Maynanator’s 1gz swap project
 

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Hey guys, I’m starting a new thread to do with my sc400. Due to various live events, choices, etc... I decided to scrap the supercharged 1uz project and go after an even more ambitious project of swapping in a 1gz fe. If ya’ll would like I can document everything that’s happened that has led up to this point. Also, I would gladly show you some of the projects that distracted me from this car for the last few years too. That said, I’ll start filling details in throughout the next few posts. Explaining where I’m at with things, what I know, and what the future of this project looks like. I just spent the greater part of an hour typing a full intro to have it disappear while uploading photos, so I’ll do a proper intro later once I have time to sit down type things back out.

So, a bit of an intro to the build. As of now, I have an engine, and a rolling chassis. I also have some other parts I’ve been collecting. So, many years ago I found out about the 1gz fe and later the Top secret supra using that engine. I instantly fell in love with the idea of that engine in my sc, but very quickly dismissed it as far too impractical and far beyond what I had the money or skill for. With that said, I decided I would keep the factory 1uz in the car and do something with it. I had purchased a supercharger kit for it that turned out to be a bust. And after years of constantly changing what I wanted to do with the car, finding other projects to be distracted by, learning more about the 1gz fe and z30 chassis, and of course finding other 1gz fe projects... I decided to bite the bullet last fall. I sent the car to a shop to have the work completed. Well, life happened... the shop pulled the motor before I could call them to tell them to pause the build and now I was in for the long haul. For now I’ll be putting the car in storage while I collect parts, save up, and wait for certain parts to be finished with prototyping. Here’s some photos of the parts I’ve collected, and I’ll post soon about how I intend to swap the motor along with what I’ve learned about the engine for those interested.

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The 1gz, it’s a very large motor especially with all the factory accessories and such on it.
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A vented hood I found on craigslist along with a photo of the car it came off of.
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I managed to track down a soarer adjustable headrest rear seat. A part i’d been looking for for a while.
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And these awesome recaro topline’s I found on craigslist. Power everything, heated and cooled. I think they’ll be able to pass for factory equipment when I get around to mounting them in the car. Oh, and the seller threw in a set of s54 throttles for free with the seats. So at some point I’ll be using them to mock up an itb intake for the v12.
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So: to swap and engine you have a few things to worry about. Oil pan clearance, motor mounts, hood clearance, accessories, fuel, coolant, connecting it to the driveline, exhaust, and wiring it up, to potentially include the necessity of a standalone ecu. With the 1gz there are certain things that make it easy to fit, and others that require some more thoughtful and expensive solutions. Probably the biggest hurdle is the oil pan clearance... or lack thereof.

the z30 chassis is designed for a rear sump. The 1gz was designed with a front sump application in mind... this would normally only require a custom pan and bam you’re past that hurdle. Unfortunately due to a weird design quirk with the oil pump... that’s not exactly an option. The oil pump on the 1gz is mounted to the bottom of the block on the front and driven by a chain, the problem here is that the oil pump and steering rack want to occupy the same space. Top secret’s solution was to run a dry sump system. Some have gotten away with hanging the motor a bit forward and just having a super forward sump, which I initially had planned to do... but after thinking about it more, and seeing QUICKSHIFT.tv’s solution... I’ve decided that’s the solution I’ll be using. Their solution: to ditch the factory pump and hang a single stage external pump off the side of the pan, driven by a cog belt off the crank damper. Then use the pick up, pan, and baffle from a 2jz rear sump pan. Their solution also includes a set of motor mounts designed to retain the factory 2jz isolators. While this design isn’t perfect, it’s about as good as you’re going to get for a street car and the work has already been done so that takes care of that headache. The upside is it’s basically plug and play, the downside is it’s costly (a good deal for what you get, but still a price has to be paid for the components and a high price is unavoidable) and uses a belt drive for the oil pump which admittedly is not my favorite idea due to the chance of the belt snapping. But, that’s the price you have to pay to get around these sorts of issues.

With the motor mounts and pan solution out of the way, the next thing to consider is transmission mounting. The good news is the bellhousing uses the common toyota a series transmission bolt pattern which means any adapter kit designed to piggy back off the auto bellhousing should work. The news gets even better as the bolt pattern, diameter, and ring gear on a 1gz flex plate are the same as a 1uz. This means that any 1uz designed flywheel will work on a 1gz v12. My plan as of now is to try and cobble together the parts I was collecting for my w58 swap to work with the 1gz. Down the line I’ll change up to a stouter transmission... but for now, I’ll be using what I have on hand to keep cost down and help speed up the process.

