Engine Rebuild (Part 3) - Timing Chain and Sump

With the crankshaft fitted, I moved on to the camshaft and timing gear. The important thing here (for timing/ firing) was to align the marks on the two sprockets before final fitting of the chain. The marks are quite subtle. On the camshaft sprocket, the relevant mark was a single painted tooth (repainted in my photo below)......... . 

Repainted timing mark on tooth of cam sprocket

........and on the crankshaft sprocket the relevant mark was a small notch between two teeth:

I was too busy to take photos, but the principle of reassembly is that with number 1 and number 4 pistons at about top dead centre, and with the chain held taught on the chain guide side (not fully taught in photo below) a straight edge should pass through the centres of the sprockets and these two marks. Turning the camshaft and sprocket and/ or crankshaft allows you to move the chain by a tooth or two until you find the 'sweet spot'.

Marks on sprockets face each other and align

I'd had a new timing chain fitted by Doctor Chevron back in 2002 and it had probably done no more than two or three miles after the engine had been refitted all those years ago. The timing chain got re-used - as did the chain guide and tensioner. I followed the assembly and alignment procedure - reading the instructions in manuals 518 and 814 very carefully. The guide was fitted and adjusted with two feeler gauges (and three hands) and the chain tensioner was fitted and 'activated'.

With the camshaft and timing chain in place, the oil pump could be fitted. The pinion on this is driven by the camshaft. 

The Oil Pump is Driven by a Gear on the Camshaft

The oil pump was correctly orientated so that the hole in the stem aligned to the threaded hole in the engine block. The pump was then pinned in place with the screw and lock nut.

Pin and Lock Nut for the Oil Pump

With the other end of the oil pump bolted to the bearing cap, the sump was fitted. Having had to sort out a stripped thread on the sump plug hole, I thoroughly cleaned the sump of any swarf before fitting it. I smeared a very thin bead of RTV silicon on the mating surfaces. Not too much as I didn't want it oozing into the sump. There is also a cork gasket that fits over the curve of the flywheel end bearing cap. That was similarly held in place with some RTV.

It's important to get the location of the two long bolts correct as these will serve the secondary purpose of holding the triangular bracket that supports the down pipe/ flex-pipe join. Where did I put that bracket.....

Long Sump Bolts for Exhaust Bracket

After the sump, the timing chain cover was fitted.

Bottom End Done - 13 August 2017