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Author Topic: How to rebuild your turbo Or: How i learned to stop worrying and love the turbo  (Read 7526 times)
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ElyasWolff
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Posts: 84



« on: May 20, 2016, 02:43:55 AM »

****Disclaimer: Do this at your own risk. This is not a Technical Order. Attention to detail is everything****

I finished rebuilding my 150,000 mile stock turbo. It had a failed oil seal on the compressor side and was blowing massive amounts on oil into my intake. Other than the failed seal it spun fine, but had some cracks in the turbine housing.

First things first, you have to get your turbo out of the car. This, and re-installation are the hardest parts of the job. There are already threads here that detail how to do this, so I will only brush on this topic... or not because getting that sucker out is not fun. Maybe just pull your whole engine, that would be MUCH easier.

You will need to order a rebuild kit for a IHI RHF5 VJ35. I bought mine from here: http://shopping.kinugawaturbo.com/turborepairrebuildkitrhf5cydlyanmar123910-18021.aspx
It worked but was missing 2 parts that can be reused, first is the washer that retains the turbine side bearing, the second is the inner thrust bearing (mine had very little ware after 150K miles.

I would also get ready to order a turbo oil return line. I paid $71 at my local dealer with an SCCA membership discount. That thing is fragile, and it can’t be repaired. I asked a friend who has 30 years experience TIG welding to try it (he can weld 2 razor blades together) and it was a failure. Just buy a new one. If you are a MazdaComp member it is $54.

Ok so you finally got your nasty old turbo out? Probably looks something like this.

I would start with soaking the thing in PB blaster. After it soaks for a bit remove the T25 screws holding the compressor and waste gate can on. I had to use an impact screw driver (the kind you hit with a hammer, not a pneumatic tool). Once those are broken free leave the compressor housing on. You want to brake them free first in case you have to hammer the screws off, because the next step will expose the turbine.

Next you will need to remove the turbine housing from the CHRA. This sucker is most likely seized on with rust and a ton of heat cycles. More PB Blaster!
Hold the CRHA/compressor housing and tap around the cast iron housing in a circular pattern with a dead blow hammer or rubber faced hammer. You don’t want to hammer one side and have the thing be crooked, it will make it harder to remove and possibly come into contact with the turbine. If in doubt turn the turbine wheel, it should not bind or make a scraping sound. You might need need a beefier hammer, I ended up needing a 2lb brass hammer.
I also scribed in an index bark between the compressor housing and CHRA, you don’t need to do that, there is a handy index pin that IHI installed for us!

Hey Look its off!.Good times from here on!
Your turbine housing will more than likely have some cracks in it. Especially around the waste gate port. This is normal. My housing had some other excessive cracks that I welded up with nickel rod. That was not fun.
This is also a good time to port the waste gate and cut a bevel leading into the waste gate port. There are pictures and some threads here on the forum.
The straight machined area of the turbine housing that the turbine auctually spins in had some rust and an uneven surface. I lightly hit it with a flap wheel to brake off the rust and get the surface back to an acceptable gap between the housing and turbine. Dont use anything more agressive than a flap wheel or sandpaper.

Remove the compressor housing that you broke loose the torx screws on earlier. It is held on with red RTV from the factory.
I marked the compressor and turbine so I could index them later. Turns out the turbine shaft and compressor wheel are balanced separately from the factory. So I don’t believe this was necessary, so if you forget to mark them don’t panic.
Remove the LEFT HAND THREAD nut on the compressor. It will slide right off the turbine shaft… (wow that sounded dirty)

Remove the 4 “T-something” torx screws.
The compressor plate is sealed to the CHRA with red RTV just like the compressor housing. Tap around it with your plastic dead blow hammer.

Slide off the”Thrust Flinger” (that is what it was called by the rebuild kit company, I am going to call it the ChupaThingy).
The chupathingy holds the compressor side oil seal, the source of my problems. I could have stopped here, but I might as well go all the way!
The oil seal mates up to the chupathingy and also seals inside the compressor plate, inspect the inner mating surface of the plate for any damage.

