Koop
Well-known member
- Joined
- Mar 16, 2005
- Messages
- 545
- Location
- Kalifornia
- Corvette
- YELLOW 69 modified GM Crate ZZ383, LS2 TBSS
I purchased and had a professional install a brand new ZZ383 GM Crate motor in my '69 Vette back in late 2004. My mechanic purchased the motor directly from the Chevy dealer, this is the version with the hypereutectic pistons, aluminum heads, roller cam etc... as seen in the GM catalog. I have the owners book, I saw it delivered, I saw it come out of the crate and all that good stuff.
Here is the out come.
It's now 2011 with about 7,500 miles on the motor, I'm driving down the road with my Dad in the passenger seat and an insane piston slap comes to life. The slap was so bad that I stopped immediately, put it on a flat bed and had it towed to the shop. The tech (the same Corvette specialist that has worked on my car for over 25 years) is something better than good, he is without question one of the best Corvette guys on the West Coast. The mechanic takes his time figuring out the knock (banging) before he tears down the engine, he didn't want to go in blind. It took a short amount of time but he narrowed it down to #5 cylinder. He looked in the top, he looked in the pan, he finally pulls the head. #5 piston is so loose that you can wiggle it back and forth and make it knock the sides of the block (there's the knock). The tolerance is so bad that # 5 actually got up high enough to crack the head. Fortunately, I did have it towed to the shop. I did stop it in time to prevent it from grinding the motor to death. It actually cracked the head while we were looking for what was wrong. Fortunately I can reuse the remaining parts, or at least the parts that aren't substandard crap.
This quality of this motor is such that I have to have the bottom end rebuilt, it needs new pistons (I'll get better stuff this time), the block will need to be bored, the cracked head repaired, the bearings are loose and sloppy and need replacement. I suppose I should have the cam measured to see how poor of a job was done on that product.
I broke the motor in properly, changed the oil often, warmed it up when cold, drove it twice a month. This isn't my first V8, I didn't mess it up. The builder did a horrible job. This Vette has been mine for 25 years, before that it was my Dad's, I've been driving this car for more than 30 years, before that I was a passenger from day 1. I know how to care for the car.
I bought the ZZ383 thinking I wouldn't have to mess with the motor for 20-30 years. I was wrong, now I get to eat the cost of an overhaul of a barely used GM factory crate motor.
Right now I'm not thrilled.
Here is the out come.
It's now 2011 with about 7,500 miles on the motor, I'm driving down the road with my Dad in the passenger seat and an insane piston slap comes to life. The slap was so bad that I stopped immediately, put it on a flat bed and had it towed to the shop. The tech (the same Corvette specialist that has worked on my car for over 25 years) is something better than good, he is without question one of the best Corvette guys on the West Coast. The mechanic takes his time figuring out the knock (banging) before he tears down the engine, he didn't want to go in blind. It took a short amount of time but he narrowed it down to #5 cylinder. He looked in the top, he looked in the pan, he finally pulls the head. #5 piston is so loose that you can wiggle it back and forth and make it knock the sides of the block (there's the knock). The tolerance is so bad that # 5 actually got up high enough to crack the head. Fortunately, I did have it towed to the shop. I did stop it in time to prevent it from grinding the motor to death. It actually cracked the head while we were looking for what was wrong. Fortunately I can reuse the remaining parts, or at least the parts that aren't substandard crap.
This quality of this motor is such that I have to have the bottom end rebuilt, it needs new pistons (I'll get better stuff this time), the block will need to be bored, the cracked head repaired, the bearings are loose and sloppy and need replacement. I suppose I should have the cam measured to see how poor of a job was done on that product.
I broke the motor in properly, changed the oil often, warmed it up when cold, drove it twice a month. This isn't my first V8, I didn't mess it up. The builder did a horrible job. This Vette has been mine for 25 years, before that it was my Dad's, I've been driving this car for more than 30 years, before that I was a passenger from day 1. I know how to care for the car.
I bought the ZZ383 thinking I wouldn't have to mess with the motor for 20-30 years. I was wrong, now I get to eat the cost of an overhaul of a barely used GM factory crate motor.
Right now I'm not thrilled.
4LT GS Roadster
