HOW TO GUIDE - LS Swapping a 300ZX - Part 1

Added: 2026-05-30

[00:00:21]Welcome back to the LOJ Conversions YouTube channel. This is one of the most requested videos that anybody has ever asked for in the history of LOJ. The number one email I receive, comments on Instagram, Facebook, you name it. Please make a video series of installing an LS engine into a Z32 300ZX. So, in this video and the following couple videos, we're granting your wish. We are installing this Crate LS3 into this 1996 300ZX 2 plus2 NA 5-speed. This is the most common combination of all the years we've been in business that we sell to customers or install into customers vehicles. Now, we've been doing LS conversions in 300 ZXs for almost 13 years now, 14 years. So, we have learned a lot over those years. We've tweaked products that we've sold. Um, we've changed the way we do things here in the shop as we learn. And now you're gaining by watching this video series. All of the experience that we have gained, all the lessons that we've learned over the last 13 years, you're going to learn in this video series as we install this engine into this car. This is a crate LS3 brand new engine. It's the 430 horse model, so it's got a stock LS3 cam. It's the most common engine that people install for the customers that we sell kits to. And this is a stock naturally aspirated 5-speed manual trans car. and we're going to keep the stock transmission, which is also the most common uh combination that we sell for.

[00:01:48]So, um I'm going to talk through this video series about some of the things that we do uniquely during these conversions. Um some of the parts that we've changed over the years, some of the options that are available on our kits. We'll explain what those options are and how they vary uh what you're doing during the install process. And I really hope you enjoy this video series.

[00:02:06]A lot of time and effort went into scheduling this and making this happen.

[00:02:09]So, we're really hoping that this is as beneficial for you as we feel it will be. So, stay tuned as we dive into this swap.

[00:02:19]So, this is a 96 Z32 300ZX 2 plus2 naturally aspirated 5-speed manual transmission car. From a mechanical standpoint, it's pretty darn stock still. I don't think there's actually any performance mods at all. Factory exhaust, factory, all that stuff. Um 96 is unique from an electronic standpoint, but not really from a mechanical standpoint. In '96, Nissan needed to make these OBD2 compliant in the United States. So, they added rear O2 sensors, an OBD2 port. The ECU is different. They got rid of variable cam timing to meet the emissions requirements. None of that really matters for what we're doing because all of that additional electronic stuff for the OBD2 port and the RO2 sensors, they just added an additional connector under the dash that you just leave unplugged. And our conversion harness for the older cars works in these as well. And it comes with its own OBD2 port. So, you know, from a I need to tune it or any of those kind of things, you plug into the uh OBD2 port from our harness rather than the one that's in the car. The one in the car just basically won't do anything anymore. Mechanically, this is a factory manual transmission car, which is a 5-speed manual. We are going to be adapting the LS engine to the stock transmission, which by far and away is the most common thing that all of our customers that buy kits do um or that we build cars for because it is the most cost effective, economical way to get uh the conversion done in these cars. Are there benefits to putting a T-56 in it?

[00:03:41]Sure. But, um big downside is like the $8,000 extra it'll cost you by the time you buy the trans and all the other supporting parts to do it. So, it is a cost savings to go this route and you can always change later if you want.

[00:03:52]That's the beauty of building cars. One of the things we're going to be doing to this car to help out keeping the factory manual trans because the factory 5-speed in these is basically like a T-56 without sixth gear as far as ratios go.

[00:04:06]Fourth is 1:1 in this. Fourth is 1:1 in a T-56. The fifth gear overdrive in this is about the same ratio as a T-56 is fifth gear and then you lose out that really tall double overdrive that a T-56 has. Uh, these cars are also fairly small with small diameter tires and they have a 408 gear from the factory. So, if you run this trans and keep the stock diff, it'll be fun as heck to drive from like a gear ratio acceleration standpoint, but your cruising RPM on the highway will be 3,000 plus RPM at like 75 mph, which is not it's not going to hurt the engine to do that. It's just going to hurt your wallet every time you need to fill up cuz you're getting like 10 miles to the gallon. So, one of the things we'll do in this, which is really common, is we're going to put an Infiniti Q45 rear differential in it.

