I am pretty sure that by now you are ready to turn the key and fire up the engine. Now take a deep breath and slowly walk away from the car. Yes, that’s right. Walk away. This may sound counter intuitive because you’re itching to get your LS-powered F-Body car on the road. However, the last thing you need is a half-cocked initial failure to set you back another month in your project. Clear your mind and relax. Then review the pre-start-up checklist and make sure everything has been done correctly.
This Tech Tip is From the Full Book, SWAP LS ENGINES INTO CAMAROS & FIREBIRDS: 1967-1981. For a comprehensive guide on this entire subject you can visit this link:
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You have transformed a common stock F-Body into a highperformance muscle car, and as such, you need to carefully inspect and monitor the systems during first start-up. If you have installed a new crate engine with a warranty or a freshly rebuilt engine pulled from a junkyard, you need to pay particular attention to the engine when it is started for the first time. If you have installed a used engine, it has run before; it should do so reliably now and you do not have to break it in.
First, you need to be alert and sharp so you can identify problems. You need to be prepared to shut the engine down immediately if a problem is discovered; you want to avoid doing any damage to it.
Be sure that all of the fluids are topped off. Make sure your oil pan is filled to capacity, which is 5 or 6 quarts. I recommend that you use actual break-in oil that contains ZDDP (such as Joe Gibbs “driven oil”). But before you actually fire up the engine, you should pre-lube it, so oil adequately coats all internal surfaces, including rocker arms, lifters, and main bearings.
If you don’t pre-lube the engine, you take a chance on damaging vital components because some areas may be starved of oil while the oil pump works up to full pressure. You invested a tremendous amount of time and money in your LS swap so you don’t want to cut corners because it could result in a fatal mistake. Goodson sells an airpressurized pre-lube tank system (PN PL-40) used with an air compressor that sends oil through the engine, but it costs $200.
Another method is to build your own pre-luber and that’s easily done. You can install a small-block Chevy oil pump in a 5-gallon plastic bucket and puncture it with an electric drill so that oil is drawn out of the bucket, routed through the engine, and returned to the bucket. Doing it this way ensures the engine is properly protected for first start-up.
Be sure to mount an oil pressure gauge on the engine so that you can verify oil pressure when you’re circulating oil through the engine.
Safety should always be paramount with any automotive project and this one is no different. Make sure the transmission is in “Park” or “Neutral” (that is, not in gear) and that the emergency brake is set. You should also chock the wheels so the car cannot roll.
This section prepares you for many of the common missteps folks make when rushing into starting their car for the first time and somehow fouling it up. Worse yet is when you’ve invited everyone over for the grand unveiling. The first celebratory beers are cracked, you hear a fizzle when you turn the key, and look like a dope when you ask everyone at the party to, “just hang on . . .”
The vehicle anti-theft system (VATS) is pretty standard on most GM vehicles. This means that the key is matched to the lock cylinder; the engine does not run if they are not harmonized. The easiest fix is to have the company that reprogramed your ECM and wiring harness edit this part out of the code. If you have full power to the car but no starter engagement, you just might have a VATS problem.
Park/Neutral or Clutch Switch
The lockout for the clutch or park/neutral switch is in the wire bundle of the LS-engine ECM. If the computer doesn’t recognize that the clutch is depressed or that the car is in Park or Neutral, the computer does not send the signal to the starter of the vehicle. Double-check that this is installed properly or as a last resort (and I don’t recommend this) you can ground the wire from the ECM to fool it into believing that the switch is depressed. This is clearly a safety item and should be wired to engage this feature whenever possible.
The LS engine typically uses hydraulics to actuate the clutch. Most, if not all, of the setups around have a fully hydraulic clutch, meaning the system uses a master and a slave cylinder. If you haven’t bled the system yet, you need to do it before you start the engine for the first time because the clutch’s default position is “engaged.” (See Chapter 7 to bleed your system effectively.)
An easy way to tell if the clutch has adequate engagement is to support the rear wheels securely on several jacks so they can spin freely. Have a helper push the clutch pedal down (disengaged) and try to turn the rear wheels with your hands. If they don’t move, you have a problem.
You should have an oil pressure gauge on your car, no debate. If you don’t, get one now! The single greatest thing that kills an engine faster than your quarter-mile times is oil starvation.
Be sure to prime the system first. General Motors recommends that you fill the engine with oil and disconnect the engine control system. Then, using an oil pressure gauge, crank the engine in 10-second bursts until oil pressure is achieved. You can remove the spark plugs to help relieve pressure in the system.
