Z32 NA Engine Rebuild Suggestions and Help

[Z32Z33]

Hey guys, I'm looking for your suggestions and opinions...

Last week my 1990 Z32 NA that I am restoring blew it's head gasket... So I've decided that I'm going to pull the motor this weekend and go ahead and rebuild it. Most of the work will be done by me, with the assistance of my local machine shop for the milling work, etc..

Please don't suggest I upgrade to a TT I have a TT and it's just fine, this is my NA and I enjoy it for entirely different reasons..

My question is what things should I focus on upgrading/replacing while I have the engine out of the car. Here's my plan so far...

1: Heads going to local machine shop for complete rebuild: acid wash, valve job, new lifters, and port and polish.

2: Block will be reconditioned as needed...

Parts I'm getting ready to order, suggestions/opinions?

3: Kevlar Timing Belt Kit includes new Oil Pump

4: Injen Technology IS Short Ram Cold Air Intake System

5: Megan Racing Stainless Steel Headers

6: Unorthodox Racing Pulley Set (4pc) with Overdrive Water Pump Pulley

7: Z1 NA Clutch & Flywheel Combo

8: New Sending Unit for oil pressure gauge

That was most of the items I could think of that I wanted to upgrade and that are hard to get to with the engine in the car, any opinions?

Did I miss anything? Is there anything on my list that I shouldn't order or a better quality version by different manufacture?

Looking for any and all info you can provide me with... your personal experiences and any "what not to do" stories... Thanks guys.

[Buster70]

I am about to start a same project on a 1995 Z32 NA as well. I look for to reading the comments in this thread.

[300ZXttZMAN]

Welcome to Nico guys I am tied up right now but I will get a rather lengthy reply for you two fellas as soon as I get a chance.

Also before I type my reply give us a budget to stay under and what is your ultimate goal with this car??

Right off the bat IMO I say forget about the kevlar timing belt. IMHO its over kill on an NA motor. Instead of the kevlar timing belt get an OEM one and save a couple bucks.

[Z32Z33]

Price is up to debate, obviously I'm trying to spend less than I would on a new motor from somewhere like Z1, so under 5K. My initial figures so far show my total to be around 3K.

As far as the Kevlar timing belt I am looking at a kit for $183 vs $120 for the OEM kit, OEM kit is rated for 60,000 miles, Kevlar kit is rated at 180,000 miles.. so for a bit more money I have a belt that should last the life of my car rather than having to do this again at 60K miles. I should note that neither kit includes a oil pump, that would be additional.

Really what I"m looking for is some advice on the machine work I should have done, for the heads here is what my plan is currently.

New valves, springs, guides etc, then de-schrouding the valves, smooth the casting, flash & knife edge the divider(s), port match the exhaust.

Now I'm curious what to do with the lower, I my pistons appear to be fine and I don't really want to overbore my block, so can I reuse the stock pistons or do I need to replace them. Is it worth having the block bored/honed, squared and torqued? Or should I just have the crank turned and put in some new bearings and blue print it... that's where I"m at now, any info you can provide would be excellent. Thanks.

[300ZXttZMAN]

Here are some issues that I am worried about. (for your sake)

Its recomended to purchase a new wiring harness after you pull the engine if you plan on not having to track down little green trolls (corrosion) in the future...

Its also recomended to purchase a new style harness for 2 reasons.

• 1. You will have the new style injectors which are less prone to failure since they don't see constant voltage and they are designed to better with stand the ethanol in todays gasolines.
  2. You will have the new PTU style plug which will not require the PTU recall harness that Nissan made

But inorder to purchase a new style harness you also have to change the injectors to the new style so you will need to purchase new style injectors and either the fuel rail or a kit with adapters:

Old style fuel rails/injectors came in these years:
1990-1992 NA - 2+2, 2+0
1993 convertibles
1990-1994 TT

New style fuel rails/injectors came in these years:
1993-1996 NA
1994-1996 convertibles
1995-1996 TT

I am not sure if the NA harness is even still avalible new. A new OEM 1995 TT 5spd harness costs about $405. All the TT guys go (eventually go) to this harness because it comes with the new style injectors and new style PTU plug. The problem with this harness is that you have to change your AC compressor plug (if you have a early style compressor) and you also have to get a +95 CAS (for TT not sure about NA) I guess you could change the plug but I was told to change the CAS itself so thats what I did.

