Please keep checking in on the progress of these parts here.
These upgrades include many new parts, and production takes some time to complete.
12.29.2025
991.1 Finger Follower Upgrade
All metals have inclusions in them. When parts are machined from these metals some of these inclusions
can be closer to the surface. We add treatments like DLC to give surfaces a harder and better wearing
surface. Oil is needed to lubricate and to remove the temperature created when surfaces are in contact.
Here are photos of the inside of the 991.1 GT3 Cylinder Head. There is an oil spray bar on the bottom
side that sprays oil upwards on to the moving parts. As this oil is not concentrated on certain parts it
results in the failures we are seeing.
The Finger Levers are the same for Intake and Exhaust. There is a jet machined into the Lever that directs
oil between the Finger Lever and Camshaft Lobe.
Oil is pumped through the Gallery cast into the Head into the Finger Stands, then through the Jets
machined into the Levers. The Intake Stands have an oil hole for this oil to go through into the Levers.
The Exhaust Stands do not have this hole.
In a mechanical “lashed” valve train, shims or some form of adjuster is fitted which gives a clearance
between the Camshaft and the type of Follower used. This lash clearance is measured and adjusted
between the Camshaft base of the lobe. As the Camshaft rotates the lobe is forced onto the Follower
lifting the Valve. Oil and heat is removed during this motion and oil is then re-deposited back onto the
Follower when the Valves close and the Camshaft on its base circle.
Our modification is to change the motion of the Valves to mechanical from Hydraulic. We are making the
Lever Stands “solid” and the lash will be added with shims located in the upper Spring Retainer. This
solution requires the Camshaft Lobes to be reprofiled as the valve motions for a solid motion is different
from hydraulic.
Back in 2016 we did this upgrade, but the parts are very expensive and more designed for high
performance and race applications. By reusing the stock Levers, we have developed a more affordable
solution.
The Finger Stands have been completed along with the new Camshaft design. As soon as we have a
repeatable reprofiling solution we will make this upgrade available.
The 992 GT3 is experiencing Lash cap failures. These caps are bouncing out of the Spring retainer ending
up in the oil sump, causing oil pump seizures. Our solution is to retain the lash caps within the Spring
retainer. As the 992 GT3 valve motion is solid and changing the 991.1 over to solid, we have decided to
include the lash cap retention into the 991.1 upgrade.
The new Pump Shaft and drive Gear attachment is completed, and these parts are now available. These
engines will also have the new Lash Pad retention system and new Cam profiles added. The full upgrade
will include a new Crankshaft so a Harmonic Damper can be fitted. Both parts are in production, and no
delivery dates are currently available. The Crankshafts are expected May 2026. This will increase the
engine displacement to 4.2L.
12.29.2025
992 GT3 Oil Pump Upgrade
Harmonics developed within the engine are causing several failures, including the oil pump. These noises
travel up the timing chains and down through the pump drive chain. The pump gear bolt fails along with
the drive machined onto the end of the drive shaft.
Failures have also happened with the lash caps bouncing out of their retainer, casting flashings finding
their way into the pump, and Camshaft Actuators failing.
These failures have resulted in a sudden engine stoppage. The particular failure shown below was a
result of the Camshaft phasing Actuator failing. The failing is a result of the harmonics, causing the bolts
holding the Actuator together to fail, resulting in the Actuator coming apart.
The 992 GT3 Valve train was redesigned to be “solid”. No oiling jets are added to the Cylinder Head,
rather jets machined into each Finger Lever.
A Crankshaft Dampener is being developed for this engine to help control the harmonics. This does
require the Crankshaft to be changed allowing the front mounting of the new Dampener assembly.
Coming soon is a 4.2L conversion for these engines that will include this new Crankshaft and Dampener.
We are working as fast as we can to get all these parts available ASAP. I will post updates each week
here on the progress.
Thank you,
Neil