Author Topic: Enigmatic 3.2JTS  (Read 1001 times)

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Ascari32

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Enigmatic 3.2JTS
« on: July 14, 2020, 09:40:13 PM »
Hi all!

Just been snooping around for information/yet more clues to this enigmatic car and came across a topic "3.2 JTS -best exhaust, etc, etc.", the last post to which was some 120 days ago.  It was suggested I start a new thread. Not sure it warrants a thread, but here are my two pennies worth anyway!

Although I felt I was done with the work on my engine, it seems I just cannot get enough of information which is relevant to the issues that have surrounded it/dogged it, from new.

Then I stumble over this site which raises some of the issues I have faced.

The Manifold cat on the 3.2 JTS are a real problem insofar as they retain so much heat, the consequences for the engine long term are dire. So, I removed them and fitted Autodelta headers. Removing the manifold cats from an Italian 147 GTA resulted in a substantial drop in engine oil temperature which simply confirmed my belief. And sure enough, mine too dropped, substantially.

I have had several conversations with Autodelta and the estimate I was given for reduced power losses due to improved flow was circa 8 bhp. research and talking to some authorities about this indicates this is a reasonable assumption.

However, the headers were always going to be done in conjunction with replacement camshafts. Again research into valve timing and having fitted after - market camshafts to four of my previous Alfa's, it became clear the JTS static timing creates NVO - Negative Valve Overlap. Exhaust valves close at 9.0 deg. Atdc, Inlet Valves open 11.5 deg. Atdc. Hardly the kind of timing one associates with performance engines. So they were also replaced.

Listening to various YouTube posts of 3.2 JTS exhaust systems, one can hear popping and farting of the exhaust after the driver has lifted, a function of NVO in my opinion and the waste of "scavenging depression" in the manifold due to exhaust valve being closed before the inlet opens.

My engine had a characteristic drone at 2500 rpm and I believed when I replaced the manifolds and the camshafts, it would be resolved. Not so! It just made matters worse. So more research was required, this time into resonators, Helmholtz' cat - backs, rear boxes and Catalytic converters.

Research indicated with "Vee" configurations, to maximise scavenging, the two halves of the exhaust system should be cross coupled. but Alfa chose to couple them after the twin cats, which are restrictive and at a point where the diameter of the exhaust increases dramatically, thus diminishing any negative pressure even further.

I really did not want to spend a shed load of money on a new cat just to prove I was right or wrong - my understanding was still primitive. So the cheapest option, given I thought the Alfa cat was also exacerbating drone in the central section of the exhaust - namely the Alfa resonator/first muffler - was to replace it.

A long search later and I found a Supersprint Central Section - no resonator - at a fair price. The supplier was very helpful with advice and it was soon fitted to my Q4.

2500 rpm drone now gone! True, wide-band exhaust noise is greater, in a pleasant way, but a total absence of "Resonance". Not only that, with the masking effect of the Alfa resonator, having been eliminated, the power in the exhaust gases is now such that the Alfa rear Boxes are overwhelmed and break up with a crackle/rasp/rattle.

However, with less restriction, it became obvious the popping and farting I attribute to NVO was absent. This would correlate with the valve timing going from negative 2.5 deg. to PVO: Positive Valve Overlap, of 23.5 deg. So the rear boxes were rattling apart "On - The - Throttle" and not "On - The - Overrun"!

Cue New Rear Boxes!

They have now arrived and will be fitted on Thursday. But, this simply dragged me back to the Alfa Twin Cat. The restriction they create, and the output of it dissipating any potential for scavenging; because of the post cat - coupling, meant I was faced with a massive modification exercise on the Alfa Cat, the front flexis from the headers and butchering the central Supersprint section to make the Alfa Cat work. Plus labour costs which don't come cheap.

Choice! Autodeltas or Supersprints Sports Cat! I chose Supersprints and as it has to be made to order, I still have five weeks to go before delivery.

It has been a massive undertaking on my part, not to mention expense. All this work was undertaken after the rebuild of my spare engine, in-itself as huge expense.

