Skimming The Head To Increase Compression, And Its Effect On Performance!

[picassoonwheels]

My Zen is going through major face-lift and internal Mods.

It is a I.0 ltr 16valve SOHC, with a compression ratio of 9.4:1
The bore is 72 mm and the stroke is 61 mm

I was wondering if there would be any gain at all if I took off a couple of mm from the head, and thus increased the compression. The valves clear the pistons and I am told that I can safely take off up to 14 mm, but I wanna keep it safe, so the maximum I would go to is say 8 mm.

I would appreciate it if anyone would be kind enough guide me as to the effect of this endeavor, and what other aspects would I have to keep in mind, and what I can expect from it.

I know, I know its much too small an engine to show any great performance gains, but since the total weight of the car is 765 kg, its a sporty little buggy and gets me there quick enuf, and in style.

All input would be appreciated.

 

[old-git]

Crikey, I don't know this engine, but I don't know of any heads where you can safely remove 8mm, let alone 14! Even if you could, this would raise the compression ratio by so much the mixture would detonate rather than burn and the head would lift off the block

Maybe you mean 0.8 and 1.4mm?

I will leave this to the experts on this forum to confirm.

Raisng the compression ratio on its own will do very little to improve performance and, unless you have access to high octane fuel, you could run into detonation issues.

 

[HDi fun]

That's if the head will go back on anyway. I think taking off that much metal (8-14mm) will result in valves and pistons colliding.

 

[old-git]

That's if the head will go back on anyway. I think taking off that much metal (8-14mm) will result in valves and pistons colliding.

I think that is a given.

 

[lutonmatt]

even .8mm is a lot
most places will go to about .20

but like og said wont do much and to a 1.0 you will never see the diff doing it save the money and get a faster car

 

[picassoonwheels]

Crikey, I don't know this engine, but I don't know of any heads where you can safely remove 8mm, let alone 14! Even if you could, this would raise the compression ratio by so much the mixture would detonate rather than burn and the head would lift off the block

Maybe you mean 0.8 and 1.4mm?

I will leave this to the experts on this forum to confirm.

Raisng the compression ratio on its own will do very little to improve performance and, unless you have access to high octane fuel, you could run into detonation issues.

Forgive me father 'coz I have erred! My bad!

What with the local dialects here its difficult to know for certain.

Now could this expert have meant 1.4 mm?

And I have a petrol station not 300 yards from me, that gives me 96 octane.

Would you regard this as high octane?

And what are the detonation issues you forsee?............

Do lemme know, coz I have some free time and really wanna do this all in one go............

Much obliged

 

[HDi fun]

95 is standard in the UK, but the Octane ratings might be different in your region.