3500 Engine Exhaust Manifold Salvage

1.0 Introduction
Significant cost savings can be achieved by salvaging the ends of certain 3500 engine exhaust manifolds.

2.0 Best Practice Description
The ends of the manifolds can be machined down, a fabricated repair sleeve can be installed, and the manifold can be returned to service.

3.0 Implementation Steps

CAUTION: SAFETY PROCEDURES FOR THE SHOP EQUIPMENT INVOLVED MUST BE FOLLOWED.

• Clean the exhaust manifold using a shot-peen or sandblast method.
• Inspect the manifold for cracks. If a crack is found, salvage of the manifold is not recommended, as the cracks may continue to propagate.
• Machine the end of the manifold to 4.374 ± .001 inches, 1.750 inches long.

Fabricate a sleeve from SAE 1040 grade mechanical tubing, DOM, 4-3/8 ID by 4-3/4 OD.
Saw cut to 1-7/8 length, trim one end square, with an inside chamfer of 45 degrees by .06 long. The inside diameter should be about 4.370 as delivered. There should be no requirement for additional machine work on the inside of the sleeve.

• Heat the fabricated sleeve to approximately 450 degrees F.
• Drop the heated sleeve onto the machined exhaust manifold. The sleeve material should provide .004 to .005 inches interference fit.

 
 Allow the sleeve to cool, then tack-weld it in 3 places. Use Messer MG250 nickel electrode, or equivalent.

•  Machine the outside diameter to finish size, 4.565 +.000, -.002 inches.

•  Wrap the finished manifold in shrink-wrap to protect it from rust and handling dama.

 4.0 Benefits

• The finished manifolds can be mixed along with new manifolds on the same engine bank, because the centerlines have not changed.
• To reduce turnaround time for an engine rebuild, sufficient quantities of spare manifolds can be inventoried.
• The manifold can be sleeved additional times, if inspection criteria about cracking are met.

5.0 Resources Required

• 22 inch swing lathe with cutting tools
• Band saw
• Arc welding equipment

 6.0 Supporting Attachments / References
See publication SEPD0611, page 36, “A new exhaust seal and a new exhaust manifold sleeve are used in the exhaust manifold groups.”

7.0 Related Best Practices
None at this time.

8.0 Acknowledgements
Jim Bailey
Machine Shop Manager
Wyoming Machinery Company
+1 307 472 1000
jmbailey@wyomingcat.com