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View Full Version : Removing Injector Hold Down Bolt


skill3
02-12-2013, 11:30 PM
I've read through a lot of post about "black death", but I couldn't find the answers to my questions. I just bought a 2006 118" SHC. It has 183,000 miles and was serviced regularly by a picky, previous owner. I have only had it for a few days. I decided to pull the cover and check for "black death". There is a small amount at the base of the #1 injector. All of the others look good. I ordered new seals and bolts from Europarts. My question is, what is the best way to remove the injector hold down bolt? Should the engine be cold or hot? Should I use PB Blaster or the new WD-40 penetrant? Any tips are greatly appreciated.
Thanks!

skydiver007
02-13-2013, 12:04 AM
Well my own experience was to get the right size torx bit which I cant remember the size and gently try to turn with a socket wrench. Mine all came right out with no problems. If like you say the previous owner took good care of her, they should come out fairly easy. If you break one, then the problems start.

I took mine out while the engine was hot, if it is locked up, you have a better chance when everything is hot. Good luck.

surlyoldbill
02-13-2013, 12:06 AM
The bolt should come out kind of easy, the injector will be a bitch if you have some Black Death.
PB Blaster is OK, but Kroil is the good stuff. Spray a generous amount of penetrating oil around the bolt and injector and drive for another few days.
Try loosening the bolt while engine is hot, if it doesn't come out easy BE CAREFUL and don't torque too hard and break it off. If it loosens at all, spray some more penetrant on it, tighten, loosen, tighten, loosen more, etc. to work the oil into the threads. You may have to drive another day or two while adding penetrant.
The injector is kind of the same procedure, except it isn't threaded. You CAN twist it a little to break the black death seal and allow the penetrating oil to seep in. One trick is to run the engine with the hold down bolt loose by a few mm; the pressure of combustion will force the injector out a little, breaking the seal. Too much operation like this will contribute to the Black Death deposits, though. I drove mine around with a loose bolt for a couple days, checking it often. The Kroil was the key to getting out my stuck injector after it loosened a bit.
INSTALLING is another matter, I broke off the hold down bolt while tightening because I came up to the stopping point too quickly and/or didn't clean the threads very well. The hold-down bolt is a little frail by design, you need to follow instructions posted elsewhere on this forum. I was able to salvage things by drilling out the broken end and installing a helicoil, and it's held for 15k so far.
"Floating the Moat" is a technique someone came up with to prevent Black Death, it involves adding a few teaspoons of oil to the little well around the injectors so they are always bathed in oil at the spot the enter the head.

skydiver007
02-13-2013, 12:14 AM
I wish someone would explain the oil around the injector purpose to me. Black death is caused by blow by at the injector seat and I cannot figure out how oil around the injector can help this ???

I would think if anything, the oil would mask the fact you have a problem and the tolerance of the injector to the bore is very tight and oil shouldn't be able to make it to the bottom of the injector.

Please enlighten me. I just don't get it.

surlyoldbill
02-13-2013, 01:21 AM
I wish someone would explain the oil around the injector purpose to me. Black death is caused by blow by at the injector seat and I cannot figure out how oil around the injector can help this ???

I would think if anything, the oil would mask the fact you have a problem and the tolerance of the injector to the bore is very tight and oil shouldn't be able to make it to the bottom of the injector.

Please enlighten me. I just don't get it.

I don't know the physics of it, other forum members have mentioned it and swear by it.

Amboman
02-13-2013, 05:59 AM
I think it would act like some hydraulic resistance effect combined in with the threads.

Boater
02-13-2013, 10:06 AM
Are you sure the guys don't fill the wells with oil to exclude water and prevent rust, thus hopefully making it easier to remove the injector if the black death returns?
That is certainly the inference I have taken from Vic's descriptions in the past, but maybe I read wrong?

Mine has no wells, but the injectors have a light smear of the ceramic grease to prevent seizing and hopefully prevent corrosion.
Then again, I don't seem to have read about black death on non-cdi injectors - is it fuel vapour or combustion gas? If combustion gas I can't see why non-cdi would be immune, if fuel, well the 5-10x difference in operating pressure would explain it.

mean_in_green
02-13-2013, 10:38 AM
That and the suggested theory of oil in the injector valley creeping over long periods into the injector threads with a helpful effect come injector removal time.

skydiver007
02-13-2013, 10:56 AM
OK then it sounds like the oil is more for injector removal support than trying to prevent black death. The injector has no threads and just pulls out. Only part that has threads is the hold down bolt.

It still seems to me that oil would mask a black death issue and might delay a response. The first time I had it, it looked like oil around the injector. If I already had oil there on purpose, I might have not thought anything about it.

And, If you are using any other kind of oil than synthetic, when oil gets hot, it produces carbon which can also stick to the injector.

Still not sold on the idea.

Aqua Puttana
02-13-2013, 12:42 PM
OK then it sounds like the oil is more for injector removal support than trying to prevent black death. The injector has no threads and just pulls out. Only part that has threads is the hold down bolt.

It still seems to me that oil would mask a black death issue and might delay a response. The first time I had it, it looked like oil around the injector. If I already had oil there on purpose, I might have not thought anything about it.

And, If you are using any other kind of oil than synthetic, when oil gets hot, it produces carbon which can also stick to the injector.

Still not sold on the idea.
The oil in the wells being worthwhile is a theory, not a proven method. My opinions...

Under normal operation the injector bores don't see that much heat. Should you develop an injector seal leak I don't see where the oil in the bores could prevent or mask that high pressure, hot escaping gas out of the cylinder from creating the normal lava like condition. In fact I would argue that the oil in the wells might be sprayed out early on and give visual evidence of splash on the black plastic cover and maybe even other evidence by increased smell from that oil spraying out.

I doubt that the oil will contribute to carbon buildup. A seal leak is quite capable of doing that all on its own. I put oil in the wells because some of my injector bodies showed rust and corrosion when I removed them. I don't think it can hurt, it may help.

As to removing the injector hold down bolts...
I recommend using a pin punch sized to just fit into the fastener head for a couple good raps to shock the threads a bit before trying extraction. There is more of my information and opinion than most people would want in my injector removal thread. vic

talkinghorse43
02-13-2013, 12:57 PM
The why of oil in the wells here:

http://sprinter-source.com/forum/showthread.php?t=5528&highlight=injector