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Tech Tips :: C3 Related Tech Tips :: ZZ4 engine Swap FAQ

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ZZ4 installation on a 1971 Corvette I have decided to write this because of the numerous posts that always come up on Corvette Forum. Your installation may vary due to options, transmission and year of your car so this is a very basic installation paper. ZZ4 Configuration: The engine itself comes with everything you need for installation but there are some things that should be known about the engine configuration so you can plan accordingly. You can call Salle Chevrolet at 1-200-545-0048 or visit www.sallee-chevrolet.com and they can custom build a ZZ4 based engine for your application. Here is how the engine is configured if you buy it stock: Part Number: 24502609 (ZZ4) Displacement: 5.7-liter(350 c.i.) Bore/Stroke: 4.00"x3.48" Engine Block: 10105123 Four Bolt Main, Cast Iron Compression Ratio: 10:1 Pistons: High silicon aluminum piston with offset pins, 10159436. Crankshaft: 12556307 Forged Steel Connecting Rods: 10108688 PM rods Camshaft: Hydraulic roller tappet (#10185071) Valve Lift (Intake/Exhaust):.474"/.510" Duration (Intake/Exhaust): 208°/221° @ .050" tappet lift Valve Lash (Intake/Exhaust):Zero/Zero Cylinder Heads: Aluminum, 58cc chambers, 12556463. Valve Diameter (Intake/Exhaust):1.94"/1.50" Valve Springs: LT4 chrome silicon, 12551483. Rocker Arm Ratio: 1.5:1, 10089648 Distributor: HEI with centrifugal and vacuum advance, 1104067. Spark Plugs: MR43LTS Gap .045, AC FR5LS Gap .035, Rapid Fire #5 Gap .045. Fuel Requirement: Unleaded Premium 92 Octane Ignition Timing: 12° BTDC @ 800 RPM, 36° total @ 3,200 RPM with vacuum advance disconnected. Max. Rec. RPM: 5800 rpm Technical Notes: Carburetor, spark plug wires, starter, oil filter and oil filter adapter, and exhaust manifolds not included. Distributor P/N 1104067 or melonized distributor gear P/N 10456413 must be used on all crate engines with steel camshafts. In the notes section you will notice what is not included with the engine. This section will explain them in more details. Carburetor – I used my Q-jet. I guess its up to you to figure out what you want. My Q-jet works great. Spark plug wires – I used MSD’s 8.5mm superconductor wires. I also changed my distributor to a MSD tach drive unit (P/N 8572) and a 6AL ignition box (P/N 6420) because my tach is driven off the distributor and I didn’t want to use my old points. 75 and later can use the HEI unit that comes with the engine and still have a functioning tach. Starter – I used the one off my old 350. A lot of people say you should use a gear reduction starter but like most of us, I was on a budget and couldn’t afford one. After a year the starter works fine and I haven’t had any problems with it yet. My starter is a lifetime warranty unit form Pep Boys so again, like the carburetor, it’s your call. Oil filter and oil filter adaptor – I used the oil filter adaptor off my old engine. Two bolts hold it on. Very easy to change over and I haven’t had any problems with it. I use the PF25A filter. Exhaust manifolds – You can use your manifolds if you want but keep in mind that the heads on the ZZ4 have “D” shaped exhaust ports and they are a little higher that the old stock cast iron heads so you may have to tweak your exhaust system a little if you use the stock manifolds. I don’t recommend using Ram Horn Manifolds because you are going to restrict breathing and hurt performance a little. I went with Headman Headers that have “D” shaped tubes. They are full length with 3” collectors but have the shorty design so clearance is not a problem. I got them from Jim Pace www.paceparts.com and you can get them painted or Ceramic coated. Other considerations: If you have a manual transmission you cannot use your old flywheel. The ZZ4 has the new style block with the one-piece rear main seal therefore the crank bolt pattern is smaller (3.0” compared to 3.58” on the old style cranks). Depending on your car and which transmission it came with, you need to figure out which flywheel you need. Flywheels with two different diameters are used on Chevrolet small-block V8, big-block V8, and V6/90° engines. Large flywheels are 14" in diameter, and have 168 teeth on the starter ring gear. Small diameter