By Steven Bull

Power is an essential part of your power boating experience, but when your engine gets sick, you’re faced with the dilemma of buying a new one or repairing the old one.

In some cases, especially on older boats, the cost to repair an engine isn’t worth the time and effort versus buying new. You’re likely better off buying something else if your engine is a late model and requires parts that are no longer manufactured since you’re looking at building everything from scratch. On the other hand, if that doesn’t apply to you, you could save a bundle by repairing or rebuilding your existing engine. If it’s done right, that is.

I overheard someone at my marina talking about having their engine rebuilt at CrossTown Engines in Toronto. The Mangov brothers, Lou and Jim, continue the business and tradition started by their father more than 50 years ago. Interest piqued, we gave them a call and asked to follow along on a project they were undertaking.

It turns out, they had just received a 5.0-litre MerCruiser engine with a cracked block after having not been properly winterized.

To begin this project, Jim stripped off the external components systematically. Depending on the engine this can take a couple hours. It would take me a few days. Watching Jim go is like watching a 1980s movie montage.

This type of problem is very common.

“We see a lot of this, and a lot of worn out engines, burning oil,” he says over the rapid clicks of ratchets. “But it keeps the cost down to rebuild it since we can salvage and re-use most of the items.”

Apart from the visual inspection where even I can diagnose the problem, they give everything a thorough check.

“You’ve definitely got to pressure test the exhaust manifolds,” Jim explained, “because they might have got cracked in the process as well but you might not be able to see it…we’ll check it out!”

When it’s all stripped down, the fabrication of a new long block assembly is next. Most of which is done in house.

“We machine in house,” Lou told me as we walked the shop floor. “We do our own crankshaft grinding, the boring, the honing. Quality control is very, very important to us.”

Lou has his system down pat. I thought he had laid out the parts on the table just for the benefit of our cameras. I mean, it looked like a display at a trade show!

But no, this is just how he operates.

“I don’t know the exact number but it’s somewhere around 13,000 engines (that I’ve rebuilt),” he said, giving the parts a once over. “It depends on the engine, but when I’m at this stage…for something like this, it’s about 2-3 hours to get it all put back together.”

That’s after about 8-10 man hours from disassembly through machine.

Once the engine is all put together, they put it on their self-built machine to test it. The hydraulic motor spins the engine at 450 RPM. They monitor oil pressure and check compression to make sure everything is functioning properly.

He also checked for oil leaks. Seeing none, it went back to Jim to reassemble before dyno testing.

“We don’t do it for every engine. It depends on the customer,” Lou said. “The cost of dyno testing the engine versus having a test down the road makes sense to some people.”

Dyno testing is the final step before it goes back to the customer. Well, it should be if all goes well.

“We test for horsepower, torque, air-fuel ratios, any oil leaks or anything that could go wrong during assembly,” Jim explained as we gave the set-up a once over, “So let’s fire it up and test it.”

Looking like a mini control room, we walked into an area with a couple of computers, light-up switches on the wall and a throttle with digital readouts — separated from the engine by reinforced glass. It’s in place should there be a catastrophic failure. Not only is the engine lined up with the dyno computers, Jim had a laptop hooked up to the engine’s ECM.

“That way I can monitor everything going on, and if any trouble codes pop up in the engine’s computer, I’ll catch it,” he said.

Every engine has different targets, so they reference the specific outputs for this engine as per MerCruiser.

It fired up like a charm and Jim used the throttle to rev it up and down. Instantly the readouts started popping up on the computer and it was bang on the targets. On the one hand I was impressed, but on the other, if you’ve done this 13,000 times you’re probably going to knock it out of the park more often than not.

The owner of this particular boat wanted privacy (likely due to some embarrassment from the winterization boo boo) so we didn’t go see it run when it was back in the water. It did check every box it needed to during the dyno testing, so as long as the marina put it back in properly, this used engine will run better than it did before it cracked.

The Mangov brothers are great guys and they clearly do great work. I just hope to never need to make use of their services (read: I better do a proper winterization). Then again, if something unforeseen happens, my engine could always be number 13,001!


CrossTown Engines was founded by Tom Mangov in 1965 and is a located in Toronto’s east end.

This My Boat Project is featured in the 2018 season of PowerBoat Television and the Winter 2018 issue of Boats&Places.

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Steven Bull is an Associate Producer and Host of PowerBoat Television. He grew up boating on runabouts and PWCs on the lakes around Huntsville, while his wife grew up on cruisers. It only took months after getting married for Steve to adopt that lifestyle. Together, they purchased a Sea Ray 380 Sundancer they keep at the Toronto Islands. A graduate of the University of Windsor’s business school, Steve worked in the front office of OHL and CFL teams before moving to Europe and working as a Ski Guide in the French Alps. He returned to Canada get a Master of Arts in Journalism from Western University (formerly UWO). Steve’s broadcast experience ranges from the BBC World Service in England, to business reporter with NTV in Kenya, and from 2010-2014 as a multi-platform reporter and host with CBC News. In 2014, Steve combined his passion for boating with his skills as a broadcaster by joining Lifestyle Integrated where he contributes to Boats&Places Magazine,,, and of course, PowerBoat Television.