skimming alli head

[lammy426]

hello there,just wondered how much it will raise the compression if i skim 10 thou off the head and whats the max that you can skim the head without problems,many thanks john

[turbinecol]

Avoid it if you can, since today's low octane fuels give pinking issues quite easily. There is a tendency to want to skim by default, but check with a proper metal straightedge and you may find it is still perfectly flat. Obviously it needs to be devoid of major scratches or corrosion.

[lammy426]

trouble is i think the crescent ports have got to be welded so its looking like i don't have a choice,do u run yours on super unleaded or v-power,thanks john

[turbinecol]

normal unleaded plus additive, which is proving OK but I do tiny mileages. I think the BP super is recommended, others supposedly might have more ethanol which isn't good. Hard to get enough info on it. Skim will be needed then but just be clear it needs to be minimised.