[00:04:51]That's going to switch it from a 408 to a 369. The diff that we're using is from the Y50 generation. So, that's 97 to01 Q45. 100% bolt-in. Bolts to the axles that are in the car, bolts into the subframe. The only difference is that the differential flange is a different bowl pattern and we have to make a drive shaft because even though we're keeping the stock trans, we move it backwards in the car 3 in to give more room for the V8 instead of a V6. So, part of our kits includes a drive shaft. So, if you plan your swap properly and you know that you're going to swap diffs, we can build you a drive shaft with the flange for the Q45 diff instead of the flange for the naturally aspirated diff that came in the car. Um, if you change rears later, you can just order the correct flange for the drive shaft and swap the flange on the drive shaft later. But again, we try to do everything one shot for this customer, so we're doing the diff at the same time we're doing the swap. Uh, some other things, um, we're going to put an exhaust system on the car. Now, this is a rare setup in the US because it's a 2 plus2. So, this car has a back seat. Ironically, in Japan, the four- seaters were the most common car sold. They sold four-seater twin turbos were the most common setup sold in Japan. They didn't even make four-seater twin turbos in the US. All of our four-seaters are um naturally aspirated.

[00:06:10]And the twin turbos in the US only came in two-seaters. Um there's also slick top two-seeers and convertible two-seeers, naturally aspirated T-top two-seeers, twin turbo T-top two-seeers.

[00:06:21]All the twin all the two plus twos are target tops. And there's this super rare cuz I know somebody's going to hit me in the comment section. There's that one year that that company made hard top convertible 2 plus2s. Yes. Okay. There's like one of them left in existence. Good luck finding it. Um but yeah, from a mechanical standpoint, the underpinnings are pretty much the same. Drive shafts longer in the 2 plus two because the wheelbase is longer, but the rest of the swap kits exactly the same. Um, we're excited to kind of hit you with all this information. And I think it's probably become apparent in this video already that like I can be a bit of verbal diarrhea when it comes to like information about Z32300 ZXs and LS engines cuz we've been doing this for a lot of years and I've been around Z32s for 20 plus years. So, uh, got a lot of weird information tidbits I can share with you. But the gist of this video is to really let you know what it takes to actually do one of these conversions.

[00:07:14]And um I think it is easily accomplishable by anybody at home using common hand tools. Um we are going to do that obviously except for the fact that we're using a lift. We're going to get diving into this thing. Blaine and I are going to start tearing apart. Um in this first video, we want to get everything torn apart in the car to prep it for the LS. So this video will hit you with engine removal, uh engine bay prep, cleaning, washing, installing parts like our heater core outlet, our returnless fuel system conversion. And we're going to do the rear diff swap in this video.

[00:07:44]Basically get the whole chassis ready to receive the LS engine. And then in the following videos, we'll be prepping the LS for install, getting the engine in the car, and then doing final stuff like wiring, first start, all that kind of stuff. So, uh, I hope you enjoy the series. Uh, I hope you're able to learn a lot from it about our current products and how we've changed things over the years. And I hope this encourages you to take on a project like this for yourself. So, basically what you're looking at here is a collection of essentially all the parts you get in an ultimate swap kit, plus the exhaust system that the customer chose to run on this car that we're doing for this conversion. There's a lot involved in one of these swaps if you want to essentially touch every system in the car the way you should if you're doing an engine conversion. I'm sure a lot of this can be home fabricated if you wanted to, but we try to sell the most complete bolt-in solution we can. from our long tube headers from Cooks that carry a lifetime warranty to the original purchaser to our PW radiator that is a direct bolt-in for this car with the outlets and all in the right position for the LS engine. So, you know, a lot of thought went into all these products and we really pride ourselves on having the most complete solution possible for your LS conversion in your Z32.

[00:08:51]Oh, look at that beautiful boat anchor.

[00:09:22]First thing we're doing right now is honestly just draining all the fluids.

[00:09:26]You can see we pulled the hood off.

[00:09:27]That's really just for easier access when we're working up top. Pulled the battery out first cuz you don't want to shock yourself taking apart anything under the car. But generally speaking, I always start out underneath draining coolant, draining engine oil, draining transmission fluid, disconnecting exhaust, all the other fun stuff underneath. And that's what we're diving into first here.

[00:10:04]So, a 96 Nissan 300 ZX is the only year that has rear O2 sensors because of the OBD2 compliance stuff in the US. So, you just saw me remove the cat. I cut the wires going to the rear O2s. It doesn't really matter. These wires run into the car to an additional connector under the dash that goes into the engine harness.

[00:10:21]That one connector has all of the powers and grounds and all for these sensors.

