2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Turbo feed line blows for the second time

Thread Tools
 
Search this Thread
 
Old 09-21-08, 11:56 PM
  #1  
Partout Performance

Thread Starter
iTrader: (24)
 
FRFC3S's Avatar
 
Join Date: Mar 2007
Location: .
Posts: 1,202
Likes: 0
Received 0 Likes on 0 Posts
Turbo feed line blows for the second time

Hello everyone. Recently the oil feed line that goes to the top of the turbo blew on me. It consists of a flange and than a small bent piece of piping with a threaded end. I replaced the part with a dealership bought part, it was like 50 bucks. Now the new one has failed on me after roughly 3,000 miles.

It always fails around the weld on the flange. What can be causing this? Are these prone to this? Is there an aftermarket replacement (i.e. a flange and -an fittings) that could stop me from buying these parts?

Thank you to all who reply. Please help me out.
Old 09-22-08, 01:28 AM
  #2  
PWNIN
 
Lewk_FCRX7's Avatar
 
Join Date: Jan 2008
Location: Melbourne, Australia
Posts: 91
Likes: 0
Received 1 Like on 1 Post
Hey mate,

Your feed line is obviously failing due to some restriction resulting in a pressure increase on the feed side. I would remove the drain line and inspect for a blockage and also look into the port on the underside of the turbo where the oil drains from. I coudn't think of anything else that could be causing it sorry... anyone else?

A blockage in this line may also be restricting the flow of oil through the T/C bearing, so the turbo might not be getting the normal ammount of heat taken away by the L.O - possibly resulting in increased sleeve/shaft wear.

I hope this helps in some way m8!

Cheers,
- Luke
Old 09-22-08, 04:49 PM
  #3  
Partout Performance

Thread Starter
iTrader: (24)
 
FRFC3S's Avatar
 
Join Date: Mar 2007
Location: .
Posts: 1,202
Likes: 0
Received 0 Likes on 0 Posts
What size flange/an fittings should I use to replace just that part? Does anybody know the thread pitch of the end of that piece so I don't have to run a line all the way to the iron?
Old 09-22-08, 05:21 PM
  #4  
not a drifter

iTrader: (133)
 
87 t-66's Avatar
 
Join Date: Jun 2004
Location: Columbus, Ohio
Posts: 9,337
Received 5 Likes on 5 Posts
Originally Posted by FRFC3S
What size flange/an fittings should I use to replace just that part? Does anybody know the thread pitch of the end of that piece so I don't have to run a line all the way to the iron?
i took the stock flange, cut off the line and welded a -4 fitting to it. i think you will have a hard time finding a metric fitting for that piece. i couldn't find one.
Old 09-22-08, 07:04 PM
  #5  
Adaptronic Distributor
RX7Club Vendor
iTrader: (12)
 
Turblown's Avatar
 
Join Date: Dec 2001
Location: Twin Cities, MN
Posts: 7,066
Received 91 Likes on 77 Posts
If you are pre-stressing the hardline it will fail at the silver solder joints. What I mean is if you have to force it into position before bolting it down thats a big no-no.

No restriction will cause that failure, not enough pressure for that too happen.
You don't want to run a SS braided hose to the turbo, there is a reason the factory doesn't do this. There is just too much heat near the turbine housing. You should hardline out several inches then use SS braided for flex and vibration. I can make one for you if you like, going to be a few more bucks than the oem unit however..
Old 09-22-08, 07:06 PM
  #6  
rotors excite me

iTrader: (16)
 
SpeedOfLife's Avatar
 
Join Date: Jun 2006
Location: Central Iowa
Posts: 4,083
Likes: 0
Received 9 Likes on 6 Posts
Originally Posted by Lewk_FCRX7
Your feed line is obviously failing due to some restriction resulting in a pressure increase on the feed side. I would remove the drain line and inspect for a blockage and also look into the port on the underside of the turbo where the oil drains from. I coudn't think of anything else that could be causing it sorry... anyone else?
I doubt this is due to a blockage issue. I've had this EXACT problem before, and it was when my turbo kept coming unbolted from the manifold. Vibration of the turbo puts a bunch of stress on that lower weld of the hard line and cracks it. I tried a new hard line, too, and it broke quickly, even when I would check to make sure my turbo was bolted down frequently. It simply didn't take much to break it, so working on the assumption that, even if I manage to lock the turbo down, it could still come loose at some point I built a custom flexible feed line. It works great. My machinist also mentioned to me that most turbochargers don't need a ton of oil so even though the feed line has a smaller diameter than the stock pipe it will run just fine and it has for probably 1000 miles or so (I just haven't put many miles on it since I fixed that line).

I'll get a pic for you before too long.
Old 09-22-08, 07:11 PM
  #7  
Adaptronic Distributor
RX7Club Vendor
iTrader: (12)
 
Turblown's Avatar
 
Join Date: Dec 2001
Location: Twin Cities, MN
Posts: 7,066
Received 91 Likes on 77 Posts
Thats a very good guess at what the real problem is. You can get the stock hardlines much cheaper used on the forums. Generally $15 a pop...
Old 09-22-08, 07:43 PM
  #8  
rotors excite me

iTrader: (16)
 
SpeedOfLife's Avatar
 
Join Date: Jun 2006
Location: Central Iowa
Posts: 4,083
Likes: 0
Received 9 Likes on 6 Posts
I'm sure pre-stressing it can be at the very least a contributing factor, too. I did consider that though when I first had the issue, and the thing is that there's always been stress on that line, for my car at least. The line never broke though until the turbo started blowing exhaust gaskets and rattled loose. Point is, a well built flex line ought to fix your problem. I used the old flange and male end and tapped threads to attach flex line.
Old 09-22-08, 10:16 PM
  #9  
Lives on the Forum

 
RETed's Avatar
 
Join Date: Feb 2001
Location: n
Posts: 26,664
Likes: 0
Received 16 Likes on 15 Posts
Originally Posted by FRFC3S
It always fails around the weld on the flange. What can be causing this?
You're doing something wrong.


