Improving the Resilience of the 3.2 JTS Engine.

[Ascari32]

Currently, suffering a bout of ill health which keeps me out of the drivers seat, and in need of a project, I return to my beloved 3.2JTS engine, with the view to modifying the timing chain system.

I have such a high regard for the Holden Block, of which none other than Porsche had a part to play in the design, that I feel there is still enough scope to dramatically improve the reliability of this fragile beauty.

The timing chain system is overcomplicated and this overcomplication lends itself to appalling reliability issues - I have yet to find a single component[electronic/sensor] that significantly affects the performance of this engine. However, the timing chain system has; in my opinion, been the major factor relating to performance reduction and ultimate failure.

So, my initial intension is to replace the lower timing chain and tensioner with a "Gear - driven system", initially to take drive from the crankshaft to the intermediate Idlers, retaining; for the time being, the upper timing chains, which are less problematic None the less, they too lend themselves to possible modification.

This is a serious project that requires access to serious engineering resources, particularly machine gear manufacturers. Given my last project involved "International Co-0peration", I again look for companies who are in a position to carry out some of the prototype work required.

If anyone can recommend specialist companies, addresses/internet sites or whatever, it would be much appreciated.

Many thanks,   

[Ascari32]

One of the factors relating to my judgement of the Holden block was recently re-enforced when I watched a program where a Porsche Carrera engine was being restored. It was "Knackered". The car itself was in superb condition but clearly the engine had been much abused. The Bores were heavily scored and the oil/sump heavily contaminated.

When the engine was taken apart it was clear a full rebore, amongst other things, was required. The Presenter of the program was superb in the way he explained issues surrounding this Porsche engine, so much so that he took me back to when asked Brian Randal to inspect my mates Subaru 2.0 flat four engine. That too was wrecked -bores and crank, as was the Carrera's crank. Brian commented on the fact that this Subaru engine was unusual as it had an "Open Deck" block", each bank had liners cast into the block but the alloy walls around the liners formed part of the "Bath Tub" water jacket. The beauty being the extra rigidity it lent the engine, plus there was no need for an "O ring" at the base of the liners as per the Busso V6. But not so rigid as "Closed Deck" blocks, or their ability to conduct heat away!

The Presenter/narrators went on to say, the open deck technique also provided less cooling around the critical head/bore interfacing region.

Designs move with the times - or should. So much so that the Porsche Carrera engine, which had a similar bore structure to my mates Subaru, had the liners within alloy bores into which the liners were cast, machined out completely. Then new oversized pistons were sourced and new liners were machined - up to replace those removed. However, the tops of the new liners/bores were machined with a series of ribs/fins around what looked like 1.5 - 2.0cm down from their tops. These fins increased the surface area through which heat would be dispersed and at the same time the block was machined to effectively "Close the Deck". This greatly improved heat dispersal at the critical interface and also improved water circulation around it.

So, there is at least one area where the Holden block is stronger - much stronger - than the Busso, and more resilient to temperature.

I wonder if any of the after-market suppliers for the Busso V6's ever thought to follow the example which this engineering shop adopted - a method that Porsche themselves went back to with future water cooled flat sixes; which could also be, given Porsche's involvement with the Holden Block, the reason it too has a "Closed Deck".

Machining new bores for the 3.2 Busso; which famously overheats and destroys gaskets, is something any serious engineering company ought to be doing, rather than just practicing Alfa's mistakes.

There are several other reasons the Holden Block is superior to the Busso.

PS - Giuseppe never designed the quad - cams, so he can't be blamed.     

[Duk]

What is it about the lower chain that causes problems?

Personally I've only had a passing glance at the 'Alloytec' engine timing chain problem.
But a look at: https://www.youtube.com/watch?v=5QLPU1Qh2oo makes some interesting points.
Filthy engine internals, from overly long service intervals (regardless of what the manufacturer specifies) and probably poor break in procedure, when the engine is brand new.