[00:10:24]So, I'm going to cut the ends off flush with the grommet to keep the floor sealed in the car. The other end of those wires in the car where it would have plugged into the factory engine harness is going to be left unplugged.

[00:10:34]So, there's no concern of stuff shorting or anything like that. And this is something you'd have to deal with on a 96 only. Any other year would not have this to even be bothered with. So, it's a little bit of information specific to this car, not to all Z32s that are getting swapped. So, I'm in the process right now of removing the U-jint on the steering column to the steering rack.

[00:10:53]And why am I doing that? Um, one, we're dropping the engine and trans out the bottom on this. So, that allows the steering rack and crossmember and all to come down from the car and leave the column in the car. But also, that still needs to come apart to get the header in, even if you're doing the install the traditional way with the cherry picker from the top. So, either way, that has to come apart. Um, I am so thankful for wherever this car came from because that thing right there is usually the deciding factor on how much of a headache we are going to have in our project. Bolt came right out and it's literally just slides on its spline like with the force of a hand. I've had ones where I've had to hit heat with a torch, bang a pry bar between the pinch to kind of break it apart and then have to use a an air hammer to knock it off that spline. So it that can really make or break the conversion. It's one of the most frustrating things about it is that one stupid little U-jint. So thank you customer from Illinois with a car that is clearly not originally from Illinois because this thing is way too rust free to be from Illinois. So cool.

[00:12:06]>> All right, so we got a little update for you guys. Uh, we're pretty much wrapped up under the car and I just want to give you an idea of what we did. I mean, you were watching B-roll, you saw all of it with hopefully some fun and entertaining music for you in the background. But, um, what we did basically was drain all the fluids. Um, we pulled the exhaust system off the car. We pulled the drive shaft out of the car. Um, the shift linkage on these cars, there's actually a bracket, a rubber isolator that's mounted to the trans tunnel inside the car. And then the bracket bolts to the transmission with four bolts coming up from the bottom and one crossbolt through the actual bottom of the shifter. So pull that crossbolt, those four bolts, and then the bracket and shifter stay with the car as we pull the engine and transmission out. Um, you can see we disconnected all of the suspension on the front end here. And that's because, like I said earlier, we're going to drop the engine out the bottom. So, this engine crossmember needs to come down out of the car and all the sus suspension needs to be disconnected to make way for that to actually come out. So, we pull the tie rod bars out or the tension rods out is the proper term. I pulled the tension buckets as well because it gives additional clearance right in this area for uh the power steering pump and alternator and AC compressor to drop through. Also makes getting the front sway bar out easier. Disconnect the tie rod ends. Disconnect the steering column from the steering rack. Be sure to mark the column and the rack before you pull it apart so when you go put it back together, you can align it properly and you don't need to get an alignment done.

[00:13:34]Sway bar is out. We pulled the sway bar.

[00:13:36]We disconnected the power steering return line. This line comes off the rack over the crossmember and up onto a hard line on the frame rail that goes to the cooler. So, you can disconnect this here and um disconnect the the feed hose from the reservoir to the pump on the other side. And then the rest of the lines all come out with the engine and trans when it gets dropped out.

[00:14:06]Okay.

[00:14:14]All right. So, we are pretty much at the point where we're ready to drop this thing out the bottom. Um, I'm going to try to recap what we did, but I'm not going to lie, what you didn't see is we stopped for lunch at one point, so I don't really remember everything. Um, AC lines all disconnected and out. Um, wiring harness we actually cut behind the driver side cylinder head because anybody who knows Z32 life knows that's absolute brutal pain in the butt to get out and we don't need to save it. Um, so we cut it. Plus, we have to use connectors off this harness anyway for wiring the LS in. So, it's not like it would be a savable part to sell later anyway. So, just cut it. Make your life easier. Uh, heater hoses we also cut cuz those get changed with the LS. We're going to talk about that in a bit. Fuel lines disconnected. All the intake nonsense for the airbox in the front of this thing. My god, there's a lot of stuff in these cars. And this isn't even a twin turbo, which is why I recommend starting with NAS in the first place. A lot of stuff came out of there. AC condenser, radiator, radiator, whatever you want to call it. Uh, radiator fan, um, all the plumbing off the front, charcoal canister, all that good stuff.

[00:15:22]We removed all that. There's a reason why these cars lose between 100 and 150 lbs when you put an LS in them. The VG is heavy, the LS is light, and all the other nonsense that you pull off, too.

