Hey guys,
I am looking to swap a 1HZ-T into my FJ40, and want to put a 5 speed behind it. 1HZ's are a bit out of my wheelhouse as my experience is with 12HT's.
Will a standard H55F bolt up to a 1HZ? Does it need a special bell housing or transmission input shaft? Any wisdom would be greatly appreciated.
My current powertrain plan is this: 1HZ-T, H55F (going to buy one new if possible), FJ60 transfer case
Thoughts and recommendations are appreciated.
Im doing this with my FJ62 with H55F, just need to change bell housing and buy clutch to suit as follows....
1. Core stack summary
**This is the combo you’re aiming for:**
- **Flywheel:** 1HZ/1HDT 275 mm diesel flywheel
- **Clutch kit:** 275 mm kit for **1HZ + H55F** (HZJ75‑style)
- **Bellhousing:** 1HZ/1HDT → H55F
- **Pilot bearing:** 1HZ/1HDT crank, to suit H55F input
- **Release bearing & fork:** To suit 1HZ/H55F bellhousing combo
That effectively turns your ex‑3F H55F into a “diesel H55F behind 1HZ”—which is a known, factory‑style configuration.
2. Selection matrix (what to ask for)
|-----------|----------------------------|-------|
| **Flywheel** | “1HZ/1HDT 275 mm diesel flywheel” | Bolts to 1HDT crank, suits 275 mm clutch |
| **Clutch kit** |
“Clutch kit for HZJ75 1HZ with H55F, 275 mm” | Ensures disc spline matches H55F + pressure plate matches flywheel |
| **Bellhousing** | “1HZ/1HDT to H55F bellhousing (HZJ7x style)” | Correct depth + patterns |
| **Pilot bearing** | “Pilot bearing for 1HZ manual with H55F” | Matches 1HDT/1HZ crank + H55F input tip |
| **Release bearing** | “Release bearing to suit 1HZ/HZJ75 clutch + H55F” | Match to clutch kit & bellhousing |
| **Clutch fork & boot** | “HZJ75 1HZ clutch fork & boot for H55F bellhousing” | Ensures geometry is right |
If a supplier asks what you’re doing, the simplest story is:
> “
I’m running a 1HZ/1HDT‑style flywheel and clutch on an H55F, like an HZJ75.”
3. Batch ordering plan (engine–gearbox interface only)
**Batch: Engine–Clutch–Gearbox Stack**
Order together so you can mock it up on the floor before the engine goes in:
- **1HZ/1HDT 275 mm flywheel**
- **HZJ75 275 mm clutch kit (pressure plate + disc + release bearing)**
- **1HZ/1HDT → H55F bellhousing**
- **Pilot bearing**
- **Clutch fork, pivot ball, boot, clips**
- **New flywheel bolts** (diesel‑rated)
- **New bellhousing bolts** (if needed)
That gives you a complete, self‑contained interface you can assemble and test:
- Clutch disc slides cleanly on H55F input
- Release bearing travel is correct
- Pilot bearing engagement is correct
- No bottoming of the input shaft in the crank
4. Quick physical checks once parts arrive
When everything’s on the bench:
1. **Disc on input shaft:**
- Slides smoothly, no slop, no binding.
2. **Bellhousing depth:**
- With bellhousing bolted to H55F and clutch/flywheel on engine, input shaft should:
- Fully engage splines
- Sit nicely in pilot bearing
- Not bottom out.
3. **Release system:**
- Fork + bearing + pressure plate fingers give a good release window (not over‑center, not marginal).
