ZR8ED Posted January 27, 2006 Share Posted January 27, 2006 A little story of my Swap of a Z31 turbo engine into a 78 280z. I figured I would post this to help answer questions for the Newbies to the site. If you have thought about swapping in a VG30ET engine into your Z because you "just" have one laying around.. read on.. I am ZR8ED aka Scott from the Ontario Z Car club in Canada. This swap was performed in 2001 by Dieter Roth. A long time mechanic, friend, and co-founder of the Ontario Z Car Association. Assistance, research, and of course funding was provided myself. The donor car was a 1986 300zxt 2+2 Automatic with low mileage and lots of rust! I had lots of spare parts from other 300 zx turbo's I'd owned and parted out including a 5speed. It took one day to pull the motor and the harness, and I spent the next two weeks cleaning, painting, taking inventory, and removing unwanted gear..."Who needs air and power steering?!" I had a tune up done to the motor with lots of new parts and gaskets. The Z master located and installed a larger throttle body, and also installed a manual boost controller. I painted everything I could and had everything assembled and ready to do trial fitting of the driveline into the car to design motor and tranny mounts... With the motor in the engine bay for measurements, some exciting developments, as well as several challenges were uncovered at this point. First, the motor can sit completely behind the front crossmember! hmm a mid engine Z?! Well it fits. The hood will close, and the oil pan is near stock in ground clearance. The first thing we measured was tranny position and gear shift lever position. Once that was determined, we noticed the very close proximity of the stock transmission mounts, and in the spirit of Nissan engineers, we were able to fit the stock 280z tranny mount by cutting and offsetting the stock tranny mount less than an inch. The darn thing looks almost factory. That became the "key" measurement reference point because for each Re & Re the engine and transmission assembly would wind up in exactly the same position. Now some challenges. The stock hood latch needed to be removed, so hood pins were purchased. The alternator braket hit the frame...a new one was made. The stock oil filter does not clear the frame, so a different style was found. The last major one, was that the turbo interfered with the steering...That required cutting of the frame to allow room for the steering to get around the turbo, also neccessitating fairly serious steering shaft mods. We had to remove the engine/tranny assembly several times for these mods and measurements, and the stock top rad support was in the way, so we removed it to speed up that process. We replaced it and tied it into the rest of the roll cage after the final installation. Custom engine mounts were fabricated, as well as the frame strengthened to support the motor in its new location. The mods to the driverside frame for the steering became much more involved than anticipated, and an additional steering knuckle was added, with a heim joint to secure the shaft at the second knuckle point (to keep the steering shaft from moving and binding on itself) It was only neccessary to move the shaft over approx a half inch!.. all this to clear the turbo. There may be lots of room for a V8, but with a turbo hanging low on the side of the block makes for a tight fit. Many hours of testing went into this. Because of the cutting of the compression rod mount and lots of the frame, considerable bracing was needed in the redesign of this structurally important area. Safety at 150mph was a driving force throughout the entire transplant, and we did not compromise on that point. In fact "Stronger and better than stock" was our motto! While this was being done, I started to assemble needed parts. I had a custom driveshaft made that uses replaceable ujoints. I ordered a high pressure fuel pump and regulator, aeroquip fittings to handle the high pressure, various pipe, lots of plate steel and aluminum plating, tubular steel, etc... More "to do" lists were made, and lots of erands had to be run, as well as shopping on the net for hard to find critical parts which were handled by myself. This took up lots of my spare time to complete. I took on this task so as to keep ahead of Dieter and have as much ready for him as possible. This was not always the case, as sometimes things took weeks to arrive, and some parts upon inspection invariably needed other specialized parts to complete a segment of the installation. During these delays, Dieter would work on all the electronics that needed attention. Most complicated of all was "blending" my stock 1978 280z electronics, that had already been modified for my carb conversion, and had been upgraded to a Jacobs electronic ignition, to the 300zxt turbo FI ecu. The brake and clutch and fuel lines needed re routing as well, and this was easiest to do while the motor was out. With the frame mods done, and the steering mods complete, all the new work was painted. After 4 more engine install/removals for more measurements, the motor was sitting on its own mounts, and everything lined up! In case you are wondering the motor went in and out a total of 16 times for the entire project! Now was the task to attach all the wiring, fuel lines, vacuum lines, throttle cable, speedo cable, as well as an oil cooler. Reinstalling the front rad crossmember and bracing was also in the design phase. To compensate for the removal of the strut brace, we added 2 more tower braces that tie the towers to the reengineered front rad support, that form an "X" infront of the motor. I already had the tower to firewall bracing long ago. My 280zx 2+2 rad was put back in the car, and lowered a half inch to make way for the extra bracing. The T5 tranny from the 300zxt is slightly shorter than the normal tranny for a 1st gen Z. So the shifter needed to be modified, and moved back 1 inch to clear the interior console (and so I could reach it..hehe) a new shift knob and boot are other little items I took care of. The throttle linkage was also a fairly easy project. We simply took the whole pedal assembly from the Z31 and put the whole thing in my Z!..it was pretty much that easy! The speedo cable, and clutch slave were also pretty straight forward. The very last things to do were the rad hoses. The 300zxt rad have the inlet and outlet on the same side of the car..mine doesn't!..Looking through parts suppliers stock of hoses was the only way. The motor was ready at this point. Sure there was wiring to be cleaned up, the ecu needed a point to mount to, and a few other asthetic details, but it was ready to fire. Dieter did an awsome job of solving these problems, and no problem stopped us for long. His previous