High Mileage Teardown

July 28, 2023 in Resources and Services

Living in Hell – 160,000 Miles of Service Revealed.
A photo documented autopsy by Jake Raby

The story and associated information you are about to read began September 3, 2002, when I first installed this engine into my 912E. The next 8 years of the engine’s life would be filled with neglect, abuse and the chores associated with being a four-season daily driver in the mountains of North Georgia over a span of 160,000 trouble-free miles.

I will begin by posting facts related to the life of this engine, when it was serviced, how it was treated and maintained. I will then share my original intent with this engine, how it was designed, how it was assembled and the parts that I used to create it. This story will illustrate the robust design of the Type 4 engine and what can be expected when Aircooled Technology takes the engine to the next level of performance, reliability, and longevity. I have kept extensive records relating to this engine for the very purposes of this autopsy that unfolds below.

As I complete the engine revitalization follow the link at the bottom of this article to see the actions that I take to prepare this engine, transaxle and entire Porsche for another decade of trouble-free service as my daily driver.
This is my personal engine, these are my accounts.

Facts for RAT Engine 20020139 – Installed into 912600985

  • Assembled late August 2002
  • Engine was based from the original 100K mile donor from 912600985
  • 2056cc “912E Special” combination
  • Average fuel economy of 32 MPG. Peak MPG 41 MPG in 2003
  • Oil consumption average 1.8qt in 5K miles
  • RAT Engine Dyno power (new) :129HP, 123lb/ft torque (see graphs at bottom)
  • Engine used synthetic lubricant ONLY after 500 mile break in
  • Engine saw two valve adjustments since new, the last recorded February 3 2003
  • Engine went 23,000 miles on a single oil service
  • Engine only saw 14 oil services in 160,000 miles (sometimes the filter wasn’t changed for 3 services in a row!)
  • This engine was pulled for autopsy only, it did NOT fail!
  • All work was done as an educational exploration and to prepare the 912E for 10 more years of service as my daily driver. (it was pulled to service the 260K mile transaxle!)
  • This engine had ZERO occurrences where it wasn’t 100% reliable
  • No repairs were made to the engine during its time in service
  • Engine used carburetors for the first 59,000 miles
  • Was converted to programmble EFI in 2004 and was used to test three different ECUs for the RAT engine program
  • Engine was built with daily driver performance in mind
  • Engine/ car saw 5 PCA DE events at Road Atlanta and Roebling Road in 2003-2004 (over 1200 track miles)
  • The final dyno chart for the engine plots 102RWHP on our dyno jet chassis dyno(see graph at bottom of page). This means the engine was making the same power as new with 160,000 hard miles on the odometer and little service performed!
  • Engine comprised 100% of RAT and OE components
  • All internal components were cryogenically enhanced with the RAT profile
  • Engine was not removed for all 8 years of service, not even for clutch service
  • After 8 years and 160,000 miles of service the engine still produced 9HP more than the original 2.0 912E factory engine rating of 76HP!
  • Until the day the vehicle came off the road for the 2010 revitalization the engine was running perfect, barely leaked oil and had no notable oil consumption.

When I traded for my 912E it was a near perfect example of a 100,000 mile, well maintained and very clean 912E. The car was all stock, but the engine had overheated and melted a cylinder head, ultimately creating a situation much like a cutting torch that melted the engine tin and the stock EFI wire harness. Since the EFI harness was melted I decided to rip off the stock EFI and replace the system with a pair of carbs.

I was looking for a good driver car, something with good heat for the winter and great reliability and longevity. I don’t have time to wrench on my own cars, which is one reason this engine has been so neglected… Plus it offered the opportunity to put what I create to the ultimate test.. If an engine can live through service this harsh in my car, my customer would never break it. So it began.. I took a few used parts from test engines, coupled those to some of my new parts and applied them to the 100K mile core that came from the car originally. I did not use exotic components, I just assembled the engine in standard form paying attention to internal clearances and applying my enhancements. I assembled the engine completely and had it on the dyno in one weekend. The combination that I designed is very similar to the of my current 2056cc Porsche offering making similar performance and offering the same reliability and longevity coupled to awesome drive-ability. The only out of the ordinary process for the era the engine was built was the cryogenic enhancement of the components, something that I believe strongly in and even more so after the autopsy of this engine.
We routinely get the questions “How long do your engines last?” and “Are your engines reliable?”… Well I think that the below pictures and captions will forever answer these questions better than anything else. The internals of this engine were in excellent condition, the bearings had near zero wear, valve guides were barely worn, cylinders only had 5% leakdown cold, etc, etc.. The crankshaft doesn’t even need polishing, it also wasn’t polished at the 100K mile original rebuild, 160K miles ago! This crank has 260,000 miles of service and is still STD/STD never machined!

Keep in mind this isn’t a stock engine.. It produced 50HP more than stock after 160K miles of service. It wasn’t pulled because it had to be for internal attention, but more because 3rd gear in the 923 gearbox was trashed and I wanted to take the opportunity to clean and inspect the engine and revitalize it with a new engine combination.
The Type 4 engine platform is robust, reliable and as pictured below incredibly resistant to neglect, abuse and lack of scheduled maintenance… Because I have treated my car like this, please don’t do the same to yours. To me engines are disposable and expendable. Thats my job and its my life.
See captions below, study the pictures in detail. You’ll see why you need a MassIVe Type 4 engine created by Aircooled Technology.