However, looking back, camshafts, headers and exhaust are inextricably linked and no amount of tinkering with one will resolve the limits of the others. Camshafts cannot function properly with POV, unless manifold restrictions are reduced. Manifold swaps cannot compensate for Alfa's appalling choice of valve timing. And without a genuine free flow exhaust system, including a properly designed cat, which combines the two banks at its input, so much of the benefit of new cams and headers is wasted.

I suppose the question is, was it all worth it. I think it is a great car which could have been up with the best of them. I just saw it as an opportunity to explore a spare Brera engine which suffered a bent crankshaft and wrecked bearings at only 40 - ish thousand miles. When my 159 engine failed at ~ 112,000 miles, it became essential to rebuild the Brera, or scap the 159. Then I would be faced with making another purchase.

The work I have done is still - just - below what I would have had to spend on another car. So at least I have got what a I wanted - a pretty powerful Q4.     
« Last Edit: July 15, 2020, 01:34:16 AM by Ascari32 »

Australia

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Re: Enigmatic 3.2JTS
« Reply #1 on: July 16, 2020, 08:09:06 AM »
Good story!

Vids please!

Colin Edwards

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Re: Enigmatic 3.2JTS
« Reply #2 on: July 16, 2020, 11:02:43 AM »
Google "Holden High Features Engine".

Not sure I agree 100% the 3.2JTS is enigmatic. 

Alfa did a pretty reasonable job of coaxing an additional 22kW out of the JTS compared to a "similar" GM/Holden 3.2.
Likely much of this came about via adopting direct injection and upping the compression ratio considerably.  Both of these measures will increase torque, however Alfa managed to get their 3.2 to produce more torque at higher revs - more power!
Unfortunately the higher combustion pressure and temperature hurts emissions / NOX etc.  Its no wonder the manifold cats get so hot.  The relatively small combustion chamber surface (including piston crown) of the JTS will conduct less heat away compared to say the big bore 12 valve 3.0 Busso.

Alfa (and their lawyers!) would be happy to have these manifold cats get stinking hot soon after starting.  This feature allows the cats to do their job and clean up the emissions when the rest of the engine is relatively cold.  An issue VW had a problem with?
Seem to recall reading somewhere Alfa did some clever stuff with regard to cam phasing at low load / low rpm in order to introduce a bit of EGR and drop combustion temps a bit to manage NOX.  Also recall mention of the 3.2JTS able to run very lean at low rpm / low throttle openings.  All to do with meeting emissions.

With regard to scavenging, its possibly less important with direct injection as the fuel mixture needs to arrive in the combustion chamber at precisely the correct moment.  Easy to do with electronics and a bit of code.  Controlling scavenging in a very precise way could be difficult, hence the popularity of turbo charging?

Colin.
« Last Edit: July 16, 2020, 11:36:41 AM by Colin Edwards »
Present
2018 Abarth 124 Spider
2015 Giulietta QV (2020 Giulietta Veloce on the way)
1987 75 3.0

Past
2009 159 3.2 Ti Q4
2012 Giulietta TCT Veloce
2006 147 Ti 2 door Selespeed
1979 Alfasud Ti 1.5

Ascari32

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Re: Enigmatic 3.2JTS
« Reply #3 on: July 26, 2020, 02:32:10 AM »
Actually, I think it was Holden/GM/Chrysler that did the good job. Personally, Alfa made a bit of a dogs breakfast out of it.

The Brera engine I bought was wrecked at 40,000 - ish miles and as I was retired by then, thought it would be a nice exercise in getting to know what made the JTS 3.2 tick. My 159 at the time was getting on for 110,000, and the chances were I would need to do something about the engine if I was going to keep her long term.

I knew the Brera had a bent crankshaft so it was a definite strip down job. Little information was available to me; the Alfa Dealers largely unhelpful and spares incredibly hard to come by and expensive when I did.

First - off was to have the crank inspected - informed it was too far gone to be pulled back. New crank thousands from Alfa. So I bought a new one from Aus + shells. A$ 900. In the mean time, I found a company which devoted all its time to engine overhauls - and they pulled the crank back. Queue regrind to first over-size , plus balancing. A couple of new con rods and a chain and tension-er kit from Mace, plus an oil pump.

