got the bottom end sorted now ive got a st170 head what are they good for standard ?? i heard they have bigger valves and bigger ports as standard i want 350/400 bhp

 

what bottom end have you got mate??

 

black top with steel rods and forged pistons why??

 

 

ST head will piss 350bhp mate.

 

ive heard the standard head would take that, maybe a reground exhaust or inlet (cant remember witch) cam from area six

 

crazycage
Auatin W or sas would be the people to speak to mate, have alook at austins resto thread, loads of info there. You have to do something with the VVT on the st head though.
Would have thought you'd be OK for that power with a worked blacktop head though?

 

thats whats i want to hear anyone no if the valve springs need doing or the standard one good

 

Would have thought you'd be OK for that power with a worked blacktop head though?[/quote]

i no that but if i can save on the porting as the st170 one has bigger valves and ports then it will save me some cash for a focus rs box

 

Good thinking

 

yep you cant just put the head of the st on the black top as there is work to be done to make it fit as its vvc

 

im told it will go straight on and i will be useing the vvt

 

Standard ST valve springs are ok as long as you're not chasing crazy revs.

Piper can reprofile the inlet cam and supply new valve springs and retainers if you do want to rev it out more.

To disable the VVT you need to tap the oil feed and put a grub screw in.

You'll also need to turn up an adaptor on a lathe to run a 2.0 Zetec vernier on the end of the inlet cam.

 

im kepping the vvt

 

For the VVT or not, just use the standard pully and time it up on the standard marks.

The pully is set at max advance as standard/rest, its only when the car see oil pressure does it retard

Simon.

 

so at what point would the head need porting ?? and differant cams??

 

IMO the cams should be good for 400 if the timing is set up.

Head 500+

S.

 

what on a standard head if so thats just saved me a lot of muney then

 

A standard ST head flows more than a ported Zetec.

Search hard enugth and you will find the flow results.

S.

 

To give you an idea - my ported ST head flows 164.8CFM @ 13mm valve lift on +1mm oversize valves

 

from what i have been told them st170 heads are the bollocks

 

it looks like the comp might be a little to high with the standard st170 head but im looking into sorting that

 

It's why i got one for mine

 

Ian Howell told me the ST170 heads flow 400 pretty easily but needs the exhaust ports taken out a bit to go any further? Also mentioned i need a cam (or cams cant remember) and uprated valve springs.


However Iam hoping whats been said here is right - Standard Cams, valve springs and ports all capable of 400 as of standard?

 

me to mate ian told me the same

 

Standard exhaust cam is good for over 400. The inlet cam can benefit from a reprofile.

Valve springs can do the bigger power - however i personally would uprate them if you're doing high revs at that power.

Valves can do good power but exhaust valves may start to suffer from raised EGTs on top speed runs.

ST170 combustion chamer is 8cc smaller than a Zetec from memory so off the shelf 9.0:1 pistons tend to go over 10.0:1 with an ST head

 

Good info there cheers, might well start building my silly spec Zetec a little earlier. What are ST170 heads worth exactly? My mate has offered me one.

 

XRT_si
i baught a complete engine for Ł450

 

I paid Ł350 for a freshly rebuilt head - and then stripped it

 

how do the st heads compare to the american zetec heads. like the one cliff s1 has on his car?

 

Haven't seen the flow figures for an american head but in all honesty - they are a completely different entity - not very much at all is interchangable between a zetec head and an ST170 head.

Some people run the valves and valve springs from an ST head in a normal zetec - but even then - machining is needed.