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PUNKMETHOD

KA24E N/A Build Plan - Need advice

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Hello Ratsun people,

first time poster here.
I do actually not own a Datsun, please don't kill me. The thing is, whenever I was reading up on N/A KA's, at some point I landed here, so I thought it'd be the best place to talk engine.

The 'project' the engine is in / will be build for is a 1989 240SX.
As I am in Germany, KA engines are scarce, especially 240 ones, which is why I will stick with the SOHC one instead of a DOHC engine.
I was inspired by videos such as https://www.youtube.com/watch?v=FzqJXqzKexA as well as various threads about the old race car 240's etc.

My plan is the following:

  • Rework the block, also get it to 89.5mm (Sorry, I am missing a couple specific terms in engine work stuff)
  • Heave the crankshaft alone as well as together with clutch, pressure plate and flywheel
  • Carillo Pro-H Beam Connecting Rods
  • Arias Sport Compact Dome Pistons (10.8:1)
  • Nismo R5 Camshaft (Regrind)
  • Custom Titanium valve springs
  • 4-2-1 Header with 2.5" catback
  • Suzuki GSXR 750 Individual Throttle Bodies
  • ECUMaster Emu ECU
  • Lightweight Flywheel
  • Injectors and Valves: I really need help here.

So, as stated, I do need help in regards of injectors and valves.
Also, I would love any criticism, tips etc. regarding the setup listed above. Things you'd change up, all that stuff.
Note: I am not yet sure if the pistons work with the R5 camshaft, since it has a pretty large valve lift. Maybe if someone can help out there with calculations too..?

Thanks in advance.

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as someone that has played around with KA-e and de's I can tell you the e heads don't flow well. Any valve size increase will need a fair amount of porting to take advantage, and you will mostly just be trading torque for hp with a very marginal power increase. After porting the shit out of my first e and dumping money into larger valves and seats it felt almost the same as stock but more robust up high.

 

Now if you were to build it for boost it would be another story. 

 

What are your goals with it?  

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Goal is to build a high comp all motor KA24E.

Where did you get the valves from?

I guess I'll have to opt for porting the head from what you're saying.

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Waste of time.

 

Sorry. But the KA will never make enough power to make the 240SX fun. Especially a single cam.

 

Easiest, most affordable N/A KA build that will be fun would be to use a 1998-2002 Nissan Frontier DOHC with a L20B EI distributor. Install KA24E flat top pistons and your favorite set of side draft carbs with a custom made manifold (cut down) S13. Carbed DOHC KA with 11.2:1 compression sounds like a good cheap time.

 

I say use the Frontier KA24DE because it does NOT have the distributor driven off the cam like an S13. Instead, it's like older Datsuns and driven off the crank. The L20B distributor will sit right in there fine.

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Easiest, most affordable N/A KA build that will be fun would be to use a 1998-2002 Nissan Frontier DOHC with a L20B EI distributor. Install KA24E flat top pistons and your favorite set of side draft carbs with a custom made manifold (cut down) S13. Carbed DOHC KA with 11.2:1 compression sounds like a good cheap time.

 

I say use the Frontier KA24DE because it does NOT have the distributor driven off the cam like an S13. Instead, it's like older Datsuns and driven off the crank. The L20B distributor will sit right in there fine.

1. As I said above, KA24DE engines are stupid hard to come by here. None are available to buy here anywhere online.

I already have a spare KA24E engine sitting around waiting to be built up, so that's settled already.

 

2. The plan I had in mind with a friend of mine actually is to run it distributor less, using VW Wasted Spark Ignition coils:

https://www.ebay.de/itm/381122067544?ul_noapp=true

 

Mapping for the ECUMaster Emu (https://supr.com/gp-power-shop/steuergeraete-ecu/allgemein-emu-ecu-master-allgemein/emu-steuergeraete-allgemein/ecumaster-emu-gb-kit-1/) will then be done with a combination of Alpha N and MAP, as I can't run MAP exclusively because of the ITBs.

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You can run MAP easily with ITBs if you tap each runner and have a vacuum resevoir.

 

The easiest distributorless ignition to setup is actually the Ford EDIS4 setup. Found on 1990s Ford Escort and others. Possibly Mazda?

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I used to build a lot of these motors for SCCA GT3 class, and in full race trim, they made 300hp, but needed constant and meticulous maintenance. At 300hp, they would last about 3 or 4 races before they needed at least an inspection.

 

You can easily get 250hp out of this engine in street trim, but going for that last 50hp is difficult and expensive.

 

Question: why do you want to use Carillo rods if you're using a stock crank? Are you planning on a custom length?