However, horror stories about timing chain stretch and oil pressure led me to investigate these aspects of the engine. Also the perpetual rear bank exhaust position sensor failure codes. Actually, it just spilled over into a two year + project, whereby I designed a Closed Loop Lubrication System: CLLS, which gets oil directly from the Oil Cooler/Filter Unit to the block plug adjacent to the rear bank primary timing chain tension-er. I included a horseshoe loop from the same unit into the main front bank cylinder head Oil Gallery. And shifted the oil pressure switch to the horseshoe, the horseshoe being 12 mm. stainless and the rear line to the timing chain tension-er, 10 mm. No worries about oil pressure or tension now!

Next, came the VVT system whereby I modified the VVT solenoids to close the bridge across the ports to ensure the cam positions were held properly when the ECU set the angle of the cams. At the same time, I modified the rear bank exhaust camshaft position sensor so that the rotor plate of the cam sprocket would cut the field of the Hall effect sensor at exactly right angles. Bosch State the output signal timing is greatly affected if there is any error. To me It looked as if it was about  10 deg. out - they state +/- 0.5 deg. in their spec I believe. These devices are very clever but require accurate alignment. And it seemed perverse that the other three were precisely aligned!

At the same time, research into this engine indicated lubrication was based upon a sump capacity of 4 litres with 1.8 litres in circulation. But the return time of oil back to the sump was particularly long, the oil pick up was high and the drains from the heads were cast into the block in such a position as to cause returning oil to be drawn into windage.

So I bought a later variant pick - up snout, and modified it to lower the screen such that I have about 1 litre extra margin before the pickup becomes exposed, particularly when cornering. I also had the windage plate extended to the full length of the sump and had the drains from the block carried below it by welding aluminium channels/covers to the sump walls, ensuring oil returning from the head, goes nowhere but directly into the sump.

It then was a question of fitting the rebuilt engine into my 159 after its wrecked engine was removed. I am still proud of the guys who did the job given they were not "Alfa Trained". There only experience with Alfa being, they had removed the Brera engine and re installed a good worker. All they asked was to see the 159 running before they started.

They transferred all the ancillaries from the 159, fitting the Autodelta manifolds at the same time, a new clutch and Dual mass flywheel + new release cylinder. The Colombo Bariani Camshafts had been installed, but some of the hydraulic lifters were in the wrong positions. So they had to come off. Happily, I had designed a camshaft removal tool so they were corrected with the engine in situ. Another job they did brilliantly well. 

I had the car Dynamometer tested with the old engine, to which I had installed the CLLS as a proving exercise, but before I modified the VVT's. She pulled 266 bhp - 270 din. However, after the VVT mods were done, performance stepped up again to an estimated 280.

However, it is a different story now. With the changes to the valve timing, the Autodelta Manifolds, a Supersprint Centre section - resonator free, new back boxes and the Supersprint Cat coming soon, I hope to be in the region of 315 bhp. At the same time I have being some road - trials, to gauge the improvements. Nothing of course can be confirmed until I get her back on the dyno but, currently having recently fitted a new set of P zeros, after 3000 miles, the rear pair don't have much life left in them. She most definitely has a rear wheel bias as the fronts are still virtually new.

I am hoping to get to a meeting as I need to try a standard 159 or Brera to compare; as the more I drive it, the more it seems it was always like this. Not so. Throttle response is brilliant, bottom - end: she can pull tall gears at low speeds without complaint and she is very quick. I must be careful as BMW and Mercs are like a red rag to a bull. Not the M's or the AMG's, but everything else. Economy is great, upper 20's urban, 30+ on motorways, docile around town, but vicious when winding her up. It continues to surprise me how she carries her weight with ease - that was not the case before.

I will have to get a remap as she ticks over beautifully at 750 rpm, but she sounds menacing, growling instead of purring. But the valve timing has changed a lot which probably accounts for it. Over 3000 rpm she sound delicious, as she piles on the revs - the new rear boxes being substantially straight through above 3k. However below? Got all the grunt in the world, but she will waken the dead in Moscow. That needs sorting. But not till the S.S. cat is fitted. Then I may have to look at doing some exhaust gating to throttle her down below 3k and opening the pipes up above. 

