3.2s and early engine work

[Milu]

I've recently been hit with a need for an engine overhaul, hopefully top-end only, on a 3.2. at 120k klm (72k miles). Am I alone in thinking this is ridiculously early? I got rid of a series2 924Turbo with 110k miles without any engine work and its still going strong, ditto a BMW320, (135k), ditto an Alfa Spider (110k). But I did nearly all the mileage.
Amongst other Porsches, I've had four 3.2s. One was a high mileage hack converted to webers I inherited on my father's death, another was owned by a guy who drove it properly and maintained it little, two are low mileage garage queens. I still have the two GQs one's a daily driver and one's been modified for politically incorrect road driving.
Guess which needed the early engine work? Yes, the two queens.
The first drove right and felt right but just wasn't anything like as quick as it should have been. This one was suffering from "London Porsche Syndrome". This is a malady afflicting Porsches that have been run-in in London traffic and only used for short stop-start journeys and never revved. The other came from Germany and I've no clues about how it was used except it was maintained to schedule and always smoked a little on start-up.
What are other people's experiences with 3.2s. Can you get high troublefree mileage's if they are used and maintained as Porsches are meant to be used and maintained or are early overhauls the rule. Bearing in mind that my father's car was converted to carbs by a previous owner and reached starship mileage and SCs seem to go on forever could the DME be the weak link and if so is there an upgrade or a way of anticipating problems? Any thoughts?

[Early_S_Man]

I think you will probably find the 'orange' elastomer valve-stem seals inside you engine, as they have been the cause of most early-mileage valve problems in the 3.2s. My recommendation is to use the white Teflon 'Perfect-Circle' seals, regardless of what comes ine the top-end gasket set! Sure, they allow a little oil seapage down the valve guides, but that is good for the valve stems and valve guides!

Without a doubt, the orange seals were a bad idea, just like magnesium crankcases for 2.7 smog-controlled engines!

I do not quite understand the obsession some 911 owners have about smoke on start-up ... every radial piston-engined aircraft ever built does the same thing ... brand-new from the factory! It has nothing to do with the tolerances or wear limits exhibited by a worn-out engine!

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[Milu]

Thanks for the info on the seals. I guess in my case the "obsession" with smoking is because they don't all do it. I've had six 911s and only one was a significant smoker. As all the expert and professional opinion that saw it said it was normal, I didn't worry about it until it increased dramatically, (60,000klm later).

[stlrj]

"...the air flow meter... return-to-zero spring inside... With age, its preload weakens resulting in a richer mixture..."

http://www.gomog.com/articles/EFIflap.html

Joe

[This message has been edited by stlrj (edited 10-07-2001).]

[Milu]

[This message has been edited by Milu (edited 10-08-2001).]

[Milu]

[This message has been edited by Milu (edited 10-08-2001).]

[Milu]

That's an interesting one. The usual theories I've come across relate to the seals or a problem with the DME causing rich running. As it happens I had to replace the airflow unit on one car just before rebuild and tinker with it on another to get it working properly. Could this be a much weaker link than we think?



[This message has been edited by Milu (edited 10-08-2001).]

[stlrj]

The air flow meter has been implicated as the cause of a cascade of events that lead to the early demise of the 3.2.

Bruce Andersen, national technical chairman, mentioned in a recent tech response that there seems to be a correlation between 3.2's running rich at idle and excessive oil consumption due to early valve guide wear.

Even general aviation has been aware of this phenomenom for decades and has explained it here: http://www.hiway.co.uk/aviation/pplir/renaissance.htm

My conclusion is that the over rich mixtues is just the tip of the iceberg in a cascade of events leading to excessive heat in critical areas such as the cylinder heads and the band aid solutions of ever larger oil coolers that bury the problem under what seems to be an elegant high tech solution.

Rich mixtues are also implicated in the poor low end performance of our 3.2's and the Pelican archives have many testamonials of how leaning the mixture caused a dramatic increase in performance.

Seems we might be on to something!

Joe

[ChrisBennet]

Originally posted by stlrj:


Even general aviation has been aware of this phenomenom for decades and has explained it here: http://www.hiway.co.uk/aviation/pplir/renaissance.htm

Joe

Thanks Joe, that is fascinating stuff!
-Chris

[Doug Zielke]

Originally posted by stlrj:

Seems we might be on to something!

Lean-burn mixtures....yet again!

[wckrause]

"Pelican archives have many testamonials of how leaning the mixture caused a dramatic increase in performance."

Seems like all of these testimonials are written by one person....hmmmm....I wonder why?


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Bill Krause
'79 911SC Euro
MY PELICAN GALLERY