Forged pistons
Thread Starter
Racer
Joined: Sep 2003
Posts: 275
Likes: 0
From: West Monroe La.
Forged pistons
I would like to hear from people who have used forged pistons in a lt1 and had any problem with the greater clearance of the forged ones over the hyper. ones being affected by the knock sensors. I am building a 383, and just got to wondering about the piston slap with forged piston when they are cold, and if it might trigger the knock sensors. Any experiences with this would be helpful. Thanks, Tom
Thread Starter
Racer
Joined: Sep 2003
Posts: 275
Likes: 0
From: West Monroe La.
Well, I don't know how I got this in the C6 section. It's supposed to be in the C4 area, and I don't know how to move it. Sorry, but if any of you could help, I'd be glad to hear from you. Tom
Drifting
Joined: Nov 2002
Posts: 1,651
Likes: 125
From: laguna niguel ca
I've got a forged 427 in my C6, with diamond forged pitons in at .0055 clearence. If there is any piston noise it's gone soon after start up, and you don't hammer the car when it's cold anyway. At least I don't. So the knock sensor concern isn't really an issue. Don't worry about it no matter what engine your talking about
Racer
Joined: May 2005
Posts: 374
Likes: 0
From: Springhill Louisiana
...
I would like to hear from people who have used forged pistons in a lt1 and had any problem with the greater clearance of the forged ones over the hyper. ones being affected by the knock sensors. I am building a 383, and just got to wondering about the piston slap with forged piston when they are cold, and if it might trigger the knock sensors. Any experiences with this would be helpful. Thanks, Tom
Race Director
Joined: Jan 2006
Posts: 18,396
Likes: 169
I have an LT4 in my Porsche 944 conversion, and definitely install a LT4 knock sensor. I was using a LT1 sensor and experiencing ignition retard from the noise the aftermarket cam and lifters were making, Swapped the sensor to LT4, and it completely eliminated the problem. Good luck.
Racer
Joined: Dec 2003
Posts: 454
Likes: 0
From: Double Oak TX
I have an LT4 in my Porsche 944 conversion, and definitely install a LT4 knock sensor. I was using a LT1 sensor and experiencing ignition retard from the noise the aftermarket cam and lifters were making, Swapped the sensor to LT4, and it completely eliminated the problem. Good luck.
You can also program the computer regarding retard but I own tuning software keeping the stock setting.
The only problem you have is posting in the wrong section.
Melting Slicks
Joined: Feb 2004
Posts: 3,307
Likes: 110
From: Tucson AZ
You will never detect the forged piston "slapping". Also, the ECU is not even looking at knock until the engine is up to minimum temp and goes into high gear. It will then advance timing just over the knock point, then retard it just under.
I wouldn't even consider a cast piston in a serious engine build. Some of the newer hyperutectic pistons made be Ok, but you cannot go wrong with a good forged piston.
I wouldn't even consider a cast piston in a serious engine build. Some of the newer hyperutectic pistons made be Ok, but you cannot go wrong with a good forged piston.
CF Senior Member
Joined: Feb 2006
Posts: 23,313
Likes: 25
From: Tucson Arizona
You will never detect the forged piston "slapping". Also, the ECU is not even looking at knock until the engine is up to minimum temp and goes into high gear. It will then advance timing just over the knock point, then retard it just under.
I wouldn't even consider a cast piston in a serious engine build. Some of the newer hyperutectic pistons made be Ok, but you cannot go wrong with a good forged piston.
I wouldn't even consider a cast piston in a serious engine build. Some of the newer hyperutectic pistons made be Ok, but you cannot go wrong with a good forged piston.
No problems with my LPE 403 motor. 
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