OB_WAN
Full Access Member
warning: up until a few weeks ago, I didn't know a damn thing about turbos so take this with a grain of salt. oh, and excuse poor terminology as well 
I do anticipate and appreciate positive criticism on these notes. If you find them useful, great. Also feel free to add your own notes to this thread if you'd like.
Please note: the below thoughts are not intended to be in chronological order.
well I'm 99% done with a rebuild of an old roto-master non-wastegated turbo.
I got an old banks setup from someone for a great price. I noticed the turbo blades looked good, not much shaft play, but saw that there was oil leaking from the exhaust (downpipe is pretty nasty but y-pipe was clean). So I figured one of the seals failed between the oiled brass bearings and the turbine wheel. I started looking around for ideas on getting it rebuilt. there are great people to do it on this board like type4 but I'm damn poor at this point so decided to tear it apart myself. Here are a few thoughts on the rebuild:
1. searching on this site provided the confidence to start tearing it apart. Thanks to everyone, especially the frequent "helpers" for your intel.
2. found a link to a youtube video that's pretty straightforward and works well to pause it while doing the steps: http://www.youtube.com/watch?v=I2CwBwrdnvA&feature=related
3. looks like for buying rebuild kits, Ron on ebay is a pretty straight shooter and his kits are pretty complete. Ron's very busy but answers the phone when called and is helpful (though has been very brief so far, probably because he's so busy) http://myworld.ebay.com/ebaymotors/johnsmith04shop/
4. My early banks turbo was a bit oddball having a carbon seal but thanks to typ4's suggestion, swapping the backing plate. since(from what I'm told) diesel's don't need carbon seals and the seals are troublesome, I'm sending my backing plate to Ron so he can get me one with a dynamic seal. For the most part these roto-masters are the Garrett T04B style so the T3/T4 rebuild kits work.
5. when removing bolts, I use a combination wrench and a hammer(my own classic technique from working on old vehicles). put the wrench on the bolts and start tapping the other end of the wrench lefty loosy. if the bolt was on there really good, give it a few good smacks. luckily none of the bolts were weakened enough to snap (possible risk some have run in to). one bolt sitting under the ?oil return flange? was a really tight fit. I had to find a thin enough open ended wrench to fit in there but it eventually worked loose.
6. crud on the exhaust turbine made it somewhat of a pain to remove exhaust turbine(was getting stuck on turbine housing) !!! - note: during reassembly I figured this statement was not the case, the reason it was so difficult to remove the housing was because the bolts while removing them had forced the turbine housing at an angle which caused the turbine blades to bind against the housing wall. I'd suggest following my reinstallation note in reverse here: completely remove those bolts that are completely accessible, slightly loosen the rest, mark housing in relation to center section, and rotate the turbine housing till a couple more bolts are completely accessible, repeat till all bolts and hardware are removed.
7. unlike the youtube video my blades were in good condition so I took care to remove the turbine. ensure as you use the deadblow hammer or other means(one of the bolts worked to help remove the turbine, the one that was a PITA to get to) that you ensure it doesn't get removed lop-sided which will cause the impeller blades to dig in to the turbine housing which could damage the blades.
8. thinking back, I wonder if dipping the entire turbo in to a bath of parts cleaner(kerosene, paint thinner, etc) overnight before disassembly would have helped to loosen/remove some of the crud in the exhaust turbine. I didn't care about the gaskets since they would be replaced anyway. Not sure if dropping an entire turbo in a bath would cause problems or not.
9. these notes are not in order of disassembly so going back to the compressor impeller disassembly step: if you think there's any chance you will not need to get the assembly rebalanced(I might not need to since everything looks like it's in great shape besides the crud) make sure you mark the shaft location in relation to the impeller location to ensure proper balance on reassembly. I used a small chisel and made a light indentation in both, marker will wear off, scribe mark or light indentation will not. the nut to hold it down is supposed to be a 0 balance nut and will be in the replacement kit so don't worry about marking the nut.
10. During dis-assembly, I read a note stating to mark everything. I missed 2 important markings. The turbine and compressor outter housings are held using retaining clips allowing rotation for custom applications. Make sure you mark the housings in relation to each other if you do not want to mess with it during install.
Take a look here for parts list to show how they fit together(T3/T4 hybrid kit): http://www.gpopshop.com/garrettt3kits.html
Okay, adding reassembly thoughts in this main post so they're easy to find.
1. I saw some others suggest that during dis-assembly, since it's difficult to replace the inner clips that hold the journal bearings, they are simply leaving the inner clips in place and only removing the outter clips to remove the bearings. Since the old inner clips might be more brittle, I'm going to replace both. The last thing I need is part of a bearing clip breaking off and dropping in to the engine simply because I was lazy. Or completely wiping out my turbo because a journal bearing lost it's location, lost oiling, and burned up the impeller. I will find or make a tool to remove/install the clips.
