Strategies for Preventing Timing Chain Stretching (Wear): what can we do?

[Car_Almond]

As has been discussed in many places on the internet, LLT v6 Camaros built before July 15 2010 have weaker timing chains. Hopefully, the new timing chains on Camaros after that are stronger. ( I know GM's Vauxhall cars in Europe had new timing chains designed for their related V6 that added carbonitriding, and am not sure if our newer North American LLT v6 timing chains have that; probably so. )

What can be done to lube those chains better? GM issued recalls on past Traverse/Acadia LLT v6's to cause the OLM to call for more frequent oil changes. I know my 2011 Camaro v6 already came from the factory with the more-frequent oil change OLM settings, as this car drives me crazy with how much it wants OLM oil changes.

Are more frequent oil changes really the answer? GM says it is. However, maybe the managers at GM are ignoring findings that say wear rates are actually worse with fresh oil. Reference: http://papers.sae.org/2003-01-3119/
http://papers.sae.org/2007-01-4133/
"In one of our previous studies it was observed that engine oil samples collected from fleet vehicles after 12,000 mile drain interval showed 10-15 % lower friction and more importantly, an order of magnitude lower wear rate than those of fresh oils." ... "As in the previous study, the results showed [in this new field study with taxi fleets] that the aged engine oils provide lower friction and much improved wear protection capability. These improvements were observed as early as the 3000 mile drain interval and continued to the 15000 mile drain interval."

So whats the best strategy?

[Car_Almond]

Also, does anybody know if the newer timing chain (post July 2010) has thicker links and/or pins and/or carbonitriding (like European Vauxhall GM V6 recalls)?

[KMPrenger]

As you are probably aware, there have been numerous conversations about the issue here on the website. The best I can gather from that, and after talking to someone who tells me had talks about this with a GM master tech that he's known for a good while.....the best recommendation is to change the oil on these cars often, and make sure to keep it topped off.

I don't know if that IS the solution, or if it just pushes back the inevitable, or if that doesn't help at all. But its all I have to go on, so that is what I do.

As for your findings on oil lubricating better as many thousands of miles of use...all I can say is that basically seems to go against everything we've ever been told. I'm not saying I know for a fact that is complete rubbish, but what I will say is there is no way in hell I'm going to run my car for 12,000 miles without an oil change.

[Car_Almond]

Thanks (man Camaros look great in blue..good pics.. mines red). Yeah, I'm about to just try to identify whatever oil does the best at sliding friction, like that seen in chain pin oscillating wear surfaces, and go with that. I guess thats a full PAO synthetic that does well on the infamous 4-ball wear test. Then change half the oil at a time at the quick OLM change intervals with filter change. I've been using Pennzoil Ultra so far, although I guess they dropped the dexos1 licensing on that one anyway. Another one to try, besides Amsoil, might be one of the euro spec long life oils meeting BMW LL-01, in hopes its antiwear package stays intact longer.

[rtcat600man]

I agree with KMP. I for one keep my oil change under 5K miles. I use Mobil 1 (have from day 14 when I did my first oil change at 750 miles). I am now closing in on 60K miles.

[Car_Almond]

I almost agree with the above. Kind of like the safe thing to do is use AC-Delco dexos1 5w-30, AC-Delco paper oil filters, and change at the OLM. Maybe there is something better. I think the average personality who bought a Camaro is not interested in minimal-safe-justOK performance though. If that were the case, we would have all bought Toy Corollas.

Yep, I know, if we don't know any better as consumers, we tend to just listen to the tech at the dealership and jiffy-lube ads that tell us to change our oil often. In this case, GM, with their recall notices for other model cars with LLT V6 engines, have also said that more frequent oil changes are the answer, and they changed the OLM to get more frequent oil changes. In contrast to that, all the evidence points to less frequent oil changes actually decrease wear.

I don't think using Mobil1 5w-30 is the answer, as that product was caught red-handed just a few years ago failing a key engine wear test, the Sequence IVA cam wear test, part of basic SM & SN tests. They lost my trust for minimal wear.

It would be great if we could just drop in some more ZDDP anti-wear additive and expect it to get to the timing chain pins/links where sliding friction is present. I don't like the idea of adding stuff to chemically balanced motor oil.

Unless there is a better solution out there, I'll use the lowest-wear oil that also has all the other performance aspects covered, from a trustworthy company (Shell Oil Pennzoil's best). Evidence from a non-Pennzoil company shows 5w-30 Oil Tests. Note the low wear from metal-to-metal contact, low volatility, other tests good. Then change the filter and half the oil at each OLM flag.

