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TVR Cerbera
How so, Fred? Porting or valve sizes?
172 Race Car
"Matteh - Doing things the hard way since 1986"
PMSL
ITB'd MK1
3 different inlet ports, one un-ported, one semi ported (CNC) and one fully ported (CNC)
TVR Cerbera
which is which?
ITB'd MK1
more done to later cars
They are all CNC machined ports...
TVR Cerbera
does anyone really know what the difference is? or is it 'what i heard' type rumours?
ITB'd MK1
got a ph1 head under the stairs that says different
ITB'd MK1
Try to find some time on tuesday. Under the stairs.....at work 
They were all CNC'd from Renault mate.
whats the "un-ported, semi-ported, fully ported" about?
The CNC operations on any head arent necessarily about flow gain, its more for repeatability between ports and between heads, especially on a mass-produced basis from a manufacturer such as renault.
whats the "un-ported, semi-ported, fully ported" about?
The CNC operations on any head arent necessarily about flow gain, its more for repeatability between ports and between heads, especially on a mass-produced basis from a manufacturer such as renault.
ITB'd MK1
I know why it's done. They are NOT all the same though. Like I said we have an early 172 head with no CNC work done, had a CNC'd 172 head in with half the port CNC'd and a 182 head with full CNC work done both very recently.
ITB'd MK1
right, just nipped into work to get some of my bits and got this head infront of me. 3 words simplify this situation. YOU ARE WRONG
I'll take some pictures tuesday, Andy's taken the camera home
ITB'd MK1
totally un-touched original casting, no CNC work
ITB'd MK1
Inlet. NO CNC porting AT ALL. (I can say it again if you still dont believe me)
Exhaust ports are also pretty small
Exhaust ports are also pretty small
ITB'd MK1
not attitude, just this....
becomes frustrating when I'm telling you that I'm looking at it as i type
becomes frustrating when I'm telling you that I'm looking at it as i type
M
mini-valver
I was told Renault heads were CNC'd from the factory. I have no proof though, lol.
ITB'd MK1
ask Rob (Humphries) about recieved information when you next speak. Interesting views
M
mini-valver
VEMS guy??
ITB'd MK1
yup thats him. Interesting discussions a few years ago about forum "facts" that turned out to be anything but accurate
M
mini-valver
Im not following??
ITB'd MK1
certain facts that are taken as read and repeated then passed on and repeated until no-one knows who came up with the fact but it's still accepted. Then you look at it from scratch and realise the only way to be sure is to find out yourself
Stan, I'll get some pics up of the non CNC'd head
yup...im basing what ive said on my experiences of these engines.
ALL the heads ive seen (and thats a fair few, of all ph's's) have been CNC'd on the inlets.
TVR Cerbera
Don't forget this is Renault you are talking about. anything is possible. depends what they had in the spares bin for that week......
my ph2 172 head was cnc'd before i ported it, on the inlet only, think it was only partial.
my ph2 172 head was cnc'd before i ported it, on the inlet only, think it was only partial.
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