I'd guess that if people would lean on their engine (make it work hard at low revs) to bed the rings into the bores correctly and with 5-7500km oil and filter changes, the internals of the engine would be cleaner and (maybe) the timing chain problem would be largely gone.

Imagine the racket from something like this?Not a valid attachment ID.

[vinsharp]

And so the Alloytec engine should show some signs of progress in design over the Busso V6. The Busso being a product of the 1960s slide-rule and grey matter design and first produced on carbs in the 70s, the Alloytec being a product of CAD, CAE testing and simulation plus and additional 40 years of global engine development to draw on.
As for any tie up with Porsche, well a friend who was a senior design engineer at GM Holden back then, travelling between Melbourne and Detroit during the engine program, says that is basically nonsense. GM acquired samples of almost every other manufactures engines and studied them carefully before embarking on any new design venture. The main design was done in Detroit and GM Holden varied some minor parameters for their own local capacity models for this market and its rather lax emission standards.
While closed block/open block designs has their various pros and cons (and nothing to do with wear on cranks), the choice for the Alloytec was driven by reducing costs of manufacture. Cast in-situ sleeves, bolts instead of studs, minimum of critical surface dimensions to machine etc. I recall reading a line from a Fiat executive who stated that the GM engine cost about 30% of a Busso to produce because of volume production.  There was certainly plenty of development and refinement left in the Busso to continue for a few more years, but it was killed off by the bean-counters when the stop-gap GM platform was adopted as an interim solution for FIATs lack of new model development.  I was told FIAT's Aviazione group relinquished sole manufacturing rights for some US fighter jet components in part for access to the GM platform. This is how that temporary arrangement was born out of mutual convenience.
Introduced into basically the same face-lifted body/platform Holden, another common complaint was increased fuel consumption of the Alloytec over and above the old cast-iron pushrod V6 it replaced. Hard to fathom but genuinely a major sales drawback initially.
Early engines suffered from terrible oil consumption and piston/bore scuffing due to the cast-in sleeves lack of heat transfer when they partly detached from the alloy block walls.
Specialist engine shops here imported oversized sleeves for refitting to blocks after boring out and removing the old loose ones. Piston rings were also redesigned.
Yes the Holden version of the Alloytec was a credible engine of the times with many hundreds of thousands sold here in Australia. However, only a fraction of those are still in service and finding serviceable units without problems is apparently a task. They also never had the reputation or the performance of the locally made FORD 24v in-line 6 'Barra" engine, which is extremely sought after today, even in the USA.
Having driven both Holdens and 939 Alfas with the Alloytec, how they managed to make a 60*V6 sound so bloody awful with that dead, soulless droning is beyond me.
The Busso V6 has, within the context of its period, been described by many in the industry as the best engine of its generation, and I doubt that the GM Alloytec will feature as much more than a footnote in automotive history.
Despite it's handicaps of age, any Busso V6 wins the aural gratification race hands down!

[bazzbazz]

Imagine the racket from something like this?Not a valid attachment ID.

May I enquire as to what it is for?

[Duk]

Imagine the racket from something like this?Not a valid attachment ID.

May I enquire as to what it is for?

The pic in my first post was attached twice, for some reason. I deleted 1 of them and that message comes up.
I don't know how to remove it. 

[Duk]

There was certainly plenty of development and refinement left in the Busso to continue for a few more years,

I'll go as far as to say that, unless Alfa had designed all new cylinder heads, they were pretty stuck.
Packaging constraints of trying to fit a V6 engine sideways under a bonnet that isn't hideous, meant they could never develop and fit a decent inlet manifold.
An effective continuously variable valve timing, was over due in its application.
The inlet ports are, in my opinion, too big.
And direct injection would probably have needed to be implemented at some stage.

The layout of the coolant plumbing at the front of the engine, means that the timing belt arrangement was far from ideal.
And the engine is just too bulky and probably heavier than what could be achieved with more effort put into the design of the block and heads.

I'll never understand the notion that people insist that the Busso engine is considered 1 of the best in the world.
Yes they sound great, but they never made any impressive power numbers. You can't realistically compare the best of the Busso with the best of the BMW NA 6 in the E46 M3.

