Discussion
Anybody had any experience on here of using their services?
Useful Feedback?
Looking to get my existing head scanned to replicate for second engine. Is this a service they undertake or is it more off the shelf to their specifications?
Website talks the talk - do the heads produce the goods?
Useful Feedback?
Looking to get my existing head scanned to replicate for second engine. Is this a service they undertake or is it more off the shelf to their specifications?
Website talks the talk - do the heads produce the goods?
I'm not going to comment on a particular company but I wonder if you really understand what CNC porting involves or how different a first cut machine produced shape can be from the template it supposedly originated from. In the States CNC head porting is big business now but they have the volumes of identical engines, mainly Chevy and Ford V8s, to warrant the initial investment both in tooling and man hours to develop each head profile.
That's a very time consuming business, getting a machine ported end result which matches the original hand produced head closely enough to flow similar amounts of air. It doesn't just happen by digitizing a shape, pressing a button and Bob's your aunty's husband. It takes days, weeks even, of flow testing and tinkering with the program and that's not even considering the valve seat which can account for up to 50% of the flow gains and which is a completely separate exercise from the CNC porting part of the job.
IME most places can't cut a decent valve seat to save their lives, even when they have state of the art equipment like Serdis or even CNC Serdis. That's because most people don't know which seat angles and widths really work best and there's an infinite number of combinations to try.
Even a well ported CNC head looks like a ploughed field inside the ports because unless you use an infinitely fine feed which would take forever the cuts don't overlap. This doesn't necessarily hurt flow once you get the right basic shape to allow for all this but that won't necessarily be the original hand ported template shape which obviously has no intersections between cuts.
There are some good articles online if you Google for them showing what is involved in state of the art Chevy CNC work. If you think you are just going to be able to take a head in somewhere and after digitising it an identical copy will magically pop out of a machine a few hours later you could be in for a considerable surprise though. Finally, all a machine can do is reproduce what it's been told to. That's no guarantee the port will actually flow well which is down to the human element in developing the right shapes and the number of real flow experts in this country can be counted on the fingers of one hand. Whether any of them also work for a CNC porting company I wouldn't like to say. Garbage in, garbage out basically as they say in computing. The CNC machine will just reproduce that garbage for as long as you want it to without getting tired, taking tea breaks or making mistakes.
Personally I don't think the UK has the volumes to make CNC porting cost effective and especially given what's happening in the economy at the moment I doubt whether any CNC porting people will be in business for very much longer. I might be wrong.
Dave Baker
Puma Race Engines.
That's a very time consuming business, getting a machine ported end result which matches the original hand produced head closely enough to flow similar amounts of air. It doesn't just happen by digitizing a shape, pressing a button and Bob's your aunty's husband. It takes days, weeks even, of flow testing and tinkering with the program and that's not even considering the valve seat which can account for up to 50% of the flow gains and which is a completely separate exercise from the CNC porting part of the job.
IME most places can't cut a decent valve seat to save their lives, even when they have state of the art equipment like Serdis or even CNC Serdis. That's because most people don't know which seat angles and widths really work best and there's an infinite number of combinations to try.
Even a well ported CNC head looks like a ploughed field inside the ports because unless you use an infinitely fine feed which would take forever the cuts don't overlap. This doesn't necessarily hurt flow once you get the right basic shape to allow for all this but that won't necessarily be the original hand ported template shape which obviously has no intersections between cuts.
There are some good articles online if you Google for them showing what is involved in state of the art Chevy CNC work. If you think you are just going to be able to take a head in somewhere and after digitising it an identical copy will magically pop out of a machine a few hours later you could be in for a considerable surprise though. Finally, all a machine can do is reproduce what it's been told to. That's no guarantee the port will actually flow well which is down to the human element in developing the right shapes and the number of real flow experts in this country can be counted on the fingers of one hand. Whether any of them also work for a CNC porting company I wouldn't like to say. Garbage in, garbage out basically as they say in computing. The CNC machine will just reproduce that garbage for as long as you want it to without getting tired, taking tea breaks or making mistakes.
Personally I don't think the UK has the volumes to make CNC porting cost effective and especially given what's happening in the economy at the moment I doubt whether any CNC porting people will be in business for very much longer. I might be wrong.
Dave Baker
Puma Race Engines.
I know the CNC Heads firm. I built the website.
They will scan your head and replicate it if you want. It would be useful to put your head on their gas flow machine to see what flow it has (and to compare cylinders and compare to their own mini heads)
Its a very time consuming process and an "expert" task to create a good head. To scan and replicate it is the "easy" bit if you have the right kit . The set up for the CNC scanning and machining process is very tricky with jigs having to be built. The finish of the port after the CNC process is remarkably smooth. It looks like there are ridges in the port but you can barely feel them with your finger. Any doubts, go for the hand finishing which gives a further 1% or so in flow.
I can say this, the results on the website come straight off the Port Flow Analyzer software. There's no manipulation of the figures. I've also seen a head with a known CFM rating being put on an engine and dyno'ed and the results are as predicted. (Providing you have appopriate recommended changes to the engine)
They will scan your head and replicate it if you want. It would be useful to put your head on their gas flow machine to see what flow it has (and to compare cylinders and compare to their own mini heads)
Its a very time consuming process and an "expert" task to create a good head. To scan and replicate it is the "easy" bit if you have the right kit . The set up for the CNC scanning and machining process is very tricky with jigs having to be built. The finish of the port after the CNC process is remarkably smooth. It looks like there are ridges in the port but you can barely feel them with your finger. Any doubts, go for the hand finishing which gives a further 1% or so in flow.
I can say this, the results on the website come straight off the Port Flow Analyzer software. There's no manipulation of the figures. I've also seen a head with a known CFM rating being put on an engine and dyno'ed and the results are as predicted. (Providing you have appopriate recommended changes to the engine)
Edited by Mort on Friday 31st October 03:28
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