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

[Car_Almond]

Originally Posted by scrming

I've seen no evidence that the new part number means any meaningful changes in the timing chains....

you seem bent on blaming the chain... and that is certainly your right... however my sources say the new chains still stretch and wear long before they should...

The evidence is there. You missed reading my earlier post with info I got from a European source on the web:

Interestingly, elsewhere on the web, there was an account of the Vauxhall service bulletin, which used the same 12633451 and 12623452 timing chains part numbers, on the V6 in Europe that is closely related to our LLT V6 here. Here is the basics of the bulletin:

Technical Service Bulletin 2895

Z28NEx - Timing chain elongation, SVS on, DTC P0016(1B) and P0018(1B) set in ECU

Insignia 2009 to 2009 - Vin 91000362 to 81145618 - A28NEH, A28NEL, A28NER, A28NET
Vectra C 2008+ - VIN 81000001+ - Z28NEH, Z28NEL, Z28NET

Complaint - Customer complain about SVS on, DTC P0016(1B) and P0018(1B) set in ECU. Further investigation reveals chain elongation.

Cause - Lack of robustness in the chain material properties aggravated by ages engine oil.

Production - Improved wear resistant timing chains (material improved and carbo-nitriding) introduced as of engine number HN 055 387 (29th Sep 2010)


Spare Parts: Part-Number: Catalogue-Number:

Primary timing chain 12633451 06 36 246
Secondary timing chain (2x) 12633452 06 36 249

[Car_Almond]

Since rtcat600man found that the timing chain part numbers changed as of July 15, 2010 production, and I noticed the new part numbers match the European change on their Technical Service Bulletin 2895.
rtcat600man--"Checked into this question, here is what I found.
12633451 and 12623452 were in production from 15July10 "

From the minimal info from 2895, best info we have is that the material changed, yet it doesn't appear like they thickened the chain pins and links for strength. I'll bet its true if you placed the old chains side by side with the new ones, you couldn't see a thickness change.

[ChadG]

Anyone know why I can't find Penzoil Ultra anywhere near me? I've looked for it everywhere can couldn't find it . . .

[Car_Almond]

Originally Posted by ChadG

Anyone know why I can't find Penzoil Ultra anywhere near me? I've looked for it everywhere can couldn't find it . . .

ORielly, Kragen, AutoZone, NAPA in your area zip 94134 assumed. WalMart stopped carrying it a few months ago darn it. PepBoys might have it.
pennzoil.com click on pennzoil locations

[shrinkdoc]

Originally Posted by scrming

He was not providing the GM corporate response.... he said plenty of details about the HFV6 and if he didn't know would ask a co-worker... Even tried to help me out when I was working with Vince trying to figure out some of the LLT tuning..

As far as the wear studies, you have to remember we are talking about one very specific engine that had a design flaw, so an overview study may not apply...

He talked about how when this issue first started to surface they went after the chain supplier saying the chains were the issues and that they went back and forth with the supplier... eventually it was determined that the oil in the LLT gets "dirty" much more quicker than anyone ever anticipated and the dirt in the oil was causing the chains to wear out prematurely... eventually this lead to the OLM recall notice...

So what is causing the dirt? Faulty air filtering or engine wear? If engine wear it must be faulty oil circulation.

[shrinkdoc]

Originally Posted by scrming

THIS!!!

I know one of the engineers who actually WORKED on the HFV6. When he seen my Camaro with the LLT the first thing he told me was to make sure I change my oil really OFTEN and don't even think about using the OLM! He couldn't stress frequent oil changes enough!

We also had an Acadia. We had the timing chains replaced at 32,000 miles and 82,000 miles, at which point the wife told me to get rid of the Acadia. I called my engineer friend to ask him about the 2011(or was it 2012) Acadia and if I would run into the timing chain issue, even though there was the supposed upgraded chains. He explained the 2011 (or was it 12) was still going to have the underlying issue because the chains themselves were NOT the actual problem and it was a larger design issue that hadn't been corrected yet... He was thinking it probably wouldn't be corrected until MY 2012 or 13 .... Needless to say I didn't buy another Acadia...

Sounds like we all be damned.

[Car_Almond]

scrming, please contact the inside-engineer and get comments on how dirt gets to the chains, how chain-surface-hardening metallurgy is working on the newer chains, whether poor oil circulation to the chain is an issue, if sludge is considered a big blockage problem, whether a high moly or zinc oil will work, any solutions or insights, what the "larger design issue" is. And if we use a 40 weight oil as a solution, do the piston jets still get enough mass up to the underside of pistons for adequate cooling.

