EFI Testing - Dyno Day 6: 1.5:1 Ratio rockers
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Schrödinger's cat - so which one am I ???

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
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13 mm deflection and 10 deg Change sounds fine to me, a longer chain would very needed, or you could look at doing it with a belt. (Andy no!! Lol!)

I did look at these oil presure controlled pulleys with a view to adapting them into the K head, but it was all looking a bit far outboard of the cam bearing for my liking, plus it would be easier to just use the fiat head with mappable valve timing....

Belt?! Pahahahahaha!

In the 13's at last!.. Just

This is amazing progress, keep up the good work

Team www.sheepspeed.com Racing

Re variable cam timing ,

what i was thinking of doing is ,

some engines had a pair of sprockets mounted on a bar in a tube .., one at either end .this tube was then mounted horizontally in the middle of the cam chain run...,halfway between the cam sprocket and the crank sprocket ..the centre part was mounted solid , and the bar inside could be moved, by oil pressure i guess, from side to side .

so you have a pretty slack chain , and the bar is over to the left taking up the slack , and the cam is max advanced , then the pair of sprockets can move to the right , and take the slack over to the other side and now your at max retard .

i cannot remember what engine had it .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Audi rings a bell for this kind of arrangement.

The problem - as I see it - with the A-series is that the chain run is so short.
To get enough sideways movement (both equally on the driven and non-driven side) to change the timing by those sort of figures the two additional sprockets would have to be just below the big (cam) sprocket and force the (new, longer) chain to loop underneath it either side (alternately).

It would be interesting to sketch it out though.

Somewhere in the garage I have a complete spare duplex set (if only I could remember where...)

Schrödinger's cat - so which one am I ???

Hmmmm....

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OK Joe, stop teasing....
What is that ???

It looks a bit like a hydraulic phase wheel but I thought they only used the hydraulic ones on engines with chain driven cams.
(for obvious reasons).
Actually, I'll take that back, I think the Volvo derived 5 pot engines used hydraulic phase wheels with belt driven cams (I'm not 100% sure but I know my current daily is chain driven VVT so it's all in oil).

I've dug out my spare duplex chainset and the issue is immediately obvious - the two sprockets are so close together that pushing the chain from either side, it doesn't really matter where you push it, it will wrap underneath the big sprocket a lot.

The fundamental issue is that with a Reynolds chain - doesn't matter whether simplex or duplex - the links have to be an even number because they alternate inner and outer link plates.
The chain appears (from a crude measurement) to be 3/8" pitch so the next possible chain length would be 3/4" longer.

And from a very quick practical test it does NOT seem we are able to "lose" 3/4" by pushing the chain in from either side or both sides.

Just a crude test on a chain and a ruler but maybe a belt is a better solution as their tooth pitch is usually less than 3/8".

Schrödinger's cat - so which one am I ???

So varying the tension on the timing chain looks like a bit of a no go then…

But I have had a quick look at the prices of a belt conversion kit – That would have to be some serious saving…
In the meantime, spend some time researching these phaser wheels and how they work.



But for now, 1.5:1 rockers now fitted





This should be interesting to see how this changes things.


But before I get back on the road, seeing as I have most of it stripped out, I’m now going to finish off the New runner welding.


I am sorry about the obscenely shiny bling below, I was just attempting to keep runners a bit cooler. Personally I’d rather accept a bit more heat soak!
I might even try to make a heat shield while it is off the car this time.







Piccy above is with the Runner fully extended. Back runner still in its original 407mm position.

Someone on here posted a picture in the past of some long cast inlet manifold for a carb, sometime in the dim distant past (I think it was Joe?), but I can’t find it now. Would just be interesting to compare.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

i think this is the sort of thing i was thinking of , its moves the sliders one way or the other .

https://www.aliexpress.com/item/32852690846.html





so if mounted in between the chain runs it would take up the slock one way or the other and so change the timing .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

LOL Rod

I think Its from the 5 cyl volvo lump used in the focus RS's,

esentially there are two oil inlets, one feeding to either side of some "vanes" solenoids balence the oil pressure to change the cam timing, its got 15deg retard marked on it.
I imagine one side is fed from a lower presure regulated feed for the lifters, and the other side has a solenoid. there must be a cam sensor for feedback too, I imagine it must be a closed loop PID type thing to stop the timing going awol.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

On 26th Jul, 2019 Graham T said:

On 26th Jul, 2019 Joe C said:
LOL Rod

I think Its from the 5 cyl volvo lump used in the focus RS's...