experience building championship racing Z's, and my lack of fear of "custom mods" and not being concerned with keeping the car "stock" enabled us to find unusual solutions to seamingly impossible problems. After triple checking, and testing every component and connection to verify its operation, With a single turn of the key, the motor roared to life instantaneously!!!! What a rush of excitement..and relief..that all this hard work, checking, and rechecking all of the many many connections and modifications. We had a working oil pressure guage, alt, boost guage and temperature all original 1978 equipment (except for the boost guage) all working together with a 1986 300zxt turbo FI system, blended with an aftermarket ignition system, with aftermarket fuel delivery, and pressure controls!! and it worked!! All that was left after this, was to clean up the car, take care of some oddball asthetic items, and start and move the car under its own power to make sure everything was tight, and that all clearances were maintained. After that, it was off to the exhaust shop for a custom exhaust and a a test cruise. Once again it was brought back for a good once over to recheck every single item that was modified. Which is as you can see, was a very large list. Lastly, it was off to the track for testing "spirited" driving conditions. It appears that traction is my newest challange. Z31 Swap list of tasks and challenges. Custom transmission mounts. (must consider shifter location) Custom motor mounts. ( steering linkage clearances) Custom exhaust (possible downpipe mods?) Custom driveshaft (driveline specialist) Upgrade fuel system back to high pressure (new routing?) Transmission speedometer cable Custom throttle linkage Clutch flexline to slave New clutch Routing of rad hoses Routing of heater core hoses Hooking up of guages (speedo, tach, oil, temp, boost, alt) Wiring in of ECU..(including placement of ECU) wiring of alt/charging/battery/grounds Custom intake piping/routing/ and air filte wiring of ignition (still use Jacobs ignition?) This is an exerpt from an article I wrote on my swap almost 5 years ago. The car has dramatically changed since this was written, but the swap has been reliable. Not a swap for the faint of heart. I "coulda had a V8" for a fraction of the cost. Quote Link to comment Share on other sites More sharing options...
260DET Posted January 27, 2006 Share Posted January 27, 2006 Thats good, have read the original and its typical and illustrative of a different engine swap. Very useful for those who think a swap is a bit like changing clothes Then there are the swaps where you can buy all the main stuff needed, bliss Quote Link to comment Share on other sites More sharing options...
mtcookson Posted January 27, 2006 Share Posted January 27, 2006 great info! i'll definitely keep all of that in mind incase i do the VG into a Z down the road. Quote Link to comment Share on other sites More sharing options...
Greywolf Posted January 27, 2006 Share Posted January 27, 2006 Excellent info! I am curious if custom manifolds relocating the turbo would allow it to sit clear of the steering column and frame rail? I accept that sitting it further forward would make a very interesting shifter neccesary, so it looks like hood pins would be needed. ...I'm leaning toward an XR6T swap if I were to do a 280Z swap, while I like the VG30ET in my 300ZX, I'm more excited by inline engines, and this swap looks like a real doozy. A friend suggested cutting the frame to integrate the Z31 turbo crossmember...looking at body manuals and measuring as best I can on paper, this looks like it would be easier to build a custom frame and crossmember. Wow. Thanks for all the info, ZR8ED! Ben Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted January 27, 2006 Author Share Posted January 27, 2006 Hi Ben: I don't think that the crossmember swap will be of much help, as the steering rack and possibly the lower control mounts would be a problem, and it would also bring the motor further forward. I should take a top down pic of the engine position..it sits very far back..only the front of the pully is over the crossmember..more or less. Moving the engine forward is an option that I have heard done, but in the end it was a failure with the handling and steering effort seriously affected. With the engine in the setback position, hood pins are a must...or else move the engine forward 3 inches.. again not a good idea...let alone the shifter. If you could do custom manifolds that would be easier..IF you can build manifolds. As you bring the turbo higher, you'll find brake lines, m/c etc starting to become a factor. If you raise the turbo position up 1-2 inches, and bring it outboard from the engine 1-2 inches, you could probably make it work...as long as you don't want a large turbo there.. T4 is easy enough.. t66's and up...??? another story. Quote Link to comment Share on other sites More sharing options...
mtcookson Posted January 27, 2006 Share Posted January 27, 2006 The idea I've always had for a turbo setup in an early Z with a V engine was to route the manifolds forward and put the turbo in front of the engine. That would give you so much free space you could use the biggest turbo you could find up there. I've only figured this out by looking at everything but do you believe this would be an option? Quote Link to comment Share on other sites More sharing options...
Silent Posted January 27, 2006 Share Posted January 27, 2006 great info! i'll definitely keep all of that in mind incase i do the VG into a Z down the road. you know you will eventually it's the "maxima" side in you that wants too Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted January 29, 2006 Share Posted January 29, 2006 The idea I've always had for a turbo setup in an early Z with a V engine was to route the manifolds forward and put the turbo in front of the engine. That would give you so much free space you could use the biggest turbo you could find up there. I've only figured this out by looking at everything but do you believe this would be an option? I had my VG30 in my 50th AE z31 with custom manifolds. the turbo was in front, right in front of the water pump. Tons of clearance on the driver's side after I did that, I plan on doing something similar when I get an s30. Quote Link to comment Share on other sites More sharing options...
mtcookson Posted January 30, 2006 Share Posted January 30, 2006 you know you will eventually it's the "maxima" side in you that wants too Yeah, the VG30 is an awesome engine. my brother wants me to put one in his S14 so I'll likely be doing a similar setup in it as well. Quote Link to comment Share on other sites More sharing options...
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