By Chris Hamann
Any successful engine build requires a competent installer. To the best of our ability and knowledge everything on the engine builder’s end was done correctly. We sourced the best possible parts and used the best industry standard procedures along with modern techniques for our engine build. With that in mind it could all be for nothing if the installer is not competent. We, as engine builders, typically take for granted that our installers are competent, adequately trained and utilize the latest equipment. All parties have a mutual interest in the job. The installer and end user also want the repairs/engine build to perform well along with providing durability.
After spending much of my career as an automotive and marine technician one of the most rewarding parts of my career is instant gratification. After grueling hours of completing a major engine repair or replacement the moment of truth arrives when it’s finally time to turn the key and crank it up. This is precisely the moment when I find out if I’m going to have a good or bad day. Thankfully, the vast majority have been great days. I credit that to utilizing a proven routine. That routine includes a plethora of post installation checks. Obviously, each routine is slightly different per the application I’m working on, but I want to touch on items that I feel are important to check before the customer takes delivery of the job to prevent a “boomerang.”
Read this article with all images in the digital issue of Engine Professional magazine https://engineprofessional.com/2025EPQ4/#p=26
For example, our shop recently installed a remanufactured 289 CID long block in a 1966 Ford Mustang. We sourced the engine from a well-known production engine remanufacturer.
My routine on this vehicle was as follows:
- Clean and inspect all parts to be re-installed onto replacement long block. Verify they are reuseable and replace, as necessary. Clean out intake manifold exhaust crossover and remove steel plate under the crossover to remove all the coking.
- Ignition system: Set point dwell, ignition timing and check total advance. I use a kV meter or an ignition scope to verify that my kV demand at idle is 8-10 kV and the off idle in neutral @2000 RPM the kV demand drops a little.
- Fuel system: Verify carburetor is in good shape and adjust the idle air mixture. Verify choke closes when cold and opens fully when warm. Verify choke pull-off is operational and adjusted correctly. I perform a suction and pressure test on the fuel pump while bolted to the engine. I verify it can produce 10-15 inHg of vacuum and 4-6 psi of pressure. I verify the diaphragm is in good shape not to dilute the crankcase with fuel.
- Cooling system: Radiator, fan, hoses, water pump, thermostat, belt tension, etc. are checked for contamination and operation. I verify no air in the system, combustion leaks into the cooling system and sufficient circulation by cranking the heat on full blast out of the vents. Heat will be excellent if engine is warmed up, no major air pockets exist, and it circulates well.
- Electrical system: Verify the battery is within 5 years old, tests good, charging system operates as designed. Battery cables are inspected and routed correctly.
- Exhaust system: Verify it’s operational and intact.
- Verify all gauges are operational and accurate.
- Verify air cleaner is in good shape and air horn gasket between carburetor and air cleaner housing.
- After test drive check for leaks and top off all fluids.
Many of the engines that most of us build is the variety what I mentioned above. Non computerized, carbureted and “old school.” Many classic cars, marine and performance engines fall into this category.
When we dive into automobile engines from current production to the last 30 years, much of the routine from the 1966 Mustang still applies, but with an electronic engine management system just about all adjustments are out of our control. Ignition system, fuel system, fuel correction, variable valve timing, cooling fan operation just to name a few things are all controlled by an ECU. Many vehicles on the road today have an electronic thermostat that the ECU commands an operating temperature specific to the operating conditions. Modern federal emission requirements are dictating the use of these high-tech systems. I’m sure you’d all agree that a wiring or ECM problem could cause a cooling fan or an electronic thermostat problem that could affect the durability of a recently installed remanufactured engine.
As luck would have it, we also recently installed a remanufactured engine into a 2015 Chevy Silverado 1500 with a 5.3L L83 after a camshaft failure. Additionally, I connected a scan tool and performed a few procedures such as a crankshaft variation relearn. This procedure erases the learned crankshaft reluctor idiosyncrasies in the engine ECU. This is a requirement per GM and many other vehicle manufacturers after a major repair or engine replacement. Not performing this procedure could cause ghost misfires, an illuminated MIL and an unwanted comeback that would be difficult to diagnose. I also clear the learned fuel trims and I want to give the ECU amnesia of the old poorly running engine. The ECU stores learned fuel trim data. Starting up a fresh new engine on old crappy fuel trims could unnecessarily add or remove fuel to a bank of cylinders which is not ideal on engine break in. Yes, they’ll most likely auto correct, but the engine must be in closed loop operation which isn’t right out of the gate on first startup. When we are ready for a test drive, I connect to a scan tool and I record the test drive. I know this may sound excessive, but there are many items I’m interested in during a test drive on modern vehicles. First, safety is important. It’s hard to watch the road and the scan tool simultaneously. Secondly, my eyeball update rate isn’t that great, and I could miss something while driving. Analyzing the test drive once back at the shop in the parking lot is much safer and I also have reduced my chances of missing something. It only takes about 5 minutes to analyze a test drive scan tool recording on most scan tools. I’m sure most of us spend more time on our social media accounts every day than it will take to analyze test drive scan data recording. The items I’m interested in on this 2015 5.3 L83 are:
- Oil pressure and variable displacement oil pump. Does the oil pressure drop when the oil pump is commanded to?
- Are my fuel trims at idle, cruise and medium load within +/- 10%?
- Since this is a traditional four wire Zirconia O2 sensor application pre and post catalyst do all four of my O2 sensors go and stay super rich at wide open throttle? They should be at least 850mv+ and stay there as long as my foot is to the floor. This confirms that the fuel delivery system and the MAF sensor is in good shape as the engine should be pig rich. (This is why I like recording and then graphing the O2 sensors to verify they are rich and stay that way.)
- Are there any misfires counted?
- Is there any knock retard observed?
- Does the engine achieve and maintain operating temperature at idle and while driving?
- At idle, with the HVAC system in the off position, does the ECU turn the cooling fan on at the specified temperature (usually 220-230°F)?
- With the A/C or defrost on does the ECU command the cooling fan on?
- Does the actual and commanded variable cam timing PIDS agree?
- Drive or keep vehicle long enough to run all the OBD-II monitors and verify they pass. If all the monitors run and there are no pending codes, the engine management system is good to go!
There are many inexpensive scan tools out there. Analyzing scan data one can tell what the ECU is doing. On an old, carbureted engine if the idle mixture screws weren’t adjusted correctly the engine would idle rough. On a modern engine the ECU can make changes on the fly to effectively “hide” small issues. Many times, engine builders get blamed because the installer didn’t have a thorough pre and post installation routine to verify the original cause of failure has been rectified and the engine sensors along with the management systems are functioning correctly. I can’t stress enough how important the installer’s part of the job is on an engine replacement. Bridging the gap between engine builders and installers is what I’d like to accomplish.
Read this article with all images in the digital issue of Engine Professional magazine https://engineprofessional.com/2025EPQ4/#p=26