So basically what I am getting at is that you seem like you want to do your car right which is great but the thing as its going to cost a hefty penny so it all depends on how much your willing to spend and if its worth it to you when most people get to the point your at they start looking into swaps.

*DISCLAIMER* Alot of this info I posted is for TT models and is correct. Since I don't have an NA I don't know as much about them as far as technical things go.
I am just trying to help.

[Z32Z33]

Thanks for the reply I do appreciate the suggestions, I will carefully inspect my harness, but I believe mine is probably in better condition than most. This car has been garage kept it's entire life and meticulously cleaned often. So far I haven't even had a broken electrical clip which in my experience is a fairly rare thing on a harness this old.

Although, heat is the worst enemy of electronics so better safe than sorry may be good advice here. I will probably try to skip this step and gamble that it will be fine, but I will be cleaning all the connectors and replacing any worn tape or coverings. If I do find any frayed wires then I will replace the harness.

I'm not interested in the swap as I already have a TT so for me there's no real point in going to the trouble and headache of doing a swap to a TT. I like the TT and I also enjoy the N/A, overall I find the N/A to be more convenient for a daily driver.

Thanks for the advice though I will consider it, and I do agree that in a normal situation most people would be much better off by replacing the harness while the motor is out, unless your harness is in remarkably good condition.

[SLE-PR]

Thanks for the reply I do appreciate the suggestions, I will carefully inspect my harness, but I believe mine is probably in better condition than most. This car has been garage kept it's entire life and meticulously cleaned often. So far I haven't even had a broken electrical clip which in my experience is a fairly rare thing on a harness this old.

Although, heat is the worst enemy of electronics so better safe than sorry may be good advice here. I will probably try to skip this step and gamble that it will be fine, but I will be cleaning all the connectors and replacing any worn tape or coverings. If I do find any frayed wires then I will replace the harness.

I'm not interested in the swap as I already have a TT so for me there's no real point in going to the trouble and headache of doing a swap to a TT. I like the TT and I also enjoy the N/A, overall I find the N/A to be more convenient for a daily driver.

Thanks for the advice though I will consider it, and I do agree that in a normal situation most people would be much better off by replacing the harness while the motor is out, unless your harness is in remarkably good condition.

I would just like to say that I think the Moderator is correct about the harness. I too have a TT and NA, just like you for the same reasons, the TT is awaiting the motor install and I changed the harness and with the motor out and is no picnic. I am doing a swap on my NA here soon and the harness will be in today. I cant imagine trying to change the harness with the motor in, the same as trying to change an EGR with it in. Wires can not only fray but they get hard and can crack from moving it around during an R & R. You could end up with broken wires under the sheathing that are not visible. Unless it has been changed recently, I feel it is cheap insurance for 400 bucks not to mention the headache of changing it later and the peace of mind that 99.999999% chance of not trouble shooting it later. After all, it is a crucial component in the system that is prone to failure. Good Luck on quest!

[t.mcginley.jr]

I found this link for a new wiring harness:

http://www.conceptzperformance.com/Cart ... php?II=293

It's $420 for either TT or NA wiring harness. There's a few more new harnesses on ebay too for around $400 each.

I was wondering if it would be possible to reuse the stock harness but wire in new style injector connectors so that you can still use the new style injectors? $420ish + $250ish for new wiring harness and injectors is a bit hefty

[Z32Z33]

Here's what I ended up doing...

My wiring harness overall was in very good condition, but as always there were a few plastic connectors that had just gotten brittle with age, primarily the fuel injector and coil pack connectors.

