Cutting the top o-ring when installing an injector?

Matt Saunoras · April 27, 2015

This had me absolutely baffled and I really don't know what the hell was going on. Putting injectors in an 06 F-550 dump already made harder by the PTO I could not get #1 or #3 in without cutting the top o-ring while tightening the hold down. Never seen or even heard of this.

Always used 15w-40 oil to lube the o-rings until right now. I must have cut 8 new o-rings on this head. Even stuck an old injector in and cut the original top o-ring.

Brushed out the bore thinking maybe some rust? Nope didn't help, tried a little light grease? No deal.

Finally Vaseline to the rescue. This has to be punishment for having a job that's been a little too easy lately.

Keith Browning · April 28, 2015

Are you using an air tool or running them down by hand?

Matt Saunoras · April 28, 2015

Hand tools only. I use a small flex 3/8" ratchet that fits my palm nicely. Really I have no idea what the deal was.

Keith Browning · April 28, 2015

Could have been a bad edge on the cups?

Brad Clayton · April 28, 2015

How did you know the oring got cut?

Matt Saunoras · April 28, 2015

I could feel it as I was tightening the injector down. Right as the top o-ring is supposed to start into the injector bore the hold down bolt would get real tight. Usually they get a little snug, then ease up as the o-ring starts into the bore.

Then I could see the sliver of o-ring sticking up on the injector body. This thing was cutting perfect round slices off the o-rings. Couldn't begin to tell you why

batmantech · April 28, 2015

I had that happen on one of the first 6.0 injectors I ever installed. Found out after it was running.

I think for me it was the angle that a was placing the injector into the cup. Maybe with that pump

in the way it was not going in at the right angle.

DieselD · April 30, 2015

interesting, never had this happen. just did a set of 8 on friday too

Keith Browning · May 2, 2015

I found several on an LCF that was getting a repeat replacement of injectors because he refused to replace the fuel tank the first time. As I recall, the injectors looked very similar to these. Not sure if they were leaking.

forddieseldoctor · May 3, 2015

I had one this last week that had a very flat side on the lower o-ring and a very black slime between the o-ring and the copper washer.

lmorris · May 27, 2015

Just talking to a customer that had the same issue with someone putting injectors in his truck and cutting the orings. At some point he had his engine replaced and ended up with 2007 heads on his 2004 short block. The 2004 injector hold downs were used and he was told that they don't line up the injector properly if used with newer heads(first I ever heard of this). Someone put all new 2007 hold downs in it and it was fine.

Edit: I had this one mixed up. I can not find any information on this, so it's hear-say. The second design injector hold downs with the bigger torx head are the ones that are not letting the injector go in straight, that's what the customer was told. His engine was a 2007 part number, so it had the new hold downs. These people sold him 8 of the old style hold downs, new orings and he claims the stalling issue was fixed.