Go Back   Rotary Car Club > Tech Discussion > RX-7 2nd Gen Specific (1986-92)

RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections.

Reply
 
Thread Tools Display Modes
Old 09-22-2013, 05:05 PM   #16
Pete_89T2
Lifetime Rotorhead
 
Pete_89T2's Avatar
 
Join Date: Apr 2010
Location: Elkton, MD
iTrader: (1)
Posts: 874
Rep Power: 15
Pete_89T2 is on a distinguished road
Default

An update... This past Friday, I took the car to Speed1 to have Dave B. take a look and give me a professional assessment of what is going on. Bottom line is the turbo is starting to fail, and it will get progressively worse. Ted nailed it with the failing turbine seal diagnosis.

While I'm happy that the engine itself is healthy, and won't need to be cracked open for a long time, I'm pissed that this turbo is failing prematurely. Like I said before, it's a BNR stage 1 rebuild, that I installed & fired up for the first time on 3/11/2011, and logged only 11,889 miles on it since then as of last Friday. And since I'm running stock boost control, it was never pushed beyond the stock 8~8.5 PSI boost pressure limits. Hell, the stock turbo had 136,XXX miles on it when I shipped it off to BNR for the rebuild, and it didn't smoke anywhere near as bad as this one does now.






Pete_89T2 is offline   Reply With Quote
Old 09-22-2013, 06:19 PM   #17
Rotary Evolution
rotaryevolution.net
 
Rotary Evolution's Avatar
 
Join Date: Feb 2011
Location: Las Vegas, NV
iTrader: (0)
Posts: 248
Rep Power: 14
Rotary Evolution is on a distinguished road
Default

just mark the wheels and rebuild it yourself, you can do it for under a hundred bucks.
__________________
http://rotaryevolution.net
Rotary Evolution is offline   Reply With Quote
Old 09-22-2013, 11:48 PM   #18
RETed
RCC Addict
 
Join Date: Mar 2008
Location: Honolulu, Hawaii USA
iTrader: (1)
Posts: 1,813
Rep Power: 18
RETed will become famous soon enough
Default

If you ever messed with that darned turbine compression ring seal, you'll know that it's a nasty design.
Out of all the nice Garrett (rebuild) parts, it's one of the worst - the thrust bearing come a close second.

I dunno if there is a trick to get that compression ring seal to install correctly consistently, but I haven't figured it out yet.
You got the blasted exhaust shield bell cup loose and getting in the way, and the design of the seal being square-edged don't help with it going in nicely!
If you end up tapping it in - which is the case most times - it's probably damaged from that light tapping.
I use LOTS of oil to try and get the seal to snap into place, and that causes a big smoke show on the initial start up...
This can help sometimes, but it's still not a guarantee!
Then you end up crossing your fingers that the smoke eventually clears up soon!


-Ted
__________________
reted_2000@yahoo.com
Technical Advisor
FC3S Pro
http://fc3spro.com/



Quote:
Originally Posted by TitaniumTT View Post
because you're only as good as your backup
RETed is offline   Reply With Quote
Old 09-23-2013, 12:49 AM   #19
don3vor
The Newbie
 
don3vor's Avatar
 
Join Date: Sep 2013
Location: elkton,md
iTrader: (0)
Posts: 18
Rep Power: 0
don3vor is on a distinguished road
Default

Pete, what kind of warranty came with the turbo if any?
don3vor is offline   Reply With Quote
Old 09-23-2013, 04:45 AM   #20
Pete_89T2
Lifetime Rotorhead
 
Pete_89T2's Avatar
 
Join Date: Apr 2010
Location: Elkton, MD
iTrader: (1)
Posts: 874
Rep Power: 15
Pete_89T2 is on a distinguished road
Default

Quote:
Originally Posted by don3vor View Post
Pete, what kind of warranty came with the turbo if any?
It was a 1 year warrantee, don't recall if there was a mileage # associated with that. Given the premature failure, I'm going to see if BNR is willing to cover at least a portion of my costs for a turbo repair. I'll be pulling it out & reinstalling it myself, so no costs there.
Pete_89T2 is offline   Reply With Quote
Old 09-23-2013, 07:05 AM   #21
Pete_89T2
Lifetime Rotorhead
 
