Camshafts ADV & RET

[mick taylor]

So you all, i was thinking about the Barra 4.0L engine in the main.

About the cam timing ! regarding the intake Cam

So in regards to how and what goes on with the Advancing and Retarding show that is taking part.

So i have heard that some may at idle advance the camshaft timing 6 Deg then set the Cam at full 6 Deg Retard from 3000RPM ?
Or could set the Cam timing half way = 0 deg at times ?

So by rights the camshaft movement can be 12 Deg all up ?

Then we can start talking about what the Exhaust Cam is doing ? and when and why ?

Now in regards to exhaust emissions, the adjusting Game would have it's part in all of this ?

Now i know that regarding ADR27A Laws, Holden changed it's V8 Cam specs so that the intake and the exhaust valves close later and the reason for the exhaust valve being close later is to put more heat into the exhaust system, their by acting some what in the regards of a cat converter in burning un burnt fuel !
So our Barra 6 may do this as well at some point ?

Now another question is, i have conflicting views on what is Advancing a Cam and Retarding a Cam ?
So lets for argument sake in a old spec talk of a 20/60 Cam i am led to believe that 5 Deg ADV will make a 20/60 become a 15/55 and NEG 5 Degree will become a 25/55 !
But looking on the Net some claim it's the other way round ?

So in regards Spark timing if we ADV to 12 Deg this means the spark is set before TDC and reason for this is that the piston has stopped in fact for how many Deg ? regarding the rod and stroke ratio ? but we can go say 40 Deg Adv spark and the reason why we need more ADV is to do with performance and also economy reasons !

So if we Adv a Cam this is the logic ?

But then again a clock face only Adv and never Retards, so clock wise is Advancing ?

[jpd80]

Re Barra I-6
The Barra 190 engine had a vane-type VCT phaser – produced by Aisin – on each camshaft
that provided continual variable adjustment within a 60 degree range (10 degrees advanced
or 50 degrees retarded from the initial pin lock position).

when observed from the front of the the engine, the crank and camshafts turn in the clockwise direction
So any advance of either cam timing or spark timing means the event has to happen earlier or in the
anti-clockwise direction.

Since it takes time for the spark plug to ignite the flame front and to to completely combust the mixture,
Firing before top dead centre is essential to time for maximum work from the combustion but this depends on,
Engine speed, mixture strength and whether full throttle, any boost pressure or high vacuum due to light throttle.

Under light throttle high vacuum conditions, the compression pressure is much lower than the nominated compression
In some instances it could be as low as 3 to 1 or 2 to 1 and combined with lean cruise mixture, more spark advance
is required to account for the slower flame travel and less dense mixture charge.

Forget all the stuff you learned about 1970s engines advancing and retarding cams,
The modern VCT engines advance and retard cams depending on load, not just RPM.
under light load, the 3- valve 5.4 V8 would retard up to 40 degree cam timing to permit
a form of internal exhaust gas recirculating to meet emission controls, I suspect the Barra does similar.
Those Aussie engineers were so smart and employed a lot of brilliant ideas in the I-6.
They even had Jaguar engineers assist with tuning the harmonics of the engine to make it smoother.

[mick taylor]

Originally Posted by jpd80

Re Barra I-6
The Barra 190 engine had a vane-type VCT phaser – produced by Aisin – on each camshaft
that provided continual variable adjustment within a 60 degree range (10 degrees advanced
or 50 degrees retarded from the initial pin lock position).

when observed from the front of the the engine, the crank and camshafts turn in the clockwise direction
So any advance of either cam timing or spark timing means the event has to happen earlier or in the
anti-clockwise direction.

Since it takes time for the spark plug to ignite the flame front and to to completely combust the mixture,
Firing before top dead centre is essential to time for maximum work from the combustion but this depends on,
Engine speed, mixture strength and whether full throttle, any boost pressure or high vacuum due to light throttle.

Under light throttle high vacuum conditions, the compression pressure is much lower than the nominated compression
In some instances it could be as low as 3 to 1 or 2 to 1 and combined with lean cruise mixture, more spark advance
is required to account for the slower flame travel and less dense mixture charge.