Since I had intended to use my stock fuel injectors I just needed the replacement connectors. I ordered mine from Z1 here:

Fuel Injector Plug (early style connector)
http://www.z1motorsports.com/product_in ... cts_id=650

Coil Pack Connector
http://www.z1motorsports.com/product_in ... ts_id=5001

Cost me about $40 and 2-4 Hours Labor to cut and solder all the connections and re-wrap them with new electrical tape.

Might not be for everyone... a new harness is the best solution but if your trying to save a buck this does work.

[t.mcginley.jr]

That's a good idea too what you did.

For my build I want to use the new style injectors, so instead of getting a new harness, Z1 sells a fuel injector adaptor kit that allows you to use the stock harness with the new style injectors for $125. You solder in the new style connectors that come with the kit and then there are adapters that you install where your stock injectors sit. Then buy a set of new style injectors and you can just drop them in. I'm thinking about grabbing a set of re-man injectors off ebay that have been sonic cleaned and tested for about $130.

[Z32Z33]

So here's the update on my current build...

Initially I was trying to just rebuild my motor but the Z Gods decided otherwise...

As I started to add up the parts and prices for the machine work and the cost of new bolts/pistons/etc. I quickly realized that this wasn't going to be a cheap adventure.

At that point I decided to look and see if I could find someone who had a rebuilt or low mileage motor I could purchase but instead I stumbled across a high performance motor, that for the money, I just couldn't pass up. So here's what's changed.

1: Heads completely rebuilt:
New lifters, valve stems, valves, valves DE-shrouded, head casting flashed and knife edged, ported and polished, new set of JWT Cams

2: Reconditioned Block:
Cylinders bored .040 over, Wiesco 88mm Pistons, Stock Rods, Clevite bearings, and ARP bolts everywhere.

3: Upper and lower plenum ported and polished, EGR delete kit installed, reworked PCV system.

4: Injen Technology IS Short Ram Cold Air Intake System with JWT Filter Cone

5: Scrapped the Megan Racing Stainless Steel Headers opted for a LaBree Motorsports complete exhaust system from headers back..
(3x the price but man it sure sounds better than the Megan's)

6: Unorthodox Racing Pulley Set (4pc) with Overdrive Water Pump Pulley - Was told not to buy this as it can upset the crank balance...

7: Z1 NA Clutch & Flywheel Combo

8: New Sending Unit for oil pressure gauge

I also wanted the new style fuel injectors but I was hoping to get mine back together and running before I went down that road. I was told that because of the extra displacement to upgrade to 370cc injectors if possible, but that the stock 270cc injectors would work but fuel mixture might be to lean at high rpm's.

Now, what I should have done was to pull my injectors from my old motor before I went to all the trouble to solder in the new wire connectors.... When I got my fuel rails off the other night I found out that my #3 injector has a nice chunk out of it, so looks like I'm going to be putting injectors in sooner than I had initially hoped. So I've been researching fuel injectors the past few days trying to figure out if I need the 370cc injectors, or if the stock 270cc injectors are preferred.

What I have found from reading on this board and the other forums is that if I do upgrade to the 370cc injectors I will need an ECU tune immediately. I am told that with the stock N/A ECU fuel map, that the 370cc injectors will provide 43% more fuel than with the 270cc injectors. Now the benefit of running the 370cc injectors is that when properly tuned I will not be lean at high rpm's as well as the 370cc injectors have to perform far fewer injections, therein allowing the fuel a longer amount of time to atomize, which in theory should result in more power and better gas mileage.

So next step, I'm picking up a set of Nissan OEM 370cc injectors off Ebay, unfortunately the old style injectors for the moment, and getting a ECU chip from SpecialtyZ.

Will see how it turns out... everything works out well then I'll drop the $800 on the new style 370cc injectors.

Oh and FYI I have been told by many many people to ONLY buy Nissan or Nismo Injectors... they all say not to buy the JECS or ANY aftermarket injector as you will have major issues.