Author Topic: Enigmatic 3.2JTS  (Read 12395 times)

0 Members and 1 Guest are viewing this topic.

torquemeister

  • Newbie
  • *
  • Posts: 17
Re: Enigmatic 3.2JTS
« Reply #30 on: November 14, 2020, 06:43:58 PM »
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA  :)
Lets be clear - Alfa took the small bore GM block and developed their own variable multivalve heads for it. A former colleague was a design engineer at GM Elizabeth at the time and he said when the first units were shipped back to GM Oz for review the engineers complained that Alfa had done what they had not been able. SIDI was a result or Alfas work.
People get misty eyed over the Busso but it could not meet EU emissions compliance so naturally Alfa had to cast about within GM and come up with a solution.
Comments re 600HP out of the engine? Seriously? Its well known that the AutoDelta SC kit boosts HP but at the expense of the transmission. So there is NO WAY that you can put down 600HP in that 939 Series configuration without major rework of the entire driveline.
Current Fleet:
2010 Brera V6 AWD Auto - Singapore
2008 Brera V6 AWD Auto - Tasmania
Previously:
1978 Alfetta GTV 2.0L - Adelaide

Ascari32

  • Full Member
  • ***
  • Posts: 184
Re: Enigmatic 3.2JTS
« Reply #31 on: November 14, 2020, 10:39:41 PM »
I would like to know what exactly what it was Alfa did that GM could not? From my studies of the both Brera and 159 engines, Vauxhall and SAAB, there is no difference in the architecture of the Block.

Whereas Alfa of old would have cast swage/baffle plates into the sump and certainly not returned oil from the heads in miniscule amounts, down cavernous channels, such that it appears in the sump at a level, and exactly in - line with the rotating Crankshaft Journals, to be immediately whipped into windage.

Neither would they have failed to see, the windage plate(s) does not extend along the full length of the sump, exacerbating "Slosh" - for want of a better term. The second plate was a latter addition by GM I am informed. Nor would the fact that the oil pick - up in the sump sits too high above the sump floor and is readily exposed if oil level are not scrupulously maintained, when lateral forces shift the oil in the un-swaged/baffled sump, have gone un - noticed.

Or that the sump was too small for the amount of oil in circulation to be healthy - deigned around a 4 litre capacity with 1.8 litres in circulation. This is a figure before the addition of VVT's on all four camshafts.

I had no interest in GM engines prior to my 159. However, these failing firmly belong to GM. So much so, that the latest incarnation of this engine; which is planned to be in production until 2026, incorporates modifications to rectify these issues.

My studies began with a wrecked 40,000-ish miler Brera engine [oil starvation] and only developed into a full-scale project when my 159 engine failed - on a parabola, with a full sump of new oil and a new oil filter. So a detailed exercise was undertaken - I was not simply going to replace what Alfa had served up to their customers. It is not being unkind to say, amongst UK Alfa enthusiasts this engine is very poorly regarded - being polite.

I can understand any sense of pride having a GM engine in and Alfa would generate for you guys. I hold the block of this engine in very high regard. It is incredibly strong and I have been reliably informed it is good for 600 BHP, but I'm not aware that it is in an Alfa 159 or a Brera. It is alleged the limiting factor with Autodelta is fuel delivery.

Having been a continuous owner of Alfa's, to the exclusion of all other marques for almost forty years, I can only think their engineering department has become so depleted that they didn't even bother about looking at the issues I have alluded to above, simply choosing to focus on reworking the Heads.

But it is generally accepted in engineering circle, it is not a good idea to have a single oil pump provide for all the needs of such a complex engine. Or, have the most fundamentally important component - lower timing chain tensioner - at the very end of the oil supply system. Or to deplete it's oil supply even further by having "Leaky VVT Solenoids". Or, fail to read the data, Bosch go to great length to supply and ensure, all four camshaft positional sensors are correctly aligned, choosing to use a boss on the front cover simply because it saved them from re-casting it in the correct orientation. The front bank inlet and exhaust sensors, plus the inlet sensor of the rear bank are perfectly aligned. The rear bank exhaust camshaft sensor is not. Bosch quote +/- 0.5deg. off - axis limit. So it is hardly surprising it is always, to my knowledge, the rear exhaust cam which flags a code for camshaft timing error!

