enginehistory.org

[jschreiber]

Hello

A V-1710 engine, from a P-38 Lightning wreck, emerged recently in France, near Laval. A preservation project is under way, and, to help the team, information on the steels and alloys used in the manufacturing of the engine would be useful. But, insofar, the here available documentation (mainly USAAF manuals and the very fine Daniel Whitney's book) gives no precise data, ie composition (or commercial name) of the light alloys used for the pistons and the cylinder heads, or the steel for the crankshaft or the connecting rods. Is such kind of information available somewhere, at least for a typical V-1710 F, since materials obviously changed during the lifetime of the engine ?

In advance, many thanks for your answers

J Schreiber, Lyon, France

[dwhitney]

Jschreiber,
The following is not a comprehensive list, but covers the main engine components.
Crankshaft: A.M.S. 6415 steel, nitrided 38 hours at 950 degF, surface hardness 500 Vickers, min. Fatigue endurance limit in bending for the V-1710-"F" nitride crankshaft is 120,000 psi.
Crankpin Oil Plug: A.M.S. 4214 Aluminum
Crankshaft Oil Plug: A.M.S. 4130 Aluminum
Crankshaft Main Bearings: A.M.S. 1013 or 1035 steel shell plated with A.E.C. A20 Silver, 0.0181 to 0.026 inches thick. A20 is 1.5% copper, balance Silver.
Connecting Rod Bearings: Same basic construction as Main Bearings, thickness of silver is 0.005 to 0.015 inches.
Piston: machined from aluminum alloy forgings of A.M.S. 4145.
Piston Rings: made by Perfect Circle Co., of their "M" Iron.
Piston Pin: A.M.S. 6250 steel, Rockwell 31C in core, Case hardened 0.025 to 0.040 inches to Rockwell 55C on both ID and OD.
Piston Pin Retainer Snap Ring: A.M.S. 6450, Rockwell 50C.
Forked and Blade Connecting Rod: A.M.S. 6415 steel, Rockwell 32-36C, shot-blasted.
Connecting Rod Bolts: A.M.S. 6415 steel, Rockwell 32-36C.
Crankcase, Upper and Lower Half: A.M.S. 4214 Aluminum, modified by AEC Spec ES-280.
Crankcase Oil Pan: A.M.S. 4424 Magnesium
Cylinder Block Bearing Plate: A.M.S. 4510 Bronze.
Crankshaft Main Bearing Stud: A.M.S. 6415 Steel, Rockwell 32-36C.
Cylinder Jacket Sleeve: A.M.S. 5510 Stainless Steel.
Cylinder Head Cover: A.M.S. 4424 Magnesium.
Cylinder Head Cover Gasket: A.M.S. 4000 aluminum.
Cylinder Head: A.M.S. 355 T7 Aluminum Casting.
Cylinder Jacket: A.M.S. 4214 Aluminum, modified by AEC Spec ES-280.
Valve Stem Guide: AEC 620 Bronze.
Intake Valve Seat: A.M.S. 5700 Steel, chrome, nickel, tungsten.
Exhaust Valve Seat: Carpenter V.S.M. chrome, molybdenum silicon steel with #1 Stellite welded on valve seat. Rockwell 45C to 50C.
Cylinder Barrel: A.M.S. 6294 steel, Rockwell 26C core, 54C case after carburized.
Cylinder Barrel Nut: A.M.S. 6320, Rockwell 26C to 32C.
Cylinder Block Stud: A.M.S. 6415, Rockwell 32 to 36C.
Camshaft: A.M.S. 6290 or 6294 steel, Rockwell 20C core, Rockwell 60C surface.
Camshaft Bevel Gear: A.M.S.6250 Steel, Rockwell 30C core, Rockwell 60C case.
Camshaft Locating Bearing: A.M.S. 4842 Bronze.
Rocker Arm Shaft Bracket: A.M.S. 4130 Aluminum.
Rocker Arm Bracket Stud: A.M.S. 6415 Steel, Rockwell 32-36C.
Rocker Arm Shaft: A.M.S. 6250, Rockwell 30C core, 60C case.
Rocker Arm: A.M.S. 6415 Steel Forging, shot blasted all over, Rockwell 31-36C.
Rocker Arm Roller: A.M.S. 6440 steel, Rockwell 60-63C.
Rocker Arm Roller Needle Bearing: A.M.S. 6440 Steel, Rockwell 57C min.
Rocker Arm Adjusting Screw: A.M.S. 6290 Steel, Rockwell 20C core, 57C case.
Intake Valve: Wilcox Rich #142 Steel (chrome, nickel, tungsten) with #6 Stellite welded on seat, nitride stem, sodium filled.
Exhaust Valve: Wilcox Rich #142 Steel (chrome, nickel, tungsten) with #6 Stellite welded on seat, nitride stem, sodium filled.
Valve Springs: A.M.S. 6450, Rockwell 46 to 50C.
Dynamic Balancer Weights: A.M.S. 6250 steel, Rockwell 30C core, 60C case.
Dynamic Balancer Pin: A.M.S. 6250 steel, Rockwell 30C core, 60C case.
Crankshaft Inner Member Coupling: A.M.S. 6470 Steel.
Reduction Gear Outer Member Coupling: A.M.S. 6470 Steel.
Propeller Shaft Reduction Gear: A.M.S. 6250 Steel, Rockwell 30C core, 58C case.
Reduction Gear Pinion: A.M.S. 6250 Steel, Rockwell 30C core, 58C case.
Reduction Gear Pinion Bearing: A.M.S. 5040 Steel shell with AEC spec 545 Silver 0.02195 to 0.02725 inches deep.

Sorry, do not have specifics on the Accessories Housing.
Dan Whitney
dwhitney@surewest.net

[jschreiber]

Thank you a lot Mr Whitney for this huge amount of information !

J Schreiber

[sithomas]

That is a wealth of information.

Any idea why Allison used a sodium cooled inlet valve?

[rwahlgren]

Thank you Dan for that list, how did you ever find all that info?
I would like to see the same for PW engines if possible.
I was also going to add that there are hand held metal spectrometers that can be used to identify metals and alloy percentages, they are a bit pricey. And for hardness a Rockwell tester would be needed.
Shops that do aerospace manufacturing may have those items and may help out.

Not to pick, but this caught my eye. I have worked with this material before
and also did a search here on the net. It is steel not aluminum.
From the list above.
(Crankshaft Oil Plug: A.M.S. 4130 Aluminum )

Since seats are listed above and mention stellite welded.
I have a question, does this mean valve faces?
Intake Valve: Wilcox Rich #142 Steel (chrome, nickel, tungsten) with #6 Stellite welded on seat, nitride stem, sodium filled.
Exhaust Valve: Wilcox Rich #142 Steel (chrome, nickel, tungsten) with #6 Stellite welded on seat, nitride stem, sodium filled.