2. I originally thought the journal bearings I received were different than the ones I had but they're not. perhaps slight change in amount of contact surface to shaft but in my benefit.
3. the piston ring on the turbine end is finicky and I messed it up when I first tried putting it on. first: make sure you do not over-stretch it when putting it on the turbine shaft. next, when sliding the shaft on to the center housing, give it a wiggle and do not force it down. if it's not allowing you to push it down via somewhat firm(but not heavy) hand pressure while/wiggling rotating the shaft, take it back off and check it. then try again. and again, till it drops in to place.
4. I'm using motor oil for reassembly lube. should work fine. I'm lubing everything that will eventually get some lubrication, shaft, bearings, seals, piston rings.
5. The compressor wheel will sit against the dynamic seal thrust collar when fully assembled, I mistakenly thought something was wrong with mine because it didn't look like the thrust collar was sitting out far enough past the backing plate. My mistake was I hadn't tightened the backing plate all the way down on the central housing first(please note the name "thrust SPRING")
6. I tightened the compressor wheel nut finger/wrench tight. I'm not sure what the specs say about how tight to have it but I didn't have a deep 12-point socket to use my torque wrenches so has to SWAG it. Hope it'll be okay.
7. the o-ring that sits between the compressor housing and the backing plate was slightly out of round making it difficult to get it sitting along the right angle and it may have been just a tiny bit small. I suppose there might be some tacky substance to help in reassembly but I simply "lightly" stretched the o-ring out until it settled in correctly. seemed to work quite well.
8. the bolts tightening down the turbine housing to the center section will rub on the center section. install bolts where they're clear and tighten them almost completely before rotating the housing to install the next set of bolts. If put all the bolts in loosely and then try to rotate the housing some of the bolts will bind on the central housing and cause the turbine blades to bind against the turbine housing. If I remembered the order correctly, I installed two opposing bolts, tightened them to the point where I could still rotate the housing, and then rotated and tightened the next two bolts.
9. there was a lot of rust and crud on the turbine housing. I ended up getting a die grinder with a wire wheel and slightly "polishing" the inside of housing as well as all the mounting surfaces. I wonder if a smooth turbine housing would improve flow and decrease backpressure at all? I certainly did not want to polish enough material off that it would cause some gasses to slip by the turbine blades but it made me curious if a smooth casting might improve exhaust flow. No matter.
I do anticipate and appreciate positive criticism on these notes. If you find them useful, great. Also feel free to add your own notes to this thread if you'd like.
Please note: the below thoughts are not intended to be in chronological order.
well I'm 99% done with a rebuild of an old roto-master non-wastegated turbo.
I got an old banks setup from someone for a great price. I noticed the turbo blades looked good, not much shaft play, but saw that there was oil leaking from the exhaust (downpipe is pretty nasty but y-pipe was clean). So I figured one of the seals failed between the oiled brass bearings and the turbine wheel. I started looking around for ideas on getting it rebuilt. there are great people to do it on this board like type4 but I'm damn poor at this point so decided to tear it apart myself. Here are a few thoughts on the rebuild:
1. searching on this site provided the confidence to start tearing it apart. Thanks to everyone, especially the frequent "helpers" for your intel.
2. found a link to a youtube video that's pretty straightforward and works well to pause it while doing the steps: http://www.youtube.com/watch?v=I2CwBwrdnvA&feature=related
3. looks like for buying rebuild kits, Ron on ebay is a pretty straight shooter and his kits are pretty complete. Ron's very busy but answers the phone when called and is helpful (though has been very brief so far, probably because he's so busy
) http://myworld.ebay.com/ebaymotors/johnsmith04shop/4. My early banks turbo was a bit oddball having a carbon seal but thanks to typ4's suggestion, swapping the backing plate. since(from what I'm told) diesel's don't need carbon seals and the seals are troublesome, I'm sending my backing plate to Ron so he can get me one with a dynamic seal. For the most part these roto-masters are the Garrett T04B style so the T3/T4 rebuild kits work.
5. when removing bolts, I use a combination wrench and a hammer(my own classic technique
from working on old vehicles). put the wrench on the bolts and start tapping the other end of the wrench lefty loosy. if the bolt was on there really good, give it a few good smacks. luckily none of the bolts were weakened enough to snap (possible risk some have run in to). one bolt sitting under the ?oil return flange? was a really tight fit. I had to find a thin enough open ended wrench to fit in there but it eventually worked loose. 6. crud on the exhaust turbine made it somewhat of a pain to remove exhaust turbine(was getting stuck on turbine housing) !!! - note: during reassembly I figured this statement was not the case, the reason it was so difficult to remove the housing was because the bolts while removing them had forced the turbine housing at an angle which caused the turbine blades to bind against the housing wall. I'd suggest following my reinstallation note in reverse here: completely remove those bolts that are completely accessible, slightly loosen the rest, mark housing in relation to center section, and rotate the turbine housing till a couple more bolts are completely accessible, repeat till all bolts and hardware are removed.
