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Allison Competition Engines, Inc., known as ACE Allisons, is located in Latrobe, Pennsylvania. There in our airconditioned shop we maintain an extensive inventory of parts, rebuildable core engines of many different models (many NOS), and our comprehensive tooling, support and test equipment used during the overhaul process.

The President of ACE Allisons is Bud Wheeler. Bud holds an FAA Powerplant certificate and has over 30 years expereince in building high performance V-1710s of all types. Critical to the success of his engine experience has been the full scale dynamometer used to develop engines and component parts through extensive testing and verification.

ACE Allisons's FAA Approved Repairs, Modifications, Alterations, and Parts

The Allison V-1710 is a marvelous piece of engineering, manufactured to very close tolerances and built with quality throughout. With manufacturing of the engine now some 60 years past the supply of quality and serviceable spare parts is significantly depleted, and in some cases nonexistent. To continue to provide our customers with the very best V-1710 possible ACE Allison's has undertaken manufacture of many new parts while developing a number of repairs to existing parts that not only returns them to service, but improves on their serviceability and reliability. So that these parts can be legally operated in aircraft engines we obtain FAA approval of the parts and repairs. In some of the following cases that process is still underway.


Early model coolant pumps are upgraded to the V-1710-G6 configuration for improved performance and leakage.

Piston Rings — Allison never had a really good ring package, hence the allowed oil consumption of up to 3.5 gph at 1000 bhp. ACE Allison's engines use an FAA approved set of three modern rings all located in grooves above the piston pin that are far superior to what was available 70 years ago. This new ring pack has proven to be very robust and when in appropriate cylinder liners, results in an engine with very little blow-by and negligible oil consumption.

Cadmium Plating — After years in service and exposure to the elements, the protective cadmium plating on external engine hardware is deteriorated or non-existent. ACE Allison's goes to the trouble to completely replate all of the external hardware to the current standard for Aerospace applications. As plating is considered to be a Major Repair, we have obtained FAA approval and have the hardware properly plated.

Coolant Pump Seal — The seal in the original pumps is prone to leakage, while the shaft itself is often found corroded. ACE Allison's FAA approved repair upgrades the seal to the configuration of the later V-1710-G6 and the shaft is chromed, resulting in a very durable, trouble free and tight seal.


ACE Allison's "Orange" Valve Springs are direct replacements for Allison's "Blue" springs which no longer meet specifications.

Gaskets & Seals — Original gaskets and seals have long ago deteriorated, dried out or become stiff and not usable. ACE Allison's has obtained FAA approval to use appropriate non-asbestos gasket material and modern seals throughout the engine. As a result our engines are known for being clean and tight.

Valve Springs — An existing valve spring may have been compressed in the same "valve open" condition for as much as 70 years. As such creep sets in and the spring no longer provides the proper closing force or dynamic response. ACE Allison's offers FAA approved direct replacement springs that fully meet Allison's original specifications. You will be amazed at how smooth running your engine is with these new springs.

Plated Silver Bearings — The V-1710 uses a number of silver plated steel shell plain bearings that require a protective overcoat to be plated onto them. These are used on the connecting rods, main bearings and propeller pinion bearings. This overcoat deteriorates over time, even on bearings in storage or in engines that are static. Application of this coating is classified as a Major Repair and requires FAA approval. ACE Allison's FAA approval assures this coating is properly applied and that the bearing is appropriate for a long service life.

Propeller Shaft Roller and Ball Bearings — While these bearings are often found to be serviceable, when they are not a problem exists as the original bearings are no longer available. ACE Allison's has obtained FAA approval to use specific new manufacture bearing as direct replacements for the originals.


Distribution drives are upgraded with new seal configuration to prevent oil contamination of the Distributors.

Distributor Drives — Always an issue with high time V-1710s has been leakage of oil from the valve galleries into the distributors. ACE Allison's has an FAA approved repair using new seals that resolves this issue.