[00:15:32]Actually cuts a ton of weight as well.

[00:15:34]So, now we've got to go back up in the air. There's a couple connectors underneath. I forgot to disconnect the variable rate power steering connectors on the rack. I got to unplug those. And then I built this little, you're going to laugh in the video, this little homemade wooden contraption that we lower the whole deal down on. Pull the four bolts or the four nuts that hold the subframe to the unibody out. Pull the remaining two bolts out of the transmission crossmember and lift the car up off of this mess. So, that is what we're going to dive into now.

[00:16:03]That's Eli. He's the shop manager. He's here to make sure, you know, we're doing everything OSHA approved.

[00:16:33]Heat.

[00:16:35]Heat.

[00:16:37]Nice catch, bud.

[00:16:46]Going that way.

[00:16:54]All right, so that actually went according to plan. Engine is out and we've got one mess of an engine bay to clean up and get ready for our next steps. So, uh Blaine's actually going to wash the trans uh wash the transmission.

[00:17:07]we pulled out and I'm going to start cleaning up the engine bay. He's also going to wash the transmission itself cuz we're going to reuse that on this swap. Um, some of the things we need to do in the engine bay before we put the LS back in is uh we're deleting the factory clutch hydraulic lines and putting in a one piece hose going from the master directly to the slave cylinder.

[00:17:28]Really just to simplify things. The factory setup with this weird high bleeder point is tricky to bleed. It's there to like dampen vibrations in the clutch pedal. is not a performance benefit in any way. So, we're going to get rid of all that. Simplifies things.

[00:17:41]We need to prep the heater core to install our heater core outlets, which we'll talk more about later when the time comes for that. We need to actually install our heater bypass block on the passenger strut tower before the engine goes back in. And I'm going to install the returnless fuel system conversion lines because they attach to the factory hard lines down on the frame rail. It can it be done with the engine in the car? Sure. But it's easier to do now.

[00:18:05]So, I'm just going to do it now. Um, so I'm going to strip out the remaining stuff that needs to get stripped out.

[00:18:09]We'll wash, then we'll install the heater cord outlets, heater bypass block, return this fuel system conversion, and get this thing ready to receive the LS engine.

[00:18:32]>> Grommet's out.

[00:18:38]I just removed the factory clutch hardline setup. Yes.

[00:18:43]All that stuff that that Eli's destroying right now. Um why? Because Nissan did a lot of stuff in the '9s to like try to solve issues or make creature comfort things like that. So, for example, clutch hard line runs from master cylinder down to this corner of the engine bay. And then there's a T-shaped block. And then off the bottom of the block is another hard line that goes to the flex line that actually goes to the slave cylinder. But off the front of that block was a/2-in diameter tube that came all the way up here to another bleeder. And if you can imagine, that large 1/2-in diameter tube filled with fluid functioned as Yes. No. Well, the other one, the big tube.

[00:19:25]>> Um, this one. Yes, that one. That big tube functioned as like a shock absorber for the fluid moving through the clutch system.

[00:19:35]Cars don't have things like that anymore. They didn't before this car.

[00:19:38]They don't after this car cuz they kind of figured out from like a it didn't really do as much as they thought it would do. And it it's actually really really frustrating to bleed and get all the air out of it. It's easy to get air shaft in. So, while we have the engine out and it's easy to work in here, I removed the whole thing. We're just going to put a one piece braided hose right from the master right through the slave. not something you have to do for the swap. Like you can run all the factory stuff, but hey, we're in here.

[00:20:01]Let's make it a little bit more reliable, a little simpler, and a little bit uh easier to maintain for uh the new owner if anything has to change that way. What else did we do? Um I fished the what was left of the factory engine harness out from behind all the brake lines. And Blaine is in the car right now removing the glove box, center console, heater. No, not heater core, evaporator and blower motor because all of that has to come down and out to give you the room to fish the other half of the engine harness that goes into the car to the ECU out. So, the grommet that's on the firewall, we actually reuse on the swap because it's a molded unique size and 90°. Um, not easy to get aftermarket. So, we have you transfer that from your car to whatever harness you're installing when you're doing the swap yourself. Um, so he's working on getting that harness out right now. I am also working on getting the fuel lines run from the back of the car to the front up the inside of the frame rail from the factory. There's two rubber hoses that go back to some hard lines back to some more rubber hoses where the factory fuel filter was. We remove everything all the way down to where the hard lines are on the frame rail and we sell a returnless fuel system conversion that puts a different fuel filter on the strut tower that actually has a built-in fuel pressure regulator in it. So the feed and return on the car go to the feed and return on that filter regulator in one. So that's regulating pressure sending fuel back to the tank. And then the line coming out the front is just feeds the engine. Because LS engines are 58 PSI returnless uh non-regulated fuel systems, whereas this engine from the factory was 43 PSI vacuum regulated. So none of that factory stuff would work with an OS. So we do that to make that work.

