92 LT1 Engine noise when cold.
Thread Starter
Heel & Toe
Joined: Aug 2005
Posts: 17
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92 LT1 Engine noise when cold.
Okay I will try to give as much info on my problem as I can:
I have a 1992 LT1 Corvette. 144000 Miles. I only use 93 octane gas and synthetic oil (10w30). Auto trans. Runs great. When I first start the car after sitting all night I hear a faint knocking that appears to be coming from the low end. Car fires right up in a split second and runs out great. When engine warms up the noise goes away. The engine shows no signs of decreased power or other problems. No leaks, no rough idle, no coolant problems. No matter if warm or cold pulls strong and runs fast. But that little knock has me worried that I need to do something. Does anyone have any answers as to why It only occurs while cold and what it is? Synthetic oil has just been changed a few weeks ago. I have noticed this problem for about a month. Am I using wrong oil? wrong gas? or what?
Thanks
Gary
I have a 1992 LT1 Corvette. 144000 Miles. I only use 93 octane gas and synthetic oil (10w30). Auto trans. Runs great. When I first start the car after sitting all night I hear a faint knocking that appears to be coming from the low end. Car fires right up in a split second and runs out great. When engine warms up the noise goes away. The engine shows no signs of decreased power or other problems. No leaks, no rough idle, no coolant problems. No matter if warm or cold pulls strong and runs fast. But that little knock has me worried that I need to do something. Does anyone have any answers as to why It only occurs while cold and what it is? Synthetic oil has just been changed a few weeks ago. I have noticed this problem for about a month. Am I using wrong oil? wrong gas? or what?
Thanks
Gary
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Joined: Oct 2000
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From: Fort Knox, KY
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Are you sure you aren't hearing your injectors clicking? This is a common LT1 problem, particulary on '92 and '93 engines.
Race Director
Joined: Feb 2003
Posts: 11,671
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From: Lake Wylie SC
Originally Posted by onedef92
Are you sure you aren't hearing your injectors clicking? This is a common LT1 problem, particulary on '92 and '93 engines.
Race Director
Joined: May 2001
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How long does this noise happen? Is it just for a few seconds or is it until the car warms up? I've driven many cars with hydraulic roller lifters that will make a little noise at startup on account of the lifters bleeding down after sitting for a while. Usually it doesn't happen if it sits overnight but can happen if it sits for a week. It'll start up and make a bit of noise until the lifters pump up. If you give it a little bit of gas you can expidite the process by raising the oil pressure.
Pro
Joined: Aug 2005
Posts: 656
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From: Fort Worth TX
My 92 did the same thing, found 2 loose header bolts on the back of the pass side. It wouldnt make a sound if was hot, but as soon as it set over night id here the ticking.. Torqued all the header bolts, and no more tick.
Race Director
Joined: Nov 2002
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From: First to Sign Grumpy's Hat Only 53 miles from Hell
St. Jude Donor '06-'09-'10-'11
I've heard the same noise on my old high mileage Mercury and a buddies Mustang..... Piston slap.... Once the piston expands a little the noise would go away. On really cold mornings you would swear the motor was going to fall apart.
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Safety Car
Joined: Feb 1999
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From: Mexico Beach FL
Originally Posted by wzdads
I've heard the same noise on my old high mileage Mercury and a buddies Mustang..... Piston slap.... Once the piston expands a little the noise would go away. On really cold mornings you would swear the motor was going to fall apart.
My '92 LT1 has done that since new, it goes away in about two minutes.
Tom Piper
Safety Car
Joined: Feb 1999
Posts: 3,504
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From: Mexico Beach FL
Originally Posted by gdarst
If it is piston slap, is this harmful. Also is there anything I can do to help without a rebuild?
Gary
Gary
I consider this normal for "short skirt" pistons.
Tom Piper
