ZZ4 Start up Procedure

[Bill75]

I did a few searches for an answer to this and couldn't find anything, sorry if I missed it.

I'm getting some conflicting info on the proper method to do the first start-up on this engine. One GM dealer said that all the ZZ engines must be started and run for 30 minutes at 2500-3000 rpm as a break in step EXCEPT the ZZ4 engine. Reason being it has roller tappets and it doesn't require the cam break in. Other GM sites just say engines with flat tappets must be started initially as I just mentioned, they don't specifically say the ZZ4 is an exception. I emailed Scogging Dickey a few days ago but no reply yet.

I know I'm far from the first guy to do this and would appreciate some good info.

Thanks

 

[brandywine]

I'll take the first shot at this. When the ZZ4 was installed in my vette, all that was done to break the cam and lifters in was to fire the motor up and run it at a fast idle (1500-2000rpm) for the first 20 minutes. You DON'T want to fire the motor up and just let it run at a slow idle (500 -1000 rpm). Mine's run fine ever since...

 

[Bill75]

I'll take the first shot at this. When the ZZ4 was installed in my vette, all that was done to break the cam and lifters in was to fire the motor up and run it at a fast idle (1500-2000rpm) for the first 20 minutes. You DON'T want to fire the motor up and just let it run at a slow idle (500 -1000 rpm). Mine's run fine ever since...

Hi Brandywine,

The header folks want the engine run for 3 minutes or so then let them cool then run it a couple of more times like that to set the ceramic I guess. They tell me if you don't there could be some spots that loose their shine, especially in the corners where they get the hotest. So it looks like I should start this with the old exhaust system until the cam and lifters are broken in, then switch over I guess. Did you go thru this header deal also??

Bill

 

[yellow77]

I have a ZZ3, less compression than a ZZ4 but otherwise identical. The engine is a roller motor and hence the cam and lifters do not need a break in period. Treat it carefully for 500 miles then drive it like you stole it

 

[Jack]

The roller cam & roller lifters DO NOT need any "special" breakin (i.e. 20-30 min @ 2500-3000 rpm). Flat tappet setups NEED breakin for 20-30 min @ 2500-3000 rpm ... but not ZZ4. If your timing is not dead on correct it can-will turn new headers' color real quick ... within a minute. Just prior to first start ... disconnect power to dist and crank motor additional 30 seconds AFTER you see at least 30psi OP on gage. Suggest petroleum oil for one hour then change O&F w/ petro again ... go out & do a hard pull under load to about 4K rpm then let off & coast ... repeat 5-6 more times ... this seats rings. Keep petro in it for 500 hard or 1000 easy miles & change O&F ... then full synthetic.
JACK:gap

 

[Bill75]

Thanks yellow77 and Jack......sounds like a plan! I guess I'll remove the headers and use the old manifolds for the break in/tune up then change them out just to be safe. I just love exhaust work .