 

The crank is definitely a weak point and needs major work to bring up to strength.

 

If you are willing to send parts to the USA for modification, I might consider sending the head to Rebello (the shop I worked for when I built the GT3 engines) and having them do the work. You might send them the crank too.

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On 7/4/2018 at 11:28 PM, mhub91 said:

You can run MAP easily with ITBs if you tap each runner and have a vacuum resevoir.

 

The easiest distributorless ignition to setup is actually the Ford EDIS4 setup. Found on 1990s Ford Escort and others. Possibly Mazda?

That's some good information regarding the usage of a MAP sensor, thanks for that.

As previously mentioned, I will likely get hold of some new VW ignition coils as linked so I can be sure of what I have.

On 7/5/2018 at 5:29 PM, Stoffregen Motorsports said:

I used to build a lot of these motors for SCCA GT3 class, and in full race trim, they made 300hp, but needed constant and meticulous maintenance. At 300hp, they would last about 3 or 4 races before they needed at least an inspection.

 

You can easily get 250hp out of this engine in street trim, but going for that last 50hp is difficult and expensive.

 

Question: why do you want to use Carillo rods if you're using a stock crank? Are you planning on a custom length?

 

The crank is definitely a weak point and needs major work to bring up to strength.

 

If you are willing to send parts to the USA for modification, I might consider sending the head to Rebello (the shop I worked for when I built the GT3 engines) and having them do the work. You might send them the crank too.

Holy crap, I did not expect to find somebody with experience like that here! I'm pretty amazed right now.

250HP definitely sounds like a nice goal. You say it is easily possible, can you elaborate more on what you seem to be needed for that?

I planned to use Carillo Rods simply as an upgrade for the OEM ones. I'd be interested in custom length regarding the crankshaft, but that requires calculation about the space between pistons at valves with the R5 camshaft, which I have no idea how to calculate as of now.

I definitely want to send a head and crankshaft to Rebello from what I'm hearing now, so that's on the list / planned now. Guess I'll have to contact them on pricing.

 

Thanks in advance guys

 

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3 hours ago, PUNKMETHOD said:

That's some good information regarding the usage of a MAP sensor, thanks for that.

As previously mentioned, I will likely get hold of some new VW ignition coils as linked so I can be sure of what I have.

Holy crap, I did not expect to find somebody with experience like that here! I'm pretty amazed right now.

250HP definitely sounds like a nice goal. You say it is easily possible, can you elaborate more on what you seem to be needed for that?

I planned to use Carillo Rods simply as an upgrade for the OEM ones. I'd be interested in custom length regarding the crankshaft, but that requires calculation about the space between pistons at valves with the R5 camshaft, which I have no idea how to calculate as of now.

I definitely want to send a head and crankshaft to Rebello from what I'm hearing now, so that's on the list / planned now. Guess I'll have to contact them on pricing.

 

Thanks in advance guys

 

Don't be amazed. I was the bottom end and final assembly guy. I know how to make the rotating and reciprocating assemblies live long, but the power mods were done by other guys in the shop. I was the I-dotter and T-crosser, making sure that the engine was assembled properly with all the components. That said, I can't really tell you anything more than the right cam, compression ratio and port job is all that's required to get the 250hp. I know, pretty ambiguous...

I wouldn't be afraid of the pistons. A good mock up will give you all the numbers you need. Using mock up valve springs and a dial indicator, along with the cam you are going to use and the valve heights already set, you can easily figure out piston to valve clearance and modify the valve pockets as needed. I have even done this on the engine with a valve modified to cut the piston by welding and grinding it to turn it into an end mill.

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Matt:

 

What needs to be done to strengthen the KA crank? Are there any differences between KA SOHC and DOHC cranks?

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My experience is limited to the KA24E cranks as that's what we built back then for GT3, so I don't know of the differences. I think the difference is in the ends of the crank. The snout and the rear bolt flange.

The main problem was that these engines didn't like to rev and the resulting failures were almost always crank related. I think 7200 rpms was about max for a completely built GT3 motor.

To make them live at 300hp, we would weld on extra counterbalance weights, then machine weight off all of the counterweights in the lathe with a knife edging process. We would then send out the cranks for various treatments including nitriding, metallaxing (harmonic vibratory treatment), shot peening, etc. We would try to use only standard journal sizes (not ground). Nitriding actually grows the metal a tiny bit, but this helped us as we liked to run tight bearing clearances.

The front of the crank was a particular problem and would snap off, so we had custom hubs made to be able to use a Fluidampr harmonic balancer. This would change the entire front drive setup, meaning none of the original pulleys or accessories would work, but since we only ran a water pump and a dry sump pump, it didn't matter for us. A dual row timing setup was also made to fit inside the front cover and this also changed things a bit as far as the front drive was concerned.

