Anyone experience broken injectors when raising pop pressure?
 

My injectors have been shimmed to achieve a pop pressure of around 2300 psi, and today I heard a knocking. I pulled the injectors and tested them... Turns out one was sticking and one failed completely.

See the pic, but the cone on the end of the spring
shattered.

https://goo.gl/photos/8T8quBH9AmYrqV8w9

I'm wondering if it's from the higher pop pressure. I replaced the nozzles and seats, but I'm trying to determine if the issue is going to return.

Spenser

I have seen several injector springs break, a few on 6.2/6.5 GMC diesels and 2 on the D24T engines. I had one spring break 1 mile after installing a 12mm pump.

A 12mm pump and raised pop pressures works the injector internals pretty good.

Many variables. We don't know the previous life of these injectors. High mileage? Overheating? Clumsy cleaning (easy to bend or deform the end of the pin)? Nozzle quality?

How many do testing by holding the nozzle at a 45deg. angle and seeing if the pin drops of its own weight?

I get what you are saying, I'll keep an eye on these and if it's a recurring problem I can lower the pressure a little.

Spenser

I got the injectors back together and put them back in. I think the one injector had been sticking for a while. It runs much smoother at an idle, and is more consistent.

Spenser

BTW Adam, I got the new turbo on and am loving it! (T3/T4 hybrid, spools much sooner and I still get 20 psi from it)

That's always a welcome result!

Did you have to do much re-shimming to get them dialed in? No drips while holding pressure slightly below pop?

Nope

Not on the good injectors, this is how I found the sticky one. It also dropped the pressure much more on my test rig and stayed open longer. The broken injector leaked so much that my test rig wouldn't build pressure.

Spenser

What are the specs on the new turbo? Did you get a chance to try the 9cm turbine on that Holset?

isn't 2300psi oem pressure?

Ehh.. I should know this... But I thought it was closer to 2000? I'll look on the side of the injectors when I get home. Its stamped in bars..

The new turbo has a turbine and housing like stock, and has a bigger compressor.

http://m.ebay.com/itm/T3-48-Compress...=1387599756020

I did buy the 9cm housing, but it didn't fit the H1C.


I forgot you just made a thread about pop pressure Russ. The reason I thought 2300 was higher than stock is the huge stack of shims in them. Maybe they had the wrong springs? I didn't build them, so I am unsure of their history.

Greenbook specs conversion math is off.

Operation AG14 shows checking injector pop value 14.5 - 16.3 MPa (2062 - 2318 psi). Should be (2103 - 2364 psi), if my calculations are correct.

Operation AG16 shows reconditioning injector pop to 15.2 - 16.3 MPa (1780 - 1920 psi). Should be (2205 - 2364 psi), if my calculations are correct.

Operation AG15 shows leak testing injector to hold 13.5 MPa (1920 psi) ( Should be 1958 psi) for 10 seconds with no drip. I like to test that for longer, and for the nozzle face to not even start to get moist.

The set of stock injectors I have are stamped with '155 Bar'... 2248 psi.

The injectors in question are not stamped with anything, but with the amount of shims in them I'm wondering if they were from a rabbit motor and were originally set lower. Or maybe the springs were weak? Like I said, I don't know their history.

At least I'm running stock pressures lol. I'll get the pop pressure up on the other set I have and install them at some point. These can stay in the engine for now.

Thanks for the help,

Spenser