Forget all the stuff you learned about 1970s engines advancing and retarding cams,
The modern VCT engines advance and retard cams depending on load, not just RPM.
under light load, the 3- valve 5.4 V8 would retard up to 40 degree cam timing to permit
a form of internal exhaust gas recirculating to meet emission controls, I suspect the Barra does similar.
Those Aussie engineers were so smart and employed a lot of brilliant ideas in the I-6.
They even had Jaguar engineers assist with tuning the harmonics of the engine to make it smoother.

Thanks, that's the way i see it.

From memory of the first Falcon 6 i was lead to believe that the Fairmont was the first to get adj cam positioning. and at idol she retarded and the advanced and at 3000 RPM she retarded again and at 3000 RPM the long intake changed to go too the short intake as well.

But they never went into the totality of the systems workings full on.

Barra 6 They still have an EGR port ? so as this is to reduce combustion temp not exceeding the ADR limit of gas that claim is so toxic.

Back in the old days the advantage of a twin Cam was one could adj the setup it you knew what you were doing to fine tune it to what you truly wanted within them limits. but nowadays we have this advancement that is way to another level ! This what i was pointing out to a mate of cars nowadays that we can run 4 cyl cars that perform so well that you would never of thought possible back in the 1990's.

I am driving a 4cy 2.4L non turbo and it could blow a good XD 5.8L away back in the day.

[MrEL]

Originally Posted by mick taylor

I am driving a 4cy 2.4L non turbo and it could blow a good XD 5.8L away back in the day.

A stock one yes.
A good one no.

[66 coupe]

Originally Posted by mick taylor

Thanks, that's the way i see it.

From memory of the first Falcon 6 i was lead to believe that the Fairmont was the first to get adj cam positioning. and at idol she retarded and the advanced and at 3000 RPM she retarded again and at 3000 RPM the long intake changed to go too the short intake as well.

But they never went into the totality of the systems workings full on.

Barra 6 They still have an EGR port ? so as this is to reduce combustion temp not exceeding the ADR limit of gas that claim is so toxic.

Back in the old days the advantage of a twin Cam was one could adj the setup it you knew what you were doing to fine tune it to what you truly wanted within them limits. but nowadays we have this advancement that is way to another level ! This what i was pointing out to a mate of cars nowadays that we can run 4 cyl cars that perform so well that you would never of thought possible back in the 1990's.

I am driving a 4cy 2.4L non turbo and it could blow a good XD 5.8L away back in the day.

download a demo of pcmtec or hptuners and you will be able to see the cam timing tables and functions etc

[mick taylor]

Originally Posted by MrEL

A stock one yes.
A good one no.

a stock off the floor 5.8L 4sp i am talking about.
Just as my Car is stock.
Sure mine does not have the torque of a 5.8L XD.

You know what i once bought a new XG Longreach ute 4.0L 5sp and had run my mates 5.8L stock XC with dual exhaust and he went out directly and bought a XG Longreach himself but found out the next day that it was speed limited to 180 KM/H and he rang them up at Ford and abused the hell out of them for that.
Mine was pre ED Falcon and i think it was the ED Falcon's that first got 180 speed limited.

Mine was speed limited to 210 KM/H.

But i remember running a XY GT side by side both from 100KM/H to 210KM/H all the way.

Not to mention my wife's stock Aurion would kill any stock GT even a XY GT.

[Franco Cozzo]

Originally Posted by mick taylor

a stock off the floor 5.8L 4sp i am talking about.
Just as my Car is stock.
Sure mine does not have the torque of a 5.8L XD.

You know what i once bought a new XG Longreach ute 4.0L 5sp and had run my mates 5.8L stock XC with dual exhaust and he went out directly and bought a XG Longreach himself but found out the next day that it was speed limited to 180 KM/H and he rang them up at Ford and abused the hell out of them for that.
Mine was pre ED Falcon and i think it was the ED Falcon's that first got 180 speed limited.

Mine was speed limited to 210 KM/H.

But i remember running a XY GT side by side both from 100KM/H to 210KM/H all the way.

