Adjusting wastegate arm on GSXR modified pressure actuator
 

I modified the wastegate actuator in my 92 300D OM602.962late last year. Sure enough after getting the car running better than it ever had the head gasket gave up on my in front of cylinder #1.

Now that i have the turbo on my bench i was wondering what is the way to adjust the linkage with the pressure actuator. Should there be pressure from the actuator holding the wastegate in the closed position? If there is pressure holding the wastegate closed it takes a few psi (testing by mityvac) due to the play in the arm hole until the gate opens.

Will there be exhuast pressure trying to push past the gate or will the exhaust pressure hold it closed?

I previously had the arm adjusted to 107mm and saw a high of 14psi at the manifold. I figured while i have it sitting here open i might as well get it done right. I also plan on moving the pressure line from the manifold port to the turbo body.

thanks,
todd

https://lh4.googleusercontent.com/_o...4/IMG_0769.JPG

https://lh3.googleusercontent.com/_o...4/IMG_0766.JPG

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Nice pictures. This is a pressure activated wastegate controller. It will allow boost till 14 PSI then it opens. If you lengthen the rod length it will open earlier than 14 PSI.

It should normally be closed. It will open when the pressure acts on the actuator. You'd want to apply pressure not vac to the actuator.

See this link to see how to hook it up for the short line to actuate:
http://www.peachparts.com/shopforum/showpost.php?p=1761755&postcount=8

Heres the links to images from gsrx:
http://www.peachparts.com/shopforum/showpost.php?p=2134931&postcount=137

If i did not have the actuator hooked up at all would the wastegate want to stay open or closed?

When adjusting the actuator arm should the wastegate disc be held tight against the port or slightly loose?

Maybe a better question, I am over-complicating this and just adjust it to 107mm? The blown head gasket may have me second-guessing too much.

It's been my experience (limited though it is) that if you lengthen the rod you do NOT decrease the opening pressure but simply have the wastegate ALWAYS open.

This happened on my car so I sepak from personal experience. After driving around for a week with no turbo I returned the throw to the 107 mm setting and all was well.

I was not able to significantly alter the opening pressure by changing the length of the rod.

Set it at 107 mm. Whether you take the pressure signal from the IP or the turbo body seems to be a personal preference; both seem to work fine.

The wastegate would want to stay open. Exhaust pushing on it would open the bypass. If you connect it to the actuator and remove the pressure line then it would always stay closed. Unregulated boost always on (BAD)

Tight against the port to produce boost. The actuator works at 14PSI.

Yes, it sounds like your over-complicating it. 107mm sounds like a winner. Just check it with the gauge after it's all done and repaired.

I realize your changing your head gasket. How many miles? Please take pictures. (I've got a small oil seap by my # one also). Gona run it till it leaks bad or creates other problems. Still getting good (30+ MPG) and oil consumption isn't outside the norm.

Thanks, that is exactly the information i was looking for.

When my head gasket went it was a spectacular smoke show for about 1/4 mile until i could pull into off the road. I literally stopped traffic behind me in both lanes until the cloud passed.

Here is what i found when pulling the head. Thanks to this board it was exactly what i was expecting:
https://lh5.googleusercontent.com/_o...U/IMG_0667.JPG

https://lh6.googleusercontent.com/_o...M/IMG_0669.JPG

And while it is apart it is a good time to clean out the intake which is coated in a lot of sludge. I have had my 300D for about a year and can't wait to see how it runs with everything cleaned up.
https://lh6.googleusercontent.com/_o...Y/IMG_0628.JPG

Great pictures. Thanks. Since the head is off you are you having any work done on it? Rebuild the injectors? A shop should be able to clean that out or you can do it yourself but it will be a very messy job.

I cleaned the crossover tube myself a few months back, not a job i care to take on myself with the manifold. Much better to trade a case of beer and let someone with a tank do it.

I am having the head gone through by a local reputable shop. With 178,000 miles on the car you can still see the cross hatching in the bore so i figure while it is apart i might as well do it right.

I am holding off on the injectors for now, i figure it is something I can do later if there is a problem.

Oh forgot to mention glow plugs also. They're coming out anyways. Might want to take care of those also.