has anyone ever heard this sound?

John84GN

Nice Monte...
Joined
Aug 18, 2001
I just put an adjustable wastegate on my 84 b/c the boost was in the 18-20 range, and I lengthened the rod about 1/2 inch. I took the car out, and I barely had knock...boost was in the 15-17 range...on the way back ( I only went about 2 miles up the road) I hear a pinging type sound...like metal rattling. no rattle under boost, but at idle, it was noticeable...not loud. Pop the hood and I'm sorry to say, that it sounds like it's coming from the turbo...if I raise the idle, no noise...just at idle.

I'm no expert, but it's probably the impellers, right?...please say no, but I think I'm right:( What, if it is this, could have caused this?!?

No problem with power, and no smoke, and the sad thing is that the turbo is AGAIN about 300 miles old...this is the second one in 2 months!!! I am startin to think bad things about my GN :(

John
 
If a turbo's blade was going to hit the housing then you would hear it...big time...and it would not be consistant....its more a fast "ripping" itself apart sound....

I would drain the oil in it, and if you don't see any metal then you are ok...even if a turbo did rip itself apart on the compressor side you would probably need to rebuild the motor because all that metal would go directly through the motor......

my guess..its a loose bolt, or a washer rattling around somewhere on the motor.....
 
My turbo made a rattling sound after it broke the shaft but if you're getting boost that's not it. Are you changing or at least flushing the oil feed line each time? I'm not completely sure, but if you damaged the turbo, it might rattle at idle and since the shaft rides on a cushion of oil and relies on pressure the rattle could go away as the oil pressure gets higher above idle. If it does have that much play I would think it would smoke.

Pop the wastegate rod off and see if the noise lessens or at least changes. The turbo will still spin but should slow down a lot. If the noise doesn't change then the noise is probably not the turbo.
 
could I have, maybe, loosened something on the compressor side when I removed the wastegate to thread it?!? All I did was take those two bolts off, that hold the wastegate on, and just put them right back in when I threaded it...sound right?

Could this just be a coincidence with the wastegate thing.

So, should I change the oil reguardless, and what if the sound doesn't go away?...All the power is there...like nothing is wrong! Still getting 15-16 lbs of boost :confused:

Thanks, John
 
Is the sound coming from the Turbo? Check your torque convertor bolts - they like to come loose.
 
When I heard that sound on mine it was new turbo time.It got a little worse each day. It did just like your desciption. I would be concerned about injestion of debris if it lets go. I could still boost up just fine.
 
sounds more like you have the gate too loose and the puck is ratling. pull the rod off and make sure you have to pull it out to get it on the puck.... you must have alil tention on it.
 
Hey Red...good call...now that you mention it, all I did was slip it on...no pull necessary...I'll go check it..."film at 11"

Thanks
 
Red...YOU DA MAN!!!... I think that that's got it...I don't hear the noise any more!!!!!:D

Boost is still in the 16-18 range, and now that I know I can't loosen the wastgate any more...is there any other way to lower the boost...I want to be in the 12-14 range until I get a new fuel system (i.e.-fuel pump, adj regulator, filter, and get my guage installed)

Thanks again Red, and me and you should meet sometime, we're only about 3 hrs away from each other, and talk GN's sometime...you talk, and I'll listen!;)
 
pulling the turbo and porting the wastegate hole bigger could help on the boost control.

once you pull the elbo off you can see were the puck hits then just port it out closer to the puck size but leave enough for it to seal.

meet up ...ok grab a snowmobile and come on out..:)

im starting to gather up some hotair stuff ..i just bought another hotair motor but its disasembled but complete (guy put a bb chevy in the car)

and i just found out that a buddy of mine just picked up an 84 gn that he's putting his 10 second sb chevy motor in and supose to have got an extra hotair motor with it so that means he has 2 motors he dont need...;)

i'll be keeping up with that guy and see ifd i can get all the parts he wont need.

im going to attempt to havea track rental at budds creek maryland when the weather gets better for a lot of the buick guys from around here and in maryland so mainly we can all meet up and have some fun to boot.

later....RED
 
Hey, I was gonna say loose puck too! ;)

Anyway, I just want to add my 2 cents about something: since I've blown more stock turbo's than any 3 people put together, I can tell everyone this:

A turbo with a floppy-assed shaft and the turbine blades hitting the housing CAN build boost!

(but--not for very long!)
 
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