Hi,
Can somebody elaborate on the reliability/robustness of direct vs indirect Toyota diesel engines?
Lucas
Can somebody elaborate on the reliability/robustness of direct vs indirect Toyota diesel engines?
Lucas
Reliability: Direct vs indirect injection (2 Viewers)
- Thread starter bikemaniac
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Main difference is the fact that indirect injection diesels inject their diesel into a pre-combustion camber ( pre-cup ) that is a wear item and is replaceable when the head is off the engine.
It also houses the glow plug tip right beside the injector. The pre-cup system is not as efficient as direct injection, and of course there is not a pre cup to have to replace with a direct injection system.
The pre-cups do crack with heat cycles overtime and can lead to metal bits being dropped into the main combustion camber and 'interfere' with pistons and such...... with catastrophic failure.
As for most reliable....most direct injection engines are computer controlled, most indirect injection engines arent, so i guess that depends on your engineering philosophy on mechanical vs computer.
It also houses the glow plug tip right beside the injector. The pre-cup system is not as efficient as direct injection, and of course there is not a pre cup to have to replace with a direct injection system.
The pre-cups do crack with heat cycles overtime and can lead to metal bits being dropped into the main combustion camber and 'interfere' with pistons and such...... with catastrophic failure.
As for most reliable....most direct injection engines are computer controlled, most indirect injection engines arent, so i guess that depends on your engineering philosophy on mechanical vs computer.
- Thread starter
- #3
Were direct injection engines manufactured by Toyota in the 1980s computer controlled??
No definitive statement can be really be made on this subject I feel.
I cant speak for all of them.. 12HT was direct injected, zero computers involved, its heritage was the venerable 2H indirect injected engine (again zero computers). In my opinion the 2H is more reliable but as much as I love the 2Hs they are a slug performance wise.
I really dont think you're going to arrive at a definitive answer for your question about which is more reliable though. I'd probably tend towards a simpler engine being more reliable, lack of a turbo always a good thing for reliability, additionally I think the inline injection pumps tend to be more rugged and long lived than the rotary pumps.
I cant speak for all of them.. 12HT was direct injected, zero computers involved, its heritage was the venerable 2H indirect injected engine (again zero computers). In my opinion the 2H is more reliable but as much as I love the 2Hs they are a slug performance wise.
I really dont think you're going to arrive at a definitive answer for your question about which is more reliable though. I'd probably tend towards a simpler engine being more reliable, lack of a turbo always a good thing for reliability, additionally I think the inline injection pumps tend to be more rugged and long lived than the rotary pumps.
GTSSportCoupe
2LTE abuser
Toyota continues to make the 1HZ indirect non turbo diesel for many markets. They do this because the mechanical IDI injection systems are robust against low quality fuel, and are very simple to maintain. These motors don't make much power though, so are generally not suitable for more developed countries high speed highways. In this regard a modern direct injection common rail diesel makes more sense.
No. I think the first direct injection Toyota diesels with computer control were the 1HDFTE and 15BFTE. These came out mid-late 90's.
