A Few Questions For The Tuning Guru’s ...

24th March 2006, 00:43

....Ok people, a few questions i need to ask and hopefully i'l get sensible answers. I dont know much about what the following 'tuning' terms do:-

1) bore out head ?

2) Skimming ?

3) Polished & Ported ?

What do the above things do, how can i benafit from them and how much does it cost to do that.

Thanks.

24th March 2006, 01:02

boreing out the head? i think you mean porting which is making the bore of the intake and exhaust ports wider!
skimming is machining a layer off the heads surface that mates with the cylindar block, therefore giving you more compression!.
polishing is fine sanding the inlet and exhaut ports to make the surface smooth to give better flow, no point doing this unlees you have mods such as a high lift cam or whatever!

24th March 2006, 01:05

boring is done in the cylindar liners where you increase the bore to give you more engine capacity. i.e you could bore it from a 1.6 to a 1.7 or 1.8
i dont know how much you could bore the vtr engine as they are wet liners!.

24th March 2006, 01:28

Oh right, well 'bore out head' is a term i heard ! so not by me, i was just asking !, anyway, yes i am intending to cam my vtr.

Ok.... wet liners?

24th March 2006, 01:39

you can either have wet liner`s which are usualy found in an engine with a cast alloy block!. liners are what the pistons slide up an down in!. wet liners are removable!.
dry liners are normally in a cast iron block and they are part of the block so they are not removable!. it is easier to bore these engines out i should imagine!.
when you remove the head you should make sure not to turn the crank if you have wet liners as this can disturb them and cause the O-ring to leak at the bottom of them causing water to get into the oil!.

24th March 2006, 03:04

Thanks for the info bud.