When maintaining ANSI B73.1 process pumps, plant engineers and procurement teams frequently face a critical question: Can Durco Mark III parts be used in Goulds 3196 pumps, and vice versa? The answer is nuanced — some components interchange directly, while others require understanding of the fundamental design differences between these two industry-standard pump platforms.

This guide provides a comprehensive, part-by-part interchangeability analysis based on 15+ years of reverse-engineering both pump families. As an independent aftermarket manufacturer producing replacement parts for both Goulds 3196 (G196 Series) and Durco Mark III (D Mark III Series), we have deep insight into where the two designs converge and where they diverge.

The Foundation: ASME B73.1 Dimensional Standard

Both Goulds 3196 and Durco Mark III pumps are manufactured to ANSI/ASME B73.1 — the governing standard for horizontal end-suction centrifugal pumps in chemical process service. This means:

• Mounting footprint is identical — baseplate bolt patterns match, so a Durco Mark III pump can be dropped directly onto a Goulds 3196 base without modification.
• Nozzle locations are standardized — suction and discharge flange positions and dimensions are consistent across both brands within the same frame size.
• Shaft centerline height — the critical dimension for coupling alignment — is the same for equivalent frame sizes (STX/Group I, MTX-LTX/Group II, XLTX/Group III).
• Overall pump dimensions (CP, D, X, E, F, Y, H, U values) match within tolerance, enabling direct whole-pump swap-outs.

Bottom line: You can replace an entire Goulds 3196 with a Durco Mark III equivalent (or our G196/D Mark III aftermarket pumps) without touching piping, baseplates, or motor mounts.

Key Design Difference: Open Impeller vs. Reverse Vane Impeller

Before diving into part-level interchangeability, it’s essential to understand the single biggest technical difference between these two pump families:

Feature	Goulds 3196 (G196 Series)	Durco Mark III (D Mark III)
Impeller Type	Open impeller	Reverse vane (semi-open) impeller
Front Clearance Adjustment	External adjustment against front casing	External adjustment against rear cover plate
Seal Chamber Pressure	Standard — front wear ring controls leakage	Reduced — rear pump-out vanes lower seal chamber pressure
Thrust Load	Higher axial thrust (open face)	Lower axial thrust (balanced by rear vanes)
Mechanical Seal Life	Standard	Extended — lower seal chamber pressure reduces seal face loading
Wear Ring Location	Front casing wear ring	No front wear ring — rear cover plate serves as wear surface

This means: You cannot simply thread a Durco impeller onto a Goulds shaft, or vice versa. The entire wet-end assembly (impeller, cover, casing) is designed as an interdependent system. However, individual power-end components are far more interchangeable.

Part-by-Part Interchangeability Matrix

The following table shows interchangeability at the component level. Use this as a quick reference when sourcing replacement parts for either pump platform.

Component	Goulds 3196 POS	Durco Mark III POS	Direct Interchange?	Notes
Casing (Volute)	100	100	⚠️ Wet-end only	Same nozzle dimensions per ANSI B73.1, but internal volute profile differs. Replace as a complete wet-end assembly.
Impeller	101	104	❌ Not directly	Open vs. reverse vane design. Shaft taper/fit may differ. Replace impeller + cover + casing as a set for cross-brand swaps.
Shaft	122	107	⚠️ Check fit	Same SAE 4140 or 316SS material. Shaft diameters at bearing seats typically match within same frame group, but impeller-end taper, keyway, and sleeve fit must be verified.
Shaft Sleeve	126	201B (Hook Sleeve)	⚠️ Check dimensions	Both use 316SS. Length and OD match within same group, but hook sleeve design on Durco requires matching gland.
Stuffing Box Cover / Seal Chamber	184 / 184M	108 (Rear Cover)	❌ Different design	Goulds uses front cover with wear ring; Durco uses rear cover plate. Not interchangeable.
Bearing Housing	228	129	⚠️ Frame-level	Bolt pattern and shaft centerline match within same frame group. Verify bearing bore diameters.
Bearing Frame / Frame Adapter	108	109A	⚠️ Assembly-level	Mounting bolt pattern often matches. Replace with bearings as a complete assembly.
Thrust Bearing	112	130 / 131	✅ Often same	Both use SKF or equivalent angular contact / deep groove bearings. Standard bearing numbers cross-reference directly.
Gland (Packing)	250	112	⚠️ Check fit	Gland bolt PCD may vary. Verify stud spacing before ordering.
Gasket — Casing	351	105	❌ Different	Casing gasket profiles are unique to each brand’s volute design.
Oil Seals (Inboard/Outboard)	332A / 333A	125 / 136	✅ Same function	Labyrinth oil seals (INPRO VBXX or equal) — cross-reference by shaft diameter and housing bore.
Oil Sight Glass	319	153 / 245	✅ Standard part	Generic component. Interchangeable if thread size matches.

