Here is a complete list of all the stuff I did while installing a VG30ET series engine and related components into my 1985 Maxima. First off, for those of you who have speculated about this swap, let me tell you one thing, it isn't as easy as it looks. Strict attention to detail is essential as there are so many little things to take in to account, and some major ones. As you probably figured out, one of the first things you will need to do is either buy a VG30ET engine or build one. It is highly recommended that you stick with the specs for the turbo series engines as this will ensure proper compression ratios. As far as the internals go, the major difference between the turbo and non-turbo VG30E series of engines is the pistons. The non-turbo engines utilize a flat-top piston which yields about 9.7:1 comp. ratio whereas the turbo engines utilize a dished piston which yields about 8.5:1 comp. ratio. If you simply add a turbo and related external components to a VG30E engine, you will for sure have to run high octane fuel to curb detonation, and although an intercooler is recommended even with a VG30ET engine, it is HIGHLY recommended if you turbo a VG30E engine, again to help curb detonation. What I did was locate a VG30ET engine out of an 86 300ZX. I picked up all the related components that I would need to go along with the install. This included such things as:
I proceeded to tear down the engine as I wanted to check the bearing clearances, cylinder ridge, etc. I chose to have the crank ground and go with .10 over bearings on the mains and rod journals. This way I was assured of tight clearances and good oil pressure. I have to admit, I sure am impressed by the way Nissan designed these engines. The main caps are not separate, they are integrated into one sturdy unit, almost like a girdle. This is the kind of stuff you can buy after market to bolt on to an engine. Not here, these engines already have it. Also, out of the four V6's I have worked on as of late, every single one was over 250,000 kms and not a single one of them had a ridge in the cylinder bores, it must be due to the higher nickel content these blocks have. Needles to say, I didn't have to bore the block, all my cylinders and pistons were well within spec. A simple hone and new rings fixed it up nice. While re-assembling the block, I obviously had to use the stock Max oil pick-up as it is very different than the 300ZX one. That being said, you have to use the stock Max oil pan as well. The trouble here is that the stock Max pan does not have an oil drain back tube to hook the turbo up to. What I did was cut the tube out of the 300ZX pan, cut a hole in my stock Max pan and weld in the tube. You have to be very precise in placement of the tube so it will line up with the turbo when mounted. That pretty much covers the bottom end. Assembly of the top end is pretty much the same as far as the heads go. No rocket science there. I chose to have my cams re-ground in order to change the profile a little. The profile I chose is better suited to a turbo motor as opposed to the stock profile. You can get away with this more so if you use the dished pistons as piston to valve clearance isn't nearly as tight as is when using the flat-top pistons. I used the stock Max lower intake and stock Max coolant lines. Due to the fact that the engine in a 300ZX is mounted front to back as opposed to side to side, you are way better off to use the stock Max cooling lines for routing to and from the radiator. This will save you some serious headaches. In using the injectors and fuel rails as off of the 300ZX motor, the fuel feed and return lines are different than on the Max so you have to lengthen them a little. No big deal. One of the most obvious changes is the upper intake. This is pretty much a direct bolt on piece with the exception of the one coolant line. The line has to be bent downwards a little to clear the new intake plenum, again, no big deal. A couple taps with a rubber mallet and you're off to the races. The EGR valve is located in a different position on the turbo version of the upper intake, so you have to use the connecting tube that goes from the rear exhaust manifold to the EGR valve as found on the 300ZX, the stock Max tube does not match up. The throttle cable is an issue as well. The wire portion that extends out of the sheath is too long to simply bolt on to the bracket. You have to do one of two things, shorten the cable by cutting it and relocating the end collet, or make a different bracket to hold the cable. I chose to shorten the cable. Details here. During this whole installation, three of the biggest challenges were the motor mount needed for the front side, the routing of the air inlet system and of course, the exhaust routing from the turbo. I got creative with the motor mount and utilized some pieces of extra stock Max mounts I had kicking around. This alternate mount is very necessary as the turbo now sits EXACTLY where the stock Max mount would be. As you can see in the pictures, I modified the bottom support member and altered the rubber mount a little. Then I made up a custom bracket and it all bolted together as though it was meant to be. Very cool!!! This set up clears the turbo, the oil feed and drain back lines, as well as the water cooling lines no problem. Next up is the air inlet system. On the 300ZX, there is a steel tube that mounts on the inlet side of the turbo which clears the backside of the alternator and then bends forward. In using that piece on the Max however, the portion that bends forward bends right in to where the A/C compressor would site. I tried to rotate the inlet tube forward and down a little, and sure enough it clears the A/C compressor, but now the waste-gate control doesn't bolt up to where it should, AND it looked as though the inlet tube would totally interfere with the stock cooling fans setup. Being that the whole air injection system on the stock Max is totally ditched in this swap, there is a whole bunch of room where it used to be. As you can see from the pics I routed the a tubes from the air inlet system over to that side where I mounted the air filter, air flow meter, etc. I wanted to maintain a cold air intake as I was not installing an intercooler at this time. As for the exhaust from the turbo, I took the stock exhaust outlet/waste-gate piece to a machine shop and had them cut the piece off so it would be square. This would allow the exhaust shop to weld up a custom fabricated piece which would bend down and around to clear the starter and mate up with the stock exhaust from the flex-pipe back. I stuck with the stock exhaust system at this point until I get all the bugs (if any) worked out and then I am going to have a 2.5 inch system installed. |