I reinstalled everything back on the turbine shaft for this step to keep the shaft straight. Once you do you can press the shaft out of the CHRA with your thumb. With it the turbine heat shield will fall out.

Here is the turbine side oil seal/piston ring

Back to the compressor side!
Remove the 3 screws on the thrust bearing. I ended up re using my old screws because they were torx and the new ones in the kit were Philips.
After the thrust bearing is off remove the thrust washer.

Under that is the inner thrust bearing which is also the retainer for the compressor journal bearing. I used a pick to pry mine up from the rear, you don’t want to damage the face of the bearing because you will have to reuse it (does not come in the kit). Also note the cutout on the bottom, you will need to realign the bearing when you reinstall it.
The journal bearing should now lift our with a scribe in one of the holes.

Remove the retaining washer from the turbine side with a scribe (You will reuse this too so don’t booger it up) and remove the journal bearing.

Your turbo is now disassembled. I cleaned my parts up in a solvent tank and media blasted the compressor housing and turbine with plastic media (the carbon on the turbine is tough and something more abrasive would be better for that). Be sure to get off all the old RTV and any gunk in the CRHA housing.

What you have should look like this

Put a new journal bearing in the compressor side (they are identical)
Align the thrust bearing

I used a socket and extension to seat it

Install the turbine journal bearing and washer, seat the washer with your socket (yes I have harbor freight tools at home. I cant afford 2 sets of Snap-Off tools)

Put the new thrust washer in with some assembly lube

Install the large thrust bearing with some assembly lube


Tighten the screws on the thrust bearing (I reused the old torx ones, not the new philips screws) I did not have a torque spec, just a few inch pounds should do it, or a small turn from hand tight with a short 1/4in ratchet.

Put the new piston ring on the turbine shaft. Try to keep it straight and just work it into the grove. This is just like installing a piston ring on a … well a regular piston.
Apply assembly lube to the turbine shaft and the journal bearings. Place the turbine heat shield onto the CHRA, and insert the turbine shaft into the CRHA. You will only need some pressure with your thumb to get the piston ring to seat in the CHRA.

Install the piston ring/oil seal on the new chupathingy.

More assembly lube!
Install the chupathingy, it will bottom out on the thrust washer.
The wear on the inner and outer thrust bearings will be what causes shaft play (if that is your problem). The thrust washer bottoms out on the “step” of the turbine shaft . The chupathingy and compressor are torqued to the turbine shaft, to a overall length set by the IHI engineers.

Apply red RTV to the mating surface between the CHRA and compressor plate. You don’t want oil leaks here!

Install the compressor plate and torque it down. Again use your judgment and/or “calibrated torque arm”. Then clean up your RTV goobers. (I did a better RTV job after I took the picture, however dont put too much on this side you dont want it flowing into the oil side of the housing.)

Install the compressor.
The kit comes with a new nut. Put on some blue locktite and tighten it 1/4 turn past finger tight. don’t forget LEFT HAND THREADS.
Now let me digress and talk about balance. The turbine and compressor both have machine marks where they were independently balanced at the factory. The nut is the only variable. If I was super anal (or if this was for an aircraft, and where money is no object) I could have the unit sent out to be balanced again. However the nut is close to the centerline of the turbine shaft and thus unable to impart much strain on the rotating assembly. So I used the new nut. I have not had any troubles with my rebuilt unit and running it up to redline.

Put a layer of red RTV on the compressor plate

Install the compressor housing and wipe up the excess RTV that spooges out.

At this point you may have noticed that your turbine spins freely (with some drag from that super thick assembly lube) but you can hear the turbine scraping against the heat shield. The heat shield is centered and held in place by the compressor housing.
Center the turbine heat shield. install the turbine housing and ensure the index dowl pin is lined up.
Beat on with a big hammer.
Install the V-Band clamp and waste gate can.

Yay for you! You have rebuilt your turbo. Happy boosting!