[ChadG]

Interesting - unfortunately the best oil I can find around here is Mobil 1 . . . although I change it every 3k miles. I can't find Penzoil Platinum and don't know much about Amsoil but am definitely interested in learning more . . . I just hit 30k miles.

[jkchambless]

I still don't understand the oil/timing chain relationship with regards to this issue. Yes, I know that in general running with low or no oil will create greater wear on engine parts....no brainer. That said, how is the oil level going to stop an inherently weak timing chain from stretching? In my case, I have changed the oil religiously, never had any oil consumption issues, and still had to have the timing chain replaced at 60K.

[Ventmaster]

His whole life, my father never changed his oil more than once a year- "whether it needed it or not"!

He never had an engine failure, or used or burned oil.

Obviously engines have changed, but LOL, maybe the old man wasn't as crazy as I thought!

[Dyk-NO]

I keep my oil changed every 1k miles, love my free oil change for 5 years at the dealers

[Car_Almond]

Originally Posted by jkchambless

I still don't understand the oil/timing chain relationship with regards to this issue. Yes, I know that in general running with low or no oil will create greater wear on engine parts....no brainer. That said, how is the oil level going to stop an inherently weak timing chain from stretching? In my case, I have changed the oil religiously, never had any oil consumption issues, and still had to have the timing chain replaced at 60K.

The chain stretching is not plastic-deformation. The stretching actually comes from wear on the chain's pins and/or links surfaces from insufficient anti-wear performance of the motor oil and to some extent by using a non-wear-hardened surface in the chain material. As each link gets a little sloppy from wear, the overall effect on the entire length of chain is to stretch from the mechanical slop added, all due to the wear. I believe this because of a clue I got from word that a cousin of our LLT v6, another HF (High Feature) V6, GM's 2.8L V6 put in Vauxhalls in Europe, had the same timing chain problems and they fixed it with carbonitriding surface treatment, which essentially decreases the steel chain's wear rates. I suppose they could also have increased the bearing surface areas of the pins/links, but not sure they did that part.

Good performing oil (assuming the chain is not oil-starved from sludge, right?!) reduces metal-to-metal wear, and hence keeps the chain from getting elongated too much. Low oil levels would mean you lose oil pressure, dashboard warnings would alert you, and I do not think we are seeing that from most people, so oil levels are not the problem.

[jkchambless]

Originally Posted by Car_Almond

. Low oil levels would mean you lose oil pressure, dashboard warnings would alert you, and I do not think we are seeing that from most people, so oil levels are not the problem.

From reading the posts on the LLT engine failures, it appears that we do not HAVE a dashboard warning for low oil levels...major oversight, if true.

[TooCool5]

Originally Posted by Car_Almond

The chain stretching is not plastic-deformation. The stretching actually comes from wear on the chain's pins and/or links surfaces from insufficient anti-wear performance of the motor oil and to some extent by using a non-wear-hardened surface in the chain material. As each link gets a little sloppy from wear, the overall effect on the entire length of chain is to stretch from the mechanical slop added, all due to the wear. I believe this because of a clue I got from word that a cousin of our LLT v6, another HF (High Feature) V6, GM's 2.8L V6 put in Vauxhalls in Europe, had the same timing chain problems and they fixed it with carbonitriding surface treatment, which essentially decreases the steel chain's wear rates. I suppose they could also have increased the bearing surface areas of the pins/links, but not sure they did that part.

Good performing oil (assuming the chain is not oil-starved from sludge, right?!) reduces metal-to-metal wear, and hence keeps the chain from getting elongated too much. Low oil levels would mean you lose oil pressure, dashboard warnings would alert you, and I do not think we are seeing that from most people, so oil levels are not the problem.

I worked for a bearing Co. who made the roller lifters for the GM 3800 V6.
Engineering did the infamous 4-ball wear test on various lubricants and additives and nothing could touch PTFE teflon.
Showed little to no wear at all. The oil additives that contained it have
been removed from the market since.
I suspect a lot of the wear is happening at start up when all the oil is drained down in the pan overnight. Also sludge builds up in this motor if you do not change the oil frequently, thus the shorter OLM change interval.
There is also a service bulletin about a check valve in the head I have never been able to get any info on at the Dealer.

[stevey_frac]

Originally Posted by jkchambless

From reading the posts on the LLT engine failures, it appears that we do not HAVE a dashboard warning for low oil levels...major oversight, if true.

We have a low oil pressure light, which I believe is similar to many cars these days.