7. unlike the youtube video my blades were in good condition so I took care to remove the turbine. ensure as you use the deadblow hammer or other means(one of the bolts worked to help remove the turbine, the one that was a PITA to get to) that you ensure it doesn't get removed lop-sided which will cause the impeller blades to dig in to the turbine housing which could damage the blades.
8. thinking back, I wonder if dipping the entire turbo in to a bath of parts cleaner(kerosene, paint thinner, etc) overnight before disassembly would have helped to loosen/remove some of the crud in the exhaust turbine. I didn't care about the gaskets since they would be replaced anyway. Not sure if dropping an entire turbo in a bath would cause problems or not.
9. these notes are not in order of disassembly so going back to the compressor impeller disassembly step: if you think there's any chance you will not need to get the assembly rebalanced(I might not need to since everything looks like it's in great shape besides the crud) make sure you mark the shaft location in relation to the impeller location to ensure proper balance on reassembly. I used a small chisel and made a light indentation in both, marker will wear off, scribe mark or light indentation will not. the nut to hold it down is supposed to be a 0 balance nut and will be in the replacement kit so don't worry about marking the nut.
10. During dis-assembly, I read a note stating to mark everything. I missed 2 important markings. The turbine and compressor outter housings are held using retaining clips allowing rotation for custom applications. Make sure you mark the housings in relation to each other if you do not want to mess with it during install.
Take a look here for parts list to show how they fit together(T3/T4 hybrid kit): http://www.gpopshop.com/garrettt3kits.html
Okay, adding reassembly thoughts in this main post so they're easy to find.
1. I saw some others suggest that during dis-assembly, since it's difficult to replace the inner clips that hold the journal bearings, they are simply leaving the inner clips in place and only removing the outter clips to remove the bearings. Since the old inner clips might be more brittle, I'm going to replace both. The last thing I need is part of a bearing clip breaking off and dropping in to the engine simply because I was lazy. Or completely wiping out my turbo because a journal bearing lost it's location, lost oiling, and burned up the impeller. I will find or make a tool to remove/install the clips.
2. I originally thought the journal bearings I received were different than the ones I had but they're not. perhaps slight change in amount of contact surface to shaft but in my benefit.
3. the piston ring on the turbine end is finicky and I messed it up when I first tried putting it on. first: make sure you do not over-stretch it when putting it on the turbine shaft. next, when sliding the shaft on to the center housing, give it a wiggle and do not force it down. if it's not allowing you to push it down via somewhat firm(but not heavy) hand pressure while/wiggling rotating the shaft, take it back off and check it. then try again. and again, till it drops in to place.
4. I'm using motor oil for reassembly lube. should work fine. I'm lubing everything that will eventually get some lubrication, shaft, bearings, seals, piston rings.
5. The compressor wheel will sit against the dynamic seal thrust collar when fully assembled, I mistakenly thought something was wrong with mine because it didn't look like the thrust collar was sitting out far enough past the backing plate. My mistake was I hadn't tightened the backing plate all the way down on the central housing first(please note the name "thrust SPRING")
6. I tightened the compressor wheel nut finger/wrench tight. I'm not sure what the specs say about how tight to have it but I didn't have a deep 12-point socket to use my torque wrenches so has to SWAG it. Hope it'll be okay.
7. the o-ring that sits between the compressor housing and the backing plate was slightly out of round making it difficult to get it sitting along the right angle and it may have been just a tiny bit small. I suppose there might be some tacky substance to help in reassembly but I simply "lightly" stretched the o-ring out until it settled in correctly. seemed to work quite well.
8. the bolts tightening down the turbine housing to the center section will rub on the center section. install bolts where they're clear and tighten them almost completely before rotating the housing to install the next set of bolts. If put all the bolts in loosely and then try to rotate the housing some of the bolts will bind on the central housing and cause the turbine blades to bind against the turbine housing. If I remembered the order correctly, I installed two opposing bolts, tightened them to the point where I could still rotate the housing, and then rotated and tightened the next two bolts.
9. there was a lot of rust and crud on the turbine housing. I ended up getting a die grinder with a wire wheel and slightly "polishing" the inside of housing as well as all the mounting surfaces. I wonder if a smooth turbine housing would improve flow and decrease backpressure at all? I certainly did not want to polish enough material off that it would cause some gasses to slip by the turbine blades but it made me curious if a smooth casting might improve exhaust flow. No matter.
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