Direct vs indirect fuel injection

[beaverhouse]

I`m a new "TBN tractor trainee" and just starting the tractor "hunt" and trying to learn as much as I can from the TBN experts!!.. I would appreciate your valued input to the pros / cons of direct vs indirect fuel injection...Depending on make/models, I`ve noticed both direct & indirect mentioned when comparing.
Should I treat this as a major deciding factor in a purchase...???
I plan to use in cold/snowy weather however the majority of seat time will be spring/summer/fall...Looking at tractors in 30-45 HP range with HST.
Tks in advance for your comments!

 

[billbill1]

The guys that have the direct injection diesels seem to be able to start in the cold weather much better. Mine isn't direct inject but always starts although I use a lower radiator hose heater for about 30 minutes. Fired right up this morning at 10 degrees.

 

[Mickey_Fx]

If I recall correctly from my reading several decades ago, there are at least 5 distinct combustion chamber designs use with diesel engines and each design has its own operating characteristics. Some designs use a precombustion chamber & indirect injection. If I recall, the precombustion chamber with indirect injection is used when higher rpm's are required.

At one time I had a MF with a Perkins engine that use direct injection. Very low compression for a diesel, 15:1, no glow plugs, & it started during the winter as quickly as a gas engine. Winter time temps here are about 30F.

I believe my Yanmar is indirect injection, has glow plugs & can operate at higher rpm's than the Perkins. Does need the use of glow plugs in the winter and doesn't start quick as quickly as the Perkinds did.

 

[6sunset6]

I have a MF 30E Backhoe with one of those Perkins engines in it. I have always wondered why it ALWAYS starts in the winter down to 0 F with no asist of any kind. 10 year ago the fuel gelled at 10 F below. Then I had to put it under a tarp with a heater for a while

 

[john_bud]

The difference is sort of like "tomAto" Vs "tOmato".

Check the PTO HP, and the fuel consumption. Ignore the gross HP, net HP, etc - just the PTO HP. How it get's there makes no difference.

It's like FEL lift cap - look the sales guy in the eye and ask how much will it lift in the bucket. Then make him write that on the sale paperwork as a condition. Amazing how much "fluff" gets blown away when you make then put it in writing!

jb

 

[art]

I wouldn't worry to much about this point.

I have a used Kubota farm tractor in stock that when it had sat for about four months and it was 22 degree's below zero it started on it's own! This tractor has 6500 hours and the no work ever done to the fuel system or engine of any type and is indirect injection! The local school has never plugged their tractor in and they have started it down to -25!

Both systems on a well built engine will start well but I give more credit to indirect for a cleaner cold start then a direct injection and they do seem to start better in the cold.

For the chance to build a tractor puller oout of one I'd take the direct injection as there are less pieces to modify for maximum performance.

I know that some companies are boosting about there direct injections cold starting ability, for what I've seen, they are better then they built before, but they still aren't up to the rest of the field.

On a well built unit either system will work for you!

 

[RobJ]

If I recall, the precombustion chamber with indirect injection is used when higher rpm's are required.

On the diesels I worked on the indirect or pre-cups as we called them were for emmisions. These engines were only used in mines. The pre-cup allowed the air/fuel to swirl more and burn longer and more completely. These engines also have lower hp ratings. As far as starting in the cold, all the pre-cup engines came standard with glow plugs, the directs did not. I can't recall exactly but I think the compression ratio was lower on the indirects to.

If you google it says that the indirects were more quiet. Hmmm, well maybe at anything higher than an idle. Mine would cackle and rattle just like my Kubota does and it's an indirect injection.

Rob