Camshafts

[MichaelElsom]

Sorry to bore everyone with yet another of my little problems.
After a great deal of delay, the head was finally removed to discover the cause of water in what now appears to be two cylinders. This revelaed a small crack which was not only external but also internal. The ful effect of this must have been hidden by KSeal which was present in the engine before the new radiator but I chose not to add again.
Bearing in mind that the head on the car not only has this crack but also a blockage in the crucial water passage around the exhaust at the back of the head which has so far refused all attempts to shift it, we have decided to use the head off the spare engine. I may have bored some of you already with problems we found with attempting to use that without too much work so the plan not to mix the two engines has been parked.
As with all my decisions, this one soon proved to have its own agenda - the two camshafts have different bearing journal sizes. This is a problem because the camshaft and rockers on the spare engine look as though they have been run without too much oil and are all badly scoured. The original camshaft has - yes you've guessed - the bigger journals.
Chatting to both James P and Mike C suggested that there should be no problem in line boring the head to take the bigger camshaft, but I remain concerned that the centre bearing housing in the head is directly above the inlet tract. According to my (Aldi sourced.....) micrometer suggests that the difference in journal size is 37.93 mm against 38.30 - so .37 mm approx. To this must be added the recommend clearance between camshaft and housing of 0.025 ÷ 0.098. We are not talking a lot but before getting anyone to remove metal, has anyone got any wisdom on this topic.
Interestingly the two camshafts are not identical in other respects and I wonder if at some stage the one in the spare engine has been reground or re-machined already. As you will have gathered I am trying to avoid the expense of a camshaft rebuild and serious work on the rockers!     

[Running Board]

as mentioned to you , my Australian friends have already done this by hard chroming the camshaft over size the line boring the head to suit with no issues at all , another has bored out the head and retro fitted bronze bearings to take up the wear , you need to be careful as the heads do wear and you get a huge oil pressure drop as a result , this is the same on Astura engines too where the cam bearings and rocker shafts wear , dropping oil pressure reading at the head alarmingly , any good engine specialist would be able to help you , Bradbury's who are doing the white  metaling on my Belna engine would certainly sort it for you