Oh and here is a 10mm wrench I modified to help me tighten the upper bolts on the oil return line after I FINALLY got the turbo installed… did I mention removal and replacement is the hardest part? (its from harbor freight so who cares)
Yeah you should pull the engine, wish I did.






Since you read all the way to the end I hope you are confident about rebuilding your turbo!
If you still have reservations, I might be willing to do this again for a few people... maybe....
« Last Edit: October 29, 2016, 04:41:13 AM by mr_hyde » Logged

2004 VR red MSM. Clapped out, beat to heck, and then rescued because this car is worthy project.
millsj
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Posts: 2575



« Reply #1 on: May 20, 2016, 12:32:30 PM »

Very interesting.  I hope I don't ever need to do this, but glad to know that there is a how-to out there if I ever have to go down this road.  Thanks for sharing.  afro
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FM full intake, FM DP and Exhaust, AFCO Shocks (550/400 lb springs), FM O2 Modifier, Hallman MBC with in-cabin controller, Stewart-Warner Boost Gauge, HDHCDD with Harness Bar, RB 1.125" Front Sway Bar, E-bay Delta Fin 27x7x2.5 FMIC, Ultra-Shield Rally Sport seats, Carbotech XP-12/10 pads, SS Brake Lines, PLX DM-100 Multi-Gauge, FM Crossflow Radiator, Spal Fans, FM Oil Cooler, custom in-dash oil pressure warning LEDS, i-Shift LED shift lights, 15x9 bronze 6UL track tires, COT NASCAR wing, DIY front splitter, fully ducted radiator.
ElyasWolff
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Posts: 84



« Reply #2 on: June 06, 2016, 05:33:33 PM »

Still running great. Installing a FM intake , BPV and MBC soon.
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2004 VR red MSM. Clapped out, beat to heck, and then rescued because this car is worthy project.
toy 4 every season
Back in the saddle again
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« Reply #3 on: June 17, 2016, 06:42:12 AM »

Very nice how to  afro thank you. I have a "new" turbo on my shelf supposedly from Kinguaw to has some end play & now knowing how it goes together I feel more comfortable taking it apart.  rock
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Spring & Fall: 05 Mazdaspeed Miata (Lava) #540 of 1428 - TurboXS MBC, FM Intake & TB, GFB recir BOV, Rear Poly Bushings, Voodoo Magnum Shift Knob, Autometer Boost Gauge, AuxMod, eBay Catless DP, eBay intercooler, Real OPG & Linear Temp Mod, Mishimoto Radiator, FM Stage 1 Fan kit, Alutec Rear Strut Tower Brace, FM O2 Modifier, FM Stage 1 clutch w/ 10.3lbs flywheel, FM Frame Rails, LRB splash guard,  Custom LED 3rd brake light, Optima red top battery
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msmny
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DD Toy :D


« Reply #4 on: June 17, 2016, 04:09:49 PM »

Interesting although over my pay grade, at least for now. But good job nonetheless  thumup How did you know you needed to do this? did you hear any noises or just taking the intake apart?
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Black Mica 05
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#1068/1428 11/9/04


« Reply #5 on: June 17, 2016, 09:38:47 PM »

Interesting although over my pay grade, at least for now. But good job nonetheless  thumup How did you know you needed to do this? did you hear any noises or just taking the intake apart?

>>>It had a failed oil seal on the compressor side and was blowing massive amounts on oil into my intake. Other than the failed seal it spun fine, but had some cracks in the turbine housing. <<<<
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When I die, I want to go peacefully like my Grandfather did, in his sleep...not screaming, like the passengers in his car
ElyasWolff
Second Gear
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Posts: 84



« Reply #6 on: June 18, 2016, 01:08:36 AM »

Very nice how to  afro thank you. I have a "new" turbo on my shelf supposedly from Kinguaw to has some end play & now knowing how it goes together I feel more comfortable taking it apart.  rock

If you live near Portland, OR I could do it for you.
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2004 VR red MSM. Clapped out, beat to heck, and then rescued because this car is worthy project.
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