Diesel injectors?

Tom P · Post by **Tom P** » Wed Aug 18, 2010 1:23 am

I am to the point of my rebuild where I can install the injectors. Is there a way I can check the injectors to see if they are working correctly? Also, do the 2 bolts have to be brought to a specific torque or just tightened? Any help or suggestions are much appreciated.

Thank you!
Tom

Post by **Brian** » Wed Aug 18, 2010 8:00 am

The best people to check injectors are diesel engineers who have the proper equipment. You can see if they are spraying or squirting by putting them on the pump with a pipe and turning the engine over, but be very careful. If you get the mist from the nozzle on your skin it could be fatal or at the minimum, amputation.

Tighten the bolts evenly and tight.

Tom P · Post by **Tom P** » Wed Aug 18, 2010 4:29 pm

Thank you for the response Brian.
I havn't begun to tackle the pump yet!
How much pressure does the pump produce?
Would hooking the injector to a compressed air valve and regulating the air pressure to match the pump pressure work?
That would tell me if they are working at least.
Unless the pump pressure is to great. I can get to about 115 lbs.

Thanks!

Tom

Post by **Brian** » Wed Aug 18, 2010 5:30 pm

Injectors work between 1300 psi and 2000 psi, an airline will not help. Even if you could get the air pressure you would not be able to see a spray pattern and this is what you need to see to identify problems.

Injectors are very easy to damage if you use the wrong tools to clean/service them. A simple scratch in the wrong place can terminally damage any injection parts in the pump or injectors. They should be serviced in a totally dust and dirt free room with brass brushes and jewelers polish for cleaning.

I was trained to service these parts by Ford but I will not touch my own because I am not equipped to do so. That is why I take mine to a service engineer and advise others to do the same. So many times I have seen a simple job turn in to a major expense.

Your best way is to put them on the pump and turn the engine over on the starter. If you do them one at a time and see that you get four columns of diesel mist from each, this is the best test you can do.

Tom P · Post by **Tom P** » Wed Aug 18, 2010 7:32 pm

Thanks for the info.
I found a Diesel shop that I can bring them to, that is the route I will take.
How about the pump? Does the same apply, or can I clean and reassemble the pump myself?

Thank you!
Tom

Gavin · Post by **Gavin** » Wed Aug 18, 2010 9:03 pm

The same applies to the pump as to the injectors

BarryM · Post by **BarryM** » Thu Aug 19, 2010 2:31 am

Tom,

You requested the torque figures for the injector hold down bolts. There are as follows:

All Fordson Major Tractors 12-15 lbs/ft.
Fordson Dexta 30-35 lbs/ft.

Tom P · Post by **Tom P** » Fri Aug 20, 2010 2:42 pm

Well, I got had my injectors checked out!
3 are junk, 1 is questionable. They also told me that since the injectors are this bad the pump is probably the same.
$85 apiece to have rebuilt, that really hurts.
I guess I dont really have a choice and the up side is I will know they will be perfect! I think I might have to see about a used pump. Unless I can rebuild it myself.

Tom

super6954 · Post by **super6954** » Fri Aug 20, 2010 10:15 pm

Hi Tom
Yeah it sucks when you have bad injectors The fuel system on any diesel is not a cheap fix anymore.
I guess you will have to hope for a good used pump. YOU WILL NOT BE ABLE TO DO THIS YOURSELF

!. It is a job for the profesionals with a $100.000 in machinery. ( thats what my guy said his kit cost anyway.

) Good luck

Regards Robert

Post by **Brian** » Sat Aug 21, 2010 2:32 pm

I would not hurry to get the pump checked! Try the injectors first and see how she goes.

Supermanuel · Post by **Supermanuel** » Wed Sep 29, 2010 12:17 pm

Major has used 2 sizes of spray holes, 0,010 and 0,011 inches. Only engine number is telling which size should be used. More important is anyhow that all are of same size. Either NL123 or NL141. Depends on pump number. With 1 mm head gasket use NL123. Thin steel gasket 0,60 mm and NL141 were only used in engines between 1425097 - 1481090. Also correct timing depends on engine number and which head gasket, piston, nozzle size and pump SPE number is. Often in older engines they are not original parts.

Leaking pressure valves and cavity erosion of elements may be expected on an old pump.

If cold engine is idling fine with all cylinders, but not more as hot the quantities injected are no more equal between cylinders. I.e. when the injected quantities are very small, it is easier to notice the difference.