FRAM PH6811 vs Baldwin B1421: Oil Filter Compatibility
Compare FRAM PH6811 and Baldwin B1421 oil filters by compatibility, dimensions, thread size, gasket fit, bypass valve, anti-drainback valve status, and match confidence. Use this comparison as a fitment review, not as an automatic substitution guarantee. Both use a M20x1.5 thread.
Quick verdict
Both use a M20x1.5 thread.
- Thread size is the first hard-fit check for any comparison of spin-on filters.
- Gasket OD and gasket ID are the most important seal-related dimensions.
- Height differences can matter for clearance even when thread and gasket fit appear close.
- Bypass and anti-drainback differences may be important, depending on the application.
FRAM PH6811 and Baldwin B1421 specifications
How matching is scored| Specification | FRAM PH6811 | Baldwin B1421 |
|---|---|---|
| Thread size | M20X1,5 | M20x1.5 |
| Gasket OD | 63 mm | 64 mm |
| Gasket ID | 57 mm | 54.1 mm |
| Can OD | 66 mm | 77 mm |
| Height | 90 mm | 87.3 mm |
| Internal bypass valve | Yes | Yes |
| Bypass PSID | 14.504 | 14 |
| Anti-drainback valve | Yes | Yes |
What matters in this specific comparison
Thread size matches: both are M20x1.5.
Gasket OD differs by 1 mm (FRAM PH6811: 63 mm, Baldwin B1421: 64 mm).
Gasket ID differs by 2.9 mm (FRAM PH6811: 57 mm, Baldwin B1421: 54.1 mm).
FRAM PH6811 is 2.7 mm taller (FRAM PH6811: 90 mm, Baldwin B1421: 87.3 mm) -- check clearance before substituting.
Can OD differs by 11 mm (FRAM PH6811: 66 mm, Baldwin B1421: 77 mm).
Both open their bypass valve in a comparable range: FRAM PH6811 at 14.504-14.504 psi, Baldwin B1421 at 14-14 psi -- these ranges do not overlap.
Open related filters
Before substituting, verify thread fit, gasket sealing dimensions, height clearance, bypass behavior, and anti-drainback requirements for your specific application.