[bazzbazz]

Imagine the racket from something like this?Not a valid attachment ID.

May I enquire as to what it is for?

The pic in my first post was attached twice, for some reason. I deleted 1 of them and that message comes up.
I don't know how to remove it. 

No, I meant the engine in the photo.

[vinsharp]

There was certainly plenty of development and refinement left in the Busso to continue for a few more years,

I'll go as far as to say that, unless Alfa had designed all new cylinder heads, they were pretty stuck.
Packaging constraints of trying to fit a V6 engine sideways under a bonnet that isn't hideous, meant they could never develop and fit a decent inlet manifold.
An effective continuously variable valve timing, was over due in its application.
The inlet ports are, in my opinion, too big.
And direct injection would probably have needed to be implemented at some stage.

The layout of the coolant plumbing at the front of the engine, means that the timing belt arrangement was far from ideal.
And the engine is just too bulky and probably heavier than what could be achieved with more effort put into the design of the block and heads.

I'll never understand the notion that people insist that the Busso engine is considered 1 of the best in the world.
Yes they sound great, but they never made any impressive power numbers. You can't realistically compare the best of the Busso with the best of the BMW NA 6 in the E46 M3.

Duk, Basically you're in step with my argument. For sure the best of the Busso was never a match for the best of the BMW M3 6cyl. The BMW engine was exactly what the Busso never was, a continually developed older base engine moving forward with the tech of the times and the required budget to achieve it. There was very little in terms of almost anything at all interchangeable between it's original form and its final. The BMW engine was also never compromised with having to fit sideways between the front wheels either.
The Busso had more to come with the will and budget to do so, but FIAT/Alfa sales and financial state was hardly comparable to any of the German makes, let alone globally. Hence it made vastly more sense to go with an interim global powertrain option for a period. Fiat/Alfa are now repeating that with the current Stellantis arrangement, probably for the duration now.

[Ascari32]

What is it about the lower chain that causes problems?

Personally I've only had a passing glance at the 'Alloytec' engine timing chain problem.
But a look at: https://www.youtube.com/watch?v=5QLPU1Qh2oo makes some interesting points.
Filthy engine internals, from overly long service intervals (regardless of what the manufacturer specifies) and probably poor break in procedure, when the engine is brand new.

I'd guess that if people would lean on their engine (make it work hard at low revs) to bed the rings into the bores correctly and with 5-7500km oil and filter changes, the internals of the engine would be cleaner and (maybe) the timing chain problem would be largely gone.

Imagine the racket from something like this?Not a valid attachment ID.

Crankcase ventilation is an issue and indeed a factory mod was quietly introduced where the hole in the PCV valve was increased. Off the top of my head I seem to remember it was drilled out to 2 - 2.5mm.

However, it is not the only issue regarding bank "A"?, the rear bank of the 3.2 JTS Alfa. Oil flow to the head is badly restricted, due mis - alignment of oil feeds from the block, through the head gasket and to the head. Also the disparity that exists between the front; bank "B" and Bank "A" oil flow/pressure doesn't help. I believe this reduces the cooling effect a decent oil flow would have on the cylinder head and the oil degrades quickly, settling on the head and camshaft bearing caps. Over a period of time the vapourised oil forms a crust/crud which lacquers both the head and the cam cover, in really bad cases, blocking the PCV.

Demand for oil is too great to support the lower timing chain tensioner, the upper tensioner, the VVT voids; advance and retard, and the continuous bleed across the VVT solenoid dividing walls, due to the flats cut into them.

As for the mis- alignment of oil feeds, this came about when the engine transitioned from fixed exhaust valve timing to full VVT action for the exhaust camshaft. To my knowledge, the Z28 of Vauxhall and SAAB; both Turbos with fixed exhaust timing do not suffer with this. The heads weren't so much an "Alfa re-design" as a "Bodge - job". The same mistake appears on current American versions, which I am informed will be in production until at least 2026.

