LT-4 internal engine noise

[Silver Vette]

Hi, just have a question to all who own a 96 LT-4. I have a knocking or rattle sound in my engine when it is cold and I first take off, it sounds kinda like a wrist pin rattle. It doesn't make this noise at an idle when it is cold, just when I take off and the engine RPM starts to climb. With in 5 minutes or so of the engine warming up the the rattle goes away. The rattle noise is not severe, but loud enough that I can here it with the windows closed taking off down the road.
Because the noise goes away as soon as the engine starts warming up, I wonder if it could be a cracked piston or just lifter noise? The engine is nice and clean inside and runs very well. I have owned this car for only two months, I have never had an LT-4 before so I am still getting use to the Lt-4's quirks.
One more question, I plan to eventually pull the engine out and do a general overhaul, I keep hearing about the LT-4 hot cam. Can some one give me information as to where I can purchase one of these along with the technical info. on it? I would like to bring my LT-4 up to 400 HP with out doing anything real major, can anyone tell me what minor modifications can be done to get 400 HP out of it and more torque?
Thanks,
Steve - Silver Vette

 

[JEFNLSA]

Hi,

Welcome to the CAC!

You can get the Hot Cam from GM Parts Direct for under $200. I highly recommend doing the "Extreme Duty" chain at the same time.

I'm sure my car is somewhere in the range you're seeking so my mods should give you an idea. Longtube headers are next on the list along w/ 4:10 gears.

Once you have the Hot Cam in, a good tune goes a long way. My car is finally runnin' like the animal it should be...

Cya,
Jeff

BTW...Not sure on the rattle thing, almost have to hear it.

 

[froggy47]

I found mine was sensitive to the oil filter used & oil change. I now stick with Delco oem filter & M1 10/30 oil. 5/30 if you are in a cold climate.

No start up noise since.

3 to 4 k oil chg interval.

 

[kwd1]

Hi,
you are describing 'piston slap'. It's a common problem on some GM motors. Some have it, some don't. Mine does. It's worse when it's cold outside. I've even heard that it is described in the GM service manual as not a service requiring problem.
Ken

 

[Vettelt193]

Hi, just have a question to all who own a 96 LT-4. I have a knocking or rattle sound in my engine when it is cold and I first take off, it sounds kinda like a wrist pin rattle. It doesn't make this noise at an idle when it is cold, just when I take off and the engine RPM starts to climb. With in 5 minutes or so of the engine warming up the the rattle goes away. The rattle noise is not severe, but loud enough that I can here it with the windows closed taking off down the road.
Because the noise goes away as soon as the engine starts warming up, I wonder if it could be a cracked piston or just lifter noise? The engine is nice and clean inside and runs very well. I have owned this car for only two months, I have never had an LT-4 before so I am still getting use to the Lt-4's quirks.
One more question, I plan to eventually pull the engine out and do a general overhaul, I keep hearing about the LT-4 hot cam. Can some one give me information as to where I can purchase one of these along with the technical info. on it? I would like to bring my LT-4 up to 400 HP with out doing anything real major, can anyone tell me what minor modifications can be done to get 400 HP out of it and more torque?
Thanks,
Steve - Silver Vette

how many miles do you have on the car?

 

[Silver Vette]

Hi, I have 80,000 miles on the car.

 

[redvette6spd]

A cat back, open the air box, long tube headers, adjustable fuel pressure regulator, Hot Cam, and a tune will get you over 400 hp