daverubberduck wrote:I think the answer to my last question is yes, I have to remove the half moon shaped plugs and undo the nuts. The tricky bit will be putting it back together. If I align the timing marks on the sprockets, then maybe double check by measuring the opening and closing angles of the valves as I did before. Am I on the right lines?
Take extreme care that you do not drop the sprocket-bolts or the tapered washers down the timing case to the sump, It will be pretty difficult getting them out again.
I usually first fix the position of the cams by taking off one of the bearing caps of each and inserting a rectangle of cereal-packet cardboard. Tightened down the cam cannot move,
Next loosen the sprocket bolts about a quarter turn.
Loosen the tensioner completely, tie a bit of wire or string to the top of the chain, so that you can lift it out of the timing case later. Lift the chain off the sprockets and lower it carefully into the timing case out of the way. Tie off the top of the retrieval wire/string.
Now you can carefully if you wish move the inlet cam by one tooth, by loosening the cardboard clamp just a bit and rotating the sprocket a little. You may need a tool made from a length of wood and two projections (nails or bolts) to lever the sprocket&cam around. Tighten the cardboard clamp.
Or take off both sprockets to check the marks are previously described, before refitting , possibly exchanging , them. {Note you might have TWO exhaust sprockets there and some other unlucky person has two inlets ones}.
When you have the cams &sprockets in approximately the right place, lift the chain back up and pull it straight up so that the bottom of the chain engages properly with the crankshaft sprocket deep below. Check that it is not kinked, peer down inside with a torch. keeping the chain taut, drape it over the exhaust sprocket so that it is taut all the way from crankshaft to exhaust sprocket.
Then drape it over the inlet sprocket with minimal slack between the sprockets.
Now gently screw in the chain tensioner, checking with a torch that it is seating ok into the chain. Take up most of the slack Tighten the sprocket bolts, then remove your cardboard from the cam cap and complete the adjustment of the tensioner to give the required half inch up & down movement of the chain between the sprockets. The sprockets& cams will move a bit during this final tensioning depending on tolerances and on wear of the timing chain. The marks on the sprockets are only approximations to within one tooth position.
Do a final tighten of the sprocket bolts, though the engine might start to turn, making it a bit difficult.
Now there is no way of being sure that the tensioner/jackshaft sprocket went on the same teeth as before, so it is essential to redo the distributor timing, from the beginning, including lifting out the distributor and reinserting it in the correct position. Remember that the centre shaft rotates a little as the spiral gear engages on the jackshaft.