Those are regular tap size. STI seems to be not available in 18x1.5, the tap would be larger. Time Serts are fine but yes you will need to make room to use it.
It is not your fault, I am almost positive it happened removing it and could have happened to anyone.Quite a job to remove that cover.
I’m in disbelief that I screwed this up so bad. Completely disgusted.
Had the pulley bolt not sheared off (not sure why that happened in like 1-4 mile of use), it would be in there, installed, no issues that I’d know. And good to go another 200k.
To add insult to injury. The broken screw could be removed with my fingernail backing it out.
Ugh.
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Agreed.It is not your fault, I am almost positive it happened removing it and could have happened to anyone.
The threads were fine when I pulled the old one. I looked them over, went through each one, etc.The Steel and Aluminum and I am not sure if I am using the proper term [I am sure one of our A&Ps will let us know ] Galvanic corrode together. I looked at your post before and knew that would happen . Time for a Timsert or Helicoil. Aluminum sucks for that. I have found that on some Aluminum you can just use the tap with out drilling for the Helicoil .
FSM prerequisites are posted above. No head or oil pan (fortunately, since then it would be an engine lift too).Agreed.
Way ahead is murky. I’ve got a right angle drill for jobs like this. You’ve got enough room to do the drilling, the TimeSert and Helicoil bits are short.
But I wouldn’t want the chips from drilling to get on the timing chain or in the pan. Some guys use grease in the flutes of the drill to catch the chips. I wouldn’t be happy with that.
I‘m leaning towards pulling the timing cover. Looks like the oil pan has to come off to accomplish that. Might have to remove the head. What does the Mercedes FSM say about removing that timing cover?
That may be the way to go.FSM prerequisites are posted above. No head or oil pan (fortunately, since then it would be an engine lift too).
I’m inclined to consider the helicoil or time sert. The prices are high. But I can remove the radiator and condenser and get a straight shot.
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I was thinking about the chips going down.
Often one uses grease to catch chips. I’m thinking maybe I can pack the rear of the hole with either electricians duct seal, grease, etc. even a piece of tape. Then drill, cut threads, etc.
My thought is if perhaps the insert is shorter than the overall threaded depth, maybe I can keep the back of the hole closed off, since it is already more than half occluded.
After all that, wipe/clean, vacuum, flush with fresh oil significantly, change the oil immediately, and go from there.
SMH.
Over $300 he said. If it was a choice between a $250 repair and a $350 new part, new part hands down.Is replacing that timing chain cover an option?
My choice? New cover.
I understand what you’re saying, am Im not looking to argue with you. But the original one was not seized in there. Once I used a slightly longer breaker bar, it came right out.The sttel and aluminum corrode together. I has been too long of a time mentally to be precise and proper with a definition and I may be wrong with the facts but the will be generally ball park? some what maybe correct hopefully. The steel and aluminum make a battery and the Aluminum being less nobel loses molecules over time and weakens.
Posssibly. And a lot of work, and time that I don’t really have.Is replacing that timing chain cover an option?
If you're gonna tackle this in place (and I probably would), don't be afraid to modify tooling as needed. For example, the provided bit appears to be a S&D (reduced shank). If you need to lop some off that shank to shorten the OAL, do it. You're just drilling aluminum and you only need enough length for the jaws of your drill chuck.
I'd probably use grease to try to capture chips, too, but what about getting really fancy and trying for a few lbs of positive pressure in the engine? Can you tap in somewhere with a regulated air line and gently pressurize the timing cover?
The tensioner wasn’t loose. The pulley on it was connected with a bolt that sheared. Was that on me? Something else? I don’t really know. I’ve done quite a few pulley replacements without issue. Something else may be misaligned on this one… I’m starting to get that feeling TBH.I think the damage was from the tensioner vibrating as it came loose.Thats what caused the powdery looking front threads. The oscillations from being loose mangled the threads.
Why did it get loose? Hard to say. Did the thread lock have time to set ? Was there something that kept the part from being torqued properly? Is the torque wrench correct ? I'd lean on the side of the fastener was not tight enough, and vibrated loose , then being loose, it ate up the threads.
I'm assuming the threads on both pieces were cleaned. But if a shard or some old thread lock was there, perhaps it caused more torque to be needed for the threads to be tight, the wrench clicked off, and the threads themselves were not tight?