Keith Browning Posted July 26, 2006 Share Posted July 26, 2006 One of our techs had sold a set of injectors to a customer with a high mileage engine that had gas run through the system. It originally came in running rough and smoking. The new injectors cured that. Since then, it has returned three times billowing white smoke and running poorly and would hydro-lock randomly. This being the "third try" the job is now mine. The previous failures indicated a poor seal at the base of the injector leaking combustion which in about 500 miles would burn away the lower fuel o-ring. By inspecting the copper seal I noticed that it was distorted like it was skewed off center and was slightly concave. It certainly was not sealing properly. I will be doing sleeves tomorrow. Okay, I'll get to the point... I also discovered the upper injector hold down bolt was loose. This bolt does not have to come out to replace injectors and I am unsure if the other tech had loosened it at some point. In your opinion is it possible for this bolt to loosen more if not initially torqued to spec? I removed it with two fingers with absolutely no resistance. Quote Link to comment Share on other sites More sharing options...
Kyle E. Grathwol Posted July 26, 2006 Share Posted July 26, 2006 In my opinion, yes. If I remember correctly that bolt has a flange that bottoms on the head and once it is torqued it would take more resistance to break it loose than if it wasn't bottomed. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 26, 2006 Author Share Posted July 26, 2006 Yes, the bolt has a shoulder and it is supposed to be tight and locked before the injector and clamp are installed. I'm looking for a possible reason for these repeated failures. One note that does not support a typical loose injector failure is that the copper seal was not pounded away or burnt away. Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted July 26, 2006 Share Posted July 26, 2006 We've seen a few that the original copper seal stays in the head and the injector won't be completely seated. Any chance it's still in there? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 26, 2006 Author Share Posted July 26, 2006 Yeah Larry, the copper seal was there and there was only one. When I loosened the old down bolt it seemed to be properly/adequately torqued. I was more concerned about the upper bolt being loose and not fully seated and torqued down. It is fairly evident that the issue is not with the injector(s) as there have been three different ones installed in this cylinder. So my attention turns to the sleeve and the copper seal itself. I looked at the ring and it appeared not to be uniformly crushed and appeared to have been pushed off center. The hole in the middle where the injector tip goes through was oblong. I removed the sleeve and inspected it. No coolant leaks. No combustion leaks under the sleeve. No cracks and it did not appear burnt. What I cannot tell is if there is any variance in the thickness of the bottom where the copper seal mates with it. The marks left in the bottom of the seal also show that the copper seal had shifted. I can only assume that the sleeve was distorted - the head looked good and clean. I installed a new sleeve and sent the truck on it's way. Keeping my fingers crossed. /forums/images/%%GRAEMLIN_URL%%/frown.gif Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted July 27, 2006 Share Posted July 27, 2006 Knock on wood... Good luck. Quote Link to comment Share on other sites More sharing options...
cworley Posted November 24, 2006 Share Posted November 24, 2006 One thing I always make sure of is blowing the oil that gets into the injector hold down bolt hole. It has a bottom and will collect whaterver falls in it(oil). & your injector hold down bolt won't go as deep as it should but will still torque right. I've had this happen to me. Good luck. Thanks again for the connector,Keith Quote Link to comment Share on other sites More sharing options...
cworley Posted November 24, 2006 Share Posted November 24, 2006 One thing I always make sure of is blowing the oil that gets into the injector hold down bolt hole. It has a bottom and will collect whaterver falls in it(oil). & your injector hold down bolt won't go as deep as it should but will still torque right. I've had this happen to me. Good luck. Thanks again for the connector,Keith Quote Link to comment Share on other sites More sharing options...
Mekanik Posted December 22, 2006 Share Posted December 22, 2006 I haven't always done this, and I never had any troubles by not dong it, but I always check the torque of the upper bolt. I can usally get it to turn a little bit and the torgue is not that much. If a injector is installed and that upper bolt is not tightened to spec I can see how the copper washer would not seal properly. Quote Link to comment Share on other sites More sharing options...
Dart505 Posted January 13, 2007 Share Posted January 13, 2007 I have changed a lot of these injectors over the years & have not had this problem personally but have got referrals from other shops with this problem.Usually the deformed or out of round copper washer was from the cumbustion gasses overheating it sense it did not seal properly it could not dissapate the heat back to the cup IMO.I always have "seated" a new injector with a soft face dead blow hammer & you can hear when they seat properly.Also I have tried different lubes for the o-rings & the best that I have found is the Lucas motor oil additive, goes right in.I have also notised the upper hold down bolt would make a 1/2 a round or so. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted January 14, 2007 Share Posted January 14, 2007 I like to "make sure" they are all the way down, too. I have noticed in the past that, if you try to draw them in with the hold down bolt, you can "visit" the bolt a few minutes later and gain more torque on them.... and you can repeat this process several times before you get solid torque. Quote Link to comment Share on other sites More sharing options...
coop Posted January 15, 2007 Share Posted January 15, 2007 here at this shop we alwqays blow out the bolt hole,then brake clean,then blow out again.we have been caught on loose injectors in the past and have not had a problem since doing this way-2 years and counting. Quote Link to comment Share on other sites More sharing options...
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