headwork..

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2.0 pinto, stock except for fr31 kent cam, 4-2-1 manifold & peco performance backbox, is there any point in having the head gas flowed and skimmed?

if so why?

and how much off the head, ive been told from 20thou to 60thou, bear in mind i want to keep a smooth tickover.

[5hane]

why dont u have a go urself ?

 

if u concentrate like you would a peice of chrome im sure it would be stage 3 +

 

not a clue on skiming tho apparantly it can be big bhp for little coin tho

[Vista]

2.0 pinto, stock except for fr31 kent cam, 4-2-1 manifold & peco performance backbox, is there any point in having the head gas flowed and skimmed?

if so why?

and how much off the head, ive been told from 20thou to 60thou, bear in mind i want to keep a smooth tickover.

 

Gas flowed? Yes, the easier it is for the air to flow into the cylinder during the induction stroke the more fuel air mixture you'll get in there. More fuel / air mixture = bigger bang and more power.

 

Skimmed? Yes, skimming reduces the size of the combustion chamber and by doing so increases your compression ratio. Also = more power. How much to skim your head by? Sorry can't help you, you'll need somebody with more engine building experience than me for that.

[old skool freestyler]

vista your a very knowlageable(sp) man

[TwoLitrePinto]

Completely agree with vista, BUT

 

Skimming = higher compression which is good, but you may need to use super unleaded as it may pink a little under load on 95 unleaded.

then if you find yourself having to use super unleaded you will want to advance the ignition timing just a tad to get the most gain.

 

Gas Flowing Definately but if your going to have a go yourself, be warned it can make things worse.

 

With the FR31, Higher compression and maybe having to run on super unleaded with timing slightly adjusted, you may find the tickover gets a TAD lumpy but nothing drastic.

 

In my Opinion, all WELL worthwhile. the skim and gas flow will give you a massive noticeable difference anyway.

 

Pinto's Love a bit of headwork

[Toby]

and how much off the head, ive been told from 20thou to 60thou, bear in mind i want to keep a smooth tickover.

 

It's not a measurement of how much to skim off, it's the measurement of the CC's in the head and gasket that's important, after all someone may have skimmed it before. The equation is swept volume + chamber & gasket CC divided by chamber and gasket CC.

 

You just need the right compression for your combination of parts. If you just increase the engine capacity and don't skim the head then you have raised the compression. You need to decide on all the bits you are going to put in the engine and then skim the head last. It sounds as if you want to be around 10.5:1, this will improve the tick over of a lumpy cam.

 

The cam timing is related to the compression an engine will stand because it's the dynamic compression that matters. Therefore if you improve the gas flow of your head you have raised the dynamic compression without skimming the head! It all gets a bit complicated and a big dollop of experience will get you closer to your ideal CR, but around 10.5:1 would IMHO, be a good place to start.

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all just a bit too confusing for me, il stick with stock, but thanks for talking me thro it guys