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Thread: Williams Helical Camshaft for SR type engines.

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2011-03-03 02:19:28
#1
Williams Helical Camshaft for SR type engines.
I originally posted this in the "All Motor" section but possibly "VVL" is a more appropriate area.

http://www.sr20-forum.com/all-motor/42043-end-road-vvl.html#post546569

This post refers to the Helical Camshaft system - described below:

Introduction

Helical camshaft - Wikipedia, the free encyclopedia

I would be interested to read peoples' opinions about this camshaft system.
2011-03-07 03:40:57
#2
Williams Helical Camshaft.
Possibly people with SR engines may be interested in the following:

Introduction
Helical camshaft - Wikipedia, the free encyclopedia

You can see from the general layout of the Suzuki GSX 250 helical cam prototype in the photos and videos that the SR-type valve gear is very similar in arrangement. This would imply that it may be possible to actually build a "bolt-in" variable camshaft for an SR engine.
When the original HC prototypes were made and tested the people behind the HC project were totally unaware of the type of valve gear on SR engines - otherwise the prototype would have most likely been an SR of some kind.
Since becoming aware of SR's the HC builders are contemplating bulding variable cams for this type of engine and would like to know if there would be much interest in these cams amonst SR owners.

To complicate things - there are actually two types of variable cam - the simpler one (called the Type 1) has a continuous duration range from standard to about 40 crankshaft degrees above this. This is the type of cam shown running in the Daihatsu Charade engine on the HC website. It would probably not be particularly difficult to build this type of cam for an SR along with a similar centrifugal controller to that shown in the video (athough, obviously the SR would require two of these arrangements).

Slightly more tricky would be to build a HC (or Type 2) cam for an SR. This typically would give a duration range of 85 to 100 degrees above standard (the prototype Suzuki is 85 degrees) basically this is enough duration to allow whatever RPM the SR bottom end could stand while retaining the standard idle speed etc.

Anyhow the builders of these cams would like to hear peoples' opinions on these cams and whether there would be enough interest to justify building some SR prototypes.

I attempted to post a similar thread to this a few days ago but (for whatever reason) it never appeared - I hope the other thread doesn't suddenly pop up as well as this one.
2011-03-08 02:33:20
#3
It looks like the earlier attempt at posting a new thread did suddenly "pop up" - sorry about that.
2011-03-08 05:24:42
#4
Originally Posted by Sheepdog
Possibly people with SR engines may be interested in the following:

Introduction
Helical camshaft - Wikipedia, the free encyclopedia

You can see from the general layout of the Suzuki GSX 250 helical cam prototype in the photos and videos that the SR-type valve gear is very similar in arrangement. This would imply that it may be possible to actually build a "bolt-in" variable camshaft for an SR engine.
When the original HC prototypes were made and tested the people behind the HC project were totally unaware of the type of valve gear on SR engines - otherwise the prototype would have most likely been an SR of some kind.
Since becoming aware of SR's the HC builders are contemplating bulding variable cams for this type of engine and would like to know if there would be much interest in these cams amonst SR owners.

To complicate things - there are actually two types of variable cam - the simpler one (called the Type 1) has a continuous duration range from standard to about 40 crankshaft degrees above this. This is the type of cam shown running in the Daihatsu Charade engine on the HC website. It would probably not be particularly difficult to build this type of cam for an SR along with a similar centrifugal controller to that shown in the video (athough, obviously the SR would require two of these arrangements).

Slightly more tricky would be to build a HC (or Type 2) cam for an SR. This typically would give a duration range of 85 to 100 degrees above standard (the prototype Suzuki is 85 degrees) basically this is enough duration to allow whatever RPM the SR bottom end could stand while retaining the standard idle speed etc.

Anyhow the builders of these cams would like to hear peoples' opinions on these cams and whether there would be enough interest to justify building some SR prototypes.

I attempted to post a similar thread to this a few days ago but (for whatever reason) it never appeared - I hope the other thread doesn't suddenly pop up as well as this one.

