Engine Rebuild

Prepare your components and fit your crankshaft and pistons

Reassembling the B-series.

The sexy bit has arrived. Up to now, there’s been the tedium of cleaning, measuring, thinking, expenditure, more measuring and more cleaning. As is true of many things in life, the quality of the final product is directly proportional to the quality of the preparation, which accounts for 90 per cent of the job. Final assembly is fun and satisfying – but there’s plenty of scope to cock up. You need to remain methodical and fastidious about cleanliness.

It’s really important to ensure that the correct assembly lubricant gets into all the right places when building the engine. In so doing, though, you’ll be applying a powerful magnet for dust and grit, which will make your freshly-remachined surfaces rapidly look very secondhand. The ideal way to minimise this risk is to thoroughly clean everything, lay out all parts, tools and gaskets in a clean environment and put the engine together in a one-off build-a-thon. However, time and space constraints mean that this probably won’t be practical. We’ll therefore be assembling the engine in manageable chunks, starting here with the main rotating and reciprocating parts.

Assembly lubricants are special oils and greases that will stay where you put them and help to prevent metal-to-metal contact both during storage and on first start-up. They’re a very worthwhile investment, especially if you’re not going to run the engine immediately after the rebuild. Choose wisely: not all assembly lubricants state that they won’t clog filters and some can hinder the bedding-in of piston rings. The lubricant we’re using is safe for both.

Before assembly, it’s important to carry out a final deep clean. It’s not the machine shop’s responsibility to clean the engine in readiness for rebuild: their final process is always to remove metal particles and swarf generated by machining – but nothing more. Remember that dirt and grit are the biggest enemies of an engine’s internals.