View Full Version : What is the difference between the 16v head & the willy
What is the difference between them? does the williams one have better flow? or are they the same with just different cams?
And leading on what would happen if you put williams cams into a 16v? how would it run? would there be a gain.
Also would there be an advantage fitting a williams head onto a 16v bottom end, running 16v cams? If there wasnt a advantage running williams cams
Thanks.
iirc the 16v head has smaller valves and smaller ports or soemthing, benr will be able to tell u more, the 16v head is better platform to have ported etc and bigger valves fitted cant help on willy cams in 16v head etc
willy head has roughly 1mm larger inlet valves. ports are slightly fettled on the willy head. as for cams, the williams runs slightly more lift (have exact figures somewhere), and yes they will fit in the 1.8 head. benefits of using the willy head on ur 1.8 is the larger inlet valve head diameter....
Casting is exactly the same.
The difference as already outlined is the minimally larger valves, 30.7 vs 31.6.
The williams head also has had a larger machining process in the valve throat, with a much less radically sharp short side. That and the 0.9mm larger valves account for the increased flow, but more importantly a much higher level of flow quality. But even then, its not great and 31.6mm valves are tiny.
The cams are everso mildly wilder, but practically useless for a swap.
If you ran a willy head on a valver bottom end, the gains are minimal, but measurable.
You will get more gains by modifying your valver head and installing commercially available 33mm megane valves. And after that i have some direct replacment 35mm valves.........thats where things start improving.
Basically on these ports you just cant get valves big enough.
Cool so better off just sticking with my head then.
What sort of gains do you get from bigger valves then? is it easy to do your self/try to teach yourself?
What other sort of headwork is worth doing? im figuring porting it will give some good gains, again is this worth trying to teach yourself?
I have to do a head gasket change soon so weighing up what is worth doing whilst the head is off.
If your putting in larger valves then just stick with your head, there is more meat to work with on a valver than williams head, so ultimately, the valver heads flow better.
Depending which valves you go for, you can do it yourself, but you'll need to strip, get the seats cut to match the valve diameters. If they are larger than the seat inserts then you have to get larger seat inserts put in.
But i wouldnt get massive valves put in if you dont port the head, it'll flow horribly due to the machining operations done to it.
Larger valves are also heavier so its a good idea to consider upping the spring pressure for install and open heights.
Fair enough, how much on average does it cost to get larger valves cut in? doesnt the timing or fuel etc, have to be adjusted having bigger valves? or does it mean its just more efficient so you get the gain there?
What valves would you recommend?
I have heard that porting isnt recomended to do on your own? are there any guides about or anyway of teaching yourself etc? if not how much on average does that cost?
Ah makes sense getting better springs where would you get these from? id guess you could use the springs which would fit onto the larger valves? or isnt it as simple as that?
What sort of gains in bhp/torque would you see if it was done?
Thanks.
I have heard that porting isnt recomended to do on your own? are there any guides about or anyway of teaching yourself etc? if not how much on average does that cost?
That's for sure :!:
Workshops that take up such tasks usualy have flowbench.
That's a machine that mesures the mass and speed
of air coming throught your ports.
Or there are workshops like this (http://www.cncheads.co.uk/index.html)
the pics of their work are :shock:
click the this word jon to see the link.
If I were in the UK I'd definatly pay them a visit :D
They are a bit expensive, but I bet it's worth it :wink:
I was geven a ROUGH quote by power engineering at Trax for £100 to supply, fit and install bigger valves and uprated springs, thats for an 8v head, so £200 for a 16v head.
Was also quoted about £375 for porting and polishing of said 8v head, was about £800 for a 16v head iirc
click the this word jon to see the link.
lol.....i did click the 'this' to see the link......the finish looks a bit rough imo........hence the :shock:
Another little point to add - Putting a Williams head on a 16v block would lower the compression ratio to approx. 8.8:1 - by my simplistic calculations. Which'll lose you loads of power. Could be good for forced induction though?
If I were in the UK I'd definatly pay them a visit :D
They are a bit expensive, but I bet it's worth it :wink:
Their work for a CNC head is expensive, because you can bang them out all day....the whole point of CNC heads were repeatability and much cheaper costs. But the problem is that every head should ideally be ported to match a certain design spec, so having only 2 maybe 3 cnc programs per head for all applications will mean you'll not get the best package for your engine system, but for the majority of low spec engines they are fine.
I was geven a ROUGH quote by power engineering at Trax for £100 to supply, fit and install bigger valves and uprated springs, thats for an 8v head, so £200 for a 16v head.
Was also quoted about £375 for porting and polishing of said 8v head, was about £800 for a 16v head iirc
Installing larger valves is the price of the valve (anywhere between £8-20 each), the seat cutting (about £2-2.5) and the new seat insert (£30-35 for copper berylliam) and ofcourse, at a minimum the bowl porting neccesary to make a larger valve flow and the whole job worthwhile.
Its an expensive, but very beneficial exercise WHEN your engine requires it.
Another little point to add - Putting a Williams head on a 16v block would lower the compression ratio to approx. 8.8:1 - by my simplistic calculations. Which'll lose you loads of power. Could be good for forced induction though?
No drop in CR, piston deck heights are the same, so are gasket compressed thickness and the chamber volumes are near identicle.
If I were in the UK I'd definatly pay them a visit :D
They are a bit expensive, but I bet it's worth it :wink:
Their work for a CNC head is expensive, because you can bang them out all day....the whole point of CNC heads were repeatability and much cheaper costs. But the problem is that every head should ideally be ported to match a certain design spec, so having only 2 maybe 3 cnc programs per head for all applications will mean you'll not get the best package for your engine system, but for the majority of low spec engines they are fine.
as with evrything else as well tho mate......cnc heads wear....and some of the machining isnt as good as it could be when they do start wearing....or breaking.
btw.....check out some of the pix on that site........big chunks out the ports etc. .........not my idea of a good job tbh
most certainly, UK CNC'ing isnt anywhere near the level that is conducted in the states unfortunately.....well, fortunately for me actually. lol
No drop in CR, piston deck heights are the same, so are gasket compressed thickness and the chamber volumes are near identicle.
I bow to your greater knowledge on that one, mate. It was a very simplistic calculation! I don't know that much about the really technical stuff such as these sorts of calulations.
How do they make the CR's the same if the chamber volumes are near identical? wouldn't 2 litre be squeezing larger volume into the same space?
deck heights and piston crown volumes.
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