1995 Nissan 300zx Twin Turbo

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A picture of the Z just before I parked it for the Winter.

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Well, back on the dyno this year. Changes are as follows.

Removed Nitrous System
Replaced 555cc with 740cc injectors
Replaced the JWT ECU with a tunable ECU - The ZEMulator.
Replaced stock manifolds with MS Manifolds
Replaced forged CP pistons witha new set of forged CP pistons that had the crowns treated.

At the end of the first pump fuel dyno the Z made 557.65 rwhp and 491.08 rwtq. Back on the dyno for the second time, to tweak the pump fuel tune and then to move on to race gas. That finalized tune saw 577.20 rwhp and 498.40 rwtq.


Comparions between two pump fuel tunes.

What I'm calling my race fuel tune is not straight race gas. The dyno was done with 1/4 tank of pump fuel (about 15 litres) and then 15 litres of C16 was poured in. So, 50/50 is the intended mixture between pump fuel and race gasoline. That's how I'll be running it at the track once the race fuel tune is done. (Which it is currently not...)

At 23.5 pounds of boost, the final tune saw 610.54rwhp and 565.55 rwtq. The car did make 619.x rwhp on one run if anyone cares. The tune is not finished and I will hopefully be hitting the dyno next week to finalize things. I'll post the final dyno numbers when I have them.


50/50 - pump/race gas dyno sheet.

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This is a picture of the Z at SIR (Saskatoon International Raceway) where it won the Sport Compact Class at the Performance Plus 2007 Fastest Street Car Shootout.

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Finally fixed all the links in this thread. Sorry about that. Also, I will do an update on the thread later this year once the car is actually putting out some numbers.

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At the end of 2007, I had a nitrous backfire in the motor which actually did some damage to the internals of the car. It bent the stock rods, valves hit pistons damaging some pistons, and the heads in fact were basically already destroyed from severe detonation that could not be fixed from the first motor that I destroyed - but I had re-used them anyway.

Right. So this in fact is the third time the motor in my Z has been taken apart. But it is the first time that I will be doing all the assembly work of the entire short and long blocks myself. The car is now finished, but I have not posted any pictures yet, and frankly after the initial bit, I got lazy with taking pics. So here are some pictures of my current build, which I am hopeful will last me a long time.

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Here's the block, with nothing in it, ready to be assembled.

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The very first thing I did was install the top side main bearings. I put a little bit of oil on them before pushing them into place. They are ACL Race bearings 4M2737H.

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Installed ARP main studs.

Finger tightened to ensure they fully seat. Then removed the studs. Applied red Permatex (loctite equivalent) and re-tightened by hand ensuring studs again fully seat. I actually used a T30 key to give just a quarter turn more on each stud after finger tight.

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Installed the other half of the main bearings. Lightly oiled them before installing.

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Install 3 oil thingies. I would have thought there would have been a tonne of oil splashing about, but I guess these are necessary. Install with 10mm w/lock washer. Six to do up.

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Gently dropped in crank shaft and it fits like a glove into the bearings.

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Install the cradle. Install washers on all studs. Apply the ARP moly lube to each nut on the threads and bottom contact surface. The ARP lube is critical because it sets the correct torque for the studs. Use of other lubricants will require other unknown torque values. Torque each to 70 ft-lbs in the pattern and manner noted in the factory service manual 3 times.

I actually used 40 ft-lbs on torque round #1. Then backed them off. Then used 55 ft-lbs on torque round #2. Then backed them off. Then I used the final torque value of 70 ft-lbs. I used the pattern noted in the service manual, and the reverse of that when backing them off. Basically same procedure as that is provided by ARP for ARP Head Stud Installation.

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Next it is time to install the rings, pistons & rods. I followed the instructions that came with the pistons & rods for preparation to go into the block. My wristpins and retainers were already installed, as I had everything weighed to make sure it was balanced. [Plug for Davenport goes here, as they did that for me as part of the weighing the assembled units.]

I put the rings on each piston as per the instructions, carefully making certain that each ring was aligned appropriately according to the positioning map. I did not use a ring expander, I just put them on by hand. I found aligning the rings to be annoying and tedious. It took a lot more time than I anticipated, but you must be patient.

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The rod bearings I selected for the Eagle Rods were all Grade 3 bearings. I measured them with a micrometer and they were good to go based on the rod journal measurements. On some of the bearings I put oil on the underside, on others I put an assembly grease. We'll see how that works out. I also put a little bit of oil on the rod journal before installing.

I removed the rod end caps, put the rod bearings in and used a ring compressor gently sliding the piston through it. Then I spun the crankshaft so the rod journal was directly beneath the cylinder for which I was installing the assembled rod/piston. I put engine oil on the cylinder walls before gently and carefully dropping the rod through the cylinder. Slowly pushing the top of the piston downwards until the rod pops onto the crank journal. At this point, I flipped the motor over, and put the rod cap on. Using ARP lube, I did up the bolts finger tight, and then alternated back and forth between bolts until the end cap was done up evenly. I then finished up with a torque wrench set to 43 ft/lbs. Rinse and repeated the process for all 6 sets of rings, pistons & rods.

In the past, I have got the piston crowns treated. This build I chose not to do so.

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Top of the engine. Dots on each piston facing front of the motor as indicated in install instructions.

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At this point I have installed the detonation sensor, and the thermostat housing. Plus the oil pick-up, oil pump, oil pan gasket and oil pan. I've also cleaned the block surface. I've slid my cometic gasket into position and am ready to install the passenger side head.

The red circle on the thermostat housing interferes with the installation of this head. Because that is super annoying, and I know I will have the heads off this thing again, I actually ground down the corner of the thermostat housing with a dremel tool. I also took a little off the part on the head that interferes and now it slides on and off nicely. This can take a lot of time, but it's worth it IMO.

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Both heads were put on, and next we are sticking in the lifters. I used a big magnet to pick-up and place the lifters. I also used a small amount of assembly grease on each lifter before putting them in place.

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Here we have the camshafts being installed on the driver's side. All cam journals and the cams had a little bit of assembly grease applied before tightening the journals. Followed service manual for torque amount and torque sequence.

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Put in some new cam shaft seals.

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Well, I'll add some more pics soon, but basically I took the Z out to the Drag Strip on this past Friday - on my first pass that I actually did a burnout [second pass of the night for me] the Z ran an 11.331 ET. I'll post the slip some day when I get it scanned.