Knock in engine
Thread Starter
Heel & Toe
Joined: Jun 2006
Posts: 15
Likes: 0
Knock in engine
I have a question I hope someone can help me. When I started my vette after being in storage for the winter, there was a knock in the motor I drove it home & parked it. About a week later I started it and drove a few miles for gas it still knocked and ran terrible, on the way home it started to run better and the knock was gone I thought it was bad fuel. A week later I start it and the knocks back, I left it idle for about 10 minutes and it seemed to quite down, so I went for a drive and it ran bad. after it seemed to warm up more it seemed to run normal and no knock. I thought maybe a stuck valve. Any ideas?
My vette is a 1969/ 350.
Thank You,
John
My vette is a 1969/ 350.
Thank You,
John
Race Director
Joined: May 2006
Posts: 18,733
Likes: 2,582
After being in storage all winter did you change the oil and filter? Did you check the oil level to see if it is low ? Can you isolate where the noise is coming from, use a length of rubber hose to act as a stethoscope. What octane gas are you using?
Melting Slicks
Joined: Jul 2013
Posts: 3,237
Likes: 31
I have a question I hope someone can help me. When I started my vette after being in storage for the winter, there was a knock in the motor I drove it home & parked it. About a week later I started it and drove a few miles for gas it still knocked and ran terrible, on the way home it started to run better and the knock was gone I thought it was bad fuel. A week later I start it and the knocks back, I left it idle for about 10 minutes and it seemed to quite down, so I went for a drive and it ran bad. after it seemed to warm up more it seemed to run normal and no knock. I thought maybe a stuck valve. Any ideas?
My vette is a 1969/ 350.
Thank You,
John
My vette is a 1969/ 350.
Thank You,
John
I had the exact same problem. Weird fix which is not in the owners manual.
1: Start car
2: Open and close drivers door three times.
3: Turn radio off
4: In a clear voice scream loudly "Who's There?"
5: The irritating knock knock sound will go away.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I have a question I hope someone can help me. When I started my vette after being in storage for the winter, there was a knock in the motor I drove it home & parked it. About a week later I started it and drove a few miles for gas it still knocked and ran terrible, on the way home it started to run better and the knock was gone I thought it was bad fuel. A week later I start it and the knocks back, I left it idle for about 10 minutes and it seemed to quite down, so I went for a drive and it ran bad. after it seemed to warm up more it seemed to run normal and no knock. I thought maybe a stuck valve. Any ideas?
My vette is a 1969/ 350.
Thank You,
John
My vette is a 1969/ 350.
Thank You,
John
Try changing the oil.
Use a light wt synthetic oil. 0w40 mobil 1 if you need the zinc and this is a flat tappet engine.
0w20 or 0w30 Mobil 1 if not concerned about the zinc.
Mobil one has a lot of detergents in it and may unstick that lifter, also the 0wt will allow oil to get where it isn't getting now easier.
Le Mans Master
Joined: Aug 2005
Posts: 6,539
Likes: 1,973
From: Temple Terrace Florida
Stuck lifter
If it is a stuck lifter, do an oil change and add a quart of Marvel Mystery Oil in the crank case. Marvel has a high concentration of detergent in it. I have used it to unstick lifters on more than a few occasions. Jerry