Pete_89T2's Avatar
 
Join Date: Apr 2010
Location: Elkton, MD
iTrader: (1)
Posts: 874
Rep Power: 15
Pete_89T2 is on a distinguished road
Default

Quote:
Originally Posted by Rotary Evolution View Post
just mark the wheels and rebuild it yourself, you can do it for under a hundred bucks.
I've given a DIY rebuild some serious thought, and if BNR tells me to go screw myself, I just might give it a try.

Quote:
Originally Posted by RETed View Post
If you ever messed with that darned turbine compression ring seal, you'll know that it's a nasty design.
Out of all the nice Garrett (rebuild) parts, it's one of the worst - the thrust bearing come a close second.

I dunno if there is a trick to get that compression ring seal to install correctly consistently, but I haven't figured it out yet.
You got the blasted exhaust shield bell cup loose and getting in the way, and the design of the seal being square-edged don't help with it going in nicely!
If you end up tapping it in - which is the case most times - it's probably damaged from that light tapping.
I use LOTS of oil to try and get the seal to snap into place, and that causes a big smoke show on the initial start up...
This can help sometimes, but it's still not a guarantee!
Then you end up crossing your fingers that the smoke eventually clears up soon!


-Ted
And this is exactly the kind of stuff that worries me about trying to rebuild it myself... Good info here Ted, I've done some web surfing and watched maybe a half dozen "how to rebuild your turbo" vids on Youtube, and naturally none of them covered these "gotcha's".
Pete_89T2 is offline   Reply With Quote
Old 09-23-2013, 09:55 AM   #22
Rotary Evolution
rotaryevolution.net
 
Rotary Evolution's Avatar
 
Join Date: Feb 2011
Location: Las Vegas, NV
iTrader: (0)
Posts: 248
Rep Power: 14
Rotary Evolution is on a distinguished road
Default

it helps if you orient the gap facing the topside of the CHRA, gravity you know. while i also bead blast the turbine wheel i do not touch the shaft, i let it soak in a carb cleaning bucket for a day then scrub it by hand. and sometimes you just get junk seals.
__________________
http://rotaryevolution.net

Last edited by Rotary Evolution; 09-23-2013 at 09:57 AM..
Rotary Evolution is offline   Reply With Quote
Old 09-24-2013, 07:43 AM   #23
Pete_89T2
Lifetime Rotorhead
 
Pete_89T2's Avatar
 
Join Date: Apr 2010
Location: Elkton, MD
iTrader: (1)
Posts: 874
Rep Power: 15
Pete_89T2 is on a distinguished road
Default

In the event that BNR doesn't assist with my turbo rebuild, can anyone recommend a good parts source for a full turbo rebuild? My understanding is that my BNR stage 1 turbo I need to rebuild can use a rebuild kit made for the stock Mazda S5 turbo, which is a Hitachi HT-18. The HT-18 uses Garrett rebuild parts in the CHRA. Found this kit on the net:

http://gpopshop.com/products-page/hi...e-rebuild-kit/

Can anyone confirm that these are the correct parts for a rebuild, and if so, would it be advisable to pay extra for the 360* thrust bearing/step-gap piston option?
Pete_89T2 is offline   Reply With Quote
Old 09-24-2013, 09:42 PM   #24
RETed
RCC Addict
 
Join Date: Mar 2008
Location: Honolulu, Hawaii USA
iTrader: (1)
Posts: 1,813
Rep Power: 18
RETed will become famous soon enough
Default

The Hitachi series turbos can use Garrett T3 / T4 internals.
You should be able to find rebuild kits for "Garrett T3 / T4" turbos no problem.

Be very careful when ordering that carbon seal.
I've had rebuild kits where the carbon seal was loose banging around with all the other parts.
This causes the carbon seal itself to chip and end up basically useless.
Good vendors would carefully package the carbon seal separately.