Jake Raby
Here #985 sits poised ready for revitalization in my personal workshop here at the RAT facility.
NASTY! 160K miles of road grime.. The worn out transaxle is responsible for the majority of the oil leakage that attracted all the nasty stuff.
Another view shows some oil leakage from the engine, but keep in mind this is synthetic oil and more prone to leakage in a vintage engine. Also, the oil that was in this engine at the time of teardown had been in the engine since 2008 when i decided not to service the engine any longer!
A slight bit of head leakage at the cylinder parting line. This began last year after using this engine for testing of a new EFI system during these tests the car was strapped to our chassis dyno for 3 days of torture, which ultimately lead to transaxle damage.
Here is a shot of the engine after having the wiring nightmare associated with 3 different EFI systems applied removed. That alternator belt has 60K miles on it!
Engine and transaxle removed, ready for transport to the RAT teardown building for autopsy.
The last time I saw this engine out of the car was 8 years ago!!
Delivery to teardown via forklift, we’ll remove the 923 transaxles next..
The engine and tranny are so dirty they look like one unit!
Transaxle removed, its time to go onto the stainless steel mortician’s teardown table
OW this thing was nasty!! Note 912E # 974 in the background!
Engine mounts were shot from the chassis dyno sessions and hard driving!
YUMMY! All this nasty debris and the engine still didn’t overheat! Dirty cooling fins attribute to warped cylinders, hot spots and failures These cylinders were in great shape only needing a plateau finish hone before being reused!
Never a head temp over 400F in 160K miles!
Cylinder head removed from bank1-2. No cracks noted, just nastiness
Bank 1-2 cylinders and pistons. These were the first Keith Black pistons we used for the Type 4 engine, they performed flawlessly with our ring package and set up!
Cylinder head from bank 3-4. Similar characteritics of 1-2 but a tad more valve guide wear. All ports passed a “fluid test” and held fluid for 5 minutes +! This head was originally melted when I received the car, it was repaired effectively and the repair held up perfectly for 160K
More shots of the 3-4 bank parts
Heavily carboned Keith Black 96mm piston. Rings were .004 worn compared to their installed sizes.
More nastiness.. The oil sumpm plate hasn’t been removed since 2005!!
Look at that nasty oil!!! How could an engine with oil that nasty look almost new inside??
Is that straight crude oil??? LOL!
Experimental Keith Black pistons.. High oil temps on the race track and extremely nasty engine oil torched these pretty good, but them measure fine and will be reused.
Case split, note the sludge in the sump but how shiny and beautiful the journals are.
Yummy. Sludge!
Center main bearing (#2) looks near new! I expected this bearing to be worn into the copper! instead there wasn’t a scratch on it!
#1 main bearing bore. Note fretting, indicative that the engine will require an alignbore, it was not alignbored at the build 160K miles ago.
#2 center main bearing from the 3-4 bank case half.. PERFECT! Zero wear!
In this build I reused the OE aluminum camshaft drive gear. It will be replaced with a RAT gear.
#3 main bearing OD view. Note the fretting
#1 Main bearing, fretting heavily evident. This is the only wear the engine has!
Camshaft bearings. Perfect, but will be replaced with RAT HD Extreme bearings
Camshaft lobes. This aggressive camshaft should be much more worn! I challenge anyone to use other components than that of RAT and experience beautiful lobes like these in even 1/2 this amount of service life!
Center main crankshaft journal… No wear, it measures perfectly!
BEAUTIFUL! Camshaft end play still where it was set at assembly, .003
Even without double thrust camshaft bearings this engine still shows no bearing wear!
Finally some wear!! This center main suffered from extreme case shuffling, probably due to higher RPM and the necessity for align bore.
Another shot of the opposing center main.
More fretting…#1 main saddle
The big nasty picture!
Beautiful! Note proper alignment of oiling passage in center main bearing
#1 main journal on crankshaft.. Beautiful and perfect!
#1 Main bearing… Beautiful!
Crank assembly broken down. All journals and bearings were above average!
Rod bearing that looks like new!!! These could be reused!
AMAZING!
Small end rod bushings slightly loose, rod big ends in need of resizing, no action was taken on these rods at the 100K build More later.. Graphs and links to the new engine to come!

Below is the power that this engine produced when new back in 2002 on the RAT Engine Dyno. Very respectable for an engine built for daily service and a long life. Look at that flat torque curve!

Here is the power the engine made before teardown, with 160,000 miles on the odometer. The first graph was with the 35,000 mile dirty air filter, the second was after the air filter was changed. The oil that was in the engine for this last dyno test had been there since 2007!!! Note that the engine still made 102 RWHP and when the 20% reduction is considered from the flywheel to the rear wheels that means the engine was just as strong after 160K as it was when new! It actually appears the engine is making MORE torque after 160K than it did new!

Anyone considering a daily driver engine for their 912E, 914 or even VW conversion should no longer wonder just how long an Aircooled Technology engine will last.

Jake Raby