Ascari32

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Re: Enigmatic 3.2JTS
« Reply #4 on: July 26, 2020, 03:53:12 AM »
Sorry, but there was a couple of other issues I addressed, but omitted from my last post.

This engine, fitted to the 159 and Brera is transversely mounted. Yet the sump is completely devoid of any baffle plates!

As part of the exercise to help prevent starvation - exposing the pick - up, I had baffle plates welded to channel oil via the oil pick - up snout; whatever the direction of travel, cornering, braking or accelerating, the oil will always pass under the pick - up.

Allegedly, complete engines were delivered to Alfa Romeo, which were then stripped down and modified to produce a performance engine worthy of the Alfa Badge. Fundamentally, very little was done. Cylinder heads and VVT's. But little else was done. One can forgive Holden for what was essentially a very straight forward unit. But not Alfa Romeo, who wanted 16500 for a replacement new engine or 12000 for a refurbished one - fully fitted.


The Holden block is superb and is as strong as an ox. The way the crankshaft is embedded into its bearings with side bolts and four main bolts per cap is impressive. The engine without VVT would have had sufficient oil pressure for normal purposes. But for Alfa to run all services from a single pump was stretching things two far. And with restrictions within the oil-ways, resulting in poor flow and pressure regulation, it does not surprise me the 3.2 JTS acquired such a poor reputation. A shame really, because it could have been a great car, up with the best. Now, so many are simply going to the breakers yard.

I am glad I found out what makes this engine tick, or not tick as the case may be. And one thing I am certain of, I shall not be parting with mine anytime soon - if ever. When modified, it is a superb engine and a classic and classy car.

Just to make one further observation. The VVT system is superb. I don't actually believe Alfa designed it, preferring to credit another division of the Fiat Group. When it works properly, it is so agile it could only have come from the Ferrari stable. It results in absolutely seamless progression right across the rev range, with oodles of torque, whatever the revs., with beautiful linearity.     
« Last Edit: July 26, 2020, 04:24:03 AM by Ascari32 »

Ascari32

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Re: Enigmatic 3.2JTS
« Reply #5 on: July 26, 2020, 06:34:06 PM »
Google "Holden High Features Engine".

Not sure I agree 100% the 3.2JTS is enigmatic. 

Alfa did a pretty reasonable job of coaxing an additional 22kW out of the JTS compared to a "similar" GM/Holden 3.2.
Likely much of this came about via adopting direct injection and upping the compression ratio considerably.  Both of these measures will increase torque, however Alfa managed to get their 3.2 to produce more torque at higher revs - more power!
Unfortunately the higher combustion pressure and temperature hurts emissions / NOX etc.  Its no wonder the manifold cats get so hot.  The relatively small combustion chamber surface (including piston crown) of the JTS will conduct less heat away compared to say the big bore 12 valve 3.0 Busso.

Alfa (and their lawyers!) would be happy to have these manifold cats get stinking hot soon after starting.  This feature allows the cats to do their job and clean up the emissions when the rest of the engine is relatively cold.  An issue VW had a problem with?
Seem to recall reading somewhere Alfa did some clever stuff with regard to cam phasing at low load / low rpm in order to introduce a bit of EGR and drop combustion temps a bit to manage NOX.  Also recall mention of the 3.2JTS able to run very lean at low rpm / low throttle openings.  All to do with meeting emissions.

With regard to scavenging, its possibly less important with direct injection as the fuel mixture needs to arrive in the combustion chamber at precisely the correct moment.  Easy to do with electronics and a bit of code.  Controlling scavenging in a very precise way could be difficult, hence the popularity of turbo charging?

Colin.

Hi,

With regard to clever things Alfa have done with cam phasing and thus valve timing, a standard 3.2 JTS engine exhaust valve closes at 9 deg. Atdc and the inlet opens at 11.5 deg Atdc., giving a NVO of 2.5 deg.

