Testing Out the Bigger Engine

Keeping up with highway traffic is much easier now that we swapped in a 2.8-liter SOHC engine from an early-'70s Mercedes coupe.
Our man Jere puts the finishing touches on our 2.8-liter engine swap by filling the cooling system with antifreeze.

We took a few months off to remodel a house and do the metal work on our Mini Cooper S project. It’s time to get back to our Mercedes. Hopefully you’ve enjoyed the stories that have run in Classic Motorsports magazine. If you haven’t seen our print publication, you are missing out. Click this link to get a free sample issue.

We went from 2.3 to 2.8 liters with this engine swap, an increase of half a liter or a little more than a 20% larger engine. Certainly this would be noticeable. It is. That said, it is still a relatively small engine with only about 140 or 150 horsepower, so our Mercedes is still no race car. One ride in our Shelby Mustang project car will quickly remind you of that.

Still, this swap not only gave us an engine that did not leak oil badly, but the car is just imminently more drivable. Being accustomed to modern cars and their capabilities, with the smaller engine had regularly reminded us how slow our Mercedes was.

With the new engine, the car feels as it should. While not awe-inspiring, it is brisk, somewhat powerful and an absolute joy to drive. Passing, pulling out into traffic and enjoying twisty two-lane roads are all just more fun. We haven’t had time to measure, but we’re sure 0-60 times are at least a couple of seconds quicker. Fuel mileage has not suffered either.

We are very pleased how simple and inexpensive this upgrade was. We did the whole job in about a week of evenings and for less than $1000. Finding one of these relatively rare engines in good shape for $600 was a big part of why this swap worked.

We are also thrilled to report that unless you are a Mercedes concours judge or work at Mercedes-Benz Classic Center, you would be hard pressed to detect the swap.

A little tip on engine swaps: When we first start and run and engine, we never use antifreeze. It is much easier and environmentally friendly to clean up water than antifreeze in case of a leak. Once we know everything is working well, we drain some of the water and replace it with the correct amount of antifreeze.

Germans with American fins? In your mailbox six times a year. Subscribe now.

Join Free Join our community to easily find more project updates.
View comments on the CMS forums
Sponsored by



More like this
Our Preferred Partners