Leaking 2.7
 

So after leaks on the first try, the second rebuild of my 2.7 (2.9 Mahle barrel and pistons) was excruciatingly meticulous. I decked the turbo valve covers and the cam chain housings and covers, carefully cleaned and sealed the breather, used a torque wrench to mount the cooler, installed an aftermarket sump cover, etc etc. Everything was perfectly clean and very carefully assembled.

All the obvious leaks now have stopped, but it still leaks quite a bit. The through bolt holes are somewhat ovalized on the cases. I did put RTV on the o-rings for the through bolts as recommended by the Pelican rebuild book. Could it be leaking out of the through bolt holes ? If so is there a fix ? The cases have had quite a bit of work (shuffle pinned, bypassed, machined to take the 2.9 pistons, etc.) and I want to use them. Any other leaks for 2.7 Mag cases I should know about ? I plan on dropping the motor again next week and want to get the thing to run dry this time.

The through bolt holes can be "spot-faced" to present a nice flat surface. This prevents the bolts from moving to one side or the other as the torque is applied. Also use the green viton o-rings for this application not the blue silicon.

-Andy

Were your through bolt o-rings in place when you torqued the case first time? That can sometimes chew up the rubber. What I like to do is get the through bolts all torqued first with out the o-rings then remove one bolt at a time, install the rings and torque it down. This is a lot easier on the o-rings