hey guys,

as some of you know my car is getting some work done to it, now im getting the combustion chamber ported and polished (450), although dave also has some heads there which have been totally ported and polished with new cam seals and stem seals with a triple agle grind for 1100 fitted. need your opinions.

thanks mike

triple agle grind? for the valves ensures a better seal for the valves....

if you can afford it i would go for the better heads. BUT i dont think you will get the gains that the extra expense.

How much porting has been done?

hey guys,

as some of you know my car is getting some work done to it, now im getting the combustion chamber ported and polished (450), although dave also has some heads there which have been totally ported and polished with new cam seals and stem seals with a tri ...(cant remeber what its called) for 1100 fitted. need your opinions.

thanks mike

only benefits on getting our heads done is the shrouding on the valves, any other porting is wasting money. Speak to ScreamingTE he has the lowdown on what should be done to heads.

the heads he is putting on have done 30 000 km. to allow better flow of air and to get newer heads, i went and bit the bullet after making a few phone calls to a few head specialists. anyways hopefully it was money well spent. if not im going to have a cry and look at my empty wallet.

mike

No one, not even the forced induction guys need to port the heads. The ports are already TOO big for the engine and the size valves we have. As magna00 said, de-shroud your inlet valves in the combustion chamber, tidy up the ports, and backcut the valves.

Seriously, check out 4 stroke performance tuning by A. Graham Bell to see what i am talking about. This bloke knows his shiz.

No one, not even the forced induction guys need to port the heads. The ports are already TOO big for the engine and the size valves we have. As magna00 said, de-shroud your inlet valves in the combustion chamber, tidy up the ports, and backcut the valves.
Seriously, check out 4 stroke performance tuning by A. Graham Bell to see what i am talking about. This bloke knows his shiz.

i believe thats part of what he is doing, it is also something to do with the fact the heads are almost new and mine are quite old. i know i wont get much performance its more to make the air to flow smoother and to help out the cams a bit.

mike

Nice man! Tell us if you notice a difference.

RPW always operates on an exchange basis, so be cautios if you got a really nice head with lets say A B C mods

You get your heads done/swapped with only A and C on them, thats about the only down side, just saying, be careful and feel free to get a 3rd opinion after the work is complete, never hurts :D

The only thing that will need to be done with a pair of old heads over new ones is to de-carb the ports, which can be done by you, and maybe acid bath them to clean out the gunk in the coolant and oil galleries. Crack test is probably a wise idea for a 2nd hand set of heads too.

As i have said previouly, the ports are already too big. Making them even bigger is only going to slow the air velocity down, and on the inlet side, you need that velocity to create swirl and promote fuel atomisation. If the air is going too slow, it will just fall in and sit on top of the piston, resulting in a slow combustion.