Spark Plugs — These are critical to the proper operation of an engine. The OEM plugs were marginal when new, and are dangerous to use today. Modern spark plugs are certainly available, but it is critical to select the proper heat range for the V-1710, and this had not been done. ACE Allison's has received FAA approval for current manufacture plugs appropriate to the V-1710.


ACE Allison's new cast stainless steel exhaust seat eliminates the need for Stellite seating surface. Otherwise, it is identical to the original.

Exhaust Valve Seats — Allison built these from tool steel, facing the insert with Stellite to provide a hard and corrosion resistant seating surface. The tool steel material corrodes badly due to the hot exhaust gas environment and exposure to moisture. ACE Allison's has developed a cast insert that directly replaces the original and is resistant to corrosion and erosion, thus insuring a long service life for your engine.

Valve Stem Repair — New valves are extremely hard to find, and expensive when they are. Old valves typically have seating surfaces that are fine, however many show effects of corrosion on the stems. ACE Allison's has developed a repair for the stem surface, returning the unit to a serviceable condition and meeting our goal of meeting Allison's specified clearances and tolerances for new parts.

Valve Guides — Experience shows that the exhaust valve guides are often worn and must be replaced. The only source of these is to remove serviceable guides from the intake side of the head. The result is a diminishing supply and the need for newly manufactured guides. In addition, when a guide is needed for a repaired valve stem the guide must be undersize so as to maintain Allison's clearances. The new guides are made from bronze as were the originals and are direct replacements.


New Valve Guides restore original clearances for both reused and honed stem valves.

Pistons — Original Allison pistons have to have the ring grooves re-cut in order to use modern rings. Also, new pistons are no longer available. ACE Allison's is now using new forged aluminum pistons that take advantage of modern piston alloys and design. These pistons are slightly lighter than OEM pistons since they do not require the oil ring to be on the bottom of the skirt. Modern anti-friction coatings are used on the skirt, while a ceramic thermal barrier coating is available for the piston crown.


ACE Allison's "Black ACE" steel cylinder liners feature hard Nickel-Carbide rnning surfaces and are direct replacements for original Allison liners, but are considerably more stabled and stronger. They also allow full compliance with Allison's original installation and honing instructions. The black coating prevents corrosion by the coolant.

Cylinder Liners — These have become a real issue within the V-1710 Warbird community. With time and use liners become worn and must be replaced, and stocks of new liners were long ago exhausted. Allison does not allow reuse of liners because the "hook taper" interference fit in the head becomes undersize after their first installation, and the bore itself is honed to final dimension after installation in the head. ACE Allison's has developed the direct replacement "Black ACE" cylinder liner exceeds Allison's original requirements and strength. An enhancement to the new steel liner is the use of a black anti-corrosive coating on the exterior of the liner; this minimizes the tendency for the coolant to corrode the liner, particularly in engines using Glycol-Water mixtures for coolant. We have the interior of the liner plated with nickel- carbide by the aviation industry's leading provider of this cutting edge technology. This results in a very hard and smooth surface that after honing is excellent at retaining lubricating oil. These materials and processes have been used successfully for many years in automobile and aviation engines and we see them to be a big improvement in the durability of the V-1710.

Rod Bolts — The OEM rod bolts may appear to be in good condition, but their past history of use is not known, and thus they are suspect. For this reason ACE Allison's is manufacturing new and stronger rod bolts specifically designed for the V-1710 as a way to insure that this uncertainty is removed.

Engine Mounting Studs — Allison was one of the first to use "thread inserts"; they were used for the studs attaching vibration isolating pads to the engine mounts. Allison used the "Aero Thread" design, which has a unique rounded thread profile. These inserts are often found missing or damaged on engines coming in for repair, and new inserts are not available. Furthermore, the studs themselves have often been lost and new ones are hard to find. "Aero Thread" was taken over by "Heli-Coil" and now only Heli-Coil inserts are manufactured. To this end ACE Allison's is offering a repair that will utilize Heli-Coils and standard thread studs.