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+--- Thread: OM 612 stripped threads in cyl head (/showthread.php?tid=6763)
OM 612 stripped threads in cyl head - Boatbuilder - 09-24-2015
Hi,
Mercedes ML 270 CDI- engine OM 612 - 5 cyl. Have stripped the threads in the aluminium head where the
M6 x 80 stretch bolt keeps the injector in place. ("limp" mode home With lot of noise )
Anybody having experience With rethreading to M8 ? Enough material in the cyl head ?
Your advice pl.
RE: OM 612 stripped threads in cyl head - Volker407 - 09-24-2015
Hello,
changing the thread to M8 is possible. Just don´t drill too deep into the head.
You also have to rebore the holding bracket which will need a very good drill...
Gruß
Volker
RE: OM 612 stripped threads in cyl head - AlanMcR - 09-24-2015
Seems like a helicoil insert would be the solution. Some clown stripped out several of the exhaust stud threads on my OM606, A box of helicoil inserts later the manifold stays on just fine.
RE: OM 612 stripped threads in cyl head - Boatbuilder - 09-24-2015
Helicoil or V-coil difficult to assemble because the threads are in the bottom of a 80 mm deep hole.
RE: OM 612 stripped threads in cyl head - carlitosgy6 - 09-24-2015
if you post picture and the hole size i can help
RE: OM 612 stripped threads in cyl head - Boatbuilder - 09-25-2015
Hi Volker, I will drill and tap M8. Have you done this before ? How much material is it before drilling through ?
kind rgds
RE: OM 612 stripped threads in cyl head - Volker407 - 09-25-2015
(09-25-2015, 03:59 AM)Boatbuilder Hi Volker, I will drill and tap M8. Have you done this before ? How much material is it before drilling through ?
kind rgds
I did this like 6-8 years ago, so I don´t exactly remember anymore. But I know 4 more people who have done this and it was not a problem. Even if they were not very skilled. ;-)
IIRC you have 10mm "buffer" on bottom.
Just measure the hole depth before and mark your drill.
Gruß
Volker
RE: OM 612 stripped threads in cyl head - barrote - 09-27-2015
do go that road....
rebore to wider tread , that depend on how much damage u have...
ask someone do do a special pin , one side the tread u opened , the other side M6 or M8 , glue it to the head with locktite green , and secure the injector with a nut. the injector sead has to be machined, and a special washer needed. failure to do this will result in same result after some time.
RE: OM 612 stripped threads in cyl head - Boatbuilder - 09-27-2015
Hi,
Hole drilled to 6,8 mm , cleaned and tapped With M8, Beacuse top of the hole had diam 7,2 mm the the M8 tap was easy to get straight.
Rebored the holding bracket to 8,5 mm and used DIN 912 M8x80 fully threaded. The bolt head had no clearance to the injector side but enough
to easily be assembled. Nice repair and works great. I have been driving for two days now and quite happy.
Thanks for all comments.