The connection between this engine and Porsche is indirect. Porsche's design house were engaged by Ford, in conjunction with a Ford in-house team for the design of Ford's V6. Several Patents were registered by Porsche in respect of some element of the V6.

When finally the project came to an end, members of the team found employment with the team developing the Alloytec.

I have been unable to get any closer to finding out what elements are "Common" to both Fords V6 and the Alloytec, but suspect it relates to crankshaft, its bearing caps and side bracings - six bolts per cap; the "Cathedral - like" design of the underside of the cylinder bores, where the walls are beautifully cast, assisting both cooling and reducing oil retention by coarsely cast walls. Also, inter-bore walls are opened, reducing any pressure pulses between pistons by a huge factor.

In my opinion, the block was not so much "Cast" as "Sculptured", which is why I use the term "Cathedral - like".

There is still much more to learn about this engine. I regard it as an unfinished gem. So little needs to be done to resolve the issues, but sadly Alfa ran out of time and the Busso was by then history.        

[Ascari32]

And so the Alloytec engine should show some signs of progress in design over the Busso V6. The Busso being a product of the 1960s slide-rule and grey matter design and first produced on carbs in the 70s, the Alloytec being a product of CAD, CAE testing and simulation plus and additional 40 years of global engine development to draw on.
As for any tie up with Porsche, well a friend who was a senior design engineer at GM Holden back then, travelling between Melbourne and Detroit during the engine program, says that is basically nonsense. GM acquired samples of almost every other manufactures engines and studied them carefully before embarking on any new design venture. The main design was done in Detroit and GM Holden varied some minor parameters for their own local capacity models for this market and its rather lax emission standards.
While closed block/open block designs has their various pros and cons (and nothing to do with wear on cranks), the choice for the Alloytec was driven by reducing costs of manufacture. Cast in-situ sleeves, bolts instead of studs, minimum of critical surface dimensions to machine etc. I recall reading a line from a Fiat executive who stated that the GM engine cost about 30% of a Busso to produce because of volume production.  There was certainly plenty of development and refinement left in the Busso to continue for a few more years, but it was killed off by the bean-counters when the stop-gap GM platform was adopted as an interim solution for FIATs lack of new model development.  I was told FIAT's Aviazione group relinquished sole manufacturing rights for some US fighter jet components in part for access to the GM platform. This is how that temporary arrangement was born out of mutual convenience.
Introduced into basically the same face-lifted body/platform Holden, another common complaint was increased fuel consumption of the Alloytec over and above the old cast-iron pushrod V6 it replaced. Hard to fathom but genuinely a major sales drawback initially.
Early engines suffered from terrible oil consumption and piston/bore scuffing due to the cast-in sleeves lack of heat transfer when they partly detached from the alloy block walls.
Specialist engine shops here imported oversized sleeves for refitting to blocks after boring out and removing the old loose ones. Piston rings were also redesigned.
Yes the Holden version of the Alloytec was a credible engine of the times with many hundreds of thousands sold here in Australia. However, only a fraction of those are still in service and finding serviceable units without problems is apparently a task. They also never had the reputation or the performance of the locally made FORD 24v in-line 6 'Barra" engine, which is extremely sought after today, even in the USA.
Having driven both Holdens and 939 Alfas with the Alloytec, how they managed to make a 60*V6 sound so bloody awful with that dead, soulless droning is beyond me.
The Busso V6 has, within the context of its period, been described by many in the industry as the best engine of its generation, and I doubt that the GM Alloytec will feature as much more than a footnote in automotive history.
Despite it's handicaps of age, any Busso V6 wins the aural gratification race hands down!

To my knowledge, there was going to be a merger with GM and Fiat and as part of that merger, GM acquired the common rail diesel. The 159 was to be a common platform for both Fiats top larger models and GM. When the marriage failed, Fiat were given £2 billion by GM as a divorce settlement, plus the 159 platform virtually free. It was, and remains a premium platform.

Agreement to supply the Alloytec had already been set in stone and the Arese plant was being wound up. Production of the Busso was to cease, although Lancia continued to use it a little longer - using engines that were already built.

