Engine knock
Thread Starter
3rd Gear
Joined: Aug 2024
Posts: 3
Likes: 0
From: NORTH CAROLINA
Engine knock
Bought a 1978 Corvette 4 speed with 383 stroker engine. It seems to want to keep running when you turn the key off. I hate having to let out the clutch to kill the engine. Is there anything I can do differently? Non-ethanol gas? High octane gas? Any suggestion is welcomed.
Burning Brakes
Joined: Dec 2017
Posts: 1,043
Likes: 414
2023 C3 of the Year Finalist - Modified
Engine run on, or “dieseling” can be caused by overly retarded timing, or carbon build up on top of the pistons.
I would start with a simple timing verification.
how many degrees are you running at idle?
I would start with a simple timing verification.
how many degrees are you running at idle?
Thread Starter
3rd Gear
Joined: Aug 2024
Posts: 3
Likes: 0
From: NORTH CAROLINA
Thx
Burning Brakes
Joined: Dec 2017
Posts: 1,043
Likes: 414
2023 C3 of the Year Finalist - Modified
2. connect positive and neg clips to back of alternator, thus provides power to timing light.
3. Place plug clamp over spark plug wire #1.
4. Locate distributor, locate vacuum advance can. Disconnect hose from carb to vac advance can. Plug end of hose with a screwdriver or pencil or something.
5. make sure all wires clear of rotating parts, start car.
6. direct timing gun to balancer and read number off timing tab.
I’m sure there’s a YouTube video that shows everything better than I typed.
This may cost $30 and not be the issue. But if it is, very easy to address.
As headsUP mentioned, it could be related to the carb
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
7 Bolt-On Upgrades From Extreme Online Store to Level Up Your C6 Corvette
Pouria Savadkouei
How Likely Are These Five 2027 Corvette Rumors to Be True?
Brett Foote
9 Best Corvettes You Can Buy for Half Price (& 1 You Should NEVER Buy!)
Joe Kucinski
8 Very Best Corvettes of Amelia Island 2026
Joe Kucinski
Top 10 WORST Corvette Engineering Failures of All Time!
Joe Kucinski
10 Records the C8 Corvette Generation Has SMASHED (& 1 Glaring Failure)
Joe Kucinski
7 Wildest Corvette Concepts Ever Made
Brett Foote
Drifting
Joined: Oct 2024
Posts: 1,656
Likes: 383
From: Toronto, Ontario
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
Safety Car
Joined: Nov 2023
Posts: 3,662
Likes: 755
2025 c3 ('74-'82) of the Year Finalist - Unmodified
Easy guys….new member asking for help. This is why many join the forum so they can learn.
To the OP, welcome aboard and there are many who will help you with your questions.
To the OP, welcome aboard and there are many who will help you with your questions.
Safety Car
Joined: Nov 2023
Posts: 3,662
Likes: 755
2025 c3 ('74-'82) of the Year Finalist - Unmodified
If not running premium fuel, with a 383 stroker, it most likely has a higher compression ratio and would require premium fuel vs a lower octane fuel. This is probably unrelated to your dieseling issue, but your engine will thank you.
Race Director
Joined: Mar 2017
Posts: 11,710
Likes: 4,363
From: Virginia
Tech Contributor
Joined: Jun 2004
Posts: 20,659
Likes: 953
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Bought a 1978 Corvette 4 speed with 383 stroker engine. It seems to want to keep running when you turn the key off. I hate having to let out the clutch to kill the engine. Is there anything I can do differently? Non-ethanol gas? High octane gas? Any suggestion is welcomed.