Frame Group Correspondence: Which Pump Sizes Match?

Use this cross-reference table to find the equivalent pump size across both brands. Pumps in the same row share identical mounting dimensions (baseplate, nozzle locations, shaft centerline).

Goulds 3196 Frame	Durco Mark III Group	Common Pump Sizes	Max Impeller	Shaft Centerline
STX	Group I (1K)	1×1.5-6, 1.5×3-6, 2×3-6, 1×1.5-8, 1.5×3-8, 2×3-8, 3×4-8	6″–8″	17.5″ (445 mm)
MTX / LTX	Group II (2K)	1×2-10, 1.5×3-10, 2×3-10, 3×4-10, 4×6-10, 1.5×3-13, 2×3-13, 3×4-13, 4×6-13, 6×8-13, 8×10-13	10″–13″	23.5″ (597 mm)
XLTX	Group III (3K)	6×8-15, 8×10-15, 3×6-14, 3×6-16, 4×6-16, 6×8-16, 8×10-16, 10×12-16, 8×10-17	15″–17″	33.875″ (860 mm)

Practical Guidelines for Cross-Brand Parts Sourcing

✅ What You CAN Safely Do

• Complete pump replacement: Our G196 and D Mark III pumps are 100% dimensionally interchangeable with both Goulds 3196 and Durco Mark III respectively — same footprint, no piping changes.
• Complete wet-end assembly: Swap a full wet-end (casing + impeller + cover) between brands if within the same frame group. Dimensions match at the adapter interface.
• Power-end components: Bearings, oil seals, bearing housings, shafts, and sleeves within the same frame group can often interchange after dimensional verification.
• Gaskets & O-rings by dimension: Generic gaskets and O-rings in standard materials (Aramid, PTFE, FKM, NBR) interchange freely when dimensions match.

❌ What You Should NOT Do

• Never mix impeller types across brands — a Goulds open impeller won’t function correctly in a Durco reverse-vane casing, and vice versa.
• Never mix casing covers across brands — the cover-to-casing interface geometry is brand-specific.
• Never assume shaft interchangeability without verification — impeller-end tapers, keyway dimensions, and sleeve-land diameters differ between the two platforms.

How We Ensure True Interchangeability

At ANSI Pumps Pro (JINAN YINGSIMAN MACHINERY CO., LTD.), every replacement part we manufacture is validated against OEM dimensional databases accumulated over 15+ years. Our process includes:

• Reverse engineering from OEM samples — we maintain complete drawing libraries for both Goulds 3196 and Durco Mark III across all frame sizes.
• CMM (Coordinate Measuring Machine) inspection — every critical dimension verified to OEM tolerances before the part leaves our facility.
• Dynamic balance testing — all impellers balanced to ISO 1940 G6.3 or better.
• 100% fit-testing — components are trial-assembled on reference fixtures to guarantee field interchangeability.
• Full MTR (Material Test Report) EN 10204 3.1 — traceable chemical and mechanical properties for every heat of material.

Need help identifying the correct replacement part? Contact our engineering team with your pump model, serial number, or OEM part number — we’ll provide a cross-reference within 24 hours.

