Tour of an Engine Rebuild Shop Part 6: Quality Control and Power Testing By Jeremy Wilson

Before a rebuilt engine goes out the door, Portland Engine Rebuilders performs extensive quality control tests.

“Bob Fairchild retools every fastener on each engine,” said Ted. “He’s responsible for every valve adjustment on every engine. He checks the cam shaft timing and he re-torques everything. He inspects every thread, so if you have, say, a bolt hole that’s marginal, he will not let it out of here. Somebody has to come up and fix it. You’ll never get an engine from us with a tainted thread in it.”

SIMTEST machine

As part of the quality control process, PER tests each engine on their SIMTEST QC180 Quality Control Engine Test Station. The machine allows you to lock a long block into place. You then connect pressurized oil lines and a driveshaft that connects to the engine’s crankshaft. The SIMTEST machine holds 25 gallons of oil and it’s pre-heated to 365 degrees, plus or minus one half degree.

SIMTEST machine - oil feed and power drive

“The SIMTEST machine has two, five-horsepower, DC electric motors and that’s your power source,” said Ted. “We set the machine to turn the engine’s crankshaft at 350 RPM. We then check the oil pressure and the oil bleed-down flow rate out of the bearings.”

“There’ll be a certain amount of oil flow through every engine family, and right on our work orders it tells you what the oil flow bleed-off rate is supposed to be. If there is an oil flow problem, it’ll point it out and blink at you. It’s pretty hard to miss it.

“Sometimes an engine never pumps up because the bearings are a little loose or there are defective lifters. A number of times we’ve installed brand new everything and the adjustments are exactly what they are supposed to be, but oil is roaring through one of the valves. It’s surging out of the rocker arm, flooding the valve, and the lifter is spongy. If you rotate it you can feel it clicking so you know there’s something wrong with the lifter. Usually it’ll be missing parts inside of itself.”

While in the SIMTEST machine, the engine does not have its sheet metal installed. Instead of returning to the engine’s oil pan, it drips into the SIMTEST machine’s base, where it goes through a pre-filter.

“The pre-filter catches the corn cobs and chicken feathers and then the oil goes into a receptacle and through three different tiers of settling out,” said Ted. “If anything does get through, it settles to the bottom and then through three different oil filters with no bypass valves. It goes through a 50 micron filter, a 25 micron filter, and then a 15 micron filter. The oil is triple-filtered and comes out clean. We service our filters every month.

“It has the added benefit of flushing the engine out and scrubbing the cam and lifters in. We don’t start rotating the engine until we see oil coming out of the rocker arms, so there are no dry starts. And the lifters are fully pumped up when you’re done. So when you start up your new car, you don’t hear anything because all the valves are operating full lift.”

As a rule, PER returns engines to customers in long block form. That is, the engine is assembled and tested but the pan, valve covers, and other sheet metal has been hot tanked, but not installed. But in some cases the customers want to do their own assembly.

“Some people like to assemble their own engine, but I ask them to bring it back in here to have us test it so we can see everything function and know it works right before they bury it with the oil pan, valve covers, and manifolding. Because if there’s a problem, it’s so much easier to work on now; once it’s in a car, it’s not so much fun anymore.”

The quality control testing gives PER a sense of confidence when an engine goes out the door.

“If an engine has a problem after it’s been though our tests, we always go ‘hmmm’ and wonder what caused it. We ask the customer to bring his car in here to get to the root cause of the problem. Nine times out of ten, it’s not our doing.”

DTS Dynamometer

As a final test, PER has a dynamometer for measuring an engines horsepower and torque output, but dyno testing requires the engine be fully assembled and operational. This works best if the engine is carbureted, but it can be done with fuel injected engines in some cases.

“We can do fuel injected providing the computer control is with the engine, which is usually a hassle because a lot of times that’s part of the car. I did a ‘55 Chevy here earlier this year, built a 383 out of it, and we got one of those FAST (Fuel Air Spark Technology) systems, from Comp Performance Group. It had its own little computer, its own little wiring harness, and all of the manifolds and injectors. It was a complete kit. It was $3600, but it came with the distributor, manifold, fuel pump, filter, and a big wiring harness. In even included the grommets for going through the bulk head. It was a bit of a plumbing deal because our customer had such big parts on his hot rod engine, but we were able to tune it up with a laptop computer. It was programmable and even came with a CD. They give you step-by-step instructions showing you how to do it. The video was really quite informative but they had all this jazzy music in the background and I found that extremely distracting. But I tell you what, it worked well! It did. So if you want to put fuel injection on some oddball car it’s a good choice, as long as there’s a manifold available for it.”