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iTrader: (5)

2003 350z, 86k miles, stock motor with nismo cams and bolt on mods.

I recently had it tuned with uprev and it showed I was still making power up to the stock rev limit of 6600. Now, this motor burns oil, so I dont want to drop too much more $$$ into it, but maybe just upgrade the valvetrain a bit to rev higher and see where the nismo cams can go.

I need reliability because this is mostly a track car that will see lots of redlining. I basically want to run this motor down until I need a complete rebuild, which is going to be a huge slippery slop. So should I spend a little on the valvetrain?

Thanks for suggestions.

kv

tcode

iTrader: (7)

Stronger valve springs and better oil pump. Revup oil pump for instance.

thekyledeg

iTrader: (1)

SG had their stock bottom end redline set at 7200 for awhile, on upgraded valvesprings of course. I know of a few builds that have theirs anywhere from 7200-7500 on the stock bottom end with no problems on upgraded v-springs. I run 7300 on my stock bottom end, but as you said your burning oil. If its your valve-stems that are the cause of the oil consumption you MIGHT be able to slip some new valve stem seals on while your doing the valvetrain. Its really more of a "is it worth it" thing in your situation IMO. If it was me, id crank it up to 7500 and see how long it lasts provided you have a backup daily/the funds to do a build while your gambling your engines life away.. but i just like to ride the lightning.

JWT Valve Springs can be had for 230+100 for their cool tool so you can change the springs with the heads in the car. Viton valve stems are 60 or OEM can be had for cheaper. You might want to do the timing guides/tensioners/water pump while your in there if your looking for reliability. so bare bones if you do it yourself itll be about 350 bucks plus oil,rtv,coolant, if you do all the work yourself for a valvespring swap.

my cam diy: https://my350z.com/forum/engine-driv...e-springs.html

Anyway, for a reliable/cheap shortblock that can take 8k all day (if your staying NA)

1. Eagle rods
2. ARP Rod Bolts
3. 11:1 Pistons of your choice
4. OEM bearings same size as the ones that came out
5. Rev-Up Oil pump
6. Qaulity balance/block hone job
7. cheers

MicVelo

^^^ This is a great recipe/good advice.

Some general points I'd add to this.... I don't know much about the Rev oil pump mentioned but the two biggest things that affect longevity of any race engine are oil supply and fuel supply. Without either, the engine's going to grenade from seizing and/or lean out.

Look into a high volume oil pump and bigger injectors with a pump to back them up (just as you would for FI applications).

On the oiling, NOT necessarily high PRESSURE, but high VOLUME and heavy duty bracing that is designed for high engine revs.

When I worked for Datsun Comp, we offered such for the L-series engines (4 and 6) as well as for U-series motors; and it was extremely rare to see them fail - even on accidental overrun, e.g., missed shifts resulting in over rev conditions, etc. Not sure if these are available for VQ, you might want to look into it. I would tend to think that Nismo has everything you'll need.

You're dead on about the valve train too. That's usually the limiting factor into whether or not you can even attain 7500. Valve followers (springs, oil seals, etc) are the weak link so yes, I'd top end the engine before looking to rev 7k+ wheel to wheel.

Good luck!

Mic

silverbullet_Z

iTrader: (3)

I'm at 7500rpm. My na thread is on here along with dyno numbers are in this section two topics below yours. Mine is also a 03

thekyledeg

iTrader: (1)

The rev-up pump should be plenty enough for your oil supply needs, z1 built a motor with one that redlines at 8400, and theyve been hounding on it for years to my knowledge its still alive. What kills our oil pumps is crank vibrations since its mounted right on the crank. Thats why its imperative to get a good bottom end balance, id include the flywheel, pressure plate disc and whatever crank pulley your running when you get the balance job so they can have it perfect. And yes I know vq are internal balance but they can balance all of these other parts so they work in harmony.

apex locator

iTrader: (5)

Hey thanks everyone for all of the useful information. Yes, silverbullet I've read your thread and notice we have the same types of mods, except I dont have any valvetrain work. I'm still deciding though because I also want to get a roll bar/harness/seat setup in place.

thekyledeg

iTrader: (1)

corbeau forza sports (FIA approved), 320each. Megan seat brackets 120 for the pair, kirkey side mounts 45 each. Boom side mount setup 485 or 820 ish for the pair.