Quick Cross-Reference: OEM Part Numbers

Common OEM casing part numbers by pump size, with our equivalent replacement reference numbers:

Pump Size	Goulds 3196 OEM Casing #	Durco Mark III OEM Casing #	Our Equivalent Ref.
1×1.5-6 (STX / Group I)	GAB100 / 104554	DKA100 / DY50794A	Available — inquire
1.5×3-6 (STX / Group I)	GAC100 / 104556	DKC100 / DY50733A	Available — inquire
2×3-6 (STX / Group I)	GAD100 / 104555	DKE100 / BY40035AU	Available — inquire
3×4-8 (STX / Group I)	GAE100 / 104557	—	Available — inquire
1.5×3-8 (MTX / Group I)	GAC100 / 104556	DAF100 / DY46070A	Available — inquire
2×3-8 (MTX / Group I)	GYB100 / D06628A	DAG100 / DY46161A	Available — inquire
3×4-8 (XLTX / Group I)	GAE100 / 104557	DYC100 / BY40035AV	Available — inquire
1×2-10 (LTX / Group II)	GAF100 / 24741	DAH100 / DY46950A	Available — inquire
1.5×3-10 (LTX / Group II)	GAGG100 / 24745	DAJ100 / CY22118A	Available — inquire
2×3-10 (LTX / Group II)	—	DAN100 / CY22235A	Available — inquire
3×4-10 (LTX / Group II)	GAH100 / 104878	DAQ100 / DY47208A	Available — inquire
4×6-10 (XLTX / Group II)	GYC100 / D06638A	DYD100 / BY40035AW	Available — inquire
1.5×3-13 (XLTX / Group II)	GAJ100 / 24960	DAU100 / CY22344A	Available — inquire
2×3-13 (XLTX / Group II)	GAL100 / 24961	DAV100 / DY50172A	Available — inquire
3×4-13 (XLTX / Group II)	GAN100 / 24962	DAW100 / DY33074A	Available — inquire
6×8-13 (XLTX / Group II)	GAP100 / D00452A02	DNA100 / DY32218AA	Available — inquire
8×10-15 (XLTX / Group III)	GAS100 / 24963	DNE100 / DY51013A	Available — inquire
3×6-16 (Group III)	—	DNB100 / DY48876AA	Available — inquire
6×8-16 (Group III)	GAT100 / D02450A	DNF100 / DY30546A	Available — inquire
8×10-17 (Group III)	—	DNH100 / CY29134A	Available — inquire

Need full interchangeability data for your specific pump size? Send us your pump nameplate details — we’ll provide a complete cross-reference and quotation within 48 hours.

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Disclaimer: Goulds® and 3196 are registered trademarks of ITT Corporation. Durco® and Mark III are registered trademarks of Flowserve Corporation. ANSI Pumps Pro is an independent aftermarket manufacturer. Part numbers are used for cross-reference identification purposes only.

The Flowserve Durco Mark III process pump is distinguished by one key engineering innovation: the reverse vane impeller. Unlike conventional open or closed impellers, the reverse vane design fundamentally changes how hydraulic forces are managed inside the pump — reducing seal chamber pressure, lowering axial thrust, and extending mechanical seal life. Understanding this technology is essential for maintenance engineers, reliability managers, and anyone sourcing replacement parts for Durco Mark III pumps.

At ANSI Pumps Pro, we have been reverse-engineering and manufacturing Durco Mark III reverse vane impellers for over 15 years. Our aftermarket impellers are cast and machined to micron-level precision, fully inheriting the performance characteristics and reliability advantages of the original OEM design.

What Is a Reverse Vane Impeller?

A conventional open impeller (as used in Goulds 3196) has vanes on the front face only. The radial clearance between the impeller front and the casing is adjusted externally to control internal recirculation and maintain hydraulic efficiency. As the impeller and casing wear, this clearance must be periodically adjusted toward the front (casing side).

A reverse vane impeller (Durco Mark III) adds a set of pump-out vanes on the rear shroud of the impeller. These rear vanes:

• Actively pump fluid away from the seal chamber — the rotating rear vanes create a centrifugal pumping action that reduces pressure at the mechanical seal faces.
• Balance axial thrust — by generating a counter-acting pressure on the back side of the impeller, rear vanes partially offset the forward hydraulic thrust, reducing bearing loads.
• Enable rear-side clearance adjustment — the Durco Mark III is designed to have its impeller clearance adjusted against the rear cover plate (not the front casing), which means the adjustment mechanism is outside the process fluid path.