Not to mention my wife's stock Aurion would kill any stock GT even a XY GT.

Thats because ADR27A/emissions stuff cripped all the old gear, it was a shitful era, then add in unleaded fuel being pox on its introduction in the mid 1980s, and it took until the 2000s for American 8 cylinder stuff to catch up to where they were in the 1960s with high compression ratios, no emissions crippling and leaded fuel.

Mind you Europe was doing much more powerful 6 and 8 cylinder stuff in the 1990s than the Americans, but it wasn't exactly in reach of the average punter, Mercedes 500SL and its M119 V8 comes to mind, its up about 100KW on a 5L Wheezer. Both naturally aspirated, 8 cylinders and 5L.

https://www.carsales.com.au/cars/det...16064371/?Cr=4

Look at this thing, absolute beast - I don't particularly like convertibles but this thing looked MINT, I'd become a hair dresser yesterday with pride if I had one of those.

Aurion beating a 1970s car is like bragging about beating Dylan Alcott in a race up a set of stairs, compare a 1971 Toyota Crown with its 2.6L I6 making 81KW against an XY GT with its 351C for a more apt comparison.

[mick taylor]

Originally Posted by Franco Cozzo

Thats because ADR27A/emissions stuff cripped all the old gear, it was a shitful era, then add in unleaded fuel being pox on its introduction in the mid 1980s, and it took until the 2000s for American 8 cylinder stuff to catch up to where they were in the 1960s with high compression ratios, no emissions crippling and leaded fuel.

Mind you Europe was doing much more powerful 6 and 8 cylinder stuff in the 1990s than the Americans, but it wasn't exactly in reach of the average punter, Mercedes 500SL and its M119 V8 comes to mind, its up about 100KW on a 5L Wheezer. Both naturally aspirated, 8 cylinders and 5L.

https://www.carsales.com.au/cars/det...16064371/?Cr=4

Look at this thing, absolute beast - I don't particularly like convertibles but this thing looked MINT, I'd become a hair dresser yesterday with pride if I had one of those.

Aurion beating a 1970s car is like bragging about beating Dylan Alcott in a race up a set of stairs, compare a 1971 Toyota Crown with its 2.6L I6 making 81KW against an XY GT with its 351C for a more apt comparison.

Bragging ? just stating a fact !
Look at the times all the way from 10KM/H to 230 KM/H the Aurion blow's away any old GT in fact !
Look at the performance of the FG Falcon 4.0L 6 sp auto and the Last V6 Commodores but hey that can not hose off an Aurion in fact, put 95 octane in the Aurion and they really get up and go better than on that 91 crap.

I think that the FG Falcon 6 will hose off any old stock GT.

I am not worshiping the Aurion at all but it's a fact. Wife bought it ! i pushed for the Falcon 6.

A XY GT makes about 245 HP DIN.
A XC 5.8L makes 162 KW = 217 HP DIN Dual exhaust, Single exhaust 188 HP = 149 KW DIN.

Aurion 3.5L makes 200 KW DIN on 91 octane and on 95 octane maybe 220 KW ?

I do not think that Unleaded dropped the power of cars at all, The VL 3.0L went real well as did the EFI XF Falcon.
Not to mention come the XD alloy head they went better than pre ADR27A 250 6 CYL in fact.

Oh the 1971 Toyota Crown i remember them, they had a huge following when talking to owners of them, i bagged them back in the day, but they could take on a HQ Holden 202 auto ? not my cuppa tea at all, but in 1980 some old dude at retirement home was trying to sell me his 202 HQ Auto and he boast it's got the Big 6 in it ! I looked at him thinking he was a retard ! Big 6 indeed !

Now on that point ? thinking back regarding older generations look what most of them drove Old Holden Grey motors and 186 Holden or 170 to 250 Falcons ! now that's gutless, what is that slow nowadays ?

[Franco Cozzo]

Originally Posted by mick taylor

Now on that point ? thinking back regarding older generations look what most of them drove Old Holden Grey motors and 186 Holden or 170 to 250 Falcons ! now that's gutless, what is that slow nowadays ?

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