[Z06] 02 Z weirdness
Thread Starter
Pro
Joined: Feb 2009
Posts: 587
Likes: 0
From: Columbus Ohio
02 Z weirdness
Took the car out for a short run to the store today. On the way I got on it a bit, and it felt great as usual. I ran through 1-2-3 pretty hard ... might have touched the limiter in 1st for an instant. Traction Control / AH were on. When I restarted it to head home the car felt like it was idling a little rough as it sometimes does on a hot restart with just a short period of sitting. On the drive back it ran like crap. I didn't hear any bad noises, no knock etc. Oil pressure and temps are normal, I checked codes when I got it home ... nothing. Any ideas ?
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
Check the posts on broken valve springs on 02/03 Z's, LS 6 motors. Don't try and restart. Pull off the valve covers and inspect for broken spring. Give it a real good eyeballing, w/ extra lighting. Good luck.
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
I see by your profile that you have a different set of heads along w/ quite a few of real great mods. I'd still start w/ spring check out .. If all are fine, might pull the rockers & check for bent push rods. Good luck.
Thread Starter
Pro
Joined: Feb 2009
Posts: 587
Likes: 0
From: Columbus Ohio
Found the problem. I pulled the passenger side valve cover. Number 4 intake rocker arm was loose ! Loose enough that I was able to pull the push rod out and take a look at it. It was fine on both ends, no damage, not bent rubbed at either tip or anything like that. Strange.
Instructor
Joined: Sep 2009
Posts: 201
Likes: 0
From: Rancho cordva Ca
Found the problem. I pulled the passenger side valve cover. Number 4 intake rocker arm was loose ! Loose enough that I was able to pull the push rod out and take a look at it. It was fine on both ends, no damage, not bent rubbed at either tip or anything like that. Strange.
Thread Starter
Pro
Joined: Feb 2009
Posts: 587
Likes: 0
From: Columbus Ohio
I dont see any damage to the valve spring at all. Is it possible the rocker bolt wasnt tightened properly and came loose ? I'm looking at the rocker arm now, I was expecting to find that it puked the needle bearings but it appears to be fine too. I am off to double check the spring.
Thanks for the replies.
Thanks for the replies.
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
If you found one rocker bolt loose, more than likely there are more. I think you may have have a broken spring.Look at that spring real good w extreme lighting. Let us know what you find.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Pro
Joined: Feb 2009
Posts: 587
Likes: 0
From: Columbus Ohio
Spring is fine and the rocker and push rod show no damage. I took off another rocker and compared the two. No difference, the rocker is fine. Checked torque on all the rockers on the head they were good, #4 intake was the only loose one. Car ran fine on the test drive. Tomorrow after work I'll pull the drivers side valve cover and check those.
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
Wow! You may have dodged a bullet. If that's all that was wrong, that would be great. If the other side checks out fine too, you may want to get ahold of respected machanic and see if you need to apply some locktite to them. Do you know how long the heads have been on the car?
Thread Starter
Pro
Joined: Feb 2009
Posts: 587
Likes: 0
From: Columbus Ohio
Engine work was done by the previous owner back in August of 2007. I've owned the car since June of this year. I did find a few little crumbs of red Loctite on the bolt that was loose. I looked at the spring from every angle I could with bright lighting but I'm wondering now if I should take it out to inspect it just to be sure. I did take a brief test ride and the car ran just as good as before, I should probably pull the passenger side cover again to TRIPLE check the spring. 
Thread Starter
Pro
Joined: Feb 2009
Posts: 587
Likes: 0
From: Columbus Ohio
Well ... I removed both springs on #4 and inspected them closely, thankfully they are fine. I checked torque on all 16 rockers and only #4 intake was loose. I guess I did just dodge the proverbial bullet and I need to add checking the rockers to my preventative maintainance list, probably once a season should be sufficient. Thanks again for the replies and suggestions.
B
B
Last edited by blazer427X3; Oct 23, 2009 at 10:02 AM.
Racer
Joined: Dec 2006
Posts: 297
Likes: 0
rocker
I think you will find this is fairly common on aftermarket valvetrains. I had the same problem with a Austin Healy with a 327 and dart heads. I put Crane Roller Rockers on it and everyonce in a while one would loosen up and it ran like crap. I finally ended up just checking them every 3000 miles and that solved the problem. I know it is much harder with our Vettes but maybe worth it.
Racer
Joined: Jan 2009
Posts: 475
Likes: 0
Im interested in this also. I just recently bought an 02 cam/head Z06. Hey Blazer I noticed you live close to me Im in Marysville. I was hoping to be able to put some more miles on mine before the real nasty weather gets here.