Problems with Brera JTS ...?

[Mick A]

Timing chains do not stretch.  They will get longer due to wear but they will certainly not stretch.

Sorry Colin, can you please clarify for me because I'm confused by that comment.

Also thought just for interests sake I would attach a photo of a timing chain on a 2.2 I replaced recently to demonstrate a worn chain vs a new chain. The photos show each end of the chains side by side.

[Colin Edwards]

Hi Mick,

I believe the increase in pitch dimension is due to pin and roller wear.
If you hold the chain at 90 degrees to its usual arc axis, the worn chain will "droop" considerably more than the new chain.  This will be due to the increased clearance between the pin and its roller/bush.

If you look closely at your worn chain you will note the gap between adjacent link ends is a tad greater than the new chain.  If the links of the old chain had stretched the gap between them would not be so great.

Back in the late 70's and early 80's I replaced many noisy Toyota Celica timing chains (the 18R engine was a POS!).  These would increase in length about 15mm in only 50K < 60K of use!  These chains were good quality DID or RK featuring DH (double hardened) pins and rollers/bushes.  The cause of the wear was lack of lubrication. 
Sometimes the chain itself contributes to the lubrication issue if the roller/bush / pin design and dimension prevents the formation of a suitable lubricant film.

It is possible the links are elongating, however that would mean they are being stressed beyond their elastic limit.  If this is the case the chain is truly a POS!  If the link is that soft that is can permanently elongate under the low loads it is subjected to, you should see pins and bushes tearing from them.  Is this the case?   

Are the new chains of an identical spec to the worn chains with regard to material specification?  Does installing a new (higher specification?) chain fix the wear issue for good?  Are we increasing oil flow or better directing it to the chain?

Colin

[Mick A]

Thanks Colin.

Can't answer material spec question sorry, I don't have that information.
Would have to request it from the manufacturer.

Installing a new chain won't fix the underlying problems you have previously mentioned.

I install a new oil sprayer on each change, the replacement sprayers seem to have a wider/better dispersion than the old ones.

Mick.

[As the day goes]

What's bad about Selenia?

One indie wont use anything but.  Not that I do. I only thought Selenia is expensive.

[Colin Edwards]

I install a new oil sprayer on each change, the replacement sprayers seem to have a wider/better dispersion than the old ones.

Hi Mick,
I recall Toyota's solution was similar.  They tightened up on the oil sprayer manufacturing tolerances.  It was just a plain hole drilled into an metal tube oil line.  The tube was cad plated after the hole was drilled and still had metal dags attached to the inside the tube around the hole.  it was more luck than good design the oil spray hit the chain! 
I had some tiny Delaval nozzles made by a watchmaker.  Two of these were silver soldered into the original oil line.  The oil flow of the two nozzles was equal to the flow of the single original, so no drop in oil pressure would result. 

Colin.

[Colin Edwards]

What's bad about Selenia?

One indie wont use anything but.  Not that I do. I only thought Selenia is expensive.

I don't think there is anything bad about Selenia lubricants.   It think the issue is more with Fiat / Alfa Romeo!

The Owners Manual / Service book for my 159 originally "recommended" engine oil changes every 25,000 km.  Stickers added to the Owners Manual at some later date "recommend" the oil change intervals be increased to every 35,000 km, yet the oil type and its Fiat specification is no different.  The manufacturer (or some influential tosser in their marketing department) figured a medium spec oil will continue to provide suitable protection for another 10,000 km past the initial recommendation!   

Selenia now make an oil that may provide this extended service interval, but the Selenia Star specified for the 3.2 JTS back in 2008 would not have been up to it!  Selenia is expensive however it is essentially a Fiat / Alfa factory spare part! 

Castrol, Mobil and Shell amongst others all produce Fiat Specification 9.55535-* compliant engine oil.  An oil compliant with Fiat 9.55535-S2 should be ok for a JTS fitted with an exhaust catalyst. 

[kaleuclint]

Well, here's the 43 page thread on ausalfa.com triggered by a desire to avoid Selenia:
http://www.ausalfa.com/viewtopic.php?f=4&t=4278&hilit=Selenia
There is some serious knowledge contained therein.

Bought myself five litres of Penrite 10tenths 5W50 on the weekend just to have some for the TBi.  Suspect it'll never get opened.  I do recall topping up the JTS with Selenia -- no idea if that was due to the engine or the oil.

[Mick A]

Thanks Colin,

I also forgot to mention the new chains make a huge difference to the performance of the engine. It's actually amazing how much power is lost in these Z22SE engines due to the changes in the timing because of the worn chains.

The owners don't usually notice the drop in power because it happens over such a long period, they simply adjust to it. So when they pick the car up after a new chain has been installed, they can't believe how much more power it has!

Mick.

[Colin Edwards]

An interesting paper on oil contamination re Direct Injection equipped engines.

Sort of explains why a JTS may dirty the oil up a bit more compared to earlier manifold injection engines.  The better torque and power of the JTS is offset a bit by slightly less efficient combustion.  Also confirms why its a good idea to regularly change engine oil and filters.   

Recently seen a number of Mazda diesel turbo failures.  All due to insufficient or non existent service!  Voided the new car warranty straight away!  The "oil" looked more like tar!