flywheels are 12-3/4" in diameter and have 153 teeth on the starter ring gear. The difference in flywheel diameters requires two distinct starter housings. Starter noses used with large diameter flywheels have two offset bolt holes; starters for small flywheels have two bolt holes which are parallel to the back of the block. Most Chevrolet blocks are drilled for both types of starters. If you are changing the diameter of your Chevrolet's flywheel, you can convert your present starter to fit the new flywheel by installing the appropriate starter nose, starter motor housing, found within each engine classification. This is not an issue if you have an automatic because the engine comes with a flexplate but you will have to note which starter nose you have and change it accordingly. I used the 14” 168 tooth flywheel GM P/N 10105832. Temperature sensors – The ZZ4’s head has a small diameter temperature sensor port between #1 and # 3 cylinders. I know the older small blocks used a larger diameter sensor at this location. I tried 3 different sensors and all three were not calibrated to my gauge. I decided to use my old sensor and there is a port in the intake manifold that is the large diameter on the front left side of the manifold right next to the thermostat housing. It is a little tight but it will clear the upper radiator hose by about 1/8th of an inch. This area of the engine runs 10o to 15o cooler that the head locations so keep this in mind if you choose to put your temp sensor at this location. Water Pump – This is the biggest question most people have about the ZZ4 swap. This is really not a big deal and there are three ways to remedy the problem. 1. Use your old water pump. It will work and all you have to do is grind down one of the timing chain cover bolts to make it fit correctly. Test fit your old pump and you will get the idea. It’s easy and doesn’t take a lot of time. 2. Get a new pump either aluminum or cast iron. I went this route and bought an Edelbrock aluminum water pump. If you do this you still have to grind the timing chain cover bolt. 3. Change the timing chain cover to the old style. I don’t recommend this as it could induce an oil leak on your brand new engine. Why risk it. This engine was dyno run at the factory and is check for quality and leaks before shipment. Fuel pump – I used a stock replacement fuel pump (new) and have not had any problems with it. My car has the fuel return line to the tank so I retained this feature. Motor Mounts – I went with Energy Suspensions Poly locking mounts. I like them and with the 405lb/ft of torque this engine puts out if the mount fails then it will keep your fan and accessories from hitting stuff. One point of advice – I installed mine with the transmission installed on the engine. If you didn’t take the transmission out of the car that’s fine. I just found it easier to do it as one unit. I also used all new hoses and belts. GM's Recommended Crate Engine Start-up Procedure 1) Safety first! If the car is on the ground, be sure the emergency brake is set, the wheels are chocked, and the transmission cannot fall out of gear. 2) Be sure to check the oil level in the engine and prime the oil system. 3) Run the engine between 2,000 and 2,5000 RPM's, with no-load on the engine for the first 30 min. 4) Adjust the distributor timing roughly by hand for a quick start up and smoothest idle possible. 5) Adjust the carburetor settings, if necessary. 6) After the first 30 minutes of the engine running, set the ignition timing according to the timing specifications. 7) Drive the vehicle with varying speeds and loads on the engine for the first 30 miles. Be sure not to use a lot of throttle of high RPM. 8) Run five or six medium-throttle accelerations to about 5,000 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH. 9) Run a couple hard-throttle accelerations up to about 5000 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH. 10) Change the oil and filter with recommended oil (10w30SG in most cases) and filter. 11) Drive the next 500 miles normally, without high RPM's (below 5,000 RPM), hard use, or extended periods of high loading. 12) Change oil and filter again. 13) Your engine is now ready for many happy cruising miles! Engine Oil Supplement P/N 1052367 can be used any time during the life of the engine.