Just got my head back from the machine shop from having new valve guides and the exhaust cam follower sleeves replaced, and would be grateful for some advice from wiser heads about some aspects of the work done before I go back to the machine shop with some questions,
Firstly, the head appears to have been refaced; it is clean and shiny, (a lot more so that when I gave it to the machine shop) and appears to have some machining marks. I didn’t ask for the head to be skimmed, and the invoice didn’t include a charge for it. I’m concerned that the machine shop may have warped the head during their work and skimmed to correct. The tops of the raised lettering on the underside of the head have just begun to be skimmed as well. Should I be concerned?
Secondly, the old cam follower sleeves were returned to me intact. I was expecting them to have been cut or machined to remove the tension before being extracted (and hence my concern about cooking the head to extract them). Is it possible to extract the sleeves without relieving the tension or cooking the head?
Thirdly, the cam followers rock in the new sleeves; almost as much as the old exhaust sleeves, and noticeably more than the inlet sleeves (which were not replaced). Is this usual, and is it likely that the new sleeves have been over machined?
Fourthly, the new valves stick slightly in the closed position, which I understand is generally a sign that the valve seats need to be refaced. This has supposedly been done (and invoiced for). Will it go once the guides have been lubricated and with a bit of lapping, or is this something that needs to be fixed by the machine shop.
I was planning to ask the machine shop if they have skimmed the head, and why, and to what tolerances they had machined the cam follower sleeves to. Is there anything else I should ask?
I’m also thinking of getting a second opinion on the clearance of the exhaust cam follower sleeves, and wondered if there was somewhere in the South Oxfordshire / Berkshire / Buckinghamshire region that could be recommended?
Any advice would be gratefully received.