The 360-degree thrust bearing would be used for higher boost.
I would not bother with it unless you're shooting for over 10 - 15psi of boost on a consistent basis.
Also, having a good (i.e. brand name aftermarket) BOV helps here.

The stepped piston ring is recommended if the price isn't that much more than the regular one.
I've had those things leak before, so they are not that much better than the regular butt joint ones.


-Ted
__________________
reted_2000@yahoo.com
Technical Advisor
FC3S Pro
http://fc3spro.com/



Quote:
Originally Posted by TitaniumTT View Post
because you're only as good as your backup
RETed is offline   Reply With Quote
Old 11-25-2013, 02:35 PM   #25
Pete_89T2
Lifetime Rotorhead
 
Pete_89T2's Avatar
 
Join Date: Apr 2010
Location: Elkton, MD
iTrader: (1)
Posts: 874
Rep Power: 15
Pete_89T2 is on a distinguished road
Default

Hey guys, after lots of back & forth emails with Bryan at BNR, I was offered a deal to consider for rebuilding my BNR Stage 1 turbo. My other option is a DIY rebuild. Below is a description of each option, and the pros & cons of each one from my perspective. Would like to hear the forum's thoughts on which option makes the most sense, and let me know if I'm missing anything here:

BNR Rebuild #2 option: BNR is offering me a discount on the 2nd rebuild for my BNR Stage 1 turbo. It will cost me $300 plus shipping, but will include a new CHRA housing and a new turbine wheel/shaft in addition to all the new rebuild components (seals, thrust bearing, journal bearings, etc.) that come with a Stage 1 rebuild. According to Bryan, he doesn't want to reuse my used turbine wheel/shaft and CHRA housing because (a) New parts result in a better rebuild and (b) cost of new parts is comparable to the cost of labor to dissemble/clean/inspect used parts, and that the cleaning (media blasting) process can sometimes render parts unusable

Pros - Comes with new turbine wheel/shaft & CHRA housing. BNR does the balancing, and this a simple remove & replace turbo job for me. Probably a faster turn-around. Total cost isn't much more expensive than a DIY rebuild, assuming I farm out the balancing job to a local turbo shop.

Cons - BNR is not willing to offer a new warranty, and BNR would not tell me the exact source of the new turbine wheel/shaft & CHRA housing - other than stating he is using an offshore manufacturer. I'm a bit concerned that offshore may mean China made parts of questionable quality.

DIY Rebuild option: As implied, I would do the rebuild myself. Never rebuilt a turbo before, but have done a lot of research on the process and feel confident that I can tackle this. I found a relatively local turbo shop in Wilmington DE that works mainly on diesel turbos that can balance my rebuilt rotating assembly for $100. As for rebuild parts, a "high performance" complete kit for the HT-18 (i.e., w/improved turbine seal plus 360* thrust bearing) costs <$120 from a number of online sources. Will go with G-Pop shop as they have comprehensive customer support and I confirmed that they pack the delicate parts correctly for shipping.

Pros - Costs a less than BNR option. Since it's DIY, I'll learn from doing it, and I'll know it was done right and if it isn't, I only have myself to blame. Well not 100% true, as I'll farm out the balancing task.

Cons - Extra time to perform the rebuild and schedule the balancing job. Potential "gotcha's" if I find out after cleaning & inspection that any of the parts I need to reuse are out of tolerance/specification for reuse. As I've had no luck finding a reputable source that sells new HT-18 turbine wheels/shafts this can become a big problem. And if I do need new parts, assuming I can find them, the additional cost is an unknown.
Pete_89T2 is offline   Reply With Quote
Old 11-25-2013, 03:30 PM   #26
RETed
RCC Addict
 
Join Date: Mar 2008
Location: Honolulu, Hawaii USA
iTrader: (1)
Posts: 1,813
Rep Power: 18
RETed will become famous soon enough
Default

Why don't you try DIY rebuild yourself and see what happens?
It sounds like you're interested in the whole process, and you learn a LOT from doing it yourself.

