Went to my local track last night for the first time in 2 years and made 11 runs down the quarter (ended up with a 2nd place finish, too ). This is also the first time I have run 1.6 ratio roller rockers at the track. At the end of the night my valvetrain sounded like it was trashed. It sounded like every rocker was tapping. Can anyone tell me if this is normal or not? I've had these roller rockers on for almost 2 years and they have about 1000 miles on them now. I just did another lash adjustment/check 3 weeks ago and everything seemed normal. The preload is currently 1/4 turn over 0 lash. The engine is a 95 LT1 with less than 10,000 miles on it (dealer warranty replacement). The car just turned 26,000 miles. I'll copy the specs off my CarDomain page for additional info:

K&N cold air into home-built ram-air box
Ported MAF
Flowmaster exhaust
No cat....shhhhh!!!
BBK Underdrive
1.6 Roller Rockers
LT4 Hot-Cam (bye bye smooth idle)
LT4 knock sensor
Melling high pressure/high volume oil pump
AutoMeter NOS, Boost, A/F Ratio gauges
Gauge pod
160 degree thermostat
TPIS Adjustable fuel pressure regulator
Jegs fuel pressure gauge
Factory oil cooler
Custom Tuner CAT tuning (Thanks to: Rick Gifford A.K.A.: BaldTurboFreak)
3:73 Motive gears
Centerforce Dual Friction clutch
B&M Ripper shifter
CAGS (skip shift eliminator)
Mobil 1 everything
A/C PF35? Can't remember...it's the "truck filter" (gives me almost an extra quart of oil). With the oil cooler the filter hangs slightly below the oil pan...it's safe =)

Any info would be greatly appreciated.

Also....throughout the evening performance didn't seem to change. The car was obviously running consistant and I have a trophy to prove it! LOL

 

one possiblity ?

i've had a set of roller-rockers make a similar noise because there was too much side-to-side clearance in the roller fulcrum needle bearings
even though the Lash was zero for a Hydraulic Cam

 

The rockers seem tight although I have not made checks on a hot motor. I haven't had a chance to even start the car since Wednesday night to see how it runs cold. I'll try to run it tonight and see what happens.

 

lifters?

 

It would be possible but I never had this issue with the stamped steel rockers. It would also be odd for all of them to go at once without some other catastrophic failure within the engine.

*UPDATE*
I got home at a reasonable time tonight and started the car up. No noise from the passenger side bank and some tapping from the #1 cylinder area. Definitely not the same ammount of noise from Wednesday night. My guess it's a heat issue that's causing things to loosen up a bit.

While I was checking things out I also noticed that my NOS fogger nozzle was missing. The fittings look like there are pliar marks on them. So....now I'm REALLY [EDIT] irritated...really. At most I was only away from the car for about 15 minutes while my girlfriend and I went to get something to eat. The field was packed with people but I can only guess that bystanders thought that whoever did this assumed the thief was the owner doing some tuning between rounds. Now I'm stuck with a hole in my intake and no spare cash to replace this thing right now. I don't even remember my jetting sizes either. Oh well...lesson learned. From now on I guess I have to babysit my car or lock everything up just to go take a leak. Leaving the hood open to let things cool down between rounds is no longer an option. I hope whoever took it blows their motor.

 

RealZ28,
I can't think of to many things lower than a person messing with another mans ride. That is sad, just plain sad. Hopefully you'll figure out what jets were in there. And by the way, I checked out your web page, sweet car you've got there.

 

You said M1 everywhere, which M1 do you have in the motor? If M1 5w-30 or 10w-30 that might be the problem, those two specifically are too thin for the LT1 racing may have warmed the oil a bit more than normal and caused more audible proof of this. Try the 0w-40 or 5w-40 or another brands Xw-30, Castrol Syntec 0w-30 that says Made in Germany on the back lable is particularly good but hard to find.

 

I use 15w-50. I'm old school. I've always used thick oil in my motors. I also have a high volume/high pressure Melling oil pump installed. Throughout the night I didn't notice much change in oil pressure. The only odd things were the valvetrain noise and my idle shot up to 1400rpm .The car ran pretty good besides that.

It's actually sunny out today so I'm going to take the car out for a long cruise and see what happens. I just gotta plug the hole in my damm intake first

Z-RATED94- And by the way, I checked out your web page, sweet car you've got there.-Z-RATED94

Thanks man. It's been a long long project. I try to do a little something every winter when I have more time and a little extra cash. I'll try to get some more detailed pics of my cars up before the warm weather goes bye bye.

It's bad enough that I have to deal with thieves at my store but to have to deal with it on "fun night racing" is just rediculous. In my 12 years of racing at that track I have never had a problem like this nor have I ever heard of anyone having a similar problem. I guess us honest folks have to compensate for the jerkoffs out there. Some of the old-timers blame the new Import and Sport Compact class. I dunno. Proof is proof. Without it, it's just a guess. I actually enjoy some of the imports and they have become such a huge class that they benefit our track tremendously. On certain nights they make up over half of the field including domestic stock, modified stock, pro mod, bikes and sleds!

 

Nozzle hole in the intake will do that to your idle

 

It's plugged. Gotta get ahold of my TunerCAT buddy and have him see what's up.

 

I wiah you could have caught the scumbag in the act !!!

What is it with people?

 

Hold on. You're running an LT-4 Hot cam AND 1.6 rockers? Against what valve springs? Please tell me you upgraded your stock LT1 springs to the correct ones that go with that cam. If not, you found your problem. Stock springs ain't gonna keep up with an aggressive high lift cam. Mighta bent a few pushrods a little crooked at high RPMs or done some damage to the lifter guts.

Sorry to hear about the theft. I know that kinda stuff makes me so mad I could spit nails.

 

1.6's go with the Hot-cam. I installed the full kit. What has me confused is that this is a recent thing and it ONLY happens after a night at the track. The car runs fine now and any other time I run it.