Injector Bolt Installation 90 degrees vs 180

2

220629

Well-known member
This is a question more than a Write-up, but I think it belongs in Write-ups so guess where it is.

The original torque spec for T1N injectors was 7 nm (62 inch lbs) + 1 ea. 90 degree turn.

At some point that was changed to 7 nm + 180 degree turn.

I installed my injectors in May 2011 220,000 miles. I used the 62 inch lbs +90 degrees method. To date Sept. 2018 326,000 miles, all of my injectors have been fine. I do have an oil change with Black Death inspection coming up. I hope I didn't just jinx myself. :bash:

For DIY types or those who know what procedure was used, what is the history of 90 degree vs 180 degree? Has +90 not lasted? Has +180 stripped any aluminum threads?

Here's my latest thoughts on procedure.

Aqua Puttana said:
My basic thoughts for the next "Black Death" triggered injector seal DIY replacement.

Parts:

* 2 ea. more injector seals and stretch bolts than I anticipate needing. The injector seal repair may not be successful. The parts to do it again may be needed.

* 1 each new/rebuilt Bosch injector on hand. The removed injector should be able to be reused/re-installed. If it needs to be disassembled to apply a puller, it should be replaced.

* Ceramic grease for coating the injector body.

* As the T1N engines are now old, it is probably good to have injector return fittings on hand. The possibility of those brittle fittings cracking increases with service time.

Added:
This set came with 5 ea. fittings, even though it says 4 cylinder. They are metal. Not brass.
https://www.amazon.com/gp/product/B012Y1GKCY


Tools:

All as listed for my first injector replacements, plus.

* 1 each modified hold down bolt as a thread cleaner.

* 1 each dowel rod with abrasive disk for seat cleaning.

* 12 gauge barrel cleaning kit for injector well cleaning.

Abreviated Procedure (Refer to original thread for details)

Plan to do one injector at a time. Plan that it may take some time for the injector loosen.

Some days before the actual injector change remove the black plastic cover. Spray Kroil or PB Blaster around on the subject injector(s). With a fully heated engine. Use a vertically aligned pin punch to strike the injector hold down fastener a few times. That may help break the bolt loose. Loosen the hold down bolt by 3 turns. Leave the black plastic cover off. Drive the Sprinter until the injector pops. It may take a week(s) to happen. Once it pops, re-tighten the 3 turns to allow temporary engine operation.

Once the injector is popped loose the rest of the repair is basically as outlined in my original thread and tips from subsequent posters. Move on to the next injector as needed.

The injector hold down threads must be CLEAN!!!

I would again use the 62 inch pounds + 90 degrees for my repair because that was successful for all 5 injectors on my 2004. I might be tempted to add a 45 degree second turn, but given the reported aluminum head thread failures I would not do 62 inch pounds +90 +90 as some recommend. I have little data, but a healthy fear.

FWIW. vic
Click to expand...

:cheers: vic
 
owner

owner

Oz '03 316CDI LWB ex-Ambo Patient Transport
Its always been 7Nm +90deg +90deg since I first owned an om612 vehicle back in '07. That was from the WIS for my W163 ML270. I didn't own an OM612 Sprinter until 4 years later, so I don't know if it was ever a single 90deg turn on ROW. I always pondered this was why you guys Stateside has so much black death compared to ROW.

So I have always done 7Nm +90+90. Not sure I would do a full 180, just because its easier to do 2x90 I reckon. I think the key to doing this job is having a surgically clean bolt hole all the way down. As long as you have that, you can be confident that nothing is going to break when torquing up properly.

I also note that apparently (if my local MB stealer can be trusted) the injector clamp has changed yet again. It started off as a machined part, then went to a forged part which has rounded edges, now its a forged part that looks exactly like the old machined part again. I even got him to double check because I was expecting the rounded part. Now there is no way to tell which clamp part version you are looking at.
Old part:


Forged Part:


New Forged part:
 
Last edited:
2

220629

Well-known member
Thanks for the info. :thumbup:

owner said:
... I didn't own an OM612 Sprinter until 4 years later, so I don't know if it was ever a single 90deg turn on ROW. I always pondered this was why you guys Stateside has so much black death compared to ROW.

...
Click to expand...
But... all of our NAS aka NAFTA engines are completely assembled over in Germany (or at least Europe) and shipped to us complete. The cargo vans get re-assembled, but to my knowledge the engines are untouched.

Any difference in injector torque procedure would only affect repaired engines.

Doktor A once commented that he thought some of our injector seal leakage aka Black Death problems relate to diesel fuel standards and quality here in North America. Required cetane here is generally lower as compared to across the pond.

