Here’s the thing about buying an old car cheap. It’s not the $1,000 up front. It’s the $5,000 in repairs to keep your rig on the road.

Greg and Marissa Frankenfield paid cash last summer to buy the Old Log Theater from Don Stolz. They plugged a few leaks, replaced some lights and climbed the steep learning curve of running a theater.

Wiser but undaunted, the Frankenfields have doubled down on their treasured little hobby house in Excelsior. They apparently felt it wasn’t risky enough just to operate a 600-seat theater as a commercial venture, because they have gone whole hog into the restaurant business — the only game that can make theater seem like a safe bet.

The Frankenfields have spent “$2 million — up to now” refurbishing the Old Log’s restaurant, bringing in guru David Shea to redesign the space, changing the menu, expanding the kitchen, redoing the lobby and sealing the theater away from ambient noise. There was heating and cooling to upgrade, spaces to build out and up.

And they did it while sandbagging the theater amid flooding on nearby Lake Minnetonka and “every other form of pestilence except locusts,” Greg Frankenfield said.

The public gets a peek when the season opens Friday with “Life Could Be a Dream,” directed by Kent Knutson, the Old Log’s artistic director and partner in the Frankenfields’ venture.

The 250-seat restaurant, which is being named Cast & Cru, will have a soft opening this Friday, in advance of firmer dates in September.

Change is difficult

Greg Frankenfield made his fortune developing software at Magenic Technologies, but he and Marissa long have been involved in theater, as board members (Mu Performing Arts, Mixed Blood) and as producers.

They wanted the Old Log, which is near their Shoreview home, and closed the deal with Stolz after a dance of several-years’ duration that seemed uncomfortable for all involved. Once the papers were signed, the Frankenfields became known in some circles as the people who had the bad manners to want to buy and operate the Old Log as a theater when it was evident the Stolz family was exhausted after Don’s 70-year run as owner.

They perhaps contributed to that impression with well-meaning changes. Longtime patrons enjoying their preshow meal wondered what this stuff called “risotto” was, and why it was there next to their walleye filet, in the spot normally reserved for mashed potatoes.

Knutson fashioned a season that had not a British farce in sight, but still favored middlebrow tastes. His boldest ventures had wildly different results. “Rancho Mirage” was a hip, newer work by Steven Dietz with a powerhouse cast including Stacia Rice, James Denton, Ann Michels and Mo Perry. It sold like wildfire (“probably could have gone twice as long,” Knutson said).

“Almost Maine,” a charming series of playlets set during the winter in a small Maine town, tanked. Apparently, a show about snow and cold didn’t capture anyone’s imagination during the longest Minnesota winter since 1492.

While they tried to poke into the Minneapolis ticket market, the Old Log came to realize again how much bus tours and west-metro ZIP codes feed the theater.

“We’re still learning a lot about audiences,” Greg Frankenfield said.

Even more change

When you enter the Old Log — still a construction zone last week — it’s what you don’t sense that catches your immediate attention. Gone is the smell of the wood in architect Herb Bloomberg’s original walls that paneled the lobby. The room now looks modern, well lit, efficient and inviting to the restaurant with an open kitchen and bigger windows.

The wood ceiling is still there, along with the huge stone fireplace that dominated the rear wall. The restaurant has a full bar, separate from the lobby, and three distinct dining areas.

Knutson is opening with “Life Could Be a Dream,” a jukebox musical of 1950s and 60s doo-wop by Roger Bean (“The Marvelous Wonderettes”). It will run into January, running in repertory during the holidays with “You’re a Good Man Charlie Brown.” Risks ahead include “Dirty, Rotten Scoundrels” and “Best Little Whorehouse in Texas,” bigger musicals with bigger budgets.

“The hardest thing for me — I know how to program — but they had this built-in audience and we had to tiptoe around that,” Knutson said about last season.

Frankenfield deflects the pressure of the new Old Log adventure with one-liners.

“I say ‘No’ a lot,” he says, when asked how he’s keeping a lid on spending. His smile, though, indicates that he’s a pushover. “It makes me feel like I’m adding value.”

He learned many painful lessons in his first year — none more so than the panic of Sept. 6, 2013. Opening night had caught them by surprise, and Frankenfield faced an audience that had waited for more than a half-hour for the curtain of “Cowgirls.” The restaurant had been overwhelmed, and Frankenfield spoke emotionally about this new challenge.

“I never want to do that again,” he said the other day, with the tone of someone fresh from a root canal.

But Frankenfield has shown patience and deep pockets in his quest to run the Old Log. He waited out the Stolzes while they flirted with developers and the Three River Parks District before the deal was struck last year.

Then the hard part started.

“I have more respect for Don than I ever had,” Frankenfield said.

“It was a hard thing to live up to what they did,” Marissa Frankenfield said. “They were icons for just keeping the place going.”