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-   -   Bad turbo (https://www.zdriver.com/forums/300zx-z31-performance-technical-227/bad-turbo-32646/)

omniserv 05-18-2011 05:30 PM

Bad turbo
 
Hello,

In another thread I have posted about our NA2T conversion we are doing.

Well today we finally got the engine running and can't seem to get any boost at all.

Here's the deal. The car runs fine but has no more power than it did before we did the conversion. We put a after market pressure gauge on it and found it has tons of vacuum. -20 and only goes to 0 (zero) when the RPM's hit 6500.

We checked the waste gate and it's not open and doesn't move at all while driving ( we put a video cam on it to make sure).

The turbo makes a nice whistle noise as it should when revving it up but we get no boost.

This is a stock intake setup with no leeks.

So our question is how do you tell if you have a bad turbo?

omniserv 05-18-2011 08:29 PM

After doing a search and reading a few other post I thought I'd add some more info.


The gauge I was using is a after market one we took off another turbo car and that gauge showed 8-10 (I assume PSI) when it boost, while it was installed on that strong running car. But on our NA2T conversion car it never shows anything more than zero. Mostly shows vacuum.

Secondly there is no exhaust at all on the car. The turbo elbow containing the waste gate is on there, but nothing else.

We did a few other test,

1. We checked to make sure the waste gate was closed, it was.

2. We purposely wired the waste gate open and test drove it, it seemed to have the same amount of power either way. To us that showed or further confirmed the turbo was the problem.

We just put that turbo in and had played with it a lot beforehand , our problem is we didn't have a known good turbo nor the experience to know if while spinning it by hand it was good or not. This one didn't have much if any end play but maybe a small amount of drag????

Seems like we are in the market for a turbo?? lol

omniserv 05-19-2011 04:41 PM

Guess we'll answer this one ourselves..lol

We indeed have a bad turbo. We took the intake pipe off and could hardly spin the shaft. So it's dead.

We wonder if all the years sitting out side ( although mounted) might have caused the oil ports in side to clog up and not allow oil to get to the bearings? We have no idea. We did crank the engine and make sure oil was pumping from the oil tube and it was.

So the engine is back out of the car again awaiting a new turbo. We did find one for $250 that had just been rebuilt.

Flacster 05-19-2011 11:02 PM

gl with that man. you should get your turbo upgraded and rebuilt for 350 at AZ turbo.

AZ-ZBum 05-20-2011 12:25 AM

*cough*

Originally Posted by AZ-ZBum (Post 295100)
I hope you didn't powdercoat the inside of the compressor housing.


Originally Posted by omniserv (Post 295130)
No we masked it off first.


Originally Posted by omniserv (Post 295135)
I can see why you said that, looking at the pics it looks like I did powder coat the inside. I had a cap in it but some of the over spray leaked in around it. There's not enough powder in there to cause a problem.

*cough*

Sucks man. Never fun to pull the turbo.

omniserv 05-21-2011 09:46 AM


Originally Posted by Flacster (Post 295642)
gl with that man. you should get your turbo upgraded and rebuilt for 350 at AZ turbo.


The turbos we have probably would not be good candidates for a rebuild. The shafts and turbine blades would probably have to be replaced. After talking to AZ turbo the cost would be much higher than $350.




Originally Posted by AZ-ZBum (Post 295647)
*cough**cough*

Sucks man. Never fun to pull the turbo.

Yea I know you keep bringing up the powder coating, if you could see the inside of it you'd see we completely taped off the casting. This turbo went bad before it even got very hot, the red powder that did get a inch or so inside did not burn off.

When we put the turbo in we were questioning if it was good. Mostly because you could feel something funny (sort of a drag).

We tried to get the turbo out without pulling the engine and it simply was not possible. So since we just put it in and everything was fresh in our minds we just pulled it out again.

Besides one of the reasons we are doing this upgrade is so our 16 YO son can get some experience doing stuff like this his self. the school he attends doesn't offer a auto shop class. He is learning a lot...lol he will be driving this car to school next year and our hope is he'll take much better care of it knowing how much work it takes to work on it. Plus he's a unbelievably good kid. he already treats this car like he should

AZ-ZBum 05-21-2011 04:44 PM

So what you're saying is that you didn't check the turbo for play before you slapped it on the motor? You say the powder coat is only an inch in. An inch in where? Is it on the area the blades sit? That's what it looked like to me. Which would be the reason it doesn't spin if that's true.

omniserv 05-21-2011 06:16 PM


Originally Posted by AZ-ZBum (Post 295712)
So what you're saying is that you didn't check the turbo for play before you slapped it on the motor? You say the powder coat is only an inch in. An inch in where? Is it on the area the blades sit? That's what it looked like to me. Which would be the reason it doesn't spin if that's true.


No the powder did not get in where the blades were. There's was not much if any end play.

This turbo came off a car that had a engine fire and was sitting for a many years. When I first got the turbo it was locked up. The intake blades we corroded to the housing. We managed to free it with PB blaster over a extended amount of time. Working the blades free took some time. But it seemed all was good.

Our thinking is that the oil passages were also corroded full and no oil was getting to the bearings or the bearings were rusted from years of sitting??? Who knows for sure. We tried to save the cost of buying another turbo and it didn't work. The only thing it cost us is time removing the motor. Plus as I've said before the experience our son is getting from all this work is priceless.


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