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ARP Hardware NAPZ 2.4


Madkaw

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Having a hard time finding ARP rod bolts and or head studs for my 83 2.4 NAPZ. 
I’ve read that it’s the same as the KA24E ? Is that the same as the KA 24DE?

Anyone have part numbers? 

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I too am interested in ARP studs. It is my understanding, that using the KA24 E head studs in a Z24 is acceptable. Summit 202-4307. There is disagreement on the KA24DE studs in a Z24, so I put it down as a no-go. Finally, there are at least two individuals (that I only know by screen name) who claim the head studs from 1.9L Saturn 91-99 DOHC, part number 165-1202 are interchangeable with the Z24.

I continue to search for interchangeable options, because the price of the ARP parts, stings a bit. I am looking to pay $100.00 (with tax and shipping, maybe a wee bit more) If you know of any upcoming ARP sales, please pass them along.

 

I am curious if there are any ARP competitors. All I can find are ARP studs or OEM studs. Are there trusted brands, stronger than stock, but either not as trusted or not as strong as  ARP for less money?

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 The Z24 doesn't make enough power to need studs.

 

 

The rod bolts are the same as the L series...... same as used in the 280zx turbo. Good to 7k + and what? 190+ hp? Z24 will never see that abuse. Save your money.

 

 

Head bolts? Probably the KA24E which followed the Z24. The DE was a little later. The Z24 head bolts are reusable, where they started using TTY bolts on the KA and they must be replaced. Measure the length of the Z head bolt and get a stud the same length. You can always add washers under the nut if too long. Why does it have to be for a Z series? as long as it's long enough.

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10 minutes ago, datzenmike said:

 The Z24 doesn't make enough power to need studs.

 

 

The rod bolts are the same as the L series...... same as used in the 280zx turbo. Good to 7k + and what? 190+ hp? Z24 will never see that abuse. Save your money.

 

 

Head bolts? Probably the KA24E which followed the Z24. The DE was a little later. The Z24 head bolts are reusable, where they started using TTY bolts on the KA and they must be replaced. Measure the length of the Z head bolt and get a stud the same length. You can always add washers under the nut if too long. Why does it have to be for a Z series? as long as it's long enough.

I don’t have them in front of me , but you are saying they are 9mm bolts ? 
Did not know they were the same as the Z series, but it makes sense . Probably he same journal sizes on all the motors .

I was curious about head studs because I am going to turbo charge my motor . ARP said they have a design calculator on their site to match up studs or have some made to length .

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I

26 minutes ago, datzenmike said:

 The Z24 doesn't make enough power to need studs.

 

 

The rod bolts are the same as the L series...... same as used in the 280zx turbo. Good to 7k + and what? 190+ hp? Z24 will never see that abuse. Save your money.

 

 

Head bolts? Probably the KA24E which followed the Z24. The DE was a little later. The Z24 head bolts are reusable, where they started using TTY bolts on the KA and they must be replaced. Measure the length of the Z head bolt and get a stud the same length. You can always add washers under the nut if too long. Why does it have to be for a Z series? as long as it's long enough.

 

That's good to hear. I didn't want to buy those studs. Thank you for weighing in.

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If I was trying to modify the Z series for power or had unlimited cash, then studs.

 

 

All L, Z, KA-E use the same rod bearing so the crank journals are the same diameter so why not keep and use the rod bolts too?

L20B and all Z series use the same main bearings but not the KA. L16/18 use smaller mains.

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Measure the length of the Z head bolt and get a stud the same length. You can always add washers under the nut if too long. Why does it have to be for a Z series? as long as it's long enough.
 

Wonder how the L20 compares . I can’t believe the head bolts are much different in diameter , but maybe they are. Then it would be a matter of length

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33 minutes ago, datzenmike said:

If I was trying to modify the Z series for power or had unlimited cash, then studs.

 

 

All L, Z, KA-E use the same rod bearing so the crank journals are the same diameter so why not keep and use the rod bolts too?

L20B and all Z series use the same main bearings but not the KA. L16/18 use smaller mains.

Mike the ka rods are narrower are you sure they use the same bearing?

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36 minutes ago, bottomwatcher said:

Mike the ka rods are narrower are you sure they use the same bearing?

 

The mains are way narrower..

.................................................................................................... L ........................................................................................K

 

F4e52N7.jpg

 

....................................................................KA-E ................................................................................................................. L or Z

 

WBQeCJk.jpg

 

 

I can measure both tomorrow or if I can find an old bearing half, test fit one.

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I can see going to the ARP hardware if you are building a high compression and a high horsepower engine. For the average 1 mill over bore a and higher lift cam I feel the money could be better spent on other more important parts.  The stock bolts, studs, and nuts are more the sufficient.

