Finally, an update worth reading! I hauled the engine out to the shop, but the big news is that I worked over the exhaust housing of the turbocharger with the die grinder to cure the bad inlet mismatch. Have a look…

There’s no problem getting the crate into the truck with the forklift at the warehouse, but getting it out at the shop required some ingenuity (engine-uity?). With the tow chain from Michael’s tractor rigged as a sling, the cherry picker was once again pressed into service.

After sitting it down on a furniture dolly so it can be rolled around the shop, I couldn’t get the damn sides of the box off fast enough… I have to hand it to Jerry and his boys, though. They build one bad-ass crate.

After spending some quality time with the new motor, I assaulted the turbocharger. The clamp that holds the turbine housing to the center section comes off effortlessly, but the joint had to be soaked in WD-40 for a week, and it still required some, uh, "persuasion" to come loose.

Although the center section housing is rusted, the turbine wheel is in great shape - no nicks, cracks, or erosion are apparent. Now, I have to figure out how to safely clean it up before I put it back together… I’ll set that aside and think about it a bit.

Here are the "Before" shots of the turbine inlet. It’s easy to see where the mismatch to the exhaust manifold is, and this will serve as a guide for the port matching process. The housing is clamped in a vise and I jammed a shop towel into the port both to catch the big pieces and to serve as a sort of depth stop. Although I want to blend the port as deeply as I can, I also don’t want to appreciably enlarge the cross-section of the lower inlet and reduce the velocity of the exhaust gas as it passes this constriction.

The cutting starts with a carbide bit. TechWeasel Tip: When using a die grinder, use the air pressure regulator to control the tool speed instead of the throttle. You’ll have better control of the tool if you can simply hold down the trigger and use both hands to direct it. Here, I found that 40psi gave me the right RPM - your mileage may vary.

Note that I’m not going all the way out to the edge of the area I want to remove. I’ll leave that for the final finish cut with less aggressive abrasives, so I don’t have to worry about overshooting the mark.

I’m trying to carry a smooth line all the way from the edge of the housing to the inside, so a lot of material must be removed. In the upper photo, you can compare the left and right sides to see just how much gets ground away. Don’t worry, though. There’s still plenty of meat left in the walls of the housing.

With the rough cut complete, the tool marks are clearly visible, but the majority of the metal that needed to be removed is gone. This stage represents about two hours of cautious work from the time I started.

With the port cut to the general shape I want, the following steps serve to smooth the walls and blend them into the throat of the inlet. First, a 40 grit cartridge roll is used to make the final changes to the shape of the inlet and remove any remaining uneven spots left by the fast-cutting but imprecise carbide bit.

I follow up with a succession of increasingly fine abrasives. Here’s an 80 grit cartridge roll…

120 grit flap wheel…

And finally the medium and fine cross-buffs are used to finish polishing out the inlet.

After a trip to the sandblasting cabinet and a thorough scrub in the parts washer to remove the grit that got past the tape over all the openings, here’s the end result. I don’t know how well it flows, but it sure looks a hell of a lot better than it did.

Other than the fact that this was a lot of work (roughly 4 hours start to finish), it was really pretty easy to accomplish. As I said before, the key is to work slowly and pay attention to what you’re doing, since it’s much easier to remove some more metal
than it is to put it back.