Reverse Vane vs. Open Impeller — Technical Comparison

Performance Factor	Open Impeller (Goulds 3196)	Reverse Vane Impeller (Durco Mark III)	Impact
Front clearance adjustment	External — adjusts impeller toward front casing	External — adjusts impeller toward rear cover plate	Reverse vane: adjustment mechanism is isolated from process fluid, reducing corrosion risk on adjustment threads
Seal chamber pressure	Near discharge pressure	30–50% lower than discharge pressure (rear vanes pump fluid away from seal)	Lower seal face pressure = longer mechanical seal life (2–3× typical MTBPM)
Axial thrust	Full forward thrust (unbalanced)	Partially balanced by rear vane counter-force	Reduced bearing loads = extended bearing life, especially on larger frame sizes
NPSH Required	Standard (open eye)	Comparable to open impeller	No significant difference — reverse vanes do not affect suction performance
Wear characteristics	Front casing and wear ring wear	Rear cover plate wear (replaceable surface)	Reverse vane: wear is on an easily replaceable cover plate, not the expensive casing
Efficiency	Standard	Comparable (rear vanes add negligible power draw)	No efficiency penalty — rear vane pumping work is recovered as pressure
Solids handling	Good (open passages)	Good (rear vanes help expel solids from seal area)	Reverse vane can be superior in services with suspended solids — rear vanes prevent solids accumulation at seal

How Clearance Adjustment Works in the Durco Mark III

Understanding the clearance adjustment mechanism is critical for proper maintenance. The Durco Mark III uses an external micrometer adjustment that moves the entire bearing housing and shaft assembly relative to the casing:

1. The shaft and impeller assembly is mounted in the bearing housing, which sits on the bearing housing adapter.
2. The adjustment bolt (jacking bolt, POS 469B) on the bearing housing moves the entire rotating assembly forward or backward.
3. Moving the impeller toward the rear cover plate closes the rear clearance gap. This is the opposite direction of conventional open impeller adjustment.
4. The shim pack (POS 111A) between the adapter and casing is adjusted to set the correct front clearance.
5. Properly set, the impeller runs with a precise gap on both front and rear faces — typically 0.015″–0.025″ (0.38–0.64 mm) depending on pump size and service temperature.

Critical maintenance note: Because rear clearance is the controlled dimension on a Durco Mark III, the rear cover plate (POS 108) serves as a sacrificial wear surface. This plate should be inspected for wear at every major service interval and replaced when grooving exceeds 1/16″ (1.6 mm).

Three Key Advantages of Reverse Vane Technology

1. Extended Mechanical Seal Life

This is the #1 reason plants choose Durco Mark III pumps for difficult sealing applications. The rear pump-out vanes reduce seal chamber pressure by 30–50% compared to a conventional open impeller. Lower pressure at the seal faces means:

• Reduced seal face loading → less heat generation → slower wear
• Lower vapor pressure margin → less risk of flashing at the seal faces
• Continuous flushing effect → rear vanes circulate fluid away from the seal, preventing stagnant hot spots

Field data from chemical plants shows 2–3× longer MTBPM (Mean Time Between Planned Maintenance) for Durco Mark III pumps vs. equivalent-sized open impeller pumps in the same service.

2. Reduced Axial Thrust and Bearing Load

In a centrifugal pump, the pressure differential across the impeller creates a net forward axial force. In a conventional open impeller, this force is carried entirely by the thrust bearing. The Durco Mark III’s rear vanes generate a counter-acting pressure distribution on the back shroud, partially balancing the axial thrust.

Result: lower thrust bearing loads, reduced bearing temperatures, and extended bearing service intervals — especially significant on larger Group II and Group III frame sizes where thrust loads can exceed 1,000 lbs (4.5 kN).

3. Superior Wear Management

In a conventional open impeller pump, wear occurs between the impeller front face and the casing — meaning the expensive casing must be replaced or re-machined when wear exceeds acceptable limits. In the Durco Mark III reverse vane design, the controlled wear surface is the rear cover plate (POS 108) — a relatively inexpensive, easily replaceable component. This design philosophy significantly reduces long-term maintenance costs.

Our Manufacturing Precision — Micron-Level Accuracy

The performance of a reverse vane impeller depends critically on manufacturing precision. The rear vane height, vane angle, and clearance gap must be held to exact tolerances — deviations as small as 0.002″ (50 microns) can alter seal chamber pressure characteristics and reduce the design benefits.

