My largely original 78 started backfiring at cold start and also runs poorly when cold, so I'm replacing the injectors and seals. I am following Brad Smith's method he made a youtube video of, but with some twists. I am pulling injectors in car, I used a 1"PVC pipe as it's its much cheaper than copper and won't leave marks. One injector of left side had carbon buildup but the other 3 don't look bad by eye. The new seals have different shape but maybe due to being in there for 42 yrs. The tension sleeves are magnetic so not aluminum as reported.also the injectors were 12 mm. I took an hour to get one side done.
i think a regular nut would suffice, I didn't need more torque than a thread or 2 could handle.

 

i'm surprized you got those tension sleeves out .... i did tried it in the past on 2 engines (with sleeves in aluminium) and no way they came loose. Just damaged/broke the sleeve.
And i sprayed them regulary days before with WD40 ...

 

Are your sleeves steel? I heard they were Al which would be more likely to fail. I'm going to spray the other side again now before I try them!

 

Barry WD 40 is not the penetration spray to use, its a water dispersant.

you need PB Blaster as it dissolves rust and will release the metals.
If you have a doubt put a few rudsty nuts in the cap,
then add enough to cover the parts,
then wait for a few hours the nuts will come out looking free of the corrosion

 

I wouldn’t use those short Mercedes injectors. The original long ones will make it work like it was designed

 

no ,they were aluminium.... and once broken they looked very thin threaded bushings !

 

thanks Stan , you could be right.... but i doubt we have "PB Blaster" in Europe... ????

 

My sleeves are aluminium, and were not too difficult to remove as I recall. Getting the old rubbers out of the sleeves was the big issue for me. At the time (nearly 20 years now) I was able to get replacement injectors for the 4 that failed spray and leak tests, but its a lot more difficult now. I have picked up a few new ones by watching ebay world wide over the years, and a couple of the brass MB types. Have never seen any negative comments from people who have fitted the MB units.
jp 83 Euro S AT 57k

 

My sleeves are aluminum and I only damaged one ( Roger has replacements ). I also added a small amount of anti-seize with a paint brush for models to the threads of the sleeves. No problems with the MB injectors although they are a little shorter.

 

I never heard any downside about the MB injectors either until I saw Greg's comments in this thread yesterday: https://rennlist.com/forums/928-foru...ext-steps.html. I used to run the MB injectors, but over time my Kjet wasn't happy. My indy, who knows these systems quite well, told me to put the original , longer injectors back in. I had him tune the system with the guages, put in the original stock injectors (after sending them to Sean for cleaning) and the car ran great. That was several years ago. I'm having a different problem now with a leaky one. I was going to swap the MB shorties back in until I saw Greg's post. My indy doesn't like using the short ones either.

 

When I did my engine build last year, I bought new injector seals and new tension rings from Roger. Also, new injectors. Original old ones came out without any problems and I just forced the rubber seals off them with my hands. Put a little silicone grease on the inside of the new ones before slipping them onto the injectors and the injector pops right into its seat. I used some Marine Grade anti-seizr on the threads of the tensioning rings when installing them. Job was very easy and it's a good thing as I had to pull them a few more times when troubleshooting a running issue that turned out to be the fuel distributor. I took them all to a local diesel shop that ran some cleaning solution through the old ones and new ones to check the spray pattern and that they didn't leak.

 

I was under the impression the original injectors were nla and the MB’s were the only option. Also was told the originals were not worth trying to clean and that there were not many options to have them cleaned either. I now assume this is false information...

 

 

Ed, Greg has certainly earned the respect he has here, and I'm a newbie to 928s and to CIS (and Rennlist), so his thoughts carry a lot of weight with me. Other than his comment I don't recall seeing any that were negative toward the shorter injectors. I get the impression that there are a lot of 928s out there using them. Could a poll be set up here to gather more input? An "in situ" video would be convincing (and cool)! And why are the longer but otherwise identical injectors twice as expensive?! I doubt that its the volume of sales.

 

They are available, at about twice the price of the shorter MB ones.