Peugeot 405 Mi16 Engine rebuild.
This page follows the rebuild of an early Peugeot 405 Mi16 engine. It highlights some of the common faults found with these engines aswell as showing some of the steps that go into a rebuild.

Onto another common problem found with the mi engine, as you can see here, with the cylinder head removed. Being all alloy, the engines literally rot from the inside out. The cylinder head had heavy indentations and once the crank, pistons and wet liners were removed, it became clear that the block had rotted in the area where the cylinder liners seal. These could be repaired but the machining is expensive and in this case it was cheaper to find another head and block. As an advantage, the pistons, liners and crank were immaculate and the bearings were original size, proving this crank had not been reground.

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The replacement head was thoroughly cleaned to remove carbon deposits and refaced. It was then reassembled with new valves, new oil stem seals, new cam seals etc. The valve guides were in excellent condition having been replaced fairly recently and the head had been ported lightly on the inlets. The exhaust ports may have been gas flowed at some stage. The camshaft oil spray bars were replaced due to blockages.   

 

Firstly, you need an Mi engine which are increasingly hard to find. This one is seen still attached to its former home - a 1989 405 which had been dry stored in a barn for 8 years. This had helped keep the engine down to just 68k miles. Somebody had played around in the engine bay a little and as a result some of the hoses were missing and the electrics were a mess. As a result the engine was removed as a non runner. With the cam cover off you can see that water had sat in the head and lightly rusted the cams and tappets - common if an engine has sat for any period of time.

A replacement bare block was sourced and built using the low mileage crank, pistons, rods and cylinder wet liners. The oil galleries were cleaned and the under piston oil spray bars replaced due to 3 of the 4 being blocked. A new water pump and Gates cambelt kit and tensioners were fitted along with the obligatory gaskets and bearings. It is absolutely essential that good quality gaskets and big end / main bearings are used. The cheap items on the market arent so cheap when they inevitably fail.

This is the completed engine. As with all our rebuilds, the engines are fully painted and the extent of the rebuild carried out can be specified to suit budgets. This engine is seen with a brand new clutch, polished and ported throttle body, new oil pipes, cleaned injectors, new manifold studs and nuts and the obligatory new thermostat, distributor cap, rotor arm etc.

The mi16 is a fantastic engine, but all too often we have customers who have been burned by cheap or poorly put together rebuilds. The mi is not a fragile engine, the majority are just poorly put together.