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Hate to bring this up, but if I were going to throw a bunch of money at a Z24, I wouldn't. I'd start with a KA24E instead. Pretty simple design and fairly easy to swap into a truck that already has a Z24. A mildly built, naturally aspirated KA24E with EFI can make about 250 HP. Is that enough HP?

 

If you are determined to stick with the Z24, and are dead set on turboing it, have the block o-ringed or find an HKS style composite steel head gasket. Those are probably not available anymore, but they are just about as good as an o-ringed block.

 

FYI - to make more than 240-ish HP with a Z24, you open a can of worms in the rotating/reciprocating assembly. You'll need to pay special attention to these parts. Probably a good idea to get custom H-beam rods and definitely forged pistons if you plan to go over let's say 250HP. The crank will need some treatments. The block oiling system will need modifications. Good tri-metal bearing are a must (not aluminum bearings). You'll spend $3000 on the bottom end alone. Or swap in a KA24E and get that same HP for just a little more.

 

You could also swap in a KA24DE, or an SR20, but I don't particularly like the SR20. Too "JDM" Hellu-fresh.

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8 minutes ago, Stoffregen Motorsports said:

Hate to bring this up, but if I were going to throw a bunch of money at a Z24, I wouldn't. I'd start with a KA24E instead. Pretty simple design and fairly easy to swap into a truck that already has a Z24. A mildly built, naturally aspirated KA24E with EFI can make about 250 HP. Is that enough HP?

 

 

 

For one it will bolt to the stock 71B transmission, though the 71C is better/stronger.

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I’m not shooting for big numbers . I’m thinking 180-200 hp . I’m going to run low boost , small turbo , just enough to make the truck peppy. Surely this engine will handle that without a 3000$ bottom end . If I swap anything , it would be an LS - lol.
This will be programmable EFI with full control of spark . Haven’t read of too many builds like that. Most guys are blow thru set ups with stock ignition . 
I plan on having the block mating surfaces touched up with a fine cut . Same with the head . OEM Nissan gasket . KA DE studs . New rod bolts . 
 

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As the Z24 makes about 100 hp you are going to have to jam twice as much air through it. Or 1 Barr of boost. In theory... in practice you'll probably need slightly more to cover losses and altitude. 14.5 PSI doesn't seem like low boost but aim for this in your build. Definitely have the block O ringed and gasket choice isn't so critical. Get better rod bolts to be safe. Oil cooler can't stress this enough. A turbo homogenize the exhaust pulses so you can better get away with a straight through or 'turbo' muffler. You want low restriction if you don't have it now. Cold air intake from in front of the rad. Don't be that boner with the so overdone cone filter sucking in hot rad air from behind. You may want to look at a charge cooling water/alcohol spray set up. Twice the power at least twice the heat so is your rad up to that? Inter cooler to drop the intake temps even farther. Cooler denser air makes more power.

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5 hours ago, Stoffregen Motorsports said:

Hate to bring this up, but if I were going to throw a bunch of money at a Z24, I wouldn't. I'd start with a KA24E instead. Pretty simple design and fairly easy to swap into a truck that already has a Z24. A mildly built, naturally aspirated KA24E with EFI can make about 250 HP. Is that enough HP?

 

If you are determined to stick with the Z24, and are dead set on turboing it, have the block o-ringed or find an HKS style composite steel head gasket. Those are probably not available anymore, but they are just about as good as an o-ringed block.

 

FYI - to make more than 240-ish HP with a Z24, you open a can of worms in the rotating/reciprocating assembly. You'll need to pay special attention to these parts. Probably a good idea to get custom H-beam rods and definitely forged pistons if you plan to go over let's say 250HP. The crank will need some treatments. The block oiling system will need modifications. Good tri-metal bearing are a must (not aluminum bearings). You'll spend $3000 on the bottom end alone. Or swap in a KA24E and get that same HP for just a little more.

 

You could also swap in a KA24DE, or an SR20, but I don't particularly like the SR20. Too "JDM" Hellu-fresh.

Damn good point!

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17 minutes ago, datzenmike said:

As the Z24 makes about 100 hp you are going to have to jam twice as much air through it. Or 1 Barr of boost. In theory... in practice you'll probably need slightly more to cover losses and altitude. 14.5 PSI doesn't seem like low boost but aim for this in your build. Definitely have the block O ringed and gasket choice isn't so critical. Get better rod bolts to be safe. Oil cooler can't stress this enough. A turbo homogenize the exhaust pulses so you can better get away with a straight through or 'turbo' muffler. You want low restriction if you don't have it now. Cold air intake from in front of the rad. Don't be that boner with the so overdone cone filter sucking in hot rad air from behind. You may want to look at a charge cooling water/alcohol spray set up. Twice the power at least twice the heat so is your rad up to that? Inter cooler to drop the intake temps even farther. Cooler denser air makes more power.

I was talking flywheel hp. I was planning in running about half that boost - maybe 6 or 7 psi .