It is alleged that McClaren wanted to buy the Busso but Fiat refused to sell, which is a shame. Arese was a very old production facility, so of course this and the low volumes led to high unit costs - the same would apply to any production facility that did not keep pace with modern production techniques.     

I was not implying the issue of crankshaft wear was associated with closed/open deck blocks, although it may have read that way. Essentially, my mates Subaru had a failed crankshaft and bearings. On inspection, Brian Randal simply commented that he was surprised at seeing an open deck. All other Subaru's he had come across had closed decks and he postured that my mates engine must have been an early one.

[Ascari32]

There was certainly plenty of development and refinement left in the Busso to continue for a few more years,

I'll go as far as to say that, unless Alfa had designed all new cylinder heads, they were pretty stuck.
Packaging constraints of trying to fit a V6 engine sideways under a bonnet that isn't hideous, meant they could never develop and fit a decent inlet manifold.
An effective continuously variable valve timing, was over due in its application.
The inlet ports are, in my opinion, too big.
And direct injection would probably have needed to be implemented at some stage.

The layout of the coolant plumbing at the front of the engine, means that the timing belt arrangement was far from ideal.
And the engine is just too bulky and probably heavier than what could be achieved with more effort put into the design of the block and heads.

I'll never understand the notion that people insist that the Busso engine is considered 1 of the best in the world.
Yes they sound great, but they never made any impressive power numbers. You can't realistically compare the best of the Busso with the best of the BMW NA 6 in the E46 M3.

Duk, Basically you're in step with my argument. For sure the best of the Busso was never a match for the best of the BMW M3 6cyl. The BMW engine was exactly what the Busso never was, a continually developed older base engine moving forward with the tech of the times and the required budget to achieve it. There was very little in terms of almost anything at all interchangeable between it's original form and its final. The BMW engine was also never compromised with having to fit sideways between the front wheels either.
The Busso had more to come with the will and budget to do so, but FIAT/Alfa sales and financial state was hardly comparable to any of the German makes, let alone globally. Hence it made vastly more sense to go with an interim global powertrain option for a period. Fiat/Alfa are now repeating that with the current Stellantis arrangement, probably for the duration now.

Agreed. Particularly with regard to putting the Busso into front wheel drive format. However, "The devil drives, where needs must." Allegedly Ford were in the running to buy Alfa, but the Italian Government decided to "Gift - it" to Fiat.

When one considers what Ford did for Jaguar, Aston Martin and Volvo, it was a missed opportunity in my view. 

[vinsharp]

I guess much of the fondness for the Busso V6 is a subjective mix of both its limited but adequate capabilities for which it was asked, plus its driving characteristics plus the soundtrack. It added up to something beyond just how well the appliance does the task of transporting a seat form point A to point B. I think this is why is has fans way beyond just us Alfa tragics.
I'm not sure that a Ford buyout would have necessarily been good long-term, they would have just flipped the brand in typical corporate style and pocketed the cash anyway: Jaguar now owned by India, Aston Martin majority owned by Arab/China consortium, Volvo owned by China.

[Ascari32]

What is it about the lower chain that causes problems?

Personally I've only had a passing glance at the 'Alloytec' engine timing chain problem.
But a look at: https://www.youtube.com/watch?v=5QLPU1Qh2oo makes some interesting points.
Filthy engine internals, from overly long service intervals (regardless of what the manufacturer specifies) and probably poor break in procedure, when the engine is brand new.

I'd guess that if people would lean on their engine (make it work hard at low revs) to bed the rings into the bores correctly and with 5-7500km oil and filter changes, the internals of the engine would be cleaner and (maybe) the timing chain problem would be largely gone.

Imagine the racket from something like this?Not a valid attachment ID.

Duk -"What is it about the lower chain that causes problems?

