S550 V8 Timing Chain discussion

[Cobra Jet]

So looking through the S550 Owners Manuals, I came across something interesting.

In the 2021 Mustang Owners Manual under "Track Use", on page 286 there is a statement about the Timing Chain, here:

So curiously, I back tracked on prior years and don't see any such statements from 2015-2019. If I missed any such statement from those Owner's manuals or supplements,, please post up.

I then checked the 2015-2020 GT350 Owners Manual Supplements and the same exists:

I checked the GT500 for years 2020 and 2021, no mention of timing chain in the GT500 supplement. ??

I also checked the GT PP2 Supplement and there isn't any mention of the Timing Chain in there either.

And lastly, checked the 2021 Mach 1 Supplement:

What IS the "service life" of an S550 V8 timing chain (normal or track use)? It's not mentioned anywhere in the owners manuals or supplements.

If the "wrench light" appears while in motion at the track for a Timing Chain notification, does that mean it appears AFTER the engine suffered a potential failure, or is the PCM that smart and aware of being able to detect a preemptive Timing Chain failure BEFORE it happens to allow the Driver (in motion and at speed) to hopefully stop the car before engine damage?


Was anyone aware that the S550 V8 PCM's can detect timing chain wear and notify the driver via a "wrench light" (DTC)? Is it the timing chain tensioners detecting the wear based on a preprogrammed service life table/code in the PCM?

Discuss.

Sponsored

 

[cmxPPL219]

This is a great find.

It makes you wonder what they trying to cover their behinds from, with this tiny statement.

The thing with timing chains, is that although they are billed has having no standard maintenance interval, and are billed as superior to timing belts (most cars with variable valve and cam timing has chains nowadays anyway) it's just that - no standard maintenance interval. Meaning, they can still fail, and if they do, you're in there now anyway. Chains also have their own problems, as some aware, such as stretching. This, putting aside other issues that can happen with tensioners that we're all familiar with.

Also, billed sometimes as "lifetime", as we know with Ford and their statements about lifetime fluids, lifetime could be defined as 150k or 175k or 200k miles/km. If you drive your car and exceed that, you're obviously into replacement territory.

My guess is that due to any excess heat / stress / and contaminants that would present themselves as wear factors in extreme environments such as racing, Ford wants to cover themselves here, if a car saw some racing or track duty, but is well under what they consider "appropriate" mileage for a timing chain replacement, under normal circumstances.
Ford may have seen enough data from dealers to warrant a save-a-behind clause somewhere for MY21.

Was anyone aware that the S550 V8 PCM's can detect timing chain wear and notify the driver via a "wrench light" (DTC)? Is it the timing chain tensioners detecting the wear based on a preprogrammed service life table/code in the PCM?

Yes, this can be done, and other OEMs have this ability.
Basically, timing chain wear is usually associated with stretching of the links. This can happen due to a lot factors like stress and heat from sustained high RPM. But also, commonly, (and seen especially in the Ecoboost 3.5L engines and others) if the oil is not changed frequently enough, and there is dirt and contaminants in there, this all gets lodged in-between chain links, acts like sandpaper and grit, wearing down the metal, and causing slack. This, in turn, when acute enough, causes timing issues, and therefore, a wrench or CEL.

And it goes without saying, but this is why the Mfr-recommended oil change intervals that keep extending out, really shouldn't be followed - OCIs should be sooner, for those who care about engine longevity.

If the "wrench light" appears while in motion at the track for a Timing Chain notification, does that mean it appears AFTER the engine suffered a potential failure, or is the PCM that smart and aware of being able to detect a preemptive Timing Chain failure BEFORE it happens to allow the Driver (in motion and at speed) to hopefully stop the car before engine damage?

By the time this is seen, the damage is done. Chain is stretched (likely, in terms of the damage type to the chain) too far out of spec. Which is why it says to replace it in this event.

 

[Jimmy Dean]

not sure why the GT500 didn't have anything, but it is likely because until '21, none of the non-shelby mustangs were warranted for heavy track use anyways.

 

[Rocketeer]

Sounds like stream of consciousness, typed up by someone working for QA and being rushed or not really able to communicate clearly. AFAIK, If MIL is on there parameter(s) have grossly exceeded, ~20%, their norms so it's not preventing wear failure, it's reporting failure already happened.

 

[luc]

not sure why the GT500 didn't have anything, but it is likely because until '21, none of the non-shelby mustangs were warranted for heavy track use anyways.

I remember a long thread regarding the fact that the 500 warranty was voided if tracked…
. https://www.mustang6g.com/forums/threads/no-2020-gt500-warranty-for-track-use.150446/

 

[Jimmy Dean]

I remember a long thread regarding the fact that the 500 warranty was voided if tracked…
. https://www.mustang6g.com/forums/threads/no-2020-gt500-warranty-for-track-use.150446/

so maybe that is why? only the GT350 and Mach 1 are not voided for track use? makes no sense why the 500 would be though.

 

[Grimreaper]

The gt350 tune has a counter based on time spent at certain revs that ticks down to the wrench light and chain replacement warning. Certain harmonics and rpms must stress things more because the tune list larger reductions in time remaining for very specific rpm ranges.

I've not seen this on the gen2 tunes or gen3.
I'll double check the mach1 tune again.

Possible this is in the tune but its just not a populated table.

 

[K4fxd]

The gt350 tune has a counter based on time spent at certain revs that ticks down to the wrench light and chain replacement warning.

What is the ECM number for this table? I have not seen it.

 

[Grimreaper]

ecm 9506, under fuel and cutoff/dfco.

 

[ice445]

ecm 9506, under fuel and cutoff/dfco.

Well that's fascinating. I wonder if this is a GT350 feature that's trickled into the GT tune for '21 MY. Maybe they collected enough data for the gen 3 coyote to build a table like this.

Sponsored