a friend of mine who works at a mini specialist garage has offered to bore out my cylinder head, skim it and polish all my pistons for free!!!
now im all for the skim n polish but what are the disadvantages of boring out my head?
he says by doin all of this he can add about an extra 20 - 25 bhp to my car
am i genuinley lucky or is this too good to be true?
Advantages And Disadvantages Of Boring Out Cylinder Heads?
Started by
ashby_steve
, Jun 27 2009 01:14 PM
3 replies to this topic
#1
ashby_steve
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Posted 27 June 2009 - 01:14 PM
#2
mars red mike
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Posted 27 June 2009 - 02:31 PM
If by 'boring out' the head you mean have it ported ie opening the ports up yes you will see an improvement but there is more to it than just going at the ports with a dremel. Skimming is just done to remove the minimum amount of metal from the head face to ensure that it is totally flat. Will raise the compression ratio a tad but no way will it give you 25 bhp increase. As for polishing the pistons, im not gonna say its crap because it dont know about it but the term 'polishing' means to remove rough and sharp edges from the insides of things like the inlet manifold, cylinder head etc to aid smooth flow into the combustion chamber. I cant see any benefit in polishing the piston crowns.
#3
somecrapname
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Posted 27 June 2009 - 03:46 PM
If by 'boring out' the head you mean have it ported ie opening the ports up yes you will see an improvement but there is more to it than just going at the ports with a dremel. Skimming is just done to remove the minimum amount of metal from the head face to ensure that it is totally flat. Will raise the compression ratio a tad but no way will it give you 25 bhp increase. As for polishing the pistons, im not gonna say its crap because it dont know about it but the term 'polishing' means to remove rough and sharp edges from the insides of things like the inlet manifold, cylinder head etc to aid smooth flow into the combustion chamber. I cant see any benefit in polishing the piston crowns.
Polishing anything adds 5bhp, kinda like painting the block red! 4 pistons all polished... easy 20brake!
#4
Pooky
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Posted 27 June 2009 - 05:59 PM
a friend of mine who works at a mini specialist garage has offered to bore out my cylinder head, skim it and polish all my pistons for free!!!
now im all for the skim n polish but what are the disadvantages of boring out my head?
he says by doin all of this he can add about an extra 20 - 25 bhp to my car
am i genuinley lucky or is this too good to be true?
Do you mean bore out the block? i.e. increase the cc of the engine? As this is a much more effective way of producing more power.
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