Research demonstrated that the waste products and thus pollutants are the last to leave the cylinder and typically are highest around the cylinder/piston/ring interface.

The piston crown of the 3.2 JTS engine is designed to produce swirl, which draws pollutants away from this area; the cylinder wall/piston/ring interface, into the centre of the piston, which has a small depression resembling a secondary combustion chamber.

The Negative Valve Overlap; in conjunction with the piston crown design, is effective because the piston is 11.5 degrees into its induction stroke before the inlet opens. However, the initial "Swirl Pattern" is sustained when cool inlet air enters the cylinder and swirls around the piston walls, cooling them and initiating the creation of a stratified charge.

The stratified charge is concentrated in the area around the small indentation, to which the previously the UN-burnt products have been drawn. The density of the charge, being stratified is thus most dense in the central region and least towards the cylinder walls.

This stratification continues to exist throughout the compression stroke; again due to piston crown design, until ~ top dead centre, at which point the fuel is injected, the injector directing the fuel to the centre of the stratified charge.

Because of the high compression ratio and importantly, the high pressure of the fuel injected, the fuel goes through a chemical reaction with the trapped Hc's/pollutants at the centre, which modifies the charge. This chemical reaction modifies the charge to the extent that almost complete destruction of pollutants occurs during combustion.

Plus, because the central indentation; pseudo secondary cylinder is small, the actual AFR in that region is quite rich - but only relative to the volume of the indentation. In terms of the total swept volume, it is extremely lean.

Central to this indentation is the spark plug, so ignition is very rapid. As the piston descends however, the increasing volume/space quickly assumes a very lean burn characteristic. Naturally there is very little power in the stroke, but there is sufficient for a solid tick-over and for periods when the driver lifts of the throttle - these are the periods when the AFR is extremely lean for the capacity of the engine. However, the result is very low emissions at low load and tick-over.

Valve timing plays a major role in this as when the engine is switched off, or on tick-over, the inlet camshaft is fully retarded and the exhaust camshaft fully advanced. This results in the engine being very easy to start and when running provides for very light load operation. 

However, critical to this is VVT agility which, given it is oil pressure derived, it is not!

Just decided to add a foot note:-

Because of the 2.5 deg. NVO and the piston being 11.5 deg. into the induction stroke, a slight depression exists, helping pull pollutants away from the cylinder wall/piston/ring region. However, with the spray lubrication of the pistons and cylinders, wetting of the rings is continuous. Therefore, to a degree, depending upon the condition of the rings, along with pollutants being drawn into the combustion chamber, oil will also be drawn.

Certainly with my 159, engine oil consumption was a real problem. It seems as though there is a connection between this and piston ring wear. A degree of negative pressure must continue beyond the initial 2.5 deg. NVO and thus, if the ring/piston/bore seal is poor, oil consumption will be high. Mine certainly was.

However, with the change of camshafts and 23.5 degree PVO, oil consumption is very low, the inlet valve now opening at 0.5 deg. Before top dead centre and the exhaust closing at 23 deg. After top dead centre.       
« Last Edit: July 26, 2020, 07:13:12 PM by Ascari32 »

sportiva

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Re: Enigmatic 3.2JTS
« Reply #6 on: July 26, 2020, 08:06:37 PM »
WOW! you should have been around when FIAT decided to use a GM/Holden engines in Alfa Romeo's
You could have told the dumb engineers how silly they were and reminded them of their stupidity
3.0 GTV6 Fiat Free
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Ascari32

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Re: Enigmatic 3.2JTS
« Reply #7 on: July 26, 2020, 08:52:35 PM »
It is not untypical of engineering today. It is not, in my opinion, that there are less gifted engineers around. Just with modern company set ups, little thought is given to the overall strength and the skills in any team. And a lot of appointments are political.

Busso was marginalised by the change over with the bias going towards Fiat appointees. It was only two years after he left the company that his V6 went into production, the "New" team having failed to come up with anything. Jano too was virtually marginalised. Chiti too.

The Space Shuttle which blew up on launch, only did so because the engineer who was responsible was bludgeoned into agreeing to the launch, despite the leaking seals on the fuel cells. He spent years suffering mental issues as a consequence.

