IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: gordyzx9r on March 10 2015, 10:23:34 PM
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So, I need to put the turbo back on now that I have it back from PTE. Taking it off was easy. I have a feeling putting it back on won't be as easy.
So, now what?
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Get some Anti-Seeze for all the bolts.
And do the downpipe last.
I'd also flatten the exhaust flange and toss the copper gasket.
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I find it easiest to bolt up the return line first
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and using studs on the return line instead of bolts makes it easier yet.
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The above three posters pretty well covered it!
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Looks like your missing one of the studs for the exhaust housing to mount to the header. Unless it's still in the exhaust housing, you'll need one more
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One other trick with the return line...
set the turbo in place and try to start the bolts. You'll notice the return line needs to be moved one way or the other to line up...
remove the turbo and tweak the line a little. What you're shooting for is for the return line to be lined up with the turbo while it's in it's happy place. That way you only need two hands to start the bolts.
Also, make sure the flange is flat. It's very easy to bend, and fortunately very easy to bend back. a couple pair of small vice grips with dull jaws make easy work out of it. I like to leave a slight convex surface to it that way the bolts get to pull it down.
A thin smear of RTV on the flange, both sides of the gasket and the housing will fend off any leaks. Let the RTV 'skin over' almost to the point of being dry, then lock it down (just like on headers, only with a gasket)
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Going to try to get this done tonight or tomorrow...fro m everything I hear, the return line is the hardest part.
Looks like your missing one of the studs for the exhaust housing to mount to the header. Unless it's still in the exhaust housing, you'll need one more
The pic with the two studs and three nuts are the original. PTE sent me three new studs (but no nuts).
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And the studs bring me to another question.
What size nuts are those? I'm going to buy new ones for the install because these three old ones don't go onto the new studs very easily and if I remember right I have to use two nuts friction locked together to install them.
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I think they are to be a distorted thread lock nut which makes them a challenge some times.
Elliptical offset nuts is a catch-all category that encompasses designs known as oval locknut or non-slotted hex locknuts,. The salient feature is that the threadform has been deformed at one end so that the threads are no longer perfectly circular. The deformed end is usually shaped into an ellipse or obround (http://en.wiktionary.org/wiki/obround) triangle. These are known as one-way nuts as the nut may be easily started on the male fastener from the bottom non-deformed portion, but are practically impossible to start from the deformed end. As the male fastener reaches the deformed section it stretches the threads of the nut elastically (http://en.wikipedia.org/wiki/Elastic_deformation) back into a circle. This action increases the friction between the nut and the fastener greatly and creates the locking action. Due to the elastic nature of the deformation the nuts can be reused indefinitely.
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they are....
I always ask Ed what size they are...:D
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Return line, easy...matched right up.
The exhaust was easy...matched right up.
Putting the 4 bolts thru the DP and mother fucker...
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That's another spot studs work well.
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Damn the luck!
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Looks like there's enough bolt sticking up to bite down on it with a GOOD set of sharp Vice-Grips.
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washer. weld. nut. weld. extract.
Basically this: https://www.youtube.com/watch?v=aRrz-cphBY4 (https://www.youtube.com/watch?v=aRrz-cphBY4)
But using the washer first gives you more surface area to weld against, especially when you weld the outside of the nut to the washer face, and then the stud to the inside of the nut.
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washer. weld. nut. weld. extract.
Basically this: https://www.youtube.com/watch?v=aRrz-cphBY4 (https://www.youtube.com/watch?v=aRrz-cphBY4)
But using the washer first gives you more surface area to weld against, especially when you weld the outside of the nut to the washer face, and then the stud to the inside of the nut.
And that is exactly how I had it taken off this morning...
Got everything on without a hiccup the second time around. Hit the pre-luber then started her up. Only got to idle her a bit before the rain clouds started rolling in so I didn't get a chance to take it out but there are no oil leaks (yet).
