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lifters/rocker arms

Edmond

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Aug 1, 2001
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Louisiana
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2003 Z06
I can hear clicking but only in cold weather. Has anyone else had this kind of experience before. Someone told me that it probably needs a rocker arm adjustment. A different person told me that the lifters need to be tightened.

Any feedback is appreciated.
 

Ken

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Jan 30, 2001
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Hermosa Beach, CA
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1987 Z51 Silver Coupe
Are you sure it's not just your injectors cycling? It fooled me when I first got a fuel injected engine. ;)

_ken :w
 

69MyWay

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Jul 3, 2001
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Auburndale, Florida
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1969 Killer Shark
It could be several things including a loose or cracked exhaust manifold that will seal up as the heat expands the metal/gasket.
 

Edmond

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69,

Yes, I have also considered that as a problem, but haven't really looked into it yet. I figure that if I were to diagnose the problem, I would have to fix it also and that could mean shutting the car down for a week (at the pace I work at).

But thank you both for your advice, I will look into both matters.
 

vigman

Motor head!!!!
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Feb 13, 2001
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Valencia, CA,USA
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88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Use the stethoscope trick

Buy a mechanics stethoscope and probe around to locate the source of the clicking. Im betting injectors too! But you never know, the tool is useful for finding such gremlins.

Or you could cheap out and use a long screwdriver, put it on the part.. stick your ear on the handle and listen. Usually you get an earful of slime from the handle, but it works too.

Mike
 

trrgod

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Feb 24, 2001
Messages
92
Location
Santa Monica CA
Corvette
1989 Black Coupe 6 sp
BullWinkle- You have hydralic lifters if you car is stock. There is no adjustment usless something is way out of spec. If that were true the noise would happen all the time.
I agree with both Ken and vigman, check out the noise from the injectors first. Good luck.
 

kfehling

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May 8, 2001
Messages
83
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Santa Rosa, CA
Corvette
1996 Collector Edition
I too have notice a "tapping" sound from my 1996 LT1 upon start up on cold mornings. It is definitely related to engine speed as it happens faster with increasing speeds. I always assumed it was the valves making a little noise until the car warmed up and have not worried about it other than keeping it under 2K RPM until it stops. Is this similar to your problem and should I be worried about it?
 

Edmond

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2003 Z06
I'd say that it's more of a nuisance than a problem. I haven't noticed any difference in driveability. But since I'm doing some mods before this summer, I would like the car to be as mechanically sound as possible.

Mechanics stethoscope? Where can I pick one of those up at? Would Pep Boys have them?
 

Edmond

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Louisiana
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2003 Z06
injectors cycling

What exactly does that mean?
Is that good/bad?
 
N

Nathan Plemons

Guest
Something you might consider is oil. What type and weight of oil are you running, how often do you drive the cars. If hydraulic lifters sit too long and drain down they will essentially loosen up the rocker arms until the lifters pump back up.

If for some reason your oil isn't getting pumped through the engine very quickly you will have the same results. When you say cold, how cold? Like 70 degrees cold or 20 degrees cold?

My dad has a 1946 Chevrolet pickup that sits for long periods of time. If it's extremely cold and the oil thickens up, or it's been sitting a while you can hear the rockers ticking for about a minute or so until the oil starts to really flow well.

A friend of mine had the exact same problem with his Ford Ranger. I've seen that this problem seems to increase more with cheap non synthetic oil. My dad uses pennzoil in the truck, and my friend used havoline in his ranger. My theory is that this oil just thickens up and doesn't flow as well.
 

kfehling

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Messages
83
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Santa Rosa, CA
Corvette
1996 Collector Edition
Nathan,

In my instance, cold means less than 40F ambient temp. I use only Mobile 1 10W-30 and often my car will sit for a week before I drive it. However, it is only on the cold mornings that I hear this sound.
 
N

Nathan Plemons

Guest
Hmm, I use Mobil 10w30 as well and haven't ever noticed any extra noise, but it could do it, my car rarely gets that cold as I park it in a heated garage.

I have parked it outside in very cold weather, but it's usually just one night. I've never noticed anything unusual, but my exhaust is VERY loud, it could easily cover up small rocker noise, plus roller rockers make a little more noise anyway.

I don't know man, if it's not oill then I don't know what to tell you. Good luck.

Hmm, actually I just noticed you said it was a 96. Is it a manual? If so then it's an LT4 which also happens to have roller rockers. They CAN actually loosen up, I've had to retighten mine a time or two. I think the OEM LT4 rockers didn't really have an adjustment, so there is probably just a torque spec. Might not hurt to pull the valve covers and retorque all the rockers.

Man I need to read more carefully. I just noticed you said 96 LT1, that makes it an auto, and also takes out the roller rockers. Sorry.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Well the oil thing COULD be part of the problem

But living in sunny So Cal the temp NEVER get's that low (hahahahahahahaha)

Every body I know runs lighter oil than me
20-50 GTX and the normal vettes use 10-30
or Mobil 1.. and I know mines to heavy BUT I never get any weird start up noises.


Get the scope..listen..and the answer will become clearer.


Mike
 

Edmond

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Location
Louisiana
Corvette
2003 Z06
I used 5W-30 Mobil. I use a Fram extra guard filter.

It only happens in that cold weather and when I say cold, that's usually 40 and under.
 
N

Nathan Plemons

Guest
I don't think the filter is your problem, but fram filters are supposed to be cheaply made. You might want to check out this website for some good info.

http://www.scuderiaciriani.com/rx7/oil_filter_study/

I've never had a problem with a fram filter but I have heard of some people that have had the filter come apart on them.
 

Edmond

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Joined
Aug 1, 2001
Messages
5,218
Location
Louisiana
Corvette
2003 Z06
I guess I'm going with the Mobil or AC Delco next time. I was going to go with the Mobil, but they didn't have them at Wal Mart and I didn't feel like driving 15 minutes to the store I usually go to.

Thanks for that article
 
B

Burnnrubber

Guest
Good Job Nathan

Hello,
Just wanted to jump in & say thanks for the great hyperlink on oil filters, I had always heard bad things about Fram, now I know why. Thanks again...
 
F

Fastvette86

Guest
I doubt that your noise is coming from the injectors. If injectors are noisy, then they'll usually stay noisy no matter the temp. When I modified my Vette I got some $450 blueprinted and flow matched injectors that make it sound like a sewing machine! Lot's of folks are amazed at how loud they are, but with a stethoscope it's obvious it's the injectors. I'd change them out, but my Vette just runs too well to bother, and I couldn't get TPIS to take them back. Can't hardly stand not to drive it!

The only time I've ever experienced a tapping sound that goes away after warmup is with forged pistons. They'll slap until they expand, not a problem it you take it easy until they're hot. Does any one know if '88s and later have forged pistons? Was your Vette rebuilt? Maybe forged pistons were used.

Get a stethoscope, you'll really wonder how you lived without one.

Had a Fram filter let go in my son's '70 Camero with a brand new Vortec engine on I5 just north of Bakersfield, CA while taking him to college last summer. It was 105 F that day and he was crusing at 100 mph and we were still getting passed! It was just like blowing a engine in NASCAR! Got it shutdown before the oil pressure went down. It blew out the O ring seal and sprayed on the header - exciting!!! Will never use a fram again.

Dennis
 

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