masti04

As the title suggests, I have an 01' Z with about 102k on the odometer. I bought it with 88k on it and have run about 10 track days on the car in the past 2 years. Due to the mileage, I want to make sure I budget for and execute the appropriate preventative maintenance during the winter off-season. Other than normal wear and maintenance items (pads, rotors, plugs, belts, fluids, etc.) are there any major engine items that I should be looking to replace as preventative measures?

The car runs great and there are zero issues with it right now, but I want to keep it that way. The "if it ain't broke, don't fix it" mentality comes into play, but with 102k and plans of 5-7 track days a year, I'm not so sure if I should just keep the motor sealed or start changing out certain items to prevent a catastrophic failure.

Specifically, I would like to know items of concern such as:
1) If changing the valve springs or doing a trunion upgrade would be appropriate?
2) Perhaps replacing the oil and water pumps?
3) Maybe replace the timing chain due to "stretch"?
4) Replace the stock damper?

Just not sure what others have experienced with respect to failures with higher mileage motors on the track??

FYI, the only mods to the car are:
* External oil cooler
* 160 deg. thermostat
* Headers, B&B exhaust
* New (approximately 5k miles) clutch, master & slave cylinder
* All fluids changed on regular intervals
* Tuned at Phoenix Performance last year to 379 whp/374 wtq

I really don't have plans for other mods, other than some suspension stuff, brake and fluid cooling.

Would like to see what others think??

Thanks,
Matt

froggy47

bosco022

I have had a rocker failure in my road race LS6, so I do suggest the Comp rocker upgrade along with some upgraded valve springs. We use the ISKY 165 A's in our mildly cammed road racer.

RapidC84B

My suggestions:

1. Fresh OEM springs (no need for $$$ springs with a stock cam). The latest iteration are blue.

2. Pull the heads and install LS7 lifters, the rollers are fully contained.

3. Smith Bros restricted flow pushrods keeps excess oil out of the top of the head.

4. LS4 high volume oil pump - 42 psi relief.

5. LS2 water pump - The one with the slimmer pulley and passenger side outlet. The LS3 pump moved the outlet to the driver side and would require a new hose.

6. Fresh OEM LS2/3 timing chain. Timing chain damper if your block is drilled for it.

I recently lost a 123k LS6 due to lifter failure.... had 4k track miles and I was going to replace the lifters in the off-season, but she didn't make it. Got a new LS1 crate motor and built it into a LS6 with a new OEM cam and my old heads and oil pan etc.

ZedO6

I'd strongly agree with these valvetrain upgrade suggestions. I just finished going through a 90K 2004 LS6 that lost trunnion bearings and luckily didn't take anything with it.

Like T.H. suggests, the new GM LS6 valve springs are more than adequate for a stock cam engine and are cheap enough to replace once a season for P.M. Do the valve seals while you are in there. Timing chain and gears make sense as well. Damn reliable engines with a little maintenance. Lots of 100K+ mile motors doing regular track duty around here

RapidC84B

Personally I've never had an issue with OEM rockers, but I always use lower mileage or new sets. Nothing wrong with the trunion upgrade, but more money to spend. Needle bearings don't hurt these motors since they can't get past the pickup screen.

Never had timing gears show any real wear either. Cam gear is easy to swap but the crank gear has to be pulled and pressed back on. Probably easy, but not something I've ever bothered with.

Good call on the valve seals... forgot about that. Recently did that on my new engine. FWIW I also had my heads milled 0.010" for a small torque bump. I race in a power/weight limited class so I can only make around 350 rwhp.

2002rich

I guess you're assuming they never get chewed up as they pass through the rotating assembly.
I had a broken lifter clip pass through the screen and found it in my Oil filter during a routine inspection.
Pulled the heads and found the culprit. Yanked all the ls7 lifters out and replaced with a set morel lifters and never had a problem since. Been 5 yrs now and still quite.

masti04

I appreciate the replies. I'll start throwing together my budget based on these suggestions.