At ANSI Pumps Pro (JINAN YINGSIMAN MACHINERY CO., LTD.), our aftermarket Durco Mark III impellers are manufactured to the same precision as OEM:

• Investment casting / lost foam casting — produces near-net-shape impeller castings with excellent surface finish and minimal porosity. We select the optimal casting method based on alloy type and impeller size.
• 5-axis CNC machining — impeller vanes, rear pump-out vanes, and shaft bores are finish-machined on CNC machining centers. Rear vane height is held to ±0.001″ (25 microns).
• CMM (Coordinate Measuring Machine) inspection — every impeller’s critical dimensions — vane profile, rear vane height, bore diameter, keyway dimensions — are verified against our OEM-derived CAD models.
• Dynamic balance to ISO 1940 G6.3 — all impellers are dynamically balanced on two-plane balancing machines. For high-speed or large-diameter impellers, we can achieve G2.5 upon request.
• PMI verification — every alloy impeller is verified for correct chemical composition using handheld XRF analysis before it enters the machining queue.

Why the Reverse Vane Matters for Your Replacement Parts Decision

When sourcing aftermarket impellers for your Durco Mark III pump, the manufacturing quality of the reverse vanes directly determines whether you’ll realize the design’s reliability benefits. A poorly cast or machined impeller — even if it “fits” — will not deliver the seal chamber pressure reduction that makes the Durco Mark III platform superior for difficult sealing applications.

Three questions to ask any aftermarket impeller supplier:

1. Do you balance every impeller, and to what standard? (Answer should be: Yes, ISO 1940 G6.3 minimum.)
2. Do you verify reverse vane height and profile against OEM specifications? (If they don’t have OEM reference data, they cannot guarantee performance.)
3. Do you provide MTR (Material Test Report) EN 10204 3.1 with traceability to the heat number? (This is non-negotiable for chemical process applications.)

Need a reverse vane impeller for your Durco Mark III? Contact our engineering team with your pump model, Group size, and required material — we’ll provide a quotation with full technical specifications within 48 hours.

Frequently Asked Questions

Q: Can I install a reverse vane impeller in a Goulds 3196 pump?
No. The Goulds 3196 casing and cover are not designed for rear-side clearance adjustment. The reverse vane impeller requires the Durco Mark III’s rear cover plate and casing geometry. However, you can replace the entire wet-end assembly.

Q: How often should I check the rear clearance on my Durco Mark III?
Check rear clearance at every seal change or bearing replacement, and at least annually for pumps in continuous service. The clearance should be checked after the pump reaches operating temperature, as thermal expansion affects the gap.

Q: Do your aftermarket impellers use the same vane geometry as OEM?
Yes. Our impellers are reverse-engineered from OEM samples and verified against our comprehensive drawing library. Hydraulic profiles, vane angles, and rear pump-out vane geometry are identical to OEM specifications.

Q: What materials do you offer for reverse vane impellers?
All standard Durco Mark III impeller materials: 316SS (CF8M), CD4MCu (Duplex), Alloy 20 (CN7M), Monel, Nickel 200, Hastelloy B, Hastelloy C-276, and Titanium Grade 2. Exotic alloys are cast in-house with full PMI verification.

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Disclaimer: Durco® and Mark III are registered trademarks of Flowserve Corporation. ANSI Pumps Pro is an independent aftermarket manufacturer. All technical data is provided for reference purposes based on our 15+ years of manufacturing experience.

When servicing a Flowserve Durco Mark III ANSI process pump, knowing the correct POS (Part Ordering System) code is essential for accurate parts identification and ordering. Every component on the Mark III — from the casing to the smallest O-ring — is assigned a unique POS number. This comprehensive breakdown covers all standard POS codes for the Durco Mark III pump family across Group I (1K), Group II (2K), and Group III (3K) frame sizes.

As an independent aftermarket manufacturer with 15+ years of experience producing ANSI B73.1 pump parts, we supply 100% dimensionally interchangeable replacements for every POS code listed below. All parts are manufactured with full EN 10204 3.1 material traceability and undergo PMI (Positive Material Identification) verification before shipment.

Durco Mark III Pump Anatomy — Parts by Location

The Durco Mark III pump can be divided into three major assemblies. Understanding where each POS code sits within the pump helps with maintenance planning and troubleshooting.

