Monday, 17 October 2011

Engine build up - part 1

With a recent bout of reasonable weather, I have been able to start assembling the bare block back into a short engine. First job was to install the cam bearings which required a quick measurement of the bores before using my home made tooling to wind them in.

It was a little tricky at first, but by the time I got to the last bearing, I had it down to a fine art! With these installed, I could lubricate the cam and slide it home as this is an easier operation without the crank in position.

Next up was the crank itself starting with the main bearings and I checked the actual oil clearance using plastigauge (a first for me!). With all well and the crank spinning freely, I could move onto the pistons. A couple of the new rings needed filing to get the correct end gap, but for the most part they dropped in without hassle, forming the short block.

With the amount of machining carried out on the block, along with aftermarket heads and tappets (‘lifters’ for the subscribers on the other side of the Atlantic) I am unable to rely on the stock pushrod length being correct. I have therefore procured an adjustable pushrod which I used to check the required length. This involved marking the tops of two valves and mocking up the top end then turning the engine through one complete cycle. This leaves a witness mark on the end of the valves which needs to be centred across the tip. The adjustable pushrod is wound in or out to centre the mark then the process is repeated and checked for a pair of valves (intake and exhaust) on each cylinder head. Now I have determined the required pushrod length, I can go ahead with purchasing them and the full engine build can continue.

In addition to this, I have been creating a CAD model of the engine as accurately as I can which will aid me in the design of the intake and exhaust manifolds. I currently have a virtual engine in a similar state to the real one as the two need to be built in parallel. The key part missing at the moment is a rocker cover model as this will determine the location of the intake manifold plenums and routing of the corresponding tracts. I will be procuring this part along with the pushrods to help progress this part of the build.

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