High Mileage Teardown
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.
-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.
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!
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.
Delivery to teardown via forklift, we’ll remove the 923 transaxles next..
The engine and tranny are so dirty they look like one unit!
OW this thing was nasty!! Note 912E # 974 in the background!
Engine mounts were shot from the chassis dyno sessions and hard driving!
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
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.
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!
More later.. Graphs and links to the new engine to come!