• Wet End (Fluid End): Parts that contact the pumped fluid — casing (100), impeller (104), rear cover plate (108), gaskets and O-rings.
• Power End (Bearing Frame): Parts that transmit and support the rotating assembly — shaft (107), bearings (130/131), bearing housing (129), oil seals (125/136).
• Seal Chamber: The interface between wet end and power end — mechanical seal (201A), gland (201C), hook sleeve (201B), packing (119).

Complete Durco Mark III POS Code Reference Table

All standard POS codes for the Flowserve Durco Mark III process pump, with available material options and our aftermarket equivalent availability:

POS Code	Part Name	Assembly	OEM Material Options	Our Aftermarket Availability	Typical Lead Time
100	Casing (Volute)	Wet End	WCB, 316SS (CF8M), CD4MCu, Alloy 20 (CN7M), Monel, Nickel, Hastelloy B/C, Titanium	✅ All materials	8-10 weeks
104	Impeller (Reverse Vane)	Wet End	316SS (CF8M), CD4MCu, Alloy 20 (CN7M), Monel, Nickel, Hastelloy B/C, Titanium	✅ All materials	8-10 weeks
105	Impeller Gasket	Wet End	Aramid Fiber with EPDM, PTFE, Graphite	✅ All materials	24-48h (stock)
107	Shaft	Power End	SAE 4140, 316SS, Alloy 20, Monel, Nickel, Hastelloy	✅ All materials	6-8 weeks
108	Rear Cover Plate	Wet End	WCB, 316SS (CF8M), CD4MCu, Alloy 20 (CN7M), Monel, Nickel, Hastelloy B/C, Titanium	✅ All materials	8-10 weeks
109	Rear Cover Gasket	Wet End	Aramid Fiber with EPDM, PTFE	✅ All materials	24-48h (stock)
109A	Bearing Housing Adapter	Power End	Ductile Iron, Cast Steel	✅ All materials	4-6 weeks
110	Bearing Housing Foot	Power End	Cast Iron / Ductile Iron	✅ Standard	3-4 weeks
111A	Shim (Adapter-to-Casing)	—	304SS	✅ Standard	24-48h (stock)
112	Gland — Packing Option	Seal Chamber	Cast Iron (Ductile Iron for STX Group)	✅ Standard	3-4 weeks
114	Stud — Gland	Seal Chamber	Steel, 304SS	✅ All materials	24-48h (stock)
115	Hex Nut — Gland	Seal Chamber	Steel, 304SS	✅ Standard	24-48h (stock)
115A	Packing Seal Cage Halves (Optional)	Seal Chamber	Glass-Filled Teflon®	✅ Standard	1-2 weeks
119	Packing (Optional)	Seal Chamber	Teflon® Impregnated Fibers, Graphite	✅ All materials	24-48h (stock)
120	Deflector — Inboard (Optional)	Power End	—	✅ On request	1-2 weeks
122	Stud — Casing	Wet End	Steel, 304SS	✅ All materials	24-48h (stock)
124	Hex Nut — Casing	Wet End	Steel, 304SS	✅ Standard	24-48h (stock)
125	Oil Seal — Inboard	Power End	Carbon-Filled Teflon® with Viton O-ring (Labyrinth type)	✅ INPRO VBXX compatible	24-48h (common sizes)
129	Bearing Housing	Power End	Cast Iron / Ductile Iron	✅ Standard	4-6 weeks
130	Bearing — Inboard	Power End	Double Row Angular Contact (SKF or equal)	✅ SKF/equivalent	24-48h (stock)
131	Bearing — Outboard	Power End	Single Row Deep Groove (SKF or equal)	✅ SKF/equivalent	24-48h (stock)
133	Oil Slinger (Optional)	Power End	—	✅ On request	1-2 weeks
134	Locknut — Bearing	Power End	Steel	✅ Standard	24-48h (stock)
135	Lockwasher — Bearing	Power End	Steel	✅ Standard	24-48h (stock)
136	Oil Seal — Outboard	Power End	Carbon-Filled Teflon® with Viton O-ring (Labyrinth type)	✅ INPRO VBXX compatible	24-48h (common sizes)
139	Key — Shaft/Coupling	Power End	Steel, 316SS	✅ All materials	24-48h (stock)
140	O-Ring — Adapter	Power End	Buna Rubber, FKM, FFKM, PTFE	✅ All materials	24-48h (stock)
153	Trico Oiler (Constant Level)	Power End	—	✅ Standard accessory	24-48h (stock)
177	Bearing Housing Drain Plug	Power End	Steel, 316SS	✅ Standard	24-48h (stock)
190	Bearing Housing Vent Plug	Power End	Steel, 316SS	✅ Standard	24-48h (stock)
190G	Cap Screw — Foot	Power End	Steel, 304SS	✅ Standard	24-48h (stock)
200	Cap Screw — Bearing Housing	Power End	Steel, 304SS	✅ Standard	24-48h (stock)
201	Cap Screw — Cover/Adapter	Seal Chamber	Steel, 304SS	✅ Standard	24-48h (stock)
201A	Mechanical Seal	Seal Chamber	Various (application-specific)	✅ All types available	2-4 weeks
201B	Hook Sleeve (Optional)	Seal Chamber	316SS, Alloy 20, Monel, Nickel, Hastelloy	✅ All materials	4-6 weeks
201C	Gland — Mechanical Seal	Seal Chamber	316SS, CD4MCu, Alloy 20, Monel, Nickel, Hastelloy	✅ All materials	3-4 weeks
201E	Gland Gasket	Seal Chamber	Aramid, PTFE, Graphite	✅ All materials	24-48h (stock)
245	Sight Gauge — Bearing Housing	Power End	Glass/Steel	✅ Standard	24-48h (stock)

