Testing a VNT?

[shelbyplaya]

Is there any way to test a VNT to make sure it's working right and that it's not just a solinoid or somthing?

[90vntShadow]

What exactly is it doing, boost wise?

[shelbyplaya]

Quote:

Originally Posted by 90vntShadow What exactly is it doing, boost wise?

nothing.....



i have a 2nd VNT i took off a daytona i parted out a few months agothat i woud like to know if it's still any good or not.

[90vntShadow]

Mine was doing nothing and it was locked up. Here is a simple check to see if it
is locked up before you go cranzy on everything else. Remove the intake boot from the
turbo and see if the turbo still turns. If not if is locked up. As far as the other one goes
it can have some side to side movement on the turbine shaft and should have no
in and out movement. Also check if the actuator moves freely. You can disconnect the
actuator and see if the nozzles are free. If not you can take the exhaust housing off
remove the veins and glass or sand blast the internal parts and reassemble with new
stainless bolts. Center section can be rebuilt with t-25 kit if needed. If you check
side to side play put a little pressure and turn the wheel and make sure it does not
rub. If it rubs at all it is no good, needs new bearings.

[shelbyplaya]

Quote:

Originally Posted by 90vntShadow Mine was doing nothing and it was locked up. Here is a simple check to see if it is locked up before you go cranzy on everything else. Remove the intake boot from the turbo and see if the turbo still turns. If not if is locked up. As far as the other one goes it can have some side to side movement on the turbine shaft and should have no in and out movement. Also check if the actuator moves freely. You can disconnect the actuator and see if the nozzles are free. If not you can take the exhaust housing off remove the veins and glass or sand blast the internal parts and reassemble with new stainless bolts. Center section can be rebuilt with t-25 kit if needed. If you check side to side play put a little pressure and turn the wheel and make sure it does not rub. If it rubs at all it is no good, needs new bearings.

thanks. i think i'm just gonna end up replacing it with a mistu turbo for the time being. the turbo spins free and dosent really have any serious shaft play. i'm gonna see if the actuator is moving free befor i go ahead and change the turbo.

[90vntShadow]

You are going to replace it with a Mitshibishi??? Why not a t-3, or do you already have
the mitsh? I think you will still have to change the manifold. I am pretty sure Mitsh has
its own manifold. Are you getting any boost at all?, or does the guage just stop dead
at 0psi. Your veins might just be stuck closed. Check all your vacuum lines going to
the actuator. I am no Vnt expert, this is my first Vnt car, but it seems hard to get any
vnt help anymore. Let me know what happens, also let me know if you want to seperate with one of those Vnt's. I am doing an experiment with my spare turbo.
I want to adapt a T03 intake housing and impeller to the Vnt center section and exhaust
housing I just need a good vnt turbine shaft.

[shelbyplaya]

Quote:

Originally Posted by 90vntShadow You are going to replace it with a Mitshibishi??? Why not a t-3, or do you already have the mitsh? I think you will still have to change the manifold. I am pretty sure Mitsh has its own manifold. Are you getting any boost at all?, or does the guage just stop dead at 0psi. Your veins might just be stuck closed. Check all your vacuum lines going to the actuator. I am no Vnt expert, this is my first Vnt car, but it seems hard to get any vnt help anymore. Let me know what happens, also let me know if you want to seperate with one of those Vnt's. I am doing an experiment with my spare turbo. I want to adapt a T03 intake housing and impeller to the Vnt center section and exhaust housing I just need a good vnt turbine shaft.

yeah i think i'm gonna replace it with a mistue turbo. i alredy have a LOW milage (50k). i pulled apart one of my core VNT's and i think i found out why they fail!


i'll take some pics and post them in a new thread in a bit.

[90vntShadow]

Heat shield?????

[shelbyplaya]

Quote:

Originally Posted by 90vntShadow Heat shield?????

it has to do with the ring gear rollers that allow the ring gear to move freely.

they rust or get carbon bulid up on them and they stop rolling. i'm gonna try to 'convince'.... and by convince i mean force them into moving once again. gotta break out the hammer and long screw driver




i'll post pics soon, i'm just to presed for time AKA lazy.

[90vntShadow]

I disassembled the exhaust housing, removed those rollers and the ring, glass peened
everything and reassembled. Did a little hand finish on a few nicked blades and other
high spots. I lost one of those rollers and had to make a new one on the lathe. Also
note that most of those parts are stainless, except for the ring, pins and the main body
that holds the blades/veins. The rollers are actually stainless. Check with a magnet, you
will see what I mean. I will post a picture of the inside of my exhaust side before and
after. Later this evening. Note, all three of the bolts holding the blade assembly snapped
off on mine when loosening, I had to drill them all out and replaced them with stainless
bolts.

[shelbyplaya]

Quote:

Originally Posted by 90vntShadow I disassembled the exhaust housing, removed those rollers and the ring, glass peened everything and reassembled. Did a little hand finish on a few nicked blades and other high spots. I lost one of those rollers and had to make a new one on the lathe. Also note that most of those parts are stainless, except for the ring, pins and the main body that holds the blades/veins. The rollers are actually stainless. Check with a magnet, you will see what I mean. I will post a picture of the inside of my exhaust side before and after. Later this evening. Note, all three of the bolts holding the blade assembly snapped off on mine when loosening, I had to drill them all out and replaced them with stainless bolts.

My screws snapped as well. I cant seem to get the insert out of the turbine housing to clean it up. I might rebulid it but the pins the rollers are attached to snapped off the insert so i dont know yet.

i still have the VNT thats in my daytona that i gotta change out for a working T3 or mistue ASAP! NO BOOST SUCKS.

i'll get pics up as soon as i can!

[90vntShadow]

Here are some before and after pics of my exhaust housing.

[shelbyplaya]

OK
soooo here we go compleat with coloured arrows and stuff for everyone who dosent understand what i said befor...










Pink = Ring gear
Green = Pins for rollers
Blue = vain controll arms
Green on the turbo core = pin alingment slots

[90vntShadow]

I agree, also my ring gear was hanging up and dragging on the sides. They should have made the pins out of stainless as well. The pins get rusty and cause the rollers to stick.
Not driving, or storing the car would probably worsen the rust situation. I think you should sell me the exhaust turbine and heatshield and scrap the rest. LOL