankendat]

30 minutes ago, bottomwatcher said:

This doesn't make any sense. I did the ka 24e swap. 240sx intake on truck block. It will cost a couple grand if you do all the work yourself and is not a drop in, but man it makes the truck a pleasure to drive. To go through all that effort maintaining a z24 is a waste of time and money. That being said the z24 with a tuned weber and doing the maintainence schedule including headbolt retorquirng is will leave you with a dead nuts reliable rig. The amount of single digit solutes you get from todays roads and drivers will have you wishing for more power. The ka e running with a manual ecu and no vss input will cut out at 3500 rpms. Need auto ecu or vss sensor input.

You're right it would be a waste of time....unless somebody had already done the legwork and assembled the parts, say tucked away in a box in the garage marked "2008"...

[Stoffregen Motorsports]

Maybe I missed it, but I don't think you said which car/truck the motor would be going in. A 720? If yes, then that's one reason in the "pro" column for building the custom motor. Being able to use all the stock motor mounts, oil pan, pulleys and brackets is kind of cool. I built one of these Z24/KA24 engines many years ago, using a 12 valve head, and it went in a 510. I also remember building a 2.0L or 2.2L with a KA head, but the details on both of these builds escape me.

[Charlie69]

20 hours ago, datzenmike said:

I don't even remember where I left my slippers two days ago..

Look down Mike they are on your feet!  LOL

[datzenmike]

Holy shit! They are!!! Guess I slept with them on.

[frankendat]

10 hours ago, Stoffregen Motorsports said:

Maybe I missed it, but I don't think you said which car/truck the motor would be going in. A 720? If yes, then that's one reason in the "pro" column for building the custom motor. Being able to use all the stock motor mounts, oil pan, pulleys and brackets is kind of cool. I built one of these Z24/KA24 engines many years ago, using a 12 valve head, and it went in a 510. I also remember building a 2.0L or 2.2L with a KA head, but the details on both of these builds escape me.

Custom rig, not 720. The evolution of this line of inquiry is as follows: I once owned a 620 with an L20B and loved it. When researching different engines for my project, I came across a guy who completed a similar project with a L20B. Wanting to follow his lead, I began searching for an L20B and found no viable options-- either-too far away, too far gone,or too over valued. To up the odds of success I, reluctantly at first, opened to the idea of a Z22, L head frankenmotor. For the last couple of months, I have been diving farther and farther down the  frankenmotor rabbit hole. <BR>

The  rationale behind this thread is engine efficiency, a stock Z24 has enough torque and horsepower for my needs, and my fall back plan is to rebuild the Z24, that I have, mill, "port", and gasket match the head, deck the block, install  a weber and call it good. But, even though I have been against fuel injection, I am forced to admit that it has been around long enough to be well sorted (stuff from KA and later) achieve equal or better performance with less fuel . The KA engine and the SR engine are too large for my project. The CA engines could be contenders, but they fall into the same category as a bunch of various engines with which I have no direct experience. I need a motor that I can fix, but even better, a motor I don't need to fix. A great option would be the engine out of a 1999-2000 Sentra, but I haven't found an example of one that has been easily and cheaply converted to  RWD.

<BR>

So, as someone with experience with various Nissan engines, what do you think would be the increase in efficiency, or better yet how many additional miles per gallon, could be achieved from swapping KA MPFI parts into a 200/240sx manifold on a Z24 bottom end, as opposed to a mostly stock Z24 with a weber? (all other variables being equal)

[Stoffregen Motorsports]

Ok, so all the benefits of putting a KA head on a Z24 bottom end have been made moot.While the Z24 and KA24 are near identical in their bore and stroke measurements, there are other differences that lean in favor of the KA for efficiency. Modern low tension piston rings and narrow rod and main bearings being chief among them. For these reasons alone, the KA would have better efficiency, from less drag/friction.

 

As per your EFI comment, I think EFI has proven itself to be far superior to carburetion. Glad you finally came around to see that.

[datzenmike]

L/Z main......... KA-E main.

Only the main bearings are narrower.

[frankendat]

4 hours ago, Stoffregen Motorsports said:

As per your EFI comment, I think EFI has proven itself to be far superior to carburetion. Glad you finally came around to see that.

 

It took my 99 Sentra to convince me. My problem with fuel injection was the inability to prime (multiport not TBI). For an engine to run it needs fuel,air,spark. When broken down on the side of  the road, I start working those three and have success. Then came computer controlled injection and "modules" and "sensors", it was no longer just fuel,air,spark and the extra stuff was crap. My 99 Sentra is the newest vehicle I have owned and I came to own it under protest and while I still am not pleased that my old school methods of engine diagnostics will not save me if broken down on the side of the road. I have put more than 100000 on the Sentra and have never been broken down on the side of any road.

 

I am still curious  about the below, if you have an educated guess...

18 hours ago, frankendat said:

as someone with experience with various Nissan engines, what do you think would be the increase in efficiency, or better yet how many additional miles per gallon, could be achieved from swapping KA MPFI parts into a 200/240sx manifold on a Z24 bottom end, as opposed to a mostly stock Z24 with a weber? (all other variables being equal)

 

[bottomwatcher]

Nissan improved the reliability, quicker starts and better fuel economy when they phased out the z 24 and replaced it with the KA.