Additional POS codes available upon request. If your required part number is not listed above, contact our engineering team with your specific requirements.

Durco Mark III Frame Groups & Pump Sizes

The Durco Mark III pump family is organized into three frame groups. Parts are designed to be interchangeable within each group. When ordering, always specify your pump’s ANSI designation (e.g., A60, A70, A80) to ensure correct parts selection.

Group	Frame	ANSI Designation	Pump Sizes (Suction × Discharge – Max Impeller)	Approx. Weight
Group I	1K	AA	1K 1.5×1LF-4, 1K 1.5×1-6, 1K 3×1.5-6, 1K 3×2-6	97–116 lbs (44–53 kg)
		AB	1K 3×2-6	103 lbs (47 kg)
		A10	1K 1.5×1LF-8, 1K 1.5×1-8, 1K 3×1.5-8	103–124 lbs (47–56 kg)
		A60	2K 3×2-8	200 lbs (90 kg)
		A70	2K 4×3-8	227 lbs (103 kg)
		Shaft centerline height: 17.5″ (445 mm). CP dimension: 7.25″ (184 mm)
		Bearing housing ref: D1201. Adapter ref for 8″: DAF108
Group II	2K	A05	2K 2×1LF-10, 2K 2×1-10A	210 lbs (95 kg)
		A50	2K 3×1.5-10A	220 lbs (100 kg)
		A60	2K 3×2-10A	226 lbs (103 kg)
		A70	2K 4×3-10, 2K 4×3-10H	225–249 lbs (101–112 kg)
		A80	2K 6×4-10, 2K 6×4-10H	290 lbs (130 kg)
		Shaft centerline height: 23.5″ (597 mm). CP dimension: 12.5″ (318 mm)
		Bearing housing ref: D2201. Adapter ref for 10″: DAH108, for 13″: DAS108
		Adapter OEM #: DAH108 = DY21806ACP, DAS108 = DY21857ABP
Group III	3K	A20	3K 3×1.5LF-13	328 lbs (149 kg)
		A30	3K 3×1.5-13	250 lbs (112 kg)
		A40	3K 3×2-13, 3K 4×3-13, 3K 4×3-13HH	250–281 lbs (112–126 kg)
		A80–A120	3K 6×4-16, 3K 8×6-16, 3K 10×8-16, 3K 10×8-17	641–992 lbs (291–450 kg)
		Shaft centerline height: 33.875″ (860 mm). CP dimension: 18.75″ (476 mm)
		Bearing housing ref: D3201. Adapter ref for Group III: DNA108 (14″), DNE108 (16″)
		Adapter OEM #: DNA108 = DY28285ACP, DNE108 = DY27463ACP

