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Discussion Starter · #1 ·
First of all, I have been reading and learning much from the folks here for a short while now. All I can say is GREAT FORUM! GREAT INFO! GREAT FOLKS HERE.

Now for my question, I have read some posts that refer to the two types of Izuzu engines. One has a Precombustion chamber and the other does not. What are the differences between the two? Also, what are the advantages of each? Fuel economy? Power? Cold starting?

Thanks in advance for the info.
 

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Precombustion chamber is a feature of indirect injection engines. The Isuzu 4BD2T is such a beast.
The fuel is injected into a chamber in the head where combustion occurs and blows out into the main cylinder.

The Isuzu 4BD1T is direction injection. Fuel is injected directly into a combustion bowl cast into the top of the piston.

Direct injection is noisier and produces higher combustion temps which produce more NOx emissions. It also works best over a narrower speed range but is more efficient (up to 20% more efficient).

Indirect injection (prechamber) is quieter and smoother, it works better over a wider speed range but loses in efficiency.

The prechamber also weakens the head compared to a direct injection motor. Many indirect injection motors survive perfectly well, but Toyota has indirect injection diesels which are infamous for cracking heads.
 

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Discussion Starter · #3 ·
Dougal, thanks for the info.

That is exactly what I was wondering.

As usual, there are trade offs for either setup. :)
 
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