oily bores

[Bob Culver]

Can cut lengths of nail or wire and file to form internal gauges. Adequate for deducing taper. But need large external mike to measure. Using separate int and ext mikes requires considerable skill to avoid significant cumulative tolerances.

[JonE]

Oily bore update... piston replacement on its way with a couple of s/h conrods to better work out which of mine have been too irregularly filed. Big find tonight... valve stems look like they have been drilled out with something very large i.e. major waggle present in all 8. This feels an immensely good find! Also other inconsistencies... standard inlets have double valve springs, or rather 3 of the 4 do. I now wonder if this engine was done by an apprentice at Usk Machining Services in 1953, who perhaps hastened its rather long term storage...

[John Cornforth]

Hi JonE

By valve stems I take it you mean valve guides. If so, replacements are available and not too hard to fit and then lightly reamed if necessary. You seem to have the opposite problem to Oxford Jack on another curent thread, who is suffering from guides that are too tight !

If possible, it's a good idea to weigh pistons and rods etc. They can be swapped around for best balance, e.g. Cylinder 1 and 2 as a pair, and Cylinder 3 and 4 as another pair.

[Dave Mann]

This brings back memories of 40 years ago when I was sent to Fiji to sort out some problems on a 9.5 Mw diesel generator set, an engine I'd never seen before. One of the problems was sticking exhaust valves which after some careful recording of valve and guide sizes was down to excessive valve/guide clearance.