turbojohn Posted October 7, 2007 Report Share Posted October 7, 2007 First a word of warning. If you buy one of those $35.00 rebuild kits off ebay. The bearings were the wide ones and the seals must be file-fit. Both can be considered good if you have a lathe and know how to fit oversize seals. There are a few tricks taking this turbo apart. First is using air pressure to blow the compressor side seal plate out. Don't try to pry on it. Just plug holes with your fingers and use an air blower to pressurize the unit, pops right out. I use a jewlers wire pliers to remove the bearing C-clips & install them. After cleaning the center section bearing cavity with a bottle brush. Fit the exhaust side seal by hand. If it doesn't fit, it's an oversize seal and must be hand fit. I use 180 grit sandpaper folded in half. Then pinch the seal on the sandpaper and slide the sandpaper in & out. You have to be careful to keep the paper even or you can sand the ends crooked. Check the fit often. You want the seal to fit snug, no end gap. When assembling, make sure to put seal end gaps at the top. Do everything you can to prevent oil leaks. I also had to file-fit the compressor side seal. The orange paint is a high temp varnish. I've used it on turbo housings in the past and it holds up well to extreme heat. Quote Link to comment Share on other sites More sharing options...
turbojohn Posted October 7, 2007 Author Report Share Posted October 7, 2007 The top picture shows the turbine seal installed. At the 3:00 position, you can just see the end gap. Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted October 7, 2007 Report Share Posted October 7, 2007 do you have to get it balanced when its all back together? when I bought my center section from garrett the tip on both the turbine and compressor shaft had grind marks from when it got balanced. Quote Link to comment Share on other sites More sharing options...
turbojohn Posted October 7, 2007 Author Report Share Posted October 7, 2007 It's a good idea to send the spinning assy off and have the balance checked. However, I didn't on this particular rebuild. I'm T25ing until I can afford to T28. I did mark the wheels and assemble it in the same position as it was before taking it apart. Rebuilding a turbo is not something everyone should do. By that I mean it takes a few special tools and a way to clean the carbon off parts. You have to be very careful with the turbine bearings. If you scratch the center section removing a C-clip, that scratch can take the bearing out. Nothing should be forced together. I have probably rebuilt a few hundred turbo's and modified around a dozen for race use. I have lots of pictures of mods I've done to turbo's over the past decade. This doesn't pertain to our cars so I'll just post pics of this T25. I should have got the camera out earlier, like when I had to narrow the bearings in the lathe. Well anyway, I got the crossover fabrication done today and installed. I painted it to cover my ugly welds. It fits really nice though. All the parts were installed and bolted in place, no preload on anything before tacking it together. Quote Link to comment Share on other sites More sharing options...
Addicted To Boost Posted October 7, 2007 Report Share Posted October 7, 2007 Nice job! I think you should have painted it a different color than bright orange though Quote Link to comment Share on other sites More sharing options...
turbojohn Posted October 7, 2007 Author Report Share Posted October 7, 2007 Thanks It's more of a burnt orange It's actually a high temp varnish. It's a long story but, you're suppose to weld stainless with helium gas as the shield to prevent carbon in the air from contaminating the stainless. Every welding place was out of helium gas. So I used Argon CO2 mix. It works but there's carbon contamination in the welds. It'll rust at some point. I started to just spray the welds, but that didn't look so good. So I just sprayed the whole thing. When I take it off again for the T28 turbo. I'll paint it with high temp black or sand the welds and polish it. Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted October 7, 2007 Report Share Posted October 7, 2007 hey whatever it takes to get good flow and flex bellows in there that do not leak. and a turbo that doesnt smoke. might not spin quite as fast as a balanced unit, but gets you by and can drive the car until you get the t-28. is the egr bung trimmed flush inside there? or does it still kind of block some of the flow like they normally do Quote Link to comment Share on other sites More sharing options...
turbojohn Posted October 7, 2007 Author Report Share Posted October 7, 2007 Yeah it's still sticking in the way of flow. I was going to trim it flush while I had the porting tool handy but forgot about it. Then I didn't have time to mess with it later on. The turbo is installed now. I started the engine and let it run for a few minutes. It sounds like I have an exhaust leak somewhere. It's not coming from the expansion joints. I'm thinking the cat is plugged up and the leak is at the down-pipe. There are springs holding the flange down there together. A bolt is missing in the down-pipe bracket behind the engine, someone's been there before I'm wanting to drop the exhaust anyway and delete the mufflers. I double checked the crossover bolts at the manifolds. It may be the EGR pipe leaking too. I'll get a cap on there and check that this week. I used goretex teflon on the turbo flanges. I'll post a picture of this stuff. Top Fuel guys use it to seal their blower manifolds and header flanges. You peel off a strip and it sticks in place. Heat doesn't affect it. Here's the thermostat housing with Gortex sealer on it, ready to install. I like this stuff. It's quick, clean and easy to clean off years later. It compresses to zero where no gasket is needed. There are different thicknesses, this is 5/16 I think. It's way overkill on this housing, but if you have it around, might as well make use of it. Quote Link to comment Share on other sites More sharing options...
GutlessSupreme Posted October 8, 2007 Report Share Posted October 8, 2007 How much does that stuff go for? and do any fluids harm it (i.e. gas/oil)? Quote Link to comment Share on other sites More sharing options...
turbojohn Posted October 8, 2007 Author Report Share Posted October 8, 2007 it's not real expensive. I bought mine from a pump supply outfit. Was after some teflon packing for a large 7" hydraulic cylinder ram for my dump truck. Some of this "string" sealer tape was on the counter. So naturally I had to play with it I had seen it before at the Summer Nationals in Topeka. The big guns were using it around their blower manifolds & intake runners, oil pan, valve covers etc. It can withstand Nitro, gasoline, oil, steam, brake fluid...everything known to man Pressure wise, it can take over 3000psi at 3500 degrees. Do you think it'll seal up that thermostat housing It's kind of weird stuff to use. Just stick it on and assemble. I used it on the transmission pan of my Suburban. After a few years I installed a deep pan on it. The Gortex teflon sealer was mashed so flat, you could see through it. It's so much better then cork or paper gaskets. They go bad with time. Not this teflon sealer stuff. It's on there for the long haul. If you do need to remove the cover. It's as simple as peeling off the old teflon and sticking on fresh stuff and slap it back together. Silicone retains moisture and rots metals. Quote Link to comment Share on other sites More sharing options...
slick Posted October 9, 2007 Report Share Posted October 9, 2007 Wow, how much was this sealer stuff??? I might pick up some of it, just for future use. Quote Link to comment Share on other sites More sharing options...
turbojohn Posted October 9, 2007 Author Report Share Posted October 9, 2007 Wouldn't you know it..found some on ebay http://cgi.ebay.com/Gore-TEX-Gasket-Tape-Expanded-PTFE-Sealant-Tape-010_W0QQitemZ120161998745QQcmdZViewItem Quote Link to comment Share on other sites More sharing options...
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