The Devil is in the Detail

Ever wondered - why torque wrenches come with a fine tooth ratchet, and why you would ever need one? Well in my case, as Engineering Manager for Norbar, I am only too aware of the need for and the benefits of a fine tooth ratchet. Lately whilst performing some fairly major ‘open heart surgery’ to my Chevrolet Camaro 350ci (5.7litre) V8, I had to use a wrench (Model 100 with Industrial ratchet). I thought at the time it would be perfect as an example to explain why fine tooth ratchets are important. To cut a long story short, I have recently changed the piston rings on my engine because unfortunately the rebuild kit included incorrect oil control rings. Yes, I probably should have spotted this but the variation between the correct and incorrect control ring is very minimal. As the car had recently been sprayed I did not want to lift some 260 Kg of engine out using a lifting hoist and risk damage to the new paint. Instead, I decided to do the work with the engine in situ. After removing the mounting bolts from the chassis and a multitude of other accessories and ancillaries the engine was jacked up by around 70mm to allow the sump pan to drop and be removed. I now had access to the whole crankshaft and connecting rods. After removing all of the connecting rod caps, I removed all 8 pistons and took out the incorrect oil control rings and fitted the correct rings. Now let me tell you, there is an awful amount of oil that is thrown and pumped around in the bottom of any internal combustion engine and you do not want to spend any more time than necessary underneath an engine with the sump removed, it literally rains oil! So you really need to have the correct tools at hand to minimise time in such an environment. You can imagine that when having to raise the engine in order to clear the chassis cross member space is limited. The rear of the engine is easier to access since the cross member is toward the front of the engine and out of the way, but as each piston is installed access to the connecting rod nuts becomes increasingly difficult.

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