Wastegate problems
 

Hey everyone,
First, I am working on upgrading a PT6266 from a VBand in-out .82ar turbine housing to a T4 divided 1.0ar. This obviously entails building a new manifold and down pipe. I am reusing the precision 46mm wastegate that has been on the car. This project is well underway, and I will be posting details soon.

Anyhow, while I was working on the fitment of the wastegate I noticed a sliver of light passing between the valve and seat. After making sure that the seat was all the way in, I took apart the can to investigate. I found that one of the set screws that holds the valve to the diaphragm had come loose and the valve had rattled around until it galled the inside of the hole and it wouldn't come loose. after trying several times to get it loose, I drilled a hole in the top of the diaphram holder and used a punch to tap the valve out. then I noticed that the top of the diaphragm holder was bulged up, as though the valve was hammered into the diaphragm.
Here's a pic side by side with and old diaphragm I had previously replaced;
https://cimg4.ibsrv.net/gimg/www.rx7...7fa381ba4c.jpg
In this picture you can see that the center is bulged up around where I drilled the hole.
I replaced the diaphragm on the left after the set screws fell out and dinged up the rubber part of the diaphragm. This make the 3rd time the set screws have backed out.

I measured the depth of the hole the valve seats in and it's about 1.5mm deeper on the bulged one.

Is there some underlying condition that would cause this? What should I look for?

I was sure someone would have something to say...

Even though I'm a relative newb with aftermarket turbos, I'm a mechanic, and have been working on cars for a living for going on 40years. I was very disappointed when I discovered that set screws were used to hold the valve to the diaphragm. I've never found them to be a lasting solution for anything involving heat or vibration.

However, when searching, I can only find a smattering of inferences to problems on wastegates that use them. Since I've seen them come loose 3 times now, I am looking at wastegates that use a better method of attachment. The one I see in the same size range is the TurboSmart Hypergate 45, and it uses a captive circlip that looks mechanically like a much better solution.
Does anyone have any input on these wastegates?

I use dual Tial 44's and haven't run into this issue. Turbosmart makes great products.

I'm a huge fan of Tial gates as well. They're the original design everyone's copied and they're 100% made in the USA. I've had the setscrews loose like you're showing on a Precision 46mm and a Chinese knockoff. Some red loctite can help, but if the metal is all galled, it may be too late.

Another vote for Tial Wastegates, customer support is TOP notch, and like others said made in the USA!!

Thanks for the input guys.
For now I have reassembled the Precision gate using the the original diaphragm seen on the left in the photo above. Knowing that this gate worked before to control the boost I figure it's best to use this to test the effectiveness of the new manifold. I've build it to provide good priority flow to the wastegate, but since it's divided now, I'll make sure it's good before we order a new gate.
https://cimg0.ibsrv.net/gimg/www.rx7...d85534e394.jpg
here's a sneak peek....

It's a common issue with precision wastegates. It's why i stopped using them.

When I asked for warranty they said my tune caused harmonics which made them come loose in those exact words.

The new Gen V turbosmart gates are extremely well engineered and qualified to levels beyond an automotive application, I'd recommend that

I use a 50mm JGS wastegate (also made in USA) on my 13b . Tial on my Mustang. Never had a wastegate issue in 20 years (combined) with either. Never knew of this set screw issue, I will stay away from Precision gates from here on out...

You made that manifold?

https://cimg6.ibsrv.net/gimg/www.rx7...fc09bdcb55.jpg
Yes I did! My first turbo manifold.

I want to make a similar one!