Material Selection Guide for Durco Mark III Replacement Parts

Choosing the correct material for your replacement parts is critical for pump longevity and process safety. We cast and machine the following alloy families in-house, with full PMI verification and EN 10204 3.1 material certification:

Material	ASTM Grade	UNS Number	Best For	Temp Limit
316 Stainless Steel	CF8M (A743)	J92900	General chemical processing, food-grade, mild corrosives	700°F (371°C)
Carbon Steel	WCB (A216)	J03002	Non-corrosive industrial service, water, oil	800°F (427°C)
Duplex SS (CD4MCu)	1B (A890)	J93372	Chloride environments, seawater, sulfuric acid, phosphoric acid	600°F (316°C)
Alloy 20	CN7M (A743)	N08007	Sulfuric acid service, pickling baths, stress-corrosion resistance	800°F (427°C)
Monel 400	M35-1 (A494)	N04400	Hydrofluoric acid, seawater, alkaline environments	800°F (427°C)
Nickel 200	CZ-100 (A494)	N02200	Concentrated caustic soda, high-temperature alkaline service	700°F (371°C)
Hastelloy C-276	CW6M (A494)	N10276	HCl, FeCl₃, wet chlorine, mixed acids — severe oxidizing environments	700°F (371°C)
Hastelloy B	CW12MW (A494)	N10001	Pure HCl, reducing environments	700°F (371°C)
Titanium Grade 2	C-3 (B367)	R50250	Wet chlorine, hypochlorites, nitric acid, oxidizing chlorides	700°F (371°C)

OEM Part Number Cross-Reference — Quick Lookup

Below is a sampling of common Durco Mark III OEM part numbers with our aftermarket equivalents. For a complete cross-reference of your specific pump model, submit your parts list.

Component	Group	OEM Part Number	Our Reference
Shaft — Group I	Group I	CY50686A (sleeved), CY50683A	D1105S / D1105
Shaft — Group II	Group II	CY32768B, CY21361BA	D2105 / D2105S
Shaft — Group III	Group III	CY50467A, CY50463A	D3105 / D3105S
Shaft Sleeve — Group I	Group I	AY50691A, AY38913AA, BY39477A	D1177
Shaft Sleeve — Group II	Group II	—	D2177
Shaft Sleeve — Group III	Group III	—	D3177
Bearing Housing — Group I	Group I	CY55739AP	D1201
Bearing Housing — Group II	Group II	CY55742AP	D2201
Bearing Housing — Group III	Group III	DY55743AP	D3201
Frame — Group I	Group I	DY55721B	D1119
Frame — Group II	Group II	DY55718A	D2119
Frame — Group III	Group III	DY55723A	D3119
Adapter — Group II, 8″	Group II	DY46074AAP	DAF108
Adapter — Group II, 10″	Group II	DY21806ACP	DAH108
Adapter — Group II, 13″	Group II	DY21857ABP	DAS108
Adapter — Group III, 14″	Group III	DY28285ACP	DNA108
Adapter — Group III, 16″	Group III	DY27463ACP	DNE108

Quality Assurance — How We Guarantee Fit

Every replacement part we ship undergoes a rigorous quality control process designed to eliminate the #1 concern with aftermarket pump parts: dimensional mismatch leading to unplanned downtime.

• CMM (Coordinate Measuring Machine) inspection — all critical mounting dimensions verified against OEM specifications with micron-level accuracy.
• Dynamic balance testing — every impeller balanced to ISO 1940 G6.3 or better, ensuring smooth operation and extended bearing life.
• Hydrostatic pressure testing — every casing tested at 1.5× rated pressure before shipment.
• 100% fit-testing — components are trial-assembled on reference fixtures or gauge plates to verify interchangeability.
• PMI (Positive Material Identification) — every alloy part verified for correct chemical composition using XRF analysis.
• EN 10204 3.1 MTR — full traceability from raw material heat number to finished part.

Ready to order? Send us your POS codes and quantities — we’ll provide pricing within 48 hours.

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Disclaimer: Durco® and Mark III are registered trademarks of Flowserve Corporation. ANSI Pumps Pro is an independent aftermarket manufacturer. POS codes and OEM part numbers are used for cross-reference identification purposes only.