When this guy did the original helical camshaft about 8 or 9 years ago, I was very interested to get something going for the SR engines and contacted him.
He was on that stage more interested in getting it patented and trying to sell the idea to major car manufacturers.
He had a feature of it in an Australian car magazine and I fell in love with the idea. Unfortunately the magazine didn't do any follow ups and it sort of died.
As I am not going to do any more development in the SR's and are busy selling everything I have, I dont have a direct interest but would love to see someone doing it.
As I could not get in contact with this guy in years, I have approach someone else with all the drawings and they were very impressed with it but funding something like that was out of my reach and put it on the backburner.
One of the major features I liked is that with the right setup you could do away with your throttle plates, have any duration you like.
Biggest drawback would have been to design a controller for it and a Ecu that could handle it, but would be doable.
Last edited by kiwi-japie on 2011-03-08 at 05-34-49.
2011-03-09 03:09:33
#5
Kiwi - I am afraid that (after much head-scratching) I have to say that we do not recall you contacting us - I assure you we would have followed up any request you might have made. Eight or nine years ago the HC had not run and we could not be sure that it would run - certainly we were not expecting the fuel-saving effects to be so pronounced.
You were probably unaware of the earlier (Type 1) cam at the time. You could have made one of these back then. This is actually the Type that we are investgating the possibility of making aftermarket cams for. The HC is a possibility for the SR but still would be a very ambitious project for us - the helical machining was tricky enough for two cylinders let alone four. But once a CNC example was made I would imagine copies would be fairly straightforward.

Perhaps you could contact us through the address given on the website. We would also be interested in whatever SR parts you have for sale - especially heads and valve gear etc.

The reason the magazine ("Performance Buildups") did not do any follow-ups was that the editor, Paul Tuzson left the magazine and I think it finally stopped being published.

As an aside here - I think Paul is probably one of the best writers/photographers on automotive technology in the world - it is a shame we don't see more of his work.
2011-03-09 04:20:51
#6
Originally Posted by Sheepdog
It looks like the earlier attempt at posting a new thread did suddenly "pop up" - sorry about that.


Your a new person so your posts had to be approved. Sorry for the delay
2011-03-09 04:46:53
#7
they haven't actually made one for the VE head have they?
2011-03-09 10:45:34
#8
waste of time. many superior models out there.

Kudos for the development to him.
2011-03-09 10:57:26
#9
Originally Posted by Autech
waste of time. many superior models out there.


care to explain?
2011-03-09 11:51:13
#10
You cant effecitvely introduce a variable lift from this setup.

So you are left with a massive variable duration at a fixed lift.

Certainly its great in that it can pick up air speeds a cylinder filling dynamics with a duration control, but you really need to get a lift option in there to get any effective gain in top end. For econobox style engine this is a great idea, and certainly for engines that are looking to perform better in mid to lower range with targets of fuel economy and increases in torque.

Anyone with an engineering degree will realse flow dynamics are not going to be ideal and at every given value of lift and valve surface area, you can only have a given range of flow volume. From a performance view (with racing and top end and continous power in mind, it will be very limited). Of course one could design the cam to tolerate a big lift to begin with - but at the cost of torque and horsepower through midrange and bottom end.

Sure increasing duration will give you the theortical ability to have a MUCH higher rpm band, but engine dynamics fall off etc etc.

It does say on a website regard the WHC:

"In its ultimate form, the Williams Helical Camshaft can give a conventional car engine better than F1 performance with fuel economy rivalling that of a diesel."

and....

"These seemingly outlandish claims are backed by sound, conventional automotive engineering theory. Given that a suitable variable duration arrangement does exist, there are few engineers who would disagree with these claims. "



I dont understand how it can give better than F1 performance? Fuel economy rivalling that of a diesel is also a big call. Diesel engines, especially turbocharged diesel engines, are near the ultimate in fuel efficiency. Diesel technolgy has pretty much blown petrol combustion engines out of the water and it wont be long before we see these in mass produced vehicles. Im definately all for hearing their theories and open to ideas
Last edited by Autech on 2011-03-09 at 12-11-24.
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