Project BMW 318is: What’s Wrong With the Engine?

Update by Ed Higginbotham to the BMW 318is project car
May 24, 2018

Our original plan was to clean the car up, basically restore or refurbish it, make a few modifications and then have a nice, original, nearly stock 318is.

After cleaning and inspecting our new purchase, it seemed that the engine was really the only major issue with the car. We knew the car had an “engine problem”, as the seller described it, with the 1.8-liter engine when we bought it.

Having messed with hundreds of old cars—many with engine problems—we suspected a bad fuel pump or at worst a blown head gasket. These M42 engines are pretty robust, and we doubted—naively, maybe—that the problem would be major.

After removing the valve cover, we noticed something was missing, something important. The timing chain had broken and was laying at the bottom of the front cover of the engine. Since the M42 is an interference engine, this caused the valves to hit the piston and deform.

Then we peered down into the timing chain area of the engine with a flashlight and saw that the idler gear for that timing chain had broken away from the intermediate plate where it is mounted.

This time we had real engine problems. While we didn’t know how bad things were, we knew the engine would have to come out.

In the video below we explain how the timing chain snapped and remove the engine from the car.

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View comments on the GRM forums
Type Q
Type Q SuperDork
5/11/18 12:12 p.m.

" ..BMW 318is: What's Wrong With the Engine?"

It's missing two cylinders? smiley

Ed Higginbotham
Ed Higginbotham Associate Editor
5/11/18 3:55 p.m.

Bump for a new video being added to this update!

irish44j UltimaDork
5/11/18 4:43 p.m.

Man, that's pretty rare (knock on wood) and usually the result of other carnage with the tensioners or guide rails.

iceracer UltimaDork
5/11/18 6:11 p.m.

Hope that catch pan is empty.

irish44j UltimaDork
5/11/18 6:29 p.m.

If anything, running M42s are a dime a dozen. I've bought a couple of them (including transmission) for $300 each. That may be the way to go here - cheaper than rebuilding, really. 

Of course be sure to scavenge your engine for useful things, especially if the timing gears are in good shape and the crank thrust bearing surface is good (both pretty uncommon on high-mileage M42s).

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