As far as fuel and water... the fuel system is a return system like the sc400 had, so making some fuel lines to connect the fuel rails to the hard-lines shouldn’t be too big of a deal. Throwing together some coolant and heater hoses shouldn’t be too big a deal.

That leaves the accessories, wiring, and one other issue: hood clearance.

Accessories wise the p/s and a/c are in the same locations as the 1uz and use similar fittings, so hooking them both up should be fairly simple.

My friend will be helping me merge the harnesses, and we’ll be swapping to a standalone at the same time for ease of install and tuning potential down the road when I do modify the engine more. I’ll more than likely end up with a Haltech unit.

And lastly hood clearance. The factory intake manifold is very tall on the 1gz as the century chassis provided plenty of hood clearance, this is absolutely not the case on the z30 chassis. At a minimum a new/modified upper intake will need to be fabricated. For now I’ll just be using a used unit from another 1gz enthusiast or throwing a solution together using the factory upper intake with new plenums. I’ll also have to fudge with the throttle linkages as the 1gz is a twin throttle motor. Later on, I’ll design an itb setup using 2 sets of s54 throttles.

I hope to make some major headway this year, fingers crossed, I should have the car up and running before the end of 2021, though I’m cautiously anticipating delays and headaches to pop up.

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Here you can see quickshift’s gorgeous billet upper pan. I’ll be placing an order as soon as they’re ready for production.
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In this shot from their Supra Supreme series you can somewhat see the issue with the oil pump location. It’s made worse by the fact the pick up mounts where the steering rack sits.

I absolutely love your fortitude in going ahead with this conversion. Sounds as if you have put a ton of thought and research into this project and I am subscribed and look forward to each and every update. I have been thinking about this since I bought my car but I wanted to go with another brand and save my 2jz for my 240Z. Enough about me, I wish you all the luck in the world on this project and as I said before, I am looking forward to all your updates.

My god those engines are so cool. I absolutely can't wait to see more!

I hope you're able to finish your build. I was looking at doing this swap about a year ago and just didn't have the cash. My plan for the oil pump issue was to trim a couple inches out of the back of the GZ oil sump to clear the steering rack and widen it to keep it's capacity. Then I was going to reroute the oil pickup toward the front a bit. It's not as elegant as the Quickshift guys parts but I liked it better than having an external oil pump. One thing working in your favor is starting with a 400, most of the accessories are in the same place and you've already got the hydraulic fan and dual exhaust. My car is a 300 so it's a pretty different layout.

You've put a lot of research into this already and I love the dedication to making this very uncommon swap happen! I like Top Secret's dry sump solution but now that I can see the pan and intended setup that Quickshift has designed for this swap I am on board with that plan. With good baffling and enough capacity in the lower pan you should be fine.

The SC/Soarer/MKIV steering rack and 1GZ oil pump locations have probably scared off many who have wanted to attempt a project like yours.

Where in the tight confines can the external oil pump fit and what model will you be using for this?

Looking forward to future progress! Excellent work so far! Planning and research to get things absolutely right are THE most important aspects of a creative and challenging project :)

I wasn’t in love with the external pump either, but i’d rather trust an external pump than an oil sump that’s not properly set up and a pick up that’s in a goofy orientation. And with my current situation, choosing a solution that’s “bolt in” is the best for me at the moment.

maybe way down the line with something like a spare motor I could prototype an oil pump driven off the crank snout like most modern engines use... but that would be a huge undertaking.

I’m not sure the brand of the pump, I do know it’s a single stage pump.

It’s mounted directly to the pan on a machined boss. It sits under the ac pump. That’s one of the benefits of their kit is the fact it’s designed to maintain the full factory front drive.

The oil pump situation is actually what initially threw me off the idea, at the time the “only” solution was to fab up a dry sump... and that’s a 10-15k ordeal in and of itself. This shelf kit really takes a LOT of the frustration out of it.

That’s a good question actually. I’d imagine there’s an internal check valve that keeps pressure. As far as priming it initially, all you’d have to do is run a drill on before you belted it to the engine.

Alright, just placed my deposit on the kit. Here’s a photo from their site for everyone who’s asking about the parts list. And for those interested in price: it’s roughly $5750 usd before shipping. No small sum, but also... you get a LOT for what you’re paying for.

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