You said earlier the rod bolts were tough ? Planned on new Nissan minimum. 

This is going to be just a slight bump in hp even 30 hp would be great . 
Don’t see the need to O-ring the block for his build . Definitely need a better finish on the mating surfaces . Head studs would be great . 
Exhaust is a given.

intercooler where it will fit . 

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2 hours ago, Madkaw said:

I’m not shooting for big numbers . I’m thinking 180-200 hp .

 

30 is do-able. Rod bolts being replaced is just me thinking ahead. 30hp is just a 'taste' of crack, next thing you know you need 60hp just to get off, then a hundred. Over build.

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8 minutes ago, datzenmike said:

 

30 is do-able. Rod bolts being replaced is just me thinking ahead. 30hp is just a 'taste' of crack, next thing you know you need 60hp just to get off, then a hundred. Over build.

I just want reliable hp gain. I want to be able to tow something and keep up with traffic . 30hp would make the truck fun for sure . 

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ARP rod bolts are only $50 for the set.

 

Pay special attention to the rotating assembly and oiling. Bust out your https://www.amazon.com/How-Hotrod-Race-Your-Datsun/dp/0936834412  book for tips on the bearings and oil galley mods. I can't remember if Z24s came with full grooved main bearings. If the new bearing aren't full groove, buy two sets and use only the bearings with grooves in them.

 

200hp is still a lot for that engine. But totally do-able on a budget.

 

A stock KA24E makes 135hp, and with a bit of tuning you can bump it up to 170hp pretty easily.

 

I would almost not call that an engine swap, as it nearly bolts in. It could be done in a weekend. An LS would be cool (I do a lot of LS swaps), but an entirely different job with weeks of fabrication, fitting, tweaking.

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21 hours ago, Stoffregen Motorsports said:

ARP rod bolts are only $50 for the set.

 

Pay special attention to the rotating assembly and oiling. Bust out your https://www.amazon.com/How-Hotrod-Race-Your-Datsun/dp/0936834412  book for tips on the bearings and oil galley mods. I can't remember if Z24s came with full grooved main bearings. If the new bearing aren't full groove, buy two sets and use only the bearings with grooves in them.

 

200hp is still a lot for that engine. But totally do-able on a budget.

 

A stock KA24E makes 135hp, and with a bit of tuning you can bump it up to 170hp pretty easily.

 

I would almost not call that an engine swap, as it nearly bolts in. It could be done in a weekend. An LS would be cool (I do a lot of LS swaps), but an entirely different job with weeks of fabrication, fitting, tweaking.

I thought the KA required fab for the oil pan on a 4WD ? 
And are these engines so fragile inside that any mods are risky ? Aren’t they using the same forged internals that Nissan used for years ? 
 

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The Z24 is basically a stroked L20B which is a stroked L16. The stroke is longer so not as high revving but the biggest deterrence is the new head put on the Z series block. It has much less potential for performance. It was designed for use not much above highway speed with low speed torque, (perfect for a truck) low emissions and efficiency and it is very good at this. Scaled up, a 2.4 liter L20B should make 115hp but the Z24 is only 105-ish. Slightly under power puts less strain on it and it will last much longer. The Z24 head gaskets tend to blow at 100K intervals but it's not clear if this is the head's fault or something about the threaded holes in the block for the head bolts. Perhaps the metallurgy or the fact the threading starts 1/4" down inside? It's avoidable if you re-torque the head bolts once a year but most owner don't or don't know about it.

 

I bought one from the wreckers from a truck in an accident, put the engine and transmission in my 620. It was impressive for it's grunt. I saved it when I got rid of the truck because it ran quiet and clean and I'm in the process of putting an L head on it to get around the restrictive head and make it a true L24B. But I digress.

 

The KA has a much improved head with 3 valves per cylinder so it makes about 30 more HP. Yes you would need to make a custom oil pan for it to clear the front differential on a 720. Keep the Z24, it is also suitable for a turbo as it has the cross flow head with lots of room for turbo plumbing on one side, intake on the other away from the heat and space between for an inter cooler. Boost will overcome, more or less, any breathing problems of the head. Dual spark plugs shortens the burn time thus shortening the timing advance making it more detonation resistant. Cross flow keeps heat away from the intake ports. The Z combustion chamber is almost a hemi shape, again more efficient and detonation resistant.

 

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56 minutes ago, Madkaw said:

I thought the KA required fab for the oil pan on a 4WD ? 
And are these engines so fragile inside that any mods are risky ? Aren’t they using the same forged internals that Nissan used for years ? 
 

The Z24 crank, as with all Nissan cranks, is cast steel, which is far better than the cast iron of a many engines of that era. The rod material is good, but they are long and skinny, which makes them bordering on fragile, but definitely ok for 200hp. It's the oiling system that lacks. It's pretty good, but the improvements/mods I listed above make it tougher and last longer.

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