Furthermore, there are four serious restrictions, cast within the block, which are difficult to overcome, without supplementary oil feeds. I believe, the latest incarnation overcomes these, but unless I get my mittens on one, cannot swear to it. The JTS system is a brilliant concept but Alfa failed to grasp the niceties of making it work - properly. There was pressure on them to introduce a replacement for the Busso. As a result they seemed to have incorporated a lot of the research work being done in an E.U. funded study. The study was intended to give guidance on emissions and although many aspects were investigated, it was intended for guidance. All manner of techniques were investigated, not all of them intended to be used in the same package, I believe. But Alfa chose to use a lot more than deemed necessary. They achieved a top rating for the engine when it was released. But very few have stood the test of time. In fact they are becoming an incredibly rare sight.

The Busso remains a brilliant benchmark engine. I have a low mileage 3.0 litre GTV. But the 3.2 JTS is, when all the encumbrances are removed and it is allowed to work properly, is more than a match for it.

However, the Busso, will remain the last truly great Alfa Romeo engine, Designed and Built in - house by one of the greatest Automotive Engineers that lived. The longevity of its production run alone speaks volumes and I do not know of a single V6 that does not owe it's design to some aspect of what Busso achieved.

The 3.2 JTS engine had what must have been the shortest of production runs in the automotive industry, let alone with Alfa. I doubt there will be many to be found in a few short years, such is its reputation. Whereas, the Busso will go on and on, as long as there are Alfa Romeo enthusiasts in the world. And I predict it will command high prices. One can pick up a 3.2 JTS for 200.

Despite this, I have an extremely high regard for this engine, once its issues have been addressed.                   
« Last Edit: November 14, 2020, 11:33:57 PM by Ascari32 »

Ascari32

  • Full Member
  • ***
  • Posts: 184
Re: Enigmatic 3.2JTS
« Reply #32 on: November 15, 2020, 03:16:08 AM »
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA  :)
Lets be clear - Alfa took the small bore GM block and developed their own variable multivalve heads for it. A former colleague was a design engineer at GM Elizabeth at the time and he said when the first units were shipped back to GM Oz for review the engineers complained that Alfa had done what they had not been able. SIDI was a result or Alfas work.
People get misty eyed over the Busso but it could not meet EU emissions compliance so naturally Alfa had to cast about within GM and come up with a solution.
Comments re 600HP out of the engine? Seriously? Its well known that the AutoDelta SC kit boosts HP but at the expense of the transmission. So there is NO WAY that you can put down 600HP in that 939 Series configuration without major rework of the entire driveline.



Let's also be clear about the pedigree of this engine. The team that developed the V6 engine for Ford/Jaguar had been broken up when the project ended. Porsche were heavily involved with it, to the extent they still hold patents on elements of its design. Ex - members of the team became involved with the new engine GM wanted develop, in which Holden also played a part.

It is a testament to it's design that Alfa chose to use it, but to be honest they were over a barrel given their engine plant was being closed. So in essence, to claim it as their own, and given the reputation the Busso had, it had to be radically different. However, the block is a modular design, in this instance specified as 3.2 litre. But it is not true they developed/modified the block further. The heads yes, with all components already available on the market - V.V.T's included. So apart from recasting the heads, little design work went into the Alfa 3.2 JTS.

To add to the woes the lower timing chain tensioner suffered was the spray jets which bleed oil from the main gallery and further reduce the supply to the tensioner. Not only that, they are low pressure and are known to jam open, allowing the block to bleed down when the engine is switched off.

Oil pressure in the Vauxhall 2.8 Insignia turbo, the Opel and SAAB turbos, do not suffer quite so badly as an extra oil feed is taken from the Oil Cooler/Filter housing to the turbo. There is a "Boss" on the Oil Cooler/Filter housing, which is left undrilled on the Alfa.Had Alfa thought more seriously about how to make the VVT's work properly, not to mention the rear timing chain tensioner, they would have used this Boss as a supplementary feed for the block. One simple Oil Line would have cured the problem of lower timing chain tension, rear bank upper timing chain tension and balanced the feed pressure for the VVT's on both banks.