Are these prone to this?
No, not with the stock turbo in the stock location.


-Ted
Old 09-22-08, 11:39 PM
  #10  
Partout Performance

Thread Starter
iTrader: (24)
 
FRFC3S's Avatar
 
Join Date: Mar 2007
Location: .
Posts: 1,202
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by RETed
You're doing something wrong.



No, not with the stock turbo in the stock location.


-Ted
I did not have the bend the part into place. It bolted right up and tightened right up.

It is the stock turbo in the stock location.
Old 09-24-08, 03:02 PM
  #11  
Partout Performance

Thread Starter
iTrader: (24)
 
FRFC3S's Avatar
 
Join Date: Mar 2007
Location: .
Posts: 1,202
Likes: 0
Received 0 Likes on 0 Posts
Is it correct that our oil intlet/outlet flanges are the equivalent of a T3 turbo's oil line flange? Can I just buy a universal T3 braided oil line kit?

Also, what is the thread size of the part where the oil line goes into the block? I saw it somewhere and I'm going to search for it now...
Old 09-24-08, 08:38 PM
  #12  
10 lb. boost, 5lb. bag

iTrader: (1)
 
Gene's Avatar
 
Join Date: Mar 2001
Location: New York, NY
Posts: 1,075
Likes: 0
Received 2 Likes on 2 Posts
Same thing just happened to me. Mine broke at hyperfest last year and caused a nice smoke condition from the oil on the hot exhaust parts. It was just a tiny crack so it was oozing, not spraying. I found a welder and someone who felt brave enough to weld on that tiny line and got it fixed up so I could complete the event. When I got home I ordered two, put one on the car and kept the other as a spare, along with my welded one.

Fast forward to this week, I noticed some oil under my car, and upon inspection, the new one is leaking. Keep in mind that I don't drive much, that part has 6-8 track days on it and maybe 5000 miles.

My own opinion as an amateur engineer is that the part is badly designed. It's very small and fragile at the connection. It's subject to pretty significant thermal and vibration stresses, and it's rigid, which puts it at risk. A more flexible connection would be far less likely to fail.

I think I'm going to put my welded one back on, it's got a huge pile of weld on it and seems pretty sturdy. Over the winter I think I'm going to fab up a flex line to run from the motor to the little hard pipe, that way I'll get flexibility but keep the hard line near the turbo so the flex part is protected from heat.
Old 09-25-08, 01:16 AM
  #13  
AAAAAAAAYYYYYY!!!

 
Tigerx7's Avatar
 
Join Date: Aug 2008
Location: IN/IL somewhere
Posts: 78
Likes: 0
Received 0 Likes on 0 Posts
does anyone know the size of that fitting that connects the two hard pipes? went to a shop to get the parts to make a SS line and they had no clue what it was, and didn't have anything that fit.
Old 09-25-08, 05:40 AM
  #14  
Lives on the Forum

 
RETed's Avatar
 
Join Date: Feb 2001
Location: n
Posts: 26,664
Likes: 0
Received 16 Likes on 15 Posts
Originally Posted by Gene
My own opinion as an amateur engineer is that the part is badly designed. It's very small and fragile at the connection. It's subject to pretty significant thermal and vibration stresses, and it's rigid, which puts it at risk. A more flexible connection would be far less likely to fail.
I've bent those pipes numerous times with no failures.
I've picked up turbos by those pipes and bent them and had to bend them back with no failures.

There is very little flex or vibration at that point cause everything is supposed to be hard mounted - the engine and the turbo.


-Ted
Old 09-25-08, 08:34 AM
  #15  
10 lb. boost, 5lb. bag

iTrader: (1)
 
Gene's Avatar
 
Join Date: Mar 2001
Location: New York, NY
Posts: 1,075
Likes: 0
Received 2 Likes on 2 Posts
It's hard mounted, but parts expand and contract when they heat and cool. A one time bending of the part won't kill it, but fatigue stress adds up over time and it eventually gives up. That or they had a defective batch or two and some of us got unlucky. I didn't do anything weird to it when I installed the new one, it bolted right up without having to force anything into place.
Old 09-25-08, 11:46 AM
  #16  
Lives on the Forum

 
RETed's Avatar
 
Join Date: Feb 2001
Location: n
Posts: 26,664
Likes: 0
Received 16 Likes on 15 Posts
True, but I believe the pieces are brazed?
A proper brazed joint should be able to handle the heat / cooling expansion / contraction no problem.

Oh, and I'm not talking about about a one-time bend.
Once these things bend, they are a pain to bend into place.
It does take several tries to ge them to line up on the engine.
I've removed / reinstalled the same turbo several times on engines with still zero failures.

Maybe I'm lucky?


-Ted
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Kyo
2nd Generation Specific (1986-1992)
3
08-14-15 02:00 PM



Quick Reply: Turbo feed line blows for the second time



All times are GMT -5. The time now is 08:18 PM.