[Car_Almond]

FWIW, I checked the latest Consumer Reports reliability survey results for 2010 Camaros, and they say that it has less than a 2% ( 1 in 50) chance of having a timing chain or other major engine problem so far. Newer models the same low rate. (So, as Gilda Radner used to say: "Never Mind...")

[FrankieBee]

Had the dreaded P0008 code last week on Wed. Stretched timing chain most likely. Dropped off car at dealership on Friday morning. By Friday afternoon chains were off (lower chain was stretched) and new parts went in.

The car was built April 2009. It had 96,000 miles when the code went off, yes 96K!!!

The tech showed me the front engine block apart and the insides of the valve covers. He could not believe how clean the engine was, with no wear on the cams.

I only started using Mobil 1 this year (after 88K miles) so I only used conventional oil the past 4 years. I usually change my oil at 30% oil level, but only the last few months I have changed it at 50%.

I don't baby the car one bit, run it at the track (with NOS), and use it as a daily driver.
I can't complain getting 98K miles before it went!!!! And this has been the only warranty issue since I had the car (July 2009).

[Car_Almond]

FrankieBee, I have a 2011 one, and I think the OLM is programmed for much shorter intervals than the 2010 models. What would you say your 30% OLM ended up being in miles, on average? ( I think the 2011 OLM goes off 0% every ~4,000 miles, seriously.)

You had the old chains, without carbonitriding material improvements added July 2010. You changed oil plenty often, got a clean sludge-free engine, and the thing still saw too much wear. Yes, at 96,000 miles, yet I've seen most timing chains on other applications go twice that easily. I do agree if anything makes it to about 100,000 miles its still not too bad, and with track use NOS. Other people have reported frequent oil changes and the chain still wears out.

Acadia/Traverse/Enclave/Outlook (Lambda) LLT V6 applications seem to have much higher rates of failures than Camaros (see Consumer Reports statistics & outraged people on their forums), and high fail rates are amongst the earlier non-Direct-Injection engines.

[FrankieBee]

Originally Posted by Car_Almond

FrankieBee, I have a 2011 one, and I think the OLM is programmed for much shorter intervals than the 2010 models. What would you say your 30% OLM ended up being in miles, on average? ( I think the 2011 OLM goes off 0% every ~4,000 miles, seriously.)

You had the old chains, without carbonitriding material improvements added July 2010. You changed oil plenty often, got a clean sludge-free engine, and the thing still saw too much wear. Yes, at 96,000 miles, yet I've seen most timing chains on other applications go twice that easily. I do agree if anything makes it to about 100,000 miles its still not too bad, and with track use NOS. Other people have reported frequent oil changes and the chain still wears out.

Acadia/Traverse/Enclave/Outlook (Lambda) LLT V6 applications seem to have much higher rates of failures than Camaros (see Consumer Reports statistics & outraged people on their forums), and high fail rates are amongst the earlier non-Direct-Injection engines.

I would say about 5k -6500 before oil changes. Now I change it more frequently, about 4-5k between changes.

[lscamaro]

Originally Posted by Car_Almond

FrankieBee, I have a 2011 one, and I think the OLM is programmed for much shorter intervals than the 2010 models. What would you say your 30% OLM ended up being in miles, on average? ( I think the 2011 OLM goes off 0% every ~4,000 miles, seriously.)

You had the old chains, without carbonitriding material improvements added July 2010. You changed oil plenty often, got a clean sludge-free engine, and the thing still saw too much wear. Yes, at 96,000 miles, yet I've seen most timing chains on other applications go twice that easily. I do agree if anything makes it to about 100,000 miles its still not too bad, and with track use NOS. Other people have reported frequent oil changes and the chain still wears out.

Acadia/Traverse/Enclave/Outlook (Lambda) LLT V6 applications seem to have much higher rates of failures than Camaros (see Consumer Reports statistics & outraged people on their forums), and high fail rates are amongst the earlier non-Direct-Injection engines.

If you have a 2011 it should be a little over 5000 miles

[Car_Almond]

Originally Posted by lscamaro

If you have a 2011 it should be a little over 5000 miles

• The OLM laws are in the engine computer software, and it counts engine revolutions (revs) and heavily weights cold coolant temperature revs against you. ...quicker for 2011 vs. 2010 models

[TooCool5]

Anyone have the timing chain procedure they could email me in a PDF?
I'd like to have it for future ref.