SimTest machines are more prevalent in engine remanufacturing operations than speed shops, but they do have features that can help engine builders struggling with lubrication issues.

“We actually use it for research and development here,” says John Edwards of Costa Mesa R&D Automotive Machine Shop in Southern California, who often posts YouTube videos of various engine projects on his shop’s 10-year-old SimTest machine.

The SimTest machine flows preheated oil under 50 to 60 psi through the engine while spinning the rotating assembly about 200 to 400 rpm. For the test in the video above, Edwards removed the front timing cover on a Chevy big-block to check oil flow to the chain. Compression checks can be made as well as visual inspection that oil is going to each rocker arm. Pressure readings can also be made throughout the engine.

“One customer was having oil issues with the lifters,” explains Edwards. “We measured a 7-pound drop from the rear lifter to the front.”

The problem was solved with strategically placed bleed holes that helped maintain consistent pressure.

Initialization, not break-in

In addition to checking for lubrication issues, the SimTest can help kickstart the break-in procedure.

“I call it an initialization of the engine,” says Edwards. “No matter how careful the engine is put together, always going to be some misalignment with the piston and rod assembly. This spins the engine over under a low-stress environment and gives the piston and rod time to acclimate to each other.”

At those low speeds and loads, the engine won’t fully seat the rings and break in a flat-tappet cam, but Edwards has seen the engine smooth out after 30 or 40 minutes of operation on the SimTest. He can tell it’s running easier when Simtest drive motor starts drawing less amperage and the engine rpm picks up slightly with no changes in the controls.

“You obviously won’t see the same amperage drop with a roller cam,” says Edwards.

Other useful checks that can be made with the SimTest include cylinder temperatures and oil drain back to the pan. One customer had issues with poor performance, so Edwards knocked out the core plugs and took temperatures of the cylinder cores. Two cylinders were 30 degrees higher than the others. When the engine was disassembled, Edwards discovered serious clearance issues in those cylinders.

“With the pan off we can also monitor the flow from the bearings,” says Edwards. “We can actually develop windage trays because we’re watching the oil and seeing where it goes.”

The SimTest machine may not prevent failures as Edwards demonstrates below, but it can help spot little problems before they develop into bigger issues.