new zz4 engine - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Buckman · 10-19-2005, 10:09 AM

Has any one put a new zz4 engine in their truck? How does it run and what fuel mileage do you get with it and with what gear ratio you use?

Dean · 10-19-2005, 11:15 AM

I bought three of these ZZ4 engines new. All three have unfortunately had problems. I'm probably one of the few that got bad ones. Still have one in my Blue K20 and it does well with the 4.11 gears and 35" tires. That one had defective valve springs, dropped valves and cracked the aluminum heads. GM finally owned up the the problem and fixed it. The 2nd one was in my other K20 when it had the same problem. GM fixed it also and I still have it on the shelf. I went back to more of a torque motor in that truck. I recently installed the third one (out of warranty by now

and it went about 10K before letting go. I was so frustrated with it that I haven't even tore it down yet. My guess is this one broke a piston or something. None of them have been abused.

I hope I have better luck with the 502 I'm getting ready to order.........no wonder I drive a toyota everday to work......

Buckman · 10-19-2005, 12:33 PM

Dean, sorry about the problems you had with the engines. sounds like I might be rebuilding the old 350. What kind of fuel mileage did you get out of them?

Dean · 10-19-2005, 01:54 PM

I have never really checked the mileage, but doesn't appear to be much different than any of my other 350s. I'm running it with an Eldebrock 1406, original exhaust manifolds, HEI and Borla mufflers. It isn't really a problem because you can wind it up, but they are not low end torque motors.

10-19-2005, 10:09 AM	#1
Buckman Registered User Join Date: Sep 2005 Location: bedford Indiana Posts: 70	new zz4 engine Has any one put a new zz4 engine in their truck? How does it run and what fuel mileage do you get with it and with what gear ratio you use?

10-19-2005, 11:15 AM	#2
Dean Senior Member Join Date: Jan 2000 Location: Cincinnati, Ohio Posts: 1,492	Re: new zz4 engine I bought three of these ZZ4 engines new. All three have unfortunately had problems. I'm probably one of the few that got bad ones. Still have one in my Blue K20 and it does well with the 4.11 gears and 35" tires. That one had defective valve springs, dropped valves and cracked the aluminum heads. GM finally owned up the the problem and fixed it. The 2nd one was in my other K20 when it had the same problem. GM fixed it also and I still have it on the shelf. I went back to more of a torque motor in that truck. I recently installed the third one (out of warranty by now and it went about 10K before letting go. I was so frustrated with it that I haven't even tore it down yet. My guess is this one broke a piston or something. None of them have been abused. I hope I have better luck with the 502 I'm getting ready to order.........no wonder I drive a toyota everday to work......

10-19-2005, 12:33 PM	#3
Buckman Registered User Join Date: Sep 2005 Location: bedford Indiana Posts: 70	Re: new zz4 engine Dean, sorry about the problems you had with the engines. sounds like I might be rebuilding the old 350. What kind of fuel mileage did you get out of them?

10-19-2005, 01:54 PM	#4
Dean Senior Member Join Date: Jan 2000 Location: Cincinnati, Ohio Posts: 1,492	Re: new zz4 engine I have never really checked the mileage, but doesn't appear to be much different than any of my other 350s. I'm running it with an Eldebrock 1406, original exhaust manifolds, HEI and Borla mufflers. It isn't really a problem because you can wind it up, but they are not low end torque motors.



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