[00:21:51]There you go. We're going to run it like that.

[00:22:00]>> So, I guess technically Robbie should have me notifications. That's all right.

[00:22:09]Yeah, I think we're going to do a depth swap, which we are putting 97 to01 Q45 R200 differential and 100% bolt-in swap.

[00:22:17]We talked about this earlier. Goes from a 408 ratio to a 369 ratio, which drops your cruising RPM about 500 RPM on the highway. A little more, little less, somewhere in that range. So, fairly budget friendly upgrade to get those cruising RPMs down because we have an engine that actually makes torque now, not a gutless naturally aspirated 3 L V6. No hating on the VG30, guys, but it's a 30-year-old 3 L V6 that made 222 horsepower and 180 lbs of torque, maybe. I think the OS does that on two cylinders. So, um, yeah, not really two cylinders. Come on.

[00:22:51]Take some sarcasm. You can laugh at the screen. Laugh with me. I'm joking. Okay.

[00:22:55]All right. Let's knock out the diff and get this day wrapped up so tomorrow we can drop that engine in the car.

[00:23:26]So, we just got the diff in there. Super easy install. Like I said, wham, bam, Christmas ham. There is a diff swapped into this car. And next we're going to move on to engine based stuff. But now you're going to cut, cut, cut. So that'll be the intro to the lights. So on a Z32300 ZX, the heater core outlets point out of the firewall right here straightforward. And with the factory VG engine that sits pretty far off the firewall, that's really not a problem to get like a bent heater hose on there to run heat in the car. But when you swap in an LS engine um with the 90° V instead of the 60° V and the fact that we need to push the engine so far back in the engine bay to give room up front for a cooling system and things like that. Um basically these two ports end up pointing straight at the back of the passenger side cylinder head which is not ideal. So one of the products we developed early on were these heater core outlets and they're a really simple thing that allows you to basically get more clearance for the engine by redirecting the heater outlets. Now, uh 1990 to I want to say sometime in '93 or '94, Nissan switched from a copper brass heater core to an aluminum heater core.

[00:24:33]And when we developed the kit, we developed it in a 1992 car. So, it had a brass heater core. And I designed these parts to essentially you cut the front portion of the nipple off for the original heater core outlet that has the barb on it that would grab the hose. And there's a second barb back here. You basically leave enough tube so that if you were to slide this on there, you have it bottomed out against that second uh rib on the heater core. And for those cars, uh we have a how-to video that's been on the site for forever. You basically put the heater core on there, and you use basic home plumbing tools, flux, solder, and a torch, and you can solder the heater core directly onto the heater core outlet, and and you're done.

[00:25:16]What we didn't realize, cuz I didn't know at the time, was that in '94 they switched to aluminum heater cores and you can't braze copper to aluminum. So on these cars, believe it or not, we use JB Weld to put the heater core outlets onto the heater core. And I know JB Weld has a bit of a negative reputation in the automotive world as kind of like a hack thing, but it is a good two-part epoxy, and two-part epoxies are great for bonding dissimilar metals. So, in that case, it's actually the best way that's I shouldn't say the best way.

[00:25:46]There's some commercial two-part epoxies that are fancier than JB Weld that come in a dispersal gun that might work better for this, but for the average shop guy doing it yourself in the driveway, JB Weld will work just fine.

[00:25:57]And that's what we're going to use on this car cuz we've used it dozens of times in the shop in cars that have aluminum heater cores. So, I will then JB Weld these outlets onto the firewall or onto the heater core outlets. I'm going to place them on there now so you can see what the idea is. But basically the uh port that's closer to the top, you orient this facing up to the side.

[00:26:18]And then this one you can see is uh a larger diameter. This is 3/4 in where this one's 5/8. And it kind of has this weird bend to it so that when you orient this one on it wraps around the other and you end up with both heater hoses pointing up and towards the passenger side. And that's because on an LS engine, the water pump outlets are also on this side. And with the 3/4 on top and the 5/8 on the bottom, when you route the hoses, they follow each other nicely to the 3/4 outlet and 5/8 outlet on the water pump. So, I'm going to get ahead and get those uh bonded on here.