When you start the car for the first time, oil pressure should be instantaneous. If you do not get any reading on your gauge within 5 to 10 seconds, shut the engine down and start diagnosing the problem. A lack of oil pressure can be many things, such as major malfunction in the oil pump. Be sure that the oil pick-up tube is matched to the oil pan before you install it in the car so you don’t have to take it apart later.
I’ve seen it more often than not that people get a little over zealous and start pounding on things unnecessarily. I once even got a little ahead of myself and forgot to put the lower power-steering hose on the build. I finally realized it after half a quart of fluid spilled all over the floor.
It helps to make a checklist of fluids that could possibly leak and simply make a mess or be a symptom of a much larger problem. Fuel leaks are the most common followed by leaks of radiator fluid, power steering fluid, brake fluid, transmission fluid, rearend housing fluids, and engine oil.
You need to verify that your fuel system provides between 58 to 60 psi. This can be checked via an external gauge or in my case, a fuel pressure gauge that is part of the gauge cluster in the dash. The easiest way to check this is to turn the key to the on-position, but do not engage the starter. You should hear the pump whine a little and this means it’s turned on. Keep in mind that the pump is designed to only turn on for 5 seconds before shutting off in the key-on position.
If you do not have pressure or can’t hear the pump prime, it needs to be corrected. Most often it is simply an easily corrected wiring issue. (This would be a good time to double-check your other wiring connections and make sure they are secure as well.)
When you are testing fuel pressure it’s usually a good idea to bleed the system of air. If you have AN fittings, a small crack with a wrench sometimes gets most of the air pockets out. Otherwise, the engine may need to be cranked and run for a short time to get all the air out of the system. This is a great time to doublecheck for leaks while the system is under pressure; you should be able to spot them rather quickly.
Nut and Bolt the Car
I cannot stress this point enough; you need to double- and sometimes triple-check your work. I highly suggest that you put the car on jack stands or up in the air and “nut and bolt” the car. This means going through the car systematically to make sure that every nut and bolt is tight and ready for service. Nothing would stink more than to find a crucial loose bolt when you’re 50 miles from home. Even Mark Stielow has said that he finds loose nuts and bolts from time to time after driving his hand-built rolling works of art.
Engine Break-In: First Firing and Test-Drive
Some people jump right in their newly built ride and take off. This may be fine for some, but I like to keep my stuff in one piece for as long as possible. The best option is to break in the engine on an engine dyno so you can control all aspects of the engine break-in. If that’s not possible and you have to break in the engine in the car I have several recommendations.
If this is your first fuel-injected engine you may be pleasantly surprised at how easily and quickly these engines start up. They self-regulate instantly. I do not recommend using the gas pedal at all while starting the engine because it can confuse the throttle position sensor; let the engine and ECM do all the work.
The engine idles relatively fast at first, roughly 800 to 1,200 rpm until it goes into “closed-loop” operation, which means that the computer has recognized that the engine is ready for normal operation. This usually means that the engine has good oil pressure, the coolant is at a safe temperature, fuel pressure is good, and there are no obvious issues with the fuel/air mixture or any sensors malfunctioning. This is a good time to monitor your gauges to make sure that they are accurate and that they are reading safe numbers for each engine statistic. If all seems well, look for leaks such as in the high-pressure power-steering line. Many leaks don’t show unless the car is running.
If no leaks are detected it is time for a test drive. There are many ways to truly break in an engine and drivetrain components. The following procedure has worked well for me for many years.
First, cycle the fuel pump a few times. It’s entirely possible you have air in the system, so I suggest cracking the system open at the fuel rail to let the air bleed out.
After the start-up it’s important to let the piston rings seat in the bores. Long gone are the days of letting the flat-tappet cams and lifters mate over time. LS engines have fixed that little problem for all of us. I recommend hitting the city streets; piston rings love a variable-RPM range during the break-in period. I also suggest keeping the RPM below 3,500 and no full throttle accelerations. Engines also hate long constant-RPM drives right away. Several engine builders have told me that this plan should be followed for the first 500 to 1,000 miles of the engine.
After the first drive, monitor the fluid levels and top off any that need it. Lunati often recommends changing the oil after 100 miles to get rid of the initial bearing wear, then at 500 miles, and then at 1,500. It has also been recommended that for LS engines, conventional oil should be used for the break-in process as it promotes piston ring and cylinder wall seating. After the 1,500-mile oil change, you should stick to the manufacturer’s recommendations for oil change intervals.
The final step is to enjoy the car! Keep an eye on all the vitals and have fun. That’s the name of the game!
Written by Eric McClellan and Posted with Permission of CarTechBooks