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Whooo Hoooo glad you got it on.
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washer. weld. nut. weld. extract.
Basically this: https://www.youtube.com/watch?v=aRrz-cphBY4 (https://www.youtube.com/watch?v=aRrz-cphBY4)
But using the washer first gives you more surface area to weld against, especially when you weld the outside of the nut to the washer face, and then the stud to the inside of the nut.
And that is exactly how I had it taken off this morning...
Got everything on without a hiccup the second time around. Hit the pre-luber then started her up. Only got to idle her a bit before the rain clouds started rolling in so I didn't get a chance to take it out but there are no oil leaks (yet).
Nice.
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Return line, easy...matched right up.
The exhaust was easy...matched right up.
Putting the 4 bolts thru the DP and mother fucker...
At least it is nice and clean. I broke several of those off when I did the last headgasket. I thought it a good time to apply neversieze to the bolts. I have another ported housing I wanted to swap, and thought it would be easier if there was neversieze on the fasteners.
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I guess while we are on this topic, is there anything special about these bolts (since they see such high heat cycles)? Does everyone just use a 10.9 bolt or ??? I'm getting ready to put my new turbo on, and I think the old bolts are looking pretty brittle and crusty.
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Hey Gavin,
Why not just install new studs in the exh hsg, that way you will only have to remove the nuts.......
Of course Stainless would be the preferred hardware of choice.....sti ll should use some sort of hi temp never seize
Believe this will take care of the issue at hand.
Dave
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What grade of stainless bolt? I'd be concerned about getting the right torque (tension actually) with stainless.
I'm OK with studs too, but I think I still have the same question, what grade, what torque?
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Torque really isn't all that important in that area. It' not like you're deflecting anything with clamping force. All you're doing is clamping the two flanges tight enough so that the thin layer of RTV can do it's job.
It's way more important to use anti-seeze on exhaust bolts, ESP anything touching the hot side of a turbo.
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I always make a stop at my favorite exhaust shop here in town with some coffees for the boys...and they set me up with the proper exhaust studs and nuts. :rock:
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Torque really isn't all that important in that area. It' not like you're deflecting anything with clamping force. All you're doing is clamping the two flanges tight enough so that the thing layer of RTV can do it's job.
It's way more important to use anti-seeze on exhaust bolts, ESP anything touching the hot side of a turbo.
I want to re-state my concern and reasoning.
A stainless bolt (of a reasonable grade) is nominally harder than a standard (say grade 5-8) steel bolt, but the tensile strength is not higher. That means higher set torque to get the right bolt stretch to maintain torque (not loosen), so you decrease your safety margin to yeilding the bolt. Over torque is just as bad, if not worse, than not enough torque. Given the thermal expansion I would say materials, grades, and fastening torque are pretty important... and will lead to keeping your flat surfaces flat.
That's the theory anyhow, I'm looking for proven methods... to which it sounds like there are no torque values or fastener strengths considered. If so, you're right earl, its not sensative enough to care.
I'm laying out my thought process, because that seems odd to me since I remember my old stock elbow wouldnt seal for crap after I took it off the first time and I didnt consider anything regarding the torque setting or bolt grade back then either.
FWIW... I just thought of another good point: thermal expansion. I dont know how much difference there is in expansion of steel vs stainless, but... since the flange is not cast iron like the factory elbow, maybe the bolts SHOULD be stainless since they will expand at the same rate as the DP flange and tension in the joint would remain pretty close? (also agrees with your logic earl)
Good talk, thanks.
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I always like the science behind how things work.
In this case, the SWAG factor is just too great. A couple 10,000ths here and there from varying thermal expansion rates really aren't going to matter. The fasteners and flanges are just too small for anything to stack up enough to be catastrophic.
In my case, I tighten the bolts down until I think the hex wrench is on he verge of distorting the fastener. That's my personal 'THDP torque sequence'. Same bolts since I installed it the first time in '98.