
More Standards, More Problems
The implementation of the Tier 4 standard in 2015 brought the strictest EPA emissions requirements for diesel engines this century. An unforeseen byproduct of this standard was the disregard of the industrial SAE specifications for flywheel housing and the flywheel adapter, specifically the section that governs the over-center clutch mounting.
Forgetting Industrial SAE Mounting
To meet growing demands and adhere to the emissions standard, engine manufacturers opted not to support the industrial SAE mounting. This meant engines had no bore for the pilot bearing, and the flywheel offset was incorrect, or both. All of this, coupled with a price increase, made for a hectic time to purchase an engine and Power Take-off (PTO).
Leading the Way
WPT was at the forefront of this issue when we released our first Pilotless® Mechanical PTO in 2015. These PTOs eliminated the need for the pilot bearing bore by using a dual main bearing assembly. This solved the first problem.
To solve the second problem, WPT created a flywheel housing and flywheel adapter for most bellhousings. These spacers and adapters, when used with our Pilotless® PTO series, made for a cost-effective solution to this new Tier 4 dilemma.
WPT Tier 4 Flywheel Housing and Flywheel Adapter Guide
Over the years, we have expanded our range of spacers and adapters. Below are charts of the most common offerings.

Zero Offset Flywheel Housing Adapters
| SAE Input | SAE Output | Type | Part Number |
|---|---|---|---|
| #2 | #4 | A | WTD-00-000 |
| #1 | #2 | A | WTD-00-001 |
| #1/2 | #1 | A | WTD-00-002 |
| #0 | #1 | A | WTD-00-003 |
| #00 | #0 | A | WTD-00-004 |
| #1 | #0 | D | WTD-00-010 |
| #1 | #3 | A | WTD-00-039 |
Flywheel Adapters
| SAE Input | SAE Output | Type | Part Number |
|---|---|---|---|
| Kubota* | 7.5" | F | WTD-00-014 |
| 15.5" | 14" | G | WTD-00-038 |
| *Consult WPT for proper fitment information | |||
Flywheel Spacers
| SAE Input | Offset | Type | Part Number |
|---|---|---|---|
| 14 inch | 1/2" | C | WTD-00-013 |
| 10.5 inch | 1" | C | WTD-00-016 |
| 7.5 inch | 1" | C | WTD-00-019 |
| 6.5 inch | 5/8" | C | WTD-00-022 |
| 7.5 inch | 13/16" | C | WTD-00-024 |
| 7.5 inch | 11/16" | C | WTD-00-032 |
Offset Flywheel Housing Adapters
| SAE Input | SAE Output | Type | Part Number |
|---|---|---|---|
| #1 | #1/2 | E | WTD-00-012 |
Flywheel Housing Spacers
| SAE Input | Offset | Type | Part Number |
|---|---|---|---|
| #5 | 1-7/8" | B | WTD-00-015 |
| #4 | 2-13/64" | B | WTD-00-017 |
| #4 | 1" | B | WTD-00-018 |
| #5 | 1-3/16" | B | WTD-00-020 |
| #5 | 5/8" | B | WTD-00-021 |
| #4 | 13/16" | B | WTD-00-023 |
| #5 | 5/8" | B | WTD-00-031 |
| #3 | 3-1/8" | B | WTD-00-033 |
| #3 | 1" | B | WTD-00-036 |
| #1 | 1-3/4" | B | WTD-00-037 |
So, whether it’s mounting a PTO to a Tier 4 engine or another application challenge, look no further than WPT Power for the solution! Contact a WPT Sales Representative at 940.761.1971 or info@wptpower.com or visit our website at www.WPTpower.com.