George Fontes has put together a good guide (PDF here) for re-sealing the intake gaskets on the M70. I followed this guide myself at times, but here are some additions and enhancements:
- When removing the fuel rail and injectors, here’s a tip: spray the lower ends of the injectors with some WD40 or equivalent, then wiggle the whole fuel rail a little and it’ll come out sort of like a Teflon® coated turd.
- Remove the the intake manifold for CYL7-12 first, that way you only have to fiddle with half the amount of nuts. Besides, you can’t remove the intake manifold for CYL1-6 without bending the hardlines for the fuel return since they’re on the same studs.
- Rubber mountings are very expensive from the dealer, about €12 each. Instead I bought four (4) new mountings from my local rubber place, total cost €17. Albeit not the same looking, they do the job.
Old rubber on the outside, new in the middle.
Based on photos found on the internet, people seem to put way too much sealing compund when re-sealing the intake gaskets on the M70. If you look closely on the mounts, the cylinder heads and intake manifolds you’ll see that there’s only about 2mm wide an area that is actually supposed to seal. When I did this I used a syringe with a 1mm opening and put a bead on the outer half/edge of the mounts actual sealing surface.
The valley was really dirty because of oil leaks from the valve covers, so I taped up the intake ports and put the gaskets back in place so I could use a pressure washer to clean it.
First some paper inside the ports and then a couple of layers of duct tape.
Then put the gaskets back in place.