Larson E. Rapp

You seem to have an L.A. gang member's notion of "disrespect."

Carlo_Carrera

The Gen II engines are Audi units, EA839 and EA888, with years of use within that brand's cars. They are proven to be solid.

///Bruce

When it applies to my dad, you’re damn right. My suggestion? STFU

Carlo_Carrera

Okay folks, this is me putting my moderator hat on. Let's drop this personal stuff, thanks.

///Bruce

Thank you.

worf928

Why don’t you re-read what I wrote that you quoted. I’ll help:


Yup.

And the other issue is that torque is not a direct measure of clamping load.

In this case (IIRC) and in the cam chain cover thread, the tightening process for the M6 (aluminum) bolts is 8 Nm + 90° (IIRC). That results - **in a steel fastener into aluminum threads **- in a clamp load that will be very close to stripping the aluminum threads. Thus, in this case, on an aluminum bolt, I would wager that the resulting clamp load is right at the point of plastic deformation. If so, then if the material isn’t over-specified then one should expect failures on the wrong end of 6-sigma on a manufacturing curve.

My theory: either the torque procedure is wrong, aluminum fasteners were substituted instead of steel at the last minute by a product engineer/accountant/idiot, or a substandard material was substituted by the supplier once production was underway and PAG wasn’t QC’ing as they should be.

chassis

Agree that torque is not a direct measure of clamp load. This is not comprehended by people happily slopping anti-seize on spark plug threads, caliper screws and wheel screws. When a torque spec is given, it is a dry torque spec, or "lightly oiled" torque spec. Lightly oiled means normal residual oil from the fastener manufacturing process, not applied oil for the purpose of friction modification. If locking compound or anti-seize compound is required, it will be specifically stated in the spec. Otherwise foreign materials (compounds) must not be used.

Aluminum screws, in a quasi-structural application such as a timing cover, are a dubious decision by Porsche to save weight. Aluminum fasteners cost more than steel fasteners of the same size. Porsche and MB make stupid decisions to save a few grams of mass, which have no effect in the grand scheme of things, and in fact cause problems such as the well-known oil leak and fastener breakage on the ill-fated 3.0/3.6TTV6 cold vee engine.

Carlo_Carrera

As I wrote, aluminum fasters are not the problem. Inappropriate or ill conceived usage is.

justabout

The aluminum bolts avoids galvanic corrosion of the magnesium cover. There are steel replacements available with insulating washers to avoid the corrosion issue.

worf928

A few grams over hundreds of fasters is kilos of mass. It does add up. And every kilo saved makes it slightly easier to meet draconian regulations that are well beyond the point of diminishing returns.

But, I agree, it is a dumb decision. Or, sad really. Sad for those that want to keep driving their Porsches for decades.

DHL

If they wanted to save weight, improve strength, and avoid galvanic corrosion they should have used Titanium bolts.

worf928

Part number? (I believe you; I want to order at least one.)

Lol. Have you priced titanium fasteners? Have you seen what Porsche charges for titanium lug bolts?

If Porsche used titanium fasteners they would bump MSRP by at least 10%

Ah! That’s it… I wonder if I can request titanium fasteners in lieu of aluminum fasteners as a CXX option?

Don’t tell the GT <x>RS folks!

stiles_s

Genuinely wanting to learn here as we own both a Porsche v6 Macan and my dad has an Audi v6 Macan. Both S. A 2018 and a 2019.

Yes, this post is concerning.
Also concerning is the issues I'm seeing with Audi's hot-v turbos, both in 4.0 and 3.0/2.9 guise. Documented everywhere, but VAG Technic's youtube channel does an especially good job unpacking it. It's a freaking horror show. Yes, some of the root causes have been updated by Audi, but others haven't and you're still dealing with a super hot "v" with many plastic parts.

So, seems kind of unfair to me to be stating absolutely that the Audi engines are the choice for durability in Macans. I think we should be honest and say that we're all arguing about which is the brightest "D grade" student when neither compare to something like Toyota's 4.0L n/a V6. These are fun, powerful engines that appear to be a long term maintenance "challenge".

Larson E. Rapp

This would be the same Toyota that is recalling and replacing 100,000 V6 engines?

If there were any horrorshow flaws in the 3.0/2.9 engines as used on the 95B.2 platform, I think we'd have started to see them appear by now.

stiles_s

You're pointing out a new engine design from Toyota that they are proactively recalling (a small percentage of production) to address a manufacturing defect.

Porsche is letting us hold the bag for all but the most egregious defects.

I noted the Toyota 4L n/a v6 intentionally. That is what I'd call a robust engine. I'd also give Audi's 3.0 SC v6 pretty solid marks for durability (to name one VWAG engine).

If the Porsche "hot v" 6s and 8s are indeed the same units shared with Audi, which I think we'd agree they are, then we *are* seeing evidence of failure show up in the broader community. I'm hopeful for all our sake that most of the teething issues and substandard components were slipstream addressed, but you're still dealing with a Hot V, which is great for responsiveness and emissions but has pretty universally been shown to cook plastic parts. Brittle parts crack, and leak, and bad things happen that are expensive to fix.