I would think 90+ 90 to get to 180 is what I would do also. Not for any particular reason but control of the operation.

vic
 
autostaretx

autostaretx

Erratic Member
Quoth the 2006 Dodge/Freightliner service manual: (chap 14, page 39)((OM 647 ))
(1) Clean injectors and recesses (Refer to 14 - FUEL SYSTEM/FUEL INJECTION/FUEL INJECTOR - STANDARD PROCEDURE).
(2) Coat injector body with anti seize lubricant then install injectors with new seals.
(3) Install tensioning claws with new screws at injectors. Tighten screws in two stages, 7 N·m (62 lbs. in.) then 90° (Fig. 13).
NOTE: If locking clamp has been pulled off at injector, the locking clamp must be replaced.
(4) Position fuel return line at injectors and secure locking clamps (Fig. 13).
NOTE: Counterhold injection lines with wrench socket at threaded connections of injectors. DO NOT over tighten.
(5) Install high pressure injection lines (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/FUEL LINES - INSTALLATION).
(6) Reconnect injector electrical connectors (Fig. 13).
(7) Connect negative battery cable.
Click to expand...
The wording is the same in the OM612 2003 service manual (chap 14, page 24)

.. so that's why we've been doing only a single 90 degree turn.

--dick
 
M

Midwestdrifter

Engineer In Residence
As long as the bolt permanently deforms, even a little, the clamp force will be consistent. In my limited experience, the 90 deg turn was sufficient to stretch the bolt for about 70 deg of the turn.
 
L

Luc

Member
I was just at the MB dealer, and asked to talk to a mechanic. He looked up the installtion specs for my VIN amd it says 62inlbs and 2x 90 deg.
I’m doing it tonight. Pucker factor at a maximum, and butt cheeks tight.

I might end up doing 90 and 45 depending how my nerves react.


Sent from my iPhone using Tapatalk
 
M

Midwestdrifter

Engineer In Residence
Assuming you don't re-use bolts and clean the hole well you will be fine. I have done the same. It feels weird stretching the bolts, because you really want to avoid that plastic deformation feeling normally. The bolt won't break if you did a good prep job.
 
L

Luc

Member
It went well!
Crazy how replacing a 0.75$ part can be so nerve wrecking.

Thanks everyone!


Sent from my iPhone using Tapatalk
 
MillionMileSprinter

MillionMileSprinter

Millionmilesprinter.com
By now I've done over 100 hold down bolt replacements in my shop at MMS Philly. Every single time I've done 90+90. Never had a snap or strip.
Of course, I ALWAYS thoroughly clean out the hole and chase the threads to make sure its clean and clear.
After talking with tons of Sprinter owners that come through my shop and quite a few people from overseas, I think Dr. A is correct about the quality of fuel we have over here in the USofA vs Europe.
Just my :2cents:
 
bubbasprinter

bubbasprinter

Member
MillionMileSprinter said:
By now I've done over 100 hold down bolt replacements in my shop at MMS Philly. Every single time I've done 90+90. Never had a snap or strip.
Of course, I ALWAYS thoroughly clean out the hole and chase the threads to make sure its clean and clear.
After talking with tons of Sprinter owners that come through my shop and quite a few people from overseas, I think Dr. A is correct about the quality of fuel we have over here in the USofA vs Europe.
Just my :2cents:
Click to expand...
MMS, Your site list a fuel injector seat cleaning kit however there is no picture or a price. Can you post a picture here? Thanks
 
Kajtek1

Kajtek1

2015 3500 X long limo RV
Luc said:
It went well!
Crazy how replacing a 0.75$ part can be so nerve wrecking.

Thanks everyone!


Sent from my iPhone using Tapatalk
Click to expand...
That is how precision mechanic works.
Still remember torqueing head on 1987 MB diesel engine.
Procedure called for 4 steps, while complicated I6 head had like 48 bolts.
Just torqueing the sequence was like 3 hr job.
Now talking 90 v/s 180 degree torque - we are talking stretch bolts.
Meaning 1/4 of turn, or 3 turns should still give the same tension (till the bolts will break).
I removed several of those bolts on different MB engines and the old bolts never had stress marks on them, so my conclusion is that the torque never had them really stressed.
For comparison - the mentioned 1987 design did call for measuring the head bolts before reusing. I did measure them and all of them were below 50% allowable stretch, so even they are relatively cheap - reusing 48 of them save me few bucks.
 
You must log in or register to reply here.

Top Bottom