3.2 motor

[Nick Triesch]

Hi folks. I have had my 85 911 now since Augest and it just runs great. It has had all the required service over the years. And has had many little things fixed but nothing major. My question is this, why does the 3.2 motor last so long? Why does my mechanic say that it could last 335,000 easy? No car does this today! My car is in very good overall orginal shape and it just kills me everytime I go on a trip and it runs and feels like it has 55,000 miles on the clock. This car is 26 years old! I feel I could drive it across the US. Nick

[DRACO A5OG]

Well properly maintained, buddy of mine has 400K+ on his. But he has an advantage he owns a Porsche Dismantle Shop.

[rusnak]

Change your oil, use good sense and 300+ is doable. I have a lot of 911 miles.

[m110]

Originally Posted by Nick Triesch

My question is this, why does the 3.2 motor last so long?

Evolution to a strong design
Top quality parts suppliers and assembly
Relatively low state of tune
Good maintenance
Overkill oiling system

[PatrickB]

As long as you don't miss a shift and over rev, you are doing well. Keep up with the valve adjust's, and oil changes, and you could see 500k.

[James Brown]

Evolution of a 45 year old good design.

[Wil Ferch]

Almost all cars can live MUCH longer than we expect to today. It comes down to being mechanically sensitive to what is happening to your car..and taking care of issues as they crop up. Oil / filters are a big issue...either do routine analysis or be maybe a little wasteful and change oil / filters frequently.

I have a 17 year old Corolla ( Prizm) I drive as my daily hack.....bought it for peanuts used and with high miles.....do oil changes every 10k miles ( ! )....and have over 252,000 trouble-free miles on the engine. Compression and leakdown are excellent. No oil leaks. No oil burning or smoke. No need to add oil between change-outs. Shift routinely at 5k or so.... I drive it to h%ll and back and don't baby it. Modern engines of all brands can survive 500k+ miles if you do your part..... or even like me abusing the engine with longish oil changes, but with quality oils/filters.

[IROC]

Originally Posted by Nick Triesch

Why does my mechanic say that it could last 335,000 easy? No car does this today!

Because - in this case - the old saying "they don't build 'em like they used to" is completely valid.

[andyt11]

I agree with all the above posts, especially the notion that they don't build them like they used to.

The only weak link in these engines is soft material for valve guides but that can be dealt with and the modern replacements are much more durable.

[cattman]

Why, theoretically, can't a well maintained 3.2 run infinitely? Why is there ANY mileage expiration, be it 350k, 500k, etc.? What happens that causes it to fail beyond repair?

I ask because if the engine on my '87 3.2 were to go, I'd rebuild or replace it. So if that happened at 300k miles, so be it. Rebuild or replace, get another 300k miles, and so on.
CATTMAN

[James Brown]

In Andersons book, a must read Nick, he states he has never rebuilt a 911 engine because it wore out.

[m110]

Originally Posted by cattman

What happens that causes it to fail beyond repair?

CATTMAN

IMS bearing will fail eventually, chain skips, valvetrain collides (my guess)

Mercedes had a 450 engine running without stopping for some ridiculous time (years), they just cycled oil while it was running. Some stationary diesels at generators in the arctic run for decades too. Without heat/cold cycles and with constant clean oil it would go for a hell of a long time

[Quicksilver]

Back in the 70s the expected lifespan of a cam in a Chevy big block was 60k to 80k miles. During the pipeline years in Alaska my dad started to see big block Chevy trucks where the cams were failing after 200k or 300k miles which made no sense because nothing in those motors lasted that long.

Turned out that the reason they lived so long was that these trucks were up on the north slope and they never turned them off even to be refueled. They just ran them three shifts a day and they only were turned off when they were serviced. Really makes you think that the Accusump preoiler might be on to something.

[Wil Ferch]

Actiually...today's engines are made more precisely....with closer tolerances and dimensions all from computer controlled machinery....that should (if all else equal) allow them to last even longer than in the past. True enough, if they cheapen up the materials and if modern oils ( due to LEGAL requirements) are worse....then that helps to balance things out.

I don't buy it that GM's V-8's had a life expectancy of 60-80k miles. Nylon sprocket cam drives were crap...OK...but cast iron blocks wear like crazy. Admit it....."normal" people are not as fanatical about maintenance as we are. But if you take ( for example) Police or Taxi drivers who put these cars to long service AND maintained them...they'd last a long time too.

[Quicksilver]

Originally Posted by Wil Ferch

...
I don't buy it that GM's V-8's had a life expectancy of 60-80k miles. Nylon sprocket cam drives were crap...OK...but cast iron blocks wear like crazy.
...

My dad was the only factory trained GM partsman in Alaska in the 70s so he had a huge sample of info to work from. The big block engines didn't wear out but the cams would very (very!) commonly lose a lobe or 2 in the 60 to 80k timeframe. The small blocks had much better lifespan with no specific weak point such as the cams.

He did say that if people would religiously add a dose of GM's EOS (1/4 can) with each oil change that seemed to make all of the shortcomings of the big block cams go away.

Not sure if the 70s and 80s EOS is the same"old" stuff that we go after for the ZPPD but the level of moly in it was an issue with plugging filters so they didn't recommend using a whole can for repeated fills after the initial breakin.

[RWebb]

911 motors contain an "extra" bearing for the crank, greatly increasing longevity

the boxer design reduces forces & stress in the engine

the 3.2L has EFI which reduces gas wash down of the cylinder walls

in general, the motors are simply a detuned design for endurance racing, and that helps them last a long time in street use or for weekend racing

[tcar]

Taxis are not a good example, they only typically have one cold start a day, if that.

Many trucks same.

The SC and Carrera motors are evolved from the 3.0 Turbo case so they are way understressed... long, long life.

[James Brown]

Now, if the US can make an automatic transmission that lasts as long as the engine...

[JBaez]

I decided to use my 88' black targa as an everyday car and now have 281k miles. The car runs like new. Change oil ever 5k with Brad Penn. I would not trade this car for a new one. I seem to find myself wanting the older cars to re-live that true Porsche air cooled feel. Best car I have ever owned and reliable as a rock.

[mystro]

Bingo!!! What other exotic sports car is so over built.

Originally Posted by IROC

Because - in this case - the old saying "they don't build 'em like they used to" is completely valid.