I'm doing an engine rebuild on my 2003 350z because i spun a few main and rod bearings. The block and heads have all been taken to a machine shop where they were both pressure tested and cleaned and I also had the block bored .040" OS. I have planned on ordering the stage 2 engine rebuild kit from z1 motorsports which will include the larger pistons, forged rods with an 11.0 compression ratio as im still keeping the car naturally aspirated. I would like some professional opinions from the enthusiast who know anything i should or should not do to have a successful and strong running engine.

 

I really suggest you read through many of the threads here and catch up on what works, what is needed and what you just need to know

 

I'd definitely read the NA stickies... Adam from Z1auto has a serious NA set up and Kwame from Z1auto is now doing a build so I'd ask either of them.

 

Z1 seems to have done more experimenting than the rest of us. I can tell you from experience, it is a VERY pretty penny to do an NA build, and you will not really see anything from it. I hope to be at about 310ish RWHP in the spring with my set up which will only be 40 more HP for the about $9k I invested into the project...

On a more positive note, My engine is well broken in and all the kinks are worked out. My 350z is still my DD and it is really fun to let it scream into the higher RPM's.

Why .040 over? I ordered I would say 90% of my stuff from IPP, I have not had problems with Z1motorsports, but I called IPP up and they went through my build ideas and helped fill in some gaps and gave me a pretty good deal. I have no doubt Z1 would do any differently.

You are doing all of this work and sticking with the stock cams? If you are NOT, I would do more research on the matter than I did and call up some different people and see what you can get suggested to you for what you are planning. I can tell you right now, my car is bottle necked because of my OBX LTH and the stock diameter TB. With the probably discontinued SG headers, and making a manifold with a larger TB, I am sure I would be creeping to 330ish. BUT you also need to look into your heart and make a budget, then double it and that is what it will cost... I budgeted $4500... Also, think about what you will be using the car for. If it is a daily driver, and you don't plan on anything wild, I would stick with a mild 260ish cam and just freshen up alot of things.

I can go on and on, and I am sure I began to ramble, but I really feel for the guys who are plunging into this and don't seem to know what they are doing. My car went down March 26 2011, and I had it running (not running well) in June. I spent the summer putting miles on it and repairing and tweaking it out to where it is now.

 

I would just do an OEM+ rebuild. (if it's a nonrev, update the rod bolts and oil pump) I wouldn't waste money on high compression pistons and forged internals, put the money into parts that actually matter. The intake manifold is garbage, and the cams (especially in the norev) are small. Those should be your primary concerns.

If it were me, I'd look at a way to increase the intake manifold's volume, bigger camshafts (JWT) and a good set of headers (You can have these made, or modify an existing set to work well....) Tune and you'll easily out power most of these guys here.