C7 vs C9 vs C-9 vs C9.3 — Which Parts Actually Interchange?
The four names get mixed up constantly — and mis-ordering one for another is the most common mistake we see.
| Engine | Fuel system | What we supply | Example part numbers |
|---|---|---|---|
| C7 / C7 ACERT | HEUI | New reproduction | 238-8091 · 268-1835 |
| C9 | HEUI | New reproduction | 235-5261 · 293-4071 · 387-9434 |
| C-9 | HEUI | Remanufactured | 188-8739 |
| C9.3 | Common rail | New reproduction | 363-0493 |
Short answer. C7 and C9 injectors are both HEUI but are not interchangeable — they look similar and differ by part number. C-9 (with the hyphen) is a different HEUI generation; its injectors are commonly supplied remanufactured. C9.3 is a common-rail engine and shares no injectors with the other three.
How each mix-up happens
"C9" vs "C-9". Same engine name, different system generation. The hyphen is doing real work: 235-5261 (C9) and 188-8739 (C-9) are not interchangeable, yet both are quoted as "C9 injector" in marketplaces.
"C9" vs "C9.3". C9.3 moved to common rail. Listings that label a C9 HEUI unit as "common rail" send buyers down the wrong path entirely — check the fuel system, not just the name.
"320 excavator" as a fitment clue. The model name 320 spans generations: 320D runs a C6.4, 320F runs a C7.1. A machine model alone never selects an injector — the stamped number on the old unit does.
What to send us
The complete number from your old injector or pump, the engine model and serial if available, and a photo of the nameplate. We confirm fitment manually before quotation — that check is the whole point of asking.
Comparison FAQ
Questions buyers ask about the four name families
Can a C9 injector replace a C-9 injector?
No. The hyphen marks a different HEUI generation — 235-5261 (C9) and 188-8739 (C-9) are not interchangeable even though both get quoted as 'C9 injector'.
Which of the four is common rail?
Only the C9.3. C7, C9 and C-9 are all HEUI, but the three still do not share injectors between families.
My machine is a 320 excavator — which family is it?
The 320 name spans generations: 320D runs a C6.4 or C6.6, 320F runs a C7.1. The engine nameplate plus the old injector's stamped number is the only way to select.
Can I order by engine model alone?
We will ask for the stamped number anyway. The same engine name covers different injector versions by year and calibration — the old unit's number is what we confirm against.
Not sure which family yours is?
Send a photo of the old unit and the engine plate. We answer with the correct family and part number.
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