Engine Rebuild: Pt2

Theo gets deep and dirty with the famous B-series unit.

In the first part of our B-series engine overhaul, we showed you how to strip your engine. Now, we’ll explain how to examine the individual parts and determine what’s good to go again, what requires machining and what’s fit only for the bin.

If your engine has covered a decent mileage, a visual inspection is likely to condemn most components. There’s a good chance it’ll need everything: a rebore with oversize pistons; a crank grind with undersize bearing shells; a camshaft and bearings; a head skim; valves, seats, guides, pushrods and cam followers; rockers and shaft; timing sprockets, chain and tensioner; an oil pump; a flywheel skim. B-series parts are cheap and readily available, so you can take a blasé ‘if in doubt, replace it’ approach.

A machine shop can take crankshaft and bore measurements and tell you the size of the pistons and bearings shells you’ll need to buy. There is, however, a lot to be said for taking measurements. If your engine turns out to be in good or recently-rebuilt condition, accurate measurement is the only way to determine whether components will go again. Never rely purely on visual inspection if you’re considering the reuse of a part – the work of the previous rebuilder is not to be trusted. Even if parts fail a visual inspection, there’s still a case for measuring everything you can. It will arm you with data that’ll give an insight into the engine’s past and may prove useful later in the rebuild.

Measuring tools that were once the preserve of specialists are now available at modest sums. A bore gauge set (from £10), a micrometer set (£30), vernier calipers (£5) and a dial test indicator (£15) are all useful. We’re showing you how to take a full set of measurements from your engine. If you think we’re being too anally retentive… then perhaps we are. Pick and choose as you will.

Thanks to Moss Europe (020 8867 2020, moss-europe.com) for expert advice.