Engine rebuild question

[richmobj]

How many miles can you get out of a rebuilt turbo engine?  I'm wondering because my 1987 GN has 135,000 miles and still has it's original bore engine.  I'm sure that I have a rebuild coming sometime in the future but was told that rebuild engines have a life expectancy of 50,000 miles on average.

[Steve Wood]

The factory engines routinely went 200,000 miles with the exception of the timing chain which usually wore out somewhere shortly past 100,000 miles.   This assumes good maintenance and not allowing detonation.  No reason a rebuild should not do the same if performed properly.

Most engines that die early have not been maintained properly and/or have been abused which includes not having a scantool and assuming everything is okay when it is not...

[richmobj]

What are the steps to changing out the timing chain?  Would I have to remove the radiator, intercooler, turbo, alternator and everything else bolted to the front of the engine in order to get to it?

[1KWIKSIX]

Yup, you will need to pull all that stuff off. To do it properly, it would be best to remove the oil pan while you're at it too.
Suggest you read, read, & read up on the steps involved.
 
If you're not 100% comfortable, maybe best to have someone experienced do the work for you.
 
Be sure to only use billet steel timing gears as the cast gears will wear out in no time.
Not sure of your set up or HP expectations, you could go with a double row timing chain, but they do not use a tensioner and can stretch excessively if you don't buy a good chain. There's lots chit out there so beware.
 
If you want to stay with a premium single row chain that utilizes the factory style tensioner (like the factory supplied)..... .go with the TA Performance one....you can contact Nick Micale at Arizona GN & he can supply these items for you.  Think Dennis Kirban also offers this unit now as well.
 
Good Luck....