Rod runs outside and starts stripping his engine down to see if his has the same arrangement.

Schrödinger's cat - so which one am I ???

Gratuitous topless shot.....

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Joe,

What's the max OD of the left and middle bits (ie, would it fit into a machined out duplex sprocket), and what's the rear view like ? - The Ford ones I've seen actually only use the oil pressure in one direction and have a massive clock type spring on the back for the return.

Schrödinger's cat - so which one am I ???

105mm, but probably enough meet to trim a little off the outside, maybe down to 100mm.

I thought the same about putting it into a chain sprocket.

That could be do-able then.

The cast recess in the duplex sprocket I've got in front of me is 96mm but the inner face of the chain runs at 112mm so the cast recess could safely be machined out to at least 105mm. (there will be some pictures up later).

What about th rear face, is a return hair/clock spring (like the Ford ones) or is it twin oil feeds like you suggested before ?

Schrödinger's cat - so which one am I ???

On 26th Jul, 2019 robert said:
i think this is the sort of thing i was thinking of , its moves the sliders one way or the other .

https://www.aliexpress.com/item/32852690846.html





so if mounted in between the chain runs it would take up the slock one way or the other and so change the timing .

Edited by Rod S on 26th Jul, 2019.

Schrödinger's cat - so which one am I ???

Rod, if you still have this to hand, what are the dimensions as per the below?





Just to work out (crudely) the actual chain deflection required.



What sort of clearance is there normally from chain to the Timing chain cover on the left?


Increasing the deflection of the chain (or belt) on the left will effect cam timing change, pulling the cam wheel clockwise, but is there a need to actuate movement in the other direction?

Reducing the tension on the left will allow the cam to naturally return to a "base timing" (anti-clockwise), so only a spring loaded tensioner to take the slack of the chain would be needed on the right?
But depending on the total chain deflection, that spring loaded tensioner might need to be travelling also?

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Yes,
Still out on the bench.
I've got the cover out of storage as well but have yet to find the backplate and tensioner.

I'll photo and measure what I've got this pm.

I don't think we could rely on the cam returning by itself - yes, there is significant drag through having to move all the valvetrain but it's not by any means constant. As any individual lobe goes over it's peak, the spring energy will start to accelerate the cam rather than drag it and whilst the next lobe doing its work of opening its valve will counteract it, it won't be near the peak so won't be absorbing as much energy. That's how I look at it anyway - if you turn a cam by hand with the belt/chain off (and obviously pistons all half way down the bore) as I had to do to reset the timing from scratch on the Cossie after the belt failure it jerks forward after you pass the lobe peak. More exaggerated on a twin cam as each cam has the lobes twice as far apart but I think the same applies to a cam that is doing all eight.

And certainly on the Ford design hydraulic VVT which only uses the pressure in one direction, there is a very substantial hair/clock spring built in to make sure it goes back.

EDIT - typo

Edited by Rod S on 27th Jul, 2019.

Schrödinger's cat - so which one am I ???

Forgot to add....

To double check my maths and see how it might work in the real world, I ordered 1m of chain and a couple of joining links to make a test chain with two extra links and also one with four.
Not automotive grade chain (that's a bit more expensive) but as it's duplex it will probably still be stronger than a standard simplex chain.....

Schrödinger's cat - so which one am I ???

On 27th Jul, 2019 Graham T said:
Rod, if you still have this to hand, what are the dimensions as per the below?

Schrödinger's cat - so which one am I ???

OK Rod,
I take you point about the cam returning on it's own.

I thought I was going to be clever and work out the amount of chain deflection required to move the cam around, but I came up with around 1.37", which cannot be right?

It will be interesting to see what the chain you have ordered shows.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675