BMW E30 M3: What you need to know before you buy

[Editor’s Note: This article originally appeared in the March 2016 issue of Classic Motorsports.]

The original BMW M3 delivers pretty much everything a gearhead could want, from a high-revving engine and track-tuned suspension to big brakes and those giant flares. Oh, and it has the international competition record to back up all the muscle. Sure, you can argue that it’s just a tarted-up BMW 3 Series, but by that logic a Shelby is merely a Mustang with stripes and a stiffer suspension. 

M3 values remained fairly stagnant for years, with good drivers hovering in the teens. As a result, owners thought nothing of modifying these cars, putting them on track, and simply writing them off if something went wrong.

Well, those days have ended.

No matter what the price, you’re buying a piece of automotive history. As legend has it, BMW M Technical Director Paul Rosche was tasked with preparing the E30-chassis BMW 3 Series for FIA Group A competition. To be eligible for competition, at least 5000 road-going versions needed to be built as well. 

Both the race and street cars relied upon BMW’s S14 engine. The street version’s 2.3 liters made about 200 horsepower–impressive stuff at the time. Big brakes came from the BMW parts bin, and massively flared fenders allowed for an increased track. An equally effective spoiler was perched atop the trunk lid. Look closely and you’ll realize that even the rear window is unique to the M3.

European dealerships first received the M3 for the 1986 model year, with Americans getting a crack at it two years later. Production ran through the 1991 model year, and to be honest, all of the American-market cars were built to nearly the same spec. Collectors tend to gravitate toward the first-year cars, but only because, well, they came first.

Shopping Advice

Rennie Bryant at Redline Bimmer has been working on E30-chassis BMWs since they were new. 

The cars are aging pretty well, but don’t buy one that’s rusty. They can rust because underneath they’re just an E30. Check the trunk, the rear quarters and the cowl around the front windshield.

Some of the parts you can just source off eBay. Other than the sport seats, the interior is all E30 stuff. 

The engines are very expensive to rebuild. Any of the specialty parts that were made just for that engine are pricey. However, just about everything is available. 

The five-bolt hubs are special, but otherwise a lot of this stuff is interchangeable. The tranny is the same unit found in the 535i and 635i. The differential is also from an E24/E28.

We just built an E30 M3 replica using all factory parts. Everything was available except the bumper brackets and the side skirts.

Karl Hugh, technical director for BMW tuner Active Autowerke, has a few pointers about these cars. 

When shopping, do a compression and leakdown test. Look for oil leaks and broken exhaust manifold studs–a common problem since they get loose and then neglect causes them to break. 

The 1988-’90 cars are common, but all years are basically the same. 

They’re very buzzy–they were built for racing and have no power unless you work the engine. But remember, this is still the most successful BMW in racing to date. You’ve got to be a purist to understand this car.

Also do a cooling system pressure test. Some cars had porous cylinder head castings in exhaust ports and can spring leaks into the exhaust. It is expensive to buy a new head.

Valve adjustments are labor intensive.

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