It is my opinion, the 3.2 JTS could have been a better engine than the Busso V6. After modification it certainly is. It is well, the Giulia 2.9 was designed by an independent team, because sure as eggs are eggs, there is nothing of worth left at Alfa after the Busso generation left. They are in my opinion simply assembling cars, the parts of which come from a multitude of sources.

   

Ascari32

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Re: Enigmatic 3.2JTS
« Reply #8 on: August 01, 2020, 04:45:15 PM »
Quote:-  "However, critical to this is VVT agility which, given it is oil pressure derived, it is not!"

Having made this statement, I feel I must justify my reasons for making it.

The rebuilding of my Brera engine did not start immediately I wrecked the 159 engine. I purchased it at least some 18 months prior to that little escapade. So by the time the 159 failed, I had done a fair bit of research into it. And it was this engine which provoked the design of my C.L.L.S. It was quite clear there were serious restrictions within the block and the main timing chain tension-er was right at the end of the oil galleries, where it simply got what was left after all other services were catered for.

With the quantity of white metal shards, liberally scattered around the Brera block, oil ways included, it was obvious the galleries would need pulling through. But I was curious about the VVT's. More so, given there appeared to be shards in them too! How could this be? There are micro-mesh screens across all three of the VVT Solenoid Ports. It became clear the VVT Rotors would need disassembling and inspecting. That is not an exercise for the faint heart-ed.

Sure enough, white metal shards littered the voids of the rotors so it was clear, the screens were not keeping contamination out. On inspecting the VVT solenoids, it was seen, "Flats" are cut into the separating "Walls" of each port, "bridging" the oil pressure feed to them, with both the advance port and the retard port. The existence of these shards in the voids, confirmed oil indeed could circumvent the ports proper and enter the voids via these flats.

From this, it became clear, when oil was flowing to advance or retard valve timing, pressure was being lost as the flats allowed oil to pass straight to the solenoid drain and out into the cylinder head. So flow rate was being reduced, increasing the time it took for the valve timing to "Set", by rotating the rotors. Fundamentally, this affects the inlet camshaft advance and the exhaust camshaft retard much more so than the inlet retard and the exhaust advance, but non the less affects the rotors in both directions. (1)

The camshaft rotors have internal spring bias which rotates them back to their "Parked" positions. These are; inlet camshaft fully retarded and exhaust camshaft fully advanced. (2)

Because of the direction of rotation of the engine, inertia forces the inlet camshaft naturally in the retard position and as a consequence, the strength of the inlet rotor spring is weak and movement is substantially dictated by oil pressure.

However, because of the direction of rotation of the engine, inertia on the exhaust camshaft is also in the retard direction. As a consequence of this, the internal spring of the exhaust rotor is extremely strong, to keep it in the advanced position. Good - luck to anyone who attempts to disassemble these rotors and then put them back together!

When the engine is switched off, the inertia of the valve train, plus the internal spring, returns the inlet camshaft rotor to the fully retarded, "parked" position, where the internal "Pin" locks it into position. In the case of the internal spring of the exhaust camshaft rotor, it is sufficiently strong enough to rotate the camshaft to the fully advanced position - against the inertia of the valve train and the "Pin" locks it into position.

At tick - over, the ECU ensures the solenoid valve ports are set such that the inlet advance port is open to "Drain" and the exhaust retard port is open to "Drain". This ensures the "Pin" remains "In". Operationally, the pin is forced out by the oil feed from the solenoid valves and initiates the "Fill" of the rotor voids to start camshaft rotation. (3)

For this very reason, tick - over should always be a rock - steady 750 rpm.

