B
brit_trader2003
Guest
Hi folks from the UK, I need help.
I have a 69 with a Custom built Big Block engine. After a couple of months since the engine has been tuned the engine develops excessive vibration when idling. This has happened 3 times subsequent to the Carb being retuned within 500 miles.
The engine is new, but run in. It is a rebored 454 with forged steel domed pistons to give a Compression Ratio of 9.5:1, Edelbrock Performer high performance Hydraulic Camshaft and Intake Manifold. Holley 750 CFM Carb with Vacuum Secondaries, Hooker Headers with Side Pipes, Hood Scoop for Cold Air Induction. I have not tested the engine but it was designed to produce 450bhp at the wheels and 500 ft/lbs torque
The problem is that within 500 miles of the carb being tuned the vibration becomes bad when idling. It rocks the car. I have had the carb retuned 3 times and the problem goes away only to return. When tuned the vibration is much reduced and the engine sounds sweet. The idling speed is correct throughout just the vibration. Once moving the engine performs as normal (mind you it does vibrate all the time plus with the sidepipes it is LOUD)
I have done some research and I have a theory that the Big Block engine vibrates moving the Idling Mixture screws which then puts the Idling out of balance, more vibration and the problem gets worse.
I am guessing that the Edelbrock Performer Camshaft makes the vibration problem worse being a 'wild cam'.
Has anybody else had this problem and what is the solution ? It is tedious putting the car into a garage every 2 months so do I have to reset the Carb when the problem manifests itself, if so how do you do it. I have a Haynes Manual for Holley Carbs but it is not as clear as I would like.
Any advice or help would be very much appreciated. Unfortunately high performance Big Block expertise is a little rare in the UK.
I have a 69 with a Custom built Big Block engine. After a couple of months since the engine has been tuned the engine develops excessive vibration when idling. This has happened 3 times subsequent to the Carb being retuned within 500 miles.
The engine is new, but run in. It is a rebored 454 with forged steel domed pistons to give a Compression Ratio of 9.5:1, Edelbrock Performer high performance Hydraulic Camshaft and Intake Manifold. Holley 750 CFM Carb with Vacuum Secondaries, Hooker Headers with Side Pipes, Hood Scoop for Cold Air Induction. I have not tested the engine but it was designed to produce 450bhp at the wheels and 500 ft/lbs torque
The problem is that within 500 miles of the carb being tuned the vibration becomes bad when idling. It rocks the car. I have had the carb retuned 3 times and the problem goes away only to return. When tuned the vibration is much reduced and the engine sounds sweet. The idling speed is correct throughout just the vibration. Once moving the engine performs as normal (mind you it does vibrate all the time plus with the sidepipes it is LOUD)
I have done some research and I have a theory that the Big Block engine vibrates moving the Idling Mixture screws which then puts the Idling out of balance, more vibration and the problem gets worse.
I am guessing that the Edelbrock Performer Camshaft makes the vibration problem worse being a 'wild cam'.
Has anybody else had this problem and what is the solution ? It is tedious putting the car into a garage every 2 months so do I have to reset the Carb when the problem manifests itself, if so how do you do it. I have a Haynes Manual for Holley Carbs but it is not as clear as I would like.
Any advice or help would be very much appreciated. Unfortunately high performance Big Block expertise is a little rare in the UK.