bigs

I'd like to hear - from folks who are way more mechanically knowledgeable than I am - both the good and the bad of 928 factory engineering.

IOW, what mechanical aspects of the car do you think are exceptionally well-engineered or innovative (especially considering how long ago the car was designed), and what other aspects you think are poorly engineered and leave you scratching your head...

blown 87

It is a pretty good car, but there are a couple of things that have left me wondering WTF.

1. what is up with the liquid filled motor mounts that last 6 months.

2. Why the open deck?

3. Why is there such a premium on parts that start with a "928" in the part number.

Other than that????

bigs

Explain to this mechanically challenged soul what an open deck is, plz.

H2

Since Porsche used the auto cam belt tensioner on the 968 in 1992...why didn't they also incorporate this on the more expensive 928 the same year... or later? Sounds like they'd already decided to ditch the 928 in about 1990 when engineering the auto tensioner for the 968 probably started.

The basic body design is timeless. But making hoses with two different sized ends is frustrating...but probably good for Porsche parts sales.

blown 87

When you pull the heads off, the holes that the pistons ride in have no support at the top, they are free standing.

On a closed deck, like a BBC, or a SBC they are solid except for oil and coolant holes.

I hope that helps, not a very good mental image on my part.

LightStriker

Good:
Trans-axial transmission giving a near 50/50 weight ratio.
Extremely strong body with quite good aerodynamic for the time.
Rust free body, engine and transmission.
Amazing suspension, which gives some of the best cornering.
Virtually indestructible engine and transmission. (At least for the non-interference version)
Really comfortable seat, and one of the most enjoyable ride ever.
Engine that gives a really great and flat hp/torque curve at almost any rpm.
Great evolution over the years, many flaws fixed.
In my opinion, Porsche most pretty car.

Bad:
Rubber dry and crumble, and there's a lot of it, vacuum, oil, coolant, it leaks, from every spot possible.
Electrical wires rust, and so they do, creating endless untraceable problems.
One of the longest timing belt ever, with a problematic water pump, coupled with the interference engine of the later years, means a whole block can be scraped in blink.
Numerous specifics cheap plastic part used for the inside, which have extremely expensive for no reason and tend to break by looking at them.
Dash, pod and middle section warp, deform and break from simply the sun heat.
Extremely complex engine, with some questionable technical choice. CIS is more like some kind of voodoo...
One of the weakest horn I've heard.
No planning on easy fix, fixing something often means taking half the engine appart, or the transmission. Hell, filling the transmission reservoir is one amazing pain.
It's heavy.

bigs

No, that works just fine. Thanks.

bigs

I'm pretty impressed with the rear suspension that allows for a degree of passive 4-wheel steering.

But locating the window switches on the center console still bugs me. I suppose I'd get used to the location if the car were my daily driver.

IIRC, the hood, front fenders, and doors are aluminum. Why not all body panels?

ptuomov

As far as the engine goes, you could look at the modular Ford 4.6L and 5.4L 4-valve engines. Those are basically improved versions of the 928 engine. It would be interesting to take a part a 928 engine and '03 Cobra 4.6L 4-valve crate engine. Whatever Ford chose to change was what they believed was an improvement in some way, possibly in terms of cost.

JHowell37

There's no excuse for them to have ever used that ****ty tensioner for the timing belt.

Why is it so hard to consistently produce quality water pumps?

A cork oil pan gasket? Even by the 80s, this was inferior.

Could stand an extra centimeter of clearance on each side of the engine.

No way to easily check the transmission fluid. Adding additional fluid is a total pain in the ***.

Fastest928

550 rwhp and climbing....test on my 500 rwhp stock intake engine with preliminary 52mm ITB setup - result of collaboration with Louis Ott.

Ben Allison

The car was narrowed fairly late in the design stage (at least I have heard this rumor a lot Explains quite a lot of the engine bay, especially some of the bits hidden underneath the fender like the coolant tank and ignition coil.

bigs

^^^

That dyno run bespeaks pretty damn good fundamental engineering! Especially for its time!

Landseer

It amazes me how they fit everything that they did into the engine compartment.

And nearly everything is serviceable with normal tools. It may be an archeological dig through layers to get to it, but you can get there. I think they did a hell of an engineering job, overall.

blown 87

That is not bad for today.