From the above, it appears obvious to the author, the camshafts; due to the continuous feed - oil "Bleed to Drain" via the solenoid "Flats", the speed of the camshaft rotation is already predisposed to be longer than necessary which compounds the issue of failures of the camshaft positional sensors - particularly the rear bank exhaust camshaft. (4)

However at a time when the ECU has "Set" the valve timing and both the inlet solenoid advance and retard ports are closed, inertia, + the internal spring will cause oil to be forced across the flats bridging the ports, causing the inlet camshaft to retard - move away from the angle dictated by the ECU. (5)

Equally, at a time when the ECU has "Set" the valve timing and both the exhaust solenoid advance and retard ports are closed, the internal spring will cause oil to be forced across the flats bridging the ports, causing the exhaust camshaft to advance - move away from the angle dictated by the ECU. (6)

Thus, the valve timing is never properly "Set", insofar as the angle chosen by the ECU is never maintained. (7)

One extremely detrimental consequence of this is, the exhaust camshaft will always be moving away from any retard angle the ECU has predicted in the direction of advance.  Perhaps one of the reasons why the front bank manifold Cat displays evidence of extreme temperature - heat corrosion? This is because, when the engine is making power, the exhaust camshafts will be retarded by the ECU. But with the internal spring forcing oil across the bridge, the exhaust camshaft will become advanced, causing the exhaust valves to open early and causing the cat, and the head, to overheat. (8)

Reading many posts on forums, there have been reports of coil packs burning out on a regular basis, high oil consumption and early degradation of oil. Plus the ubiquitous rear bank exhaust camshaft position sensor failure code. It is inconceivable that Alfa set out to combine so many weak elements in the redesign of the Holden V6.

So there must have be a common denominator to all these issues, surely? Oil pressure certainly has a great bearing on timing chain tension and inadequate pressure will result in poor mechanical timing between front and rear VVT rotors. Reduced oil pressure will also increase the delay in the camshafts setting time between banks (Hydraulic Timing). And a leaky VVT System which fails to "Hold" the correct valve timing angle chosen by the ECU will result in power loss, overheating of cylinder heads, manifold catalytic converters and early oil degradation.

It is all very well to think that the oil temperature gauge on the instrument panel of these vehicles is sitting at the ideal. But that is the temperature of oil in the sump. Research has shown that actual "Bearing Face Temperatures", particularly under load condition, can be as much as 45 degrees higher depending upon application.

This neglects the fact that the returning oil from the heads, exits the block, via huge drainage ports, clinging to their walls by skin effect, where rotating journals immediately pull it into windage, coating the hot, cavernous internal block and increasing the transit time for it to return to the sump.

Chrysler demonstrated that the engine oil of a V8 could be sucked into windage and rotated around the crank, with the sump being completely emptied.

This was at a time when they were experimenting with windage plates and subsequently scrapers. However, the windage plate in this engine did not exist in the original version and was only added later. But it does not extend the full length of the sump. With the latest incarnation of this engine - will run until 2026 - it does. Plus they have made extensive modifications to the block including increased sump capacity and baffle plates to prevent surge. And I am led to believe improvements in oil pressure an flow distribution.

Heavy going I know - sorry for that. But I felt the need to justify my comments.

 P.S. It was only some 2 - 3 years later when considering speeding the VVT timing up further that I investigated other systems which use separate oil pumps to derive their oil pressure. The intention was to use two high pressure pumps from the BMW V 8/10/12 - Vanos system I believe. I subsequently bought a couple which I intend to fit at a later date, relieving the engine oil pump of this duty and using the Vanos for everything other than the crankshaft and timing chains.

However, when I came across BMW's solenoid valve, there were no "Flats bridging the ports and if my memory serves me correctly, they only have a screen over the oil pressure feed port. Certainly the screens across the Alfa solenoids will introduce a pressure drop. BMW however appear to protect their system by only having a screen over the inlet, given no oil can circumvent it.

