Lancia Stratos

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Engine Rebuild 2014 after Blown Head Gasket

The detonation that blew the gasket also damaged a couple of pistons, the surface on the head and a couple of the liners (these were scored from stuck piston rings)

The Heads were skimmed at MBE racing’s workshop and only needed 8tho of material removing to clean them up, so the damage wasn’t too bad.

The two scored liners were not so good & needed replacing. Also I had grooved the tops of the liners, but needed to make a new groove for an O-ring. I managed to source a decent set of used liners from Autolusso. These were taken to Dennis Vessey who machined a groove in the top face of the liner and fitted a 1mm diameter Stainless wire. The wire protrudes about 12thou to bite into the head gasket and help to secure the gasket.

The liners also had 1mm machined of the bottom to clear the THS connecting rods.

Two of the pistons had the rings stuck in the top two grooves, and most of them had marks from the detonation, so it was decided to renew all of them. This also allowed the dish to be made slightly deeper 3cc of material was removed when compared to the existing pistons. This dropped the CR from 8.6 to 8.3:1, just for that bit of extra safety margin.

Surprisingly even though the pistons had a deeper dish, they weighed 8grms more than the last pistons. They were sent to vibration free who matched the new pistons to the weight of the old pistons by cone grinding the Gudgeon pins. This avoided having to have the complete engine re-balanced.

The Bottom end was dismantled and all the bearings checked. There was no sign of any problems with the big ends or mains, so at least that is one thing that I shouldn’t need to worry about. The Shells were like new, so were re-used.

The Engine was assembled with a Victor Reinz Gasket set.

Water Pumps

One of the possible issues with the engine was too little water flow from the way the Davis Craig pumps were controlled – to be sure of sufficient water flow after the rebuild, the mechanical water pump has been re-installed & the two Davis Craig Pumps replaced with a higher flow Stewart components pump. To regulate the temperature I have installed a remote Thermostat in the front of the car close to the radiator, that way the booster pump has full flow whether the thermostat is open or closed.