For my 1989 740 turbo:

I recently replaced the turbo on my car. It is failing. It was not rebalanced. Joy. I took it apart when I got it from a guy off ebay and called him about the rebuild. He said it was rebalanced. I specifically asked about it. Now after 3k, the boost is a bit lower and it's leaking a lot of oil. So that's one thing that I'm wrestling with now. My brother took the car on a long trip and about halfway through it, an exhaust leak developed. Eventually one cylinder died completely. So it limped home on 3 cylinders and the leak got worse. I figured that I torqued the nuts enough, but I guess it wasn't enough. They are supposed to be lock nuts. They had come loose. It ruined the new exhaust gaskets and melted two of my new IPD performance wires. Now I have two of my old wires back on the car.

So here are the questions:

What is the torque spec for the exhaust manifold nuts? I couldn't find it in my green books.

IPD won't warrantee the wires, so should I push them for just the two I need or get a whole new set? The car already has a random missfire that the new IPD wires did not solve (so it's probably not the wires). But should I replace them all for good measure (not for my wallet's sake)?

Should I pull the engine and harness my bicycle under the hood?

 

Bump.

 

can't answer to the rest of that, but I just fixed a long running random misfire at idle that had gradually been getting worse on my 855T by replacing the distributor cap and rotor. at 120K miles the original cap was looking pretty crusty inside, with black tracks all the way around, and serious erosion and crust on the contacts inside as well as the rotor.

changing the cap on a 850 turbo is a PIA (later 850/v70's lost the distributor entirely in favor of $$$ coil-over-plug wires)

 

I've been suspecting the cap for that. I've got my old one I might slap in. I don't ever remember it misfiring with that one.

 

25-30 ft/lbs. on the exhow caust manifold. Take a good look under the car at your exhaust hangers. Turbo cars have a particularly tough time keeping the exhaust hangers in working order. 240's had a hanger that bolted to the bell housing. This really stabilizes the exhaust line against engine torque. I've not heard of lock nuts on the exhaust manifold studs but that doesn't mean that isn't how they came from the factory. I do know the three studs at the back of the turbo where it bolts to the down pipe are definitely lock nuts. Without a hanger holding the pipe tight...those at the back of the turbo will work loose often.

 

Why would IPD warrant wires you damaged?
The turbo manifolds loosen the nuts holding them to the head a lot, I tighten the one son my car every few months or so, I think it's the severe heat cycles the turbo manifold is subjected to.
When you install the exhaust manifold gaskets, make sure the shiny metal part goes towards the manifold too, the metal allows the manifold to move around on the gasket as it heats and cools. Frequently blowing gaskets is a sign they're installed/torqued incorrectly.
For what it's worth, I've had absolutely no problems with the exhaust downstream of the turbo on my car, nor of it loading up the manifold. make sure the lower stay off the manifold to the block is there too.
As for your misfire, every used car I buy gets a new coil, plugs, leads, rotor and cap. It's cheap when you consider the extra performance, reliability and mileage you get out of it, no one ever changes rotors, caps or coils and they do degrade after 20+ years.

 

Both those posts have a lot of info. I may have had them under torqued after all. I put them to 20 to 25ft-lbs. The coil is a good idea. The thing checks fine, but it would make sense.

Because of rule number one of good business: The customer is always right. So, do you think I should replace all the wires for good measure or try to get IPD to sell me the two I need.

 

Good news:

I fixed the old wires. IPD told me I couldn't buy wires separately and was unwilling to contact the manufacturer to even try. So I got the name of the manufacturer and went to work. Kingborne Wire Werks was willing to sell individual wires to me with no problem. They are a custom wire manufacturer, so I didn't think it was a long shot to begin with. But even better, all I needed was new boots and to screw them on. $7.26 a piece. Much better than $70 for a new set from IPD. ZLE 205 is the Kingsborne part number for those who may be interested. Just unscrew the old and screw on the new wire boots. I'm going to write IPD and see if they will spred this to their customer service department.

Here are a few pics too.

 

I think your 89 will have the Mitsu turbo, right? I know the Garrett T3's don't need to be balanced but I do think I remember that Mitsus do. I started rebuilding my own turbos, it's not too tough at all. The best place I've found to buy rebuild kits is G-Pop Shop Not only are the prices good, they know their stuff. Customer support is super!