It is claimed the lower timing chain tensioner has a non return valve fitted to sustain the oil in its piston/cylinder, allegedly to sustain timing chain tension. That is not true. there is a small non return valve at the input to the cylinder, with a small orifice. But there is not one on the front face which forces the piston towards the timing chain tensioner guide. So, when back - pressure exists on "Over-run", the oil is forced out to the extent that the piston withdraws back into the barrel, as far as the "Auto - adjustment" pin allows. When the system is new, this is a relatively small distance. But as the timing chain ages/high mileage, the distance increases.

Eventually the "Pin" of the adjustment mechanism takes a considerable amount of impact and in some cases I have seen the pin sheered off. Either way, the oil pressure is not enough to sustain the tension on the lower timing chain at which point, errors start to occur with camshaft timing. It is also possible for the lower timing chain to "Slip" one or two teeth on the crankshaft sprocket and again there have been instances where the chain had come off the sprocket and jammed between it and the block.

The hydraulic tensioner was modified on later engines apparently, but the problem remains.

Even though I have supplemented oil flow to the lower tensioner, via a 10mm. line direct from the oil cooler/filter output to the block, I don't think it it is enough to overcome this phenomenon altogether. the orifice on the front face of the tensioner, to the chain is just too big.

Had it been small and the non return valve at the input to the cylinder/barrel, from the oil gallery been larger, it is possible this problem could be solved. 

[Ascari32]

What is it about the lower chain that causes problems?

Personally I've only had a passing glance at the 'Alloytec' engine timing chain problem.
But a look at: https://www.youtube.com/watch?v=5QLPU1Qh2oo makes some interesting points.
Filthy engine internals, from overly long service intervals (regardless of what the manufacturer specifies) and probably poor break in procedure, when the engine is brand new.

I'd guess that if people would lean on their engine (make it work hard at low revs) to bed the rings into the bores correctly and with 5-7500km oil and filter changes, the internals of the engine would be cleaner and (maybe) the timing chain problem would be largely gone.

Imagine the racket from something like this?Not a valid attachment ID.

Much to my wife's annoyance, my spare 100,000 mile + spare block is sitting in our lobby where I continue to both analyse it and marvel at the unmarked bores, which could fool one into thinking they are brand new.

Further observations I would make are.

1) The High feature 3.2 JTS engine has 11.4:1 compression ratio and there are considerable "Blow - by" products, of which water vapour is a major component.

2) The discharges from the VVT solenoid valves, virtually drain straight back to the sump via the holes in the heads exposing the timing chains below the sprockets, so very little of this oil "Wets" the cylinder heads. 

3) Whereas Bank B has a single drainage port from the head back to the sump and is at the distant end from the VVT's the rear Bank A has two, both large. The front one directs oil back to the sump adjacent to the first crankshaft journal. The drain void is so large, any oil clings to the walls and discharges directly into the path of the rotating crank, whipping it up into windage, where moisture laden blow-by products mix with it. There certainly must be a degree of emulsification due to this factor.

4) Because of the rotation of the crankshaft, the gaseous blow-by products; Hydrocarbons and water vapour which swirl around the rotating journals are partially directed up the two drainage ports of Bank A, whilst at the same time returning oil is pulled into windage.

5) The second drainage port presents the same problem, whipping oil up into windage at the other end of the block. N.B. the direction of crank rotation ensures this.

An additional consequence is, there is little standing oil left to assist in cooling the head.

6) Bank A however, with its single drain to the rear has the advantage of creating some pooling of oil on the head, plus, where it drains, the crankshaft journal is rotating downwards towards the sump.

7) Exacerbating these problems is the fact that the drainage channels from the heads, appear in the sump above the Windage Plate. My solution has been to weld aluminium covers over the sump casting to carry the oil from the drainage channels, below and into the sump. I have also extended the Windage Plate and lowered the Oil Pick - up Snout/Screen and fitted "Swage Plates"? to direct oil across the face of the snout and reduce surge.

On revisiting my project, I now intend to block off the front oil return channel of Bank A and have oil solely returned to the sump by the second channel, which is virtually opposite that of Bank B's However, by carrying all three drainage channels below the windage plate, into the oil, no windage gases can "Directly" get into the camshaft covers.