He is here George, just been busy with daughter buying a new house and moving and grandad duties.
OK, quick scan through some of the posts on this subject so forgive me if I miss something or get the wrong end of the stick.
In no particular order, valve clearances closing up, mainly down to valve seat erosion and valves pocketing in the head, because of the ratio of cam lift to valve movement even a small amount of valve pocketing can close a valve clearance considerably. As an aside I never bothered with valve noise on a competition engine and used the valve clearance to regulate the valve timing on individual cylinders. So long as the gap never went below the minimum stated a few thou extra to ‘phase’ the valve timing with a clock gauge and DTI was the way I set them up. It’s amazing how much inaccuracy there is in even brand name camshaft lobe phasing!
Ascertaining TDC for checking valves, again not that critical as the clearance is set on the back of the cam so when the valves are ‘on the rock’, you can achieve exactly the same effect by (on a petrol engine) turning the engine with distributor cap off and setting the clearance for both valves on the cylinder that’s firing (it will be very close to TDC and both valves on the heel of the cam.
On a ‘Satans Fluid’ engine it’s more difficult but if your struggling to turn it over don’t forget unless it’s an automatic you can pop it in top gear and rock it to observe the valves and get them on the rock for adjustment. Just use care that you don’t bump start it, if it’s ancient pull the stop cable out, if it’s modern crack open the injection pipes.
Hope that helps, back to entertaining a 6 and 13 year old…… they may end up on eBay 🤣
BR
Colin
