Wastegate repair (aluminum TIG build-up)

I got an external 35mm type wastegate that wasn't manufactured quite right, so today I got to fixing it.

The problem was the surface for the banjo fitting of the boost pressure signal wasn't flat and was quite a ways off from square to how the banjo fitting hole was tapped, so I couldn't just file it flat either.

I fixed it by doing some TIG welding build-up around the threaded hole to build up the surface where it was low. To avoid needing to re thread the hole through this process, I just stuck a steel bolt into the hole and TIG built up some aluminum material around that bolt.

Then I carefully filed it flat (with the mating surface perpendicular to the axis of the threaded hole, of course) and chased the threads and... now it works! Good as new (No actually, make that *better* than new! :D)

Jakeru, what vehicle do you use the wastegate on and did you make the exhaust fittings to mount it.

The drive pressure to boost ratio on my 2008 CTD starts to increase non-linearly at about 24 psi, so I am considering making a flange that will mate to the EGR cooler port and then plumb in a Tial wastegate.

Oh, and good job on the repair.

Ken

Quick tip for the future is that the threads on the banjo bolts for most wastegates will work with an NPT threaded fitting if needed. I have used push to connect swivel elbows in place of the barbed banjo's numerous times. No wirried about sealing to teh flat surface witht eh copper or aluminum washers.

Great work as uaual!

John

is that an ebay tial gate?
never had that problem on the genuine units i've used.

in any case, good work!

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Originally Posted by kenwhite

Jakeru, what vehicle do you use the wastegate on and did you make the exhaust fittings to mount it.

The drive pressure to boost ratio on my 2008 CTD starts to increase non-linearly at about 24 psi, so I am considering making a flange that will mate to the EGR cooler port and then plumb in a Tial wastegate.

Oh, and good job on the repair.

Ken

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Thanks Ken. I'm just planning to sell this wastegate. When it had problems, I couldn't with good conscious sell it for anything but a really low, "good for parts only" price when it had problems. But now that I've fixed it up (I went through the rest of it as well and got it all functioning properly and smoothly, I should be able to sell it for some good coin without worry.

I have installed a similar wastegate on a 1.9 liter VNT (variable nozzle) VW TDI turbo. I found it helped maintain a rock-solid boost pressure, and eliminated boost spikes inherent with the VNT boost control system. I did mount it on an EGR flange too. ;)

Quote:

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Originally Posted by sportbike

Quick tip for the future is that the threads on the banjo bolts for most wastegates will work with an NPT threaded fitting if needed. I have used push to connect swivel elbows in place of the barbed banjo's numerous times. No wirried about sealing to teh flat surface witht eh copper or aluminum washers.

Great work as uaual!

John

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Yeah, that's the kind of repair I'd do if I didn't have an aluminum welding outfit. ;)

If there were an NPT tap size that (sort of) fit this fitting, I'll bet it's be a 1/8" NPT, because the thread pitch was pretty tight. It was metric; I just checked and found M10 x 1.0mm thread pitch.

But anyhow, I like the banjo fitting in a lot of cases; as it can be rotated for a variety of hose routing positions. Its also easy to remove/reinstall, by just loosening the banjo bolt.

I have some other banjo fittings that would fit this wastegate too, really neat quality aluminum banjo fitting and I think nickel plated steel bolt with soft aluminum crush washers.