[00:26:52]Now, we'll allow the JB Weld to set up overnight. Um some in some instances, I'll pressure test these to make sure we got a good bond before uh putting everything back together. And we'll probably do that off camera in the morning when we start up. But, um, basically that's what I've got going on here. So, once I get those installed, you can basically install the LS engine.

[00:27:09]The cylinder head will be right about here, but your heater hoses will come right out from behind it. Um, these outlets actually work great in other Z32 conversions, too. Like, if you're doing a Jay-Z swap or an RB swap, they run into similar issues with the heater core interfering with parts of the engine.

[00:27:23]So, um, we designed them for LS's. You can use them in a bunch of different conversions that require you to get your heater core outlets out from behind an engine that's got to be tight up against the firewall. So, we have the fuel sending unit out of this Z32 here on the bench. And for all of our conversions, we run an air mode of 340 L per hour fuel pump. And um you can obviously see that this fuel pump diameter wise is quite a bit smaller than the factory fuel pump. So, a question we get often is how do you mount that in there? And honestly, we take the factory fuel pump out and we remove the rubber sleeve that's around the factory fuel pump. And when you put the rubber or the foam sleeve that comes with the aeromotive pump on it, you can basically put one inside the other and either using the factory clamp or a hose clamp, clamp it all together and mount the pump in the semi unit using the same mounting gears that are molded into this rubber sleeve.

[00:28:16]Then you can transfer the fuel sock from the factory pump onto the air motor pump. It will work on here. And then the length is essentially the same. So, you put a new hose, which the fuel pump comes with new hose to connect the top of the sending unit to here. You transfer the sock on here. The same goes for a two-seater, though the sending unit looks very different. And the two-seater has a long hose coming off of it with the sock on the bottom. Still the same concept. You're basically replacing the factory pump with this pump, trying to reuse as much of the factory mounting hardware as you can. Um Blaine's about to get this thrown in there. Obviously, the plug doesn't plug in either, but the um basically you can cut the wires off of this and cut the wires on the sending unit and splice the two together to make your power connections. It's unfortunate with how old these Z32s are now. No fuel pump companies make a drop-in pump that's the same format and size as the factory pump anymore. Years ago, you used to be able to get this old Bosch pump, but they're not available anymore either. So, there's really no way to do this without some customization. And we found that this pump matches the flow requirements of a basic naturally aspirated LS engine the best using our returnless fuel system conversion. You don't get run into fuel pressure issues. It's basically the best all-around combo for 95% of the swaps that are out there. So, um just hope that little bit of tech info helps you understand how to do that install and uh helps some of the footage that we capture here really uh helps you understand exactly what we got going on.

[00:29:41]>> So, I'm getting started on the fuel system here. So, we're going to get these lines hooked to the old return hose and feed hose. Uh, if you read the instructions if you had this kit, the larger port is the feed port. The smaller port is the return, which you could see on this filter here and regulator.

[00:30:00]The rear line coming up on the frame rail is your feed. So, we're going to hook the return down to there. So, then we're going to find the larger port for the feed. We're going to install that on the rear line on the frame rail and come up, connect that.

[00:30:28]I have my two clamps on here for tightening those down. This nifty little hose, which has the quick disconnect for this filter and the quick disconnect for the GM fuel rail, will just pop in, connect right to your GM fuel rail. As you can see, this is a lot easier to do when the engine is out of the car. It's kind of tight once the engine's back in trying to get down inside here. So, this is one of the things we recommend doing before you put the new LS engine into your 300ZX. I am putting the factory heat shield back on just to keep these a little protected from the long tube headers that will be going in this car.

[00:31:15]All right, so we're going to install the heater bypass block into this car right on the strut tower here. Um, this is a product we developed to solve a uh water pump cavitation problem when you block coolant flow through the heater hoses on an LS engine. So, you may or may not be aware, but LS engines don't tolerate the heater core circuit being blocked very well. Um, that's why a lot of guys you see that build like race cars or whatnot, there's like a I forget the gates part number, but there's a hose you can buy that's U-shaped to loop the heater core outlets on the water pump to allow flow to continue. When you block flow, you starve the impeller side of the water pump. And when that pump is spinning, it creates little air bubbles from the lack of flow, which uh air bubbles then infiltrate the whole cooling system. They prevent coolant flow. It just causes a cascading effect of overheating on the engines basically.