How does this relate to building a 250hp street motor? Well, the counterweights and knife edging may help, but probably isn't totally necessary. Keeping the revs down is probably the safest insurance on a street engine.

 

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On 7/7/2018 at 7:12 PM, Stoffregen Motorsports said:

That said, I can't really tell you anything more than the right cam, compression ratio and port job is all that's required to get the 250hp.

I wouldn't be afraid of the pistons. A good mock up will give you all the numbers you need. Using mock up valve springs and a dial indicator, along with the cam you are going to use and the valve heights already set, you can easily figure out piston to valve clearance and modify the valve pockets as needed. I have even done this on the engine with a valve modified to cut the piston by welding and grinding it to turn it into an end mill.

 

That sounds great! If that's the case, I believe the list I have written down together with porting should give me a satisfying result. The idea with the modified valve also is kinda genius. No idea if that's something "normal", but to me it is pretty amazing, as I've never heard about it.

 

On 7/7/2018 at 8:11 PM, Stoffregen Motorsports said:

My experience is limited to the KA24E cranks as that's what we built back then for GT3, so I don't know of the differences. I think the difference is in the ends of the crank. The snout and the rear bolt flange.

The main problem was that these engines didn't like to rev and the resulting failures were almost always crank related. I think 7200 rpms was about max for a completely built GT3 motor.

To make them live at 300hp, we would weld on extra counterbalance weights, then machine weight off all of the counterweights in the lathe with a knife edging process. We would then send out the cranks for various treatments including nitriding, metallaxing (harmonic vibratory treatment), shot peening, etc. We would try to use only standard journal sizes (not ground). Nitriding actually grows the metal a tiny bit, but this helped us as we liked to run tight bearing clearances.

The front of the crank was a particular problem and would snap off, so we had custom hubs made to be able to use a Fluidampr harmonic balancer. This would change the entire front drive setup, meaning none of the original pulleys or accessories would work, but since we only ran a water pump and a dry sump pump, it didn't matter for us. A dual row timing setup was also made to fit inside the front cover and this also changed things a bit as far as the front drive was concerned.

How does this relate to building a 250hp street motor? Well, the counterweights and knife edging may help, but probably isn't totally necessary. Keeping the revs down is probably the safest insurance on a street engine.

 


I've read / heard about the crankshaft being one of the main problems of the engine during my own research before. Would it be possible to simply send two crankshafts, one being a spare one to cut off weights to add onto the other one or are extra weights not a problem?

Also, can you tell more about the Fluidampr? I've done some searching, however I only found them for the RB26/350Z engines?
Could other harmonic balancers do the job? Only ones I found are made by Powerbond / Well Auto. Will link those.
https://www.precisionintl.com/BrandSearch.aspx?Brand=Powerbond&Cat=54&Make=54&Model=&Engine=1323
https://www.ebay.com/itm/Well-Auto-HARMONIC-BALANCER-CRANK-PULLEY-KA24E-2-4L-for-98-04-FRONTIER-XTERRA-/321974802346

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The counterweights are custom made out of plate steel, so you don't need two cranks.

 

The Fluidampr was also a custom piece. Actually just the hub was custom, and then the pulleys were custom from March Pulleys. Rebello had those parts made for their use, though they may sell them to you if they're still available.

 

Any harmonic balancer will be better than nothing, but the Fluidampr style is a racing style balancer.

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That's some very helpful information already, thanks for that.

 

Just by chance, can you tell more about valves used as well as injectors, fuel pump and such?

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8 hours ago, PUNKMETHOD said:

That's some very helpful information already, thanks for that.

 

Just by chance, can you tell more about valves used as well as injectors, fuel pump and such?

Ferrea valves (custom).

 

These engines ran on PHH44 Mikunis and 50mm Solex's when I built them. EFI wasn't legal then for SCCA, but it is now, and since then, the guys at Rebello have found more power.

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If your looking to run a distributorless ignition definitely look into megajolt, it uses a Ford Edis system which is fairly easy to source. It's pretty easy to set up. Both Duke and I are running it on our carb'ed DEs.

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Thanks for all the replies so far, they're very helpful.

Can anyone give some input in terms of converting the KA24E from hydraulic lifters to solid lifters?

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Unless you're a competent machinist, you need to send those out to have modified. Rebello Racing will modify them for you, not sure of the cost. I used to do them when I worked there, by drilling out the hydraulic parts, then machining the tops flat, then using silver solder to braze in a threaded insert. The "elephant's feet" may be hard to find if you don't know what you're looking for.

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