Wednesday, 11 February 2015

Triumph Stag engine rebuild complete - on to the next jobs.

The Stag engine rebuild is now complete, the engine is back in the car, has been run to temperature a few times, tuned and road tested. All that remains is for the owner to reclaim his prize possession at the weekend.

We seem to have a plethora of six cylinder engine work underway at present. The first is a TR5 unit which is being fully rebuilt to more or less standard spec but with an unleaded head and balanced bottom end, following an unfortunate incident when last used on a touring trip to Europe. This would seem to have been caused by a prolonged period of detonation – have a look at the piston!

The second one is a Vitesse mark two which the owner wishes to have the cylinder head somewhat ‘breathed upon’ to increase power output particularly in the mid-range and to generally optimise efficiency and improve gas flow by fitting different sized valves and cleaning up the ports and throats. We will also fairly obviously be converting this one to run on unleaded fuel – it would be silly not to at this stage.

The third one is a 2500 carburettor engine intended for a 2000 saloon, which is being built to a recipe which I have successfully used many times now. This is designed to maximise the torque of these units whilst improving the breathing and top end performance with twin 1¾ inch SU HS6 carbs on the longer 2500S inlet manifold, a custom camshaft, different valves, a little head work and a balanced bottom end. This recipe usually delivers around 140 bhp or so with a good spread of torque and a lovely smooth free-revving engine which is still perfectly tractable in traffic and not too heavy on fuel. As such it seems to be about the best compromise I have come across for road use with a good performance.