I am replacing the head gasket on a 1988 740/760 turbo and I am buffaloed by how to separate the exhaust manifold from the head because the turbo is attached to both the manifold and the block (via the oil drain). How do I get the exhaust manifold clear of the head without causing problems with the turbo oil drain? My Haynes manual is silent on this topic.

 

you undo the 2 oil drain bolts on the turbo and separate them. then your have to find the hidden bolt that connects the manifold to the support bracket which then attaches to the block. leave the turbo on the manifold. It is anoyying, because the support bracket is not slotted. I slotted the bracket so it is easier to work with.

Here is the bracket (I slotted the hole with the arrow):


Turbo and manifold removed (the hidden bolt by red arrow):

 

I love this site!

 

I'm guessing your 88 still has the original exhaust manifold, not the 90+ in the photos. I don't know about the Mitsus used in 88 but the earlier T# Garretts were mounted from the back side, meaning you have to pull the exhaust manifold to swap turbos. The nice thing about the 90+ manifold, other than the performance gains, is that the studs are on the outside, meaning the turbo can be pulled w/o pulling the mani! The oil return pipe to block is a friction fit; you'll want to score a new o-ring from the dealer before putting everything together. Ileft the drain tube on my assembly when pulling as I recall. Those two bolts under the turbo are a biatch to get to.

 

Thanks to both of you, TIPSP and swiftjustice44. I already have the O ring on order. Can I leave the manifold/turbo assembly in the car and connected to the rest of the exhaust, or should I pull it right out of the car? I can see a hardline connected to the top of the turbo via a 2 bolt flange and disappearing somewhere below the turbo. Is the oil supply line? Is the drain attached to the bottom of the turbo?

swiftjustice44 - it looks like this turbo is mounted from the backside. I think the whole layout was designed by the same humorist who designed the heater in the 240.

I am not sure if it was lucky or unlucky in that the timing belt broke when I tried to move the car out of the driveway to do the head gasket and replace the timing belt - annoying, but if it had broken any sooner I would have needed a tow and I only have one free tow left for the year.