[00:32:02]So, you never want to block coolant flow through your heater hoses. And on older Nissan, this does not apply to like 350Zs or the newer cars we make kits for, but the 300's, 240SXs, older cars, there's a valve under the dash that when you turn the heat off, it blocks coolant flow through the heater core. This is a lesson I learned the hard way 13, 14 years ago when I first swapped the Z32. Uh, in the summer on mild days, it would still overheat like crazy. And if you just turn the heat on a little bit to allow some flow, the car would cool back down and stop overheating. So this bypass block um just there's no moving parts in here.

[00:32:40]It's 100% operating on the principle of fluid flow follows the path of le least resistance. So um there are two ports that are just drilled straight through that will allow the coolant to flow in and through this heater block without a problem. But if you were to block the side that's connected to the heater core on the vehicle, there is a machined H inside of here that now gives the coolant coming in a path to recirculate and go back to the water pump. So you're not actually blocking flow in the water pump. One of the convenient points is that we then use the port that we had to use to drill that H as a mounting point for a coolant temp sensor. So, if you're using this in a race car you're building, a vintage muscle car, whatever, and you want to put an aftermarket coolant temp sender, uh we include an adapter to a 1/8 NPT, which is really common for most coolant temp sensors. And most coolant temp sensors are one wire because they actually measure resistance to ground. So, you'll notice this little screw here. So, if you install this, say, on a old pickup truck or muscle car, and it's just dangling between the heater hoses, the block isn't grounded. And if you hook the one wire to your sender, your gauge still won't work because it can't measure the resistance to ground. So, what you would do in that instance is take a little wire, put it around this ground screw, and ground it to the chassis or the engine somewhere. You complete the circuit for the gauge, and your gauge will work. Uh, on this particular car and all the Z32s, um, we always mount the heater bypass blocks to the top of the strut tower on this side.

[00:34:06]And what we'll do is we'll actually drill and tap holes in the sheet metal.

[00:34:10]Um, right here it's like triple wall thick, so it's actually thick enough to put a tap in. Back here it's thin, so we'll put a riv nut. And then we'll bolt it in place. And since it's bolted to the chassis in that install, that completes the ground circuit. And we don't actually need the ground wire. And then for a Z32, we have a little adapter fitting that allows you to install the factory Nissan 300ZX gauge sender into the heater bypass block. um which will then allow the factory coolant temp gauge to work without adding this sender to some port on the engine itself. So the LS engine will have its own coolant temp sensor that the ECU will read and then this sender is used to make the gauge work. Frankly, that's how the factory Z32 works. There's two coolant temp sensors. One's a two wire for the ECU and one's a one wire for the gauge.

[00:34:58]We're just reusing the factory gauge sender. Our wiring harness that we sell for the conversions comes with the wire in it already to connect to this so that your gauge works. It really makes it as simple as possible. And when we install this, we always install it with the 3/4 in ports up and the 5/8 down. If you'll notice, the heater core outlets are 3/4 up, 5/8 down. And on the water pump itself, the 3/4 is forward and the 5/8 is back. So you can run the 3/4 hose up over there and the 5/8 down below to the water pump. It just makes the routing very neat and tidy looking. So, we're going to go ahead and get this installed. Now, it's another thing that's just easier to do with the engine out of the car if you want to get a drill in here or anything to mount it.

[00:35:37]So, we'll get that knocked out. And once that's done, essentially the engine bay is ready to receive the LS engine. Um, so we're going to kind of the home stretch of prep work before we're ready to do the fun stuff, which is actually throwing the motor in the car.

[00:36:03]All right, so that's a wrap on day one worth of work on this car. We've been at it for about 8 or 9 hours at this point, which with two of us working, but also taking a lot of breaks for filming stuff like this, it's a little slower progress, but this is kind of where I want to end up on day one. We've got the engine bay completely prepped and ready to receive the LS engine. We got the differential swapped. We got everything washed down, ready to go, the grimy transmissions cleaned up. So, tomorrow we'll get that meated to the LS engine.

[00:36:29]We'll fill you in on the next video of that whole process. And thanks so much for tuning in. Definitely like, subscribe so you're notified uh when the next video drops because we are going to do a three-part series on this whole deal. And I'm excited to share this progress with you.