Thanks,
Matt

6SPEEDZ

Valve springs - OEM or PSI LS1511ML's
Timing Chain - LS2 or C5R
Oil Pump - Katech they have an O ring with their pump that fits tighter allowing for less aeration in the oil.
Rod Bolts - ARP or Katech

Not an engine part but I would highly recommend changing the torque tube couplers and possibly the torque tube bearings. When they fail they will destroy the torque tube assembly.

You could also consider pinning the stock dampner. At the very least I would mark a line on the bolt and the dampner to make sure the bolt is not backing out.

froggy47

Good idea on the dampener bolt, however in my case it was fine one lap & backed off the next. I would pin it or better put an ati on it.

geerookie

This is a good starting list. 3 and part of 6 are not needed and IMO cause problems down the road and at worst are band-aids for the root problems.
ATI damper over the stock one for a track car that sees multiple days per year for sure. Timing chains die due to improper high RPM crank dampening.
The extra oil in the valve covers is to dampen the valve spring harmonics. KaTech used to have a great article about valve spring harmonics on their website but I haven't seen it for a few years.

You don't really need the fancy ported and polished oil pump if you use the factory high volume pump for motors with VVT (or what every GM calls it).

On an '01 motor you should already have the stronger GM rod bolts so don't waste the time and effort to replace them.

And REPLACE the driveshaft Guibo's if they are more than 2 years old!

RapidC84B

I just took my 123k mile torque tube apart and it all looked and smelled brand new. I don't agree that the guibos need replacement that frequently. Maybe if you have one of the older cars (pre '01) with the smaller torque tube, but not the later 12MM bolt ones.




On the restricted flow pushrods I guess we can agree to disagree. I've read the stuff on how they dampen spring harmonics, but these cars push a ton of oil to the top end at high rpm use sine they're not priority main oiling. Giving the heads the "right" amount of oil vs. too much helps IMO.

You say a fresh timing chain isn't needed at 100k miles? I'd never leave the stocker in there. The LS2/3 chain is much beefier than the LS6 chain (it has replaced it permanently now) and is only like $32. The chain damper is another cheap and easy add if the block is drilled for it.

geerookie

Wait until you have a Guibo let go and then you will be willing to replace every 2 years. Ask Doug who was at the Glen this past weekend with 2 year old Guibo's that let go on Friday and ruined his whole weekend

Anyway, I went back and looked....You are CORRECT, REPLACE the Timing Chain with an LS2 chain! I was meaning the need for adding the Timing Chain Damper.

I edited my original post to correct my mistake.

RapidC84B

Was it an OEM 2001+ guibo? I've heard lots of bad stories about poly ones going to crap or junk aftermarket ones going to crap, but not the OEM rubber ones. I pulled mine apart with the intention of replacing it all, but it literally looked perfect.

6SPEEDZ

I had a 2002 12mm let go on me at Autobahn a few years ago. Yes it was the OEM rubber guibo's. I would rather replace what looks like perfectly good one's than have to buy a torque tube. New cost is in the thousands used they are not bad but you still have to find them.

geerookie

Yes it was an '01 and later Guibo. The damage or break down is internal. You cannot see it. If you can see it you are either really lucky or too late


Some Examples Below:

FASTFATBOY

I would do a leak down test on that engine. If it passes leave it alone.

Do a trunion upgrade, PAC 1518 springs and run it.

When I bought my Z28 it had 188,000 miles on it. It had oil leaks so I pulled it and built it into a LS6. I did three weekends with it like that.

txoutlaw55

The 01 Z is a fantastic car. I've been autocrossing my 01 since 02. It's pretty much stock. I run it with sticky tires. I've had to replace the torque tube couplers and the plastic sway bar end links. The most important thing to watch on your 01 is oil consumption. If you spend a lot of time in high RPMs, pour a little extra oil in before you race it.

One other pointer--the 01 has a different cam profile than the later models. I shift mine around 5500 RPMs--it doesn't really make power beyond that point.

Have a good time with it!

RapidC84B

Is that what you tell all your competitors?

txoutlaw55

Shhhhhh...