Why did Alfa do what they did is a mystery to me!       
« Last Edit: August 01, 2020, 05:16:45 PM by Ascari32 »

sportiva

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Re: Enigmatic 3.2JTS
« Reply #9 on: August 01, 2020, 08:42:25 PM »
 Alfa Romeo as I know it ceased in 1986 so don't blame Alfa Romeo for the 159's poor engineering.
One of the most embarressing moments for me as a long time Alfa Romeo owner was learning that a GM/ FIAT engine had made it into the engine bay of a car badged as an Alfa Romeo. 
« Last Edit: August 01, 2020, 08:54:50 PM by sportiva »
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ex
75 2.5
2.0 Alfetta Sportiva #22
1.8 Alfetta
1.2 alfasud
2 75 parted out
15 alfettas parted
10 gtv parted
5 alfasuds parted
156 sele

Ascari32

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Re: Enigmatic 3.2JTS
« Reply #10 on: August 01, 2020, 09:11:13 PM »
But how do you feel about a Ferrari engine in and Alfa?  I still feel, Fiat provided a bit of certainty at the time they acquired Alfa and no one knew how things would go - a lot has happened in the World since then. But the biggest mistake for me, was pursue front wheel drive for cars above the size of the Sud.

The 159, Brera and Spider build quality is superb. But as Alfa/Fiat had already decided to close so many of their facilities, there was little option as far as engines were concerned. But the Holden Engine is really not that bad as a power plant. As I say, the block is brilliant and immensely strong. As a work horse; stock engine it is fine. It was Alfa themselves that wanted it to be something else. For that there is no excuse. And there are lots of engineers who cry "Budget - cuts" as a means of  excusing their shoddy work. Not just in Alfa. No, for me it is down to them and no one else that the 159/Brera failed. There are guys on the Continent running these things at 600 bhp, so clearly it is strong enough to take it.

I just hope there is enough people willing to take them on as they can be very special. It would be a shame for them to go the way of the Alfa 6. However, I feel so strongly about the failings of the 3.2 JTS, I would be happy to put a Holden Badge on it. And keep the Alfa Badge for my 3.0 GTV. But even that has a Fiat Tipo chassis/floor pan.
 
« Last Edit: August 01, 2020, 09:14:39 PM by Ascari32 »

sportiva

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Re: Enigmatic 3.2JTS
« Reply #11 on: August 02, 2020, 08:08:16 AM »
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA  :)
3.0 GTV6 Fiat Free
156JTS

ex
75 2.5
2.0 Alfetta Sportiva #22
1.8 Alfetta
1.2 alfasud
2 75 parted out
15 alfettas parted
10 gtv parted
5 alfasuds parted
156 sele

kaleuclint

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Re: Enigmatic 3.2JTS
« Reply #12 on: August 02, 2020, 03:18:58 PM »
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA  :)
Let's be clear.  Pomigliano d'Arco was never a 'Fiat' plant pre-takeover.  It's the spiritual home of Alfa Romeo Avio and the place where the RA 1000 RC.41 engine was built (in the first factory), powering the Macchi C.202 in my avatar!.  Might not be Arese, it's not Milan, but it's Alfa heritage.

I don't have any issue having Fiat Powertrain Technologies product (the TBi) under my hood.

Serious admiration for the technical knowledge conveyed in this informative thread.  If only you were actually consulting to FCA...
2011 159 ti 1750TBi

Ascari32

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Re: Enigmatic 3.2JTS
« Reply #13 on: August 02, 2020, 03:53:02 PM »
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA  :)

Brilliant! If only I could tease the "Lions Head"; not Vauxhall - sorry if I offended Holden Fans, out and insert an Alfa one, that would really put the cat amongst the pigeons. It is no more than a lot of Alfa fans feel and would lay the ghost to rest - they could then get back to talking about cars such as the 155, the one that Fiat killed the Lancia for, to steal their engine He! He!
« Last Edit: August 02, 2020, 06:12:52 PM by Ascari32 »

sportiva

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Re: Enigmatic 3.2JTS
« Reply #14 on: August 02, 2020, 04:04:06 PM »
The old AlfaSud plant were the last 159 was built is very close if not next door to the aviation division.
 I acknowledge and understand the history of the two plants and the radial engines alfa romeo built under the leader ship of Ugo Gobbarto were splendid examples of engineering.
« Last Edit: August 02, 2020, 05:39:59 PM by sportiva »
3.0 GTV6 Fiat Free
156JTS

ex
75 2.5
2.0 Alfetta Sportiva #22
1.8 Alfetta
1.2 alfasud
2 75 parted out
15 alfettas parted
10 gtv parted
5 alfasuds parted
156 sele