As a fall-back, you can always go BNR if the DIY fails?
$300 is cheap, considering that $100 is going to the rebuild kit itself.
Even a cheapie CHRA is going to be at least $100, so the last $100 is BNR's labor?
That's a great deal...

As for sourcing of parts...
I would worry a little about China, but I would not be surprised...
My Garrett GT-R ball-bearing series turbos all had stickers: "MADE IN MEXICO".
I was kinda pissed my ~$1,500 turbos were MADE IN MEXICO, but what can you do, right?
I know there's a lot of turbo parts coming out of South America (Brazil?) also.
As a side, I think Brembo also has a factory for in South America?

Although not BRAND NEW, there are lots of used HT-18's out there.
It might cost you maybe $100 for one, but the RA's should be in good shape, or at least be minimum rebuildable.


-Ted
__________________
reted_2000@yahoo.com
Technical Advisor
FC3S Pro
http://fc3spro.com/



Quote:
Originally Posted by TitaniumTT View Post
because you're only as good as your backup
RETed is offline   Reply With Quote
Old 11-25-2013, 06:28 PM   #27
Pete_89T2
Lifetime Rotorhead
 
Pete_89T2's Avatar
 
Join Date: Apr 2010
Location: Elkton, MD
iTrader: (1)
Posts: 874
Rep Power: 15
Pete_89T2 is on a distinguished road
Default

Quote:
Originally Posted by RETed View Post
Why don't you try DIY rebuild yourself and see what happens?
It sounds like you're interested in the whole process, and you learn a LOT from doing it yourself.
It would be a great learning project, and even if I end up not rebuilding my own turbo, I might just pick up a boneyard turbo off of any car/truck to practice on. Tear down, clean/inspect & reassemble with the same old & worn parts just for practice. Sort of like a doctor practicing surgery on cadavers!

Quote:
Originally Posted by RETed View Post
As a fall-back, you can always go BNR if the DIY fails?
$300 is cheap, considering that $100 is going to the rebuild kit itself.
Even a cheapie CHRA is going to be at least $100, so the last $100 is BNR's labor?
That's a great deal...
I haven't asked BNR that question yet, but I don't think he would honor that deal if I DIY'ed it myself first and it failed. $300 is a great deal, and I think he's doing it at that price to stand behind his work and maintain a good reputation. He's basically giving me all the new parts/rebuild kit at his cost, and the rest is labor/profit. Price he gave me on the turbine wheel/shaft was $100, and $65 on the CHRA housing, so the $135 left over covers the rebuild parts & labor. BNR can probably get his rebuild kits for maybe $40~50 each in quantity, as opposed to the $100 I would have to pay retail. The compressor wheel I have in there is practically brand new (<12K miles on it). So by using the new parts, he saves himself a big chunk of his cleaning & inspection labor that he would have incurred to reuse the old turbine wheel/shaft & CHRA housing. That's with the standard rebuild kit though (270* thrust bearing, standard turbine seals); if I opt for the high performance versions it would cost me $40~50 more.

Quote:
Originally Posted by RETed View Post
As for sourcing of parts...
I would worry a little about China, but I would not be surprised...
My Garrett GT-R ball-bearing series turbos all had stickers: "MADE IN MEXICO".
I was kinda pissed my ~$1,500 turbos were MADE IN MEXICO, but what can you do, right?
I know there's a lot of turbo parts coming out of South America (Brazil?) also.
As a side, I think Brembo also has a factory for in South America?

Although not BRAND NEW, there are lots of used HT-18's out there.
It might cost you maybe $100 for one, but the RA's should be in good shape, or at least be minimum rebuildable.


-Ted
Yup, the unknown quality of these new offshore parts has me a bit concerned... To mitigate that risk I think I'll just ask him to send my original parts that were replaced back with the turbo. That way if this next BNR rebuild ever does fail, I'll have some spare parts to draw from and use the best/better ones for a DIY rebuild. Agree it's easy enough to find a used HT-18 to use for parts, but you really don't know what you got until you tear it down, clean & inspect it.
Pete_89T2 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 09:32 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Hosted by www.GotPlacement.com
Ad Management by RedTyger