RHB5 Rebuild
Rebuilding an IHI RHB5 turbocharger.
This guide is written for the above turbo, however, many of the principles are very similar and the internals will be of almost the same layout.
You will see in this guide, that the seals inside a turbo are very small and delicate. They face extreme conditions. One side is roasted to the point at which it glows red, and the other is constantly cooled by the inducted air flowing thru it. So it shows how important it is to allow everything to warm up gently and expand to its normal operating conditions before you boot it down to the Spar for a Mars Bar and a paper! SO RESPECT YOUR TURBO!!
I HAVE NEVER DONE THIS TO A TURBO BEFORE AND I AM BY NO MEANS AN EXPERT. THE GUIDE WRITTEN IS HOW I DID IT FROM MY OWN KNOWLEDGE AND EXPERIENCE. IM NOT TELLING YOU HOW TO GO ABOUT IT, IT'S A GUIDE. DON'T COME CRYING BECAUSE THE NUT FELL OFF AND GOT DRAWN INTO YOUR ENGINE, OR STUCK IN YOUR INTERCOOLER. I WILL SYMPATHISE BUT WILL OFFER NO ACCEPTANCE OF BLAME. THERE MAY BE SOME EXPLETIVES USED IN THE DESCRIPTIONS. IF YOU'RE OFFENDED, DRY YOUR EYES! IM JUST WARNING YOU
Some of you may remember the mighty 1ltr GTti from the first Japerformance RR day making some interesting smells and smoke as it heaved out all 100 ponies. I knew the turbo was dieing but didn't care if it gave way the bits would get filtered out in the intercooler before they made it to the engine. A couple of days later the seals died good and proper. Having exhausted all my spare turbos and having to resort to fitting a hybrid that is laggy and horrible to drive with (but an absolute rocket after 5kRPM!) I found a seller on E-Bay selling rebuild kits for £58 delivered. Now, considering a recon unit is £380 + surcharge, it's definitely worth a shot if you have the tools and reasonable experience in the workshop.
Before you start though, consider this, if it was in the Haynes manual it would be about a 3 spanner job. And bearing in mind that Haynes writes their books on brand new cars, everything is a piece of piss to them. But it's not like this in real life. In reality your turbo will have done in excess of 60,000 miles and if it's like mine will have been glowing red hot almost all the time its out. The 4x6mm machine screws that hold on the turbine housing are mild steel and the exhaust volute is cast iron, the heat makes the bolts on that side extremely brittle and will shear as soon as you look at them. So make sure you can deal with this before you start. (note1)
And consider the fact the a specialist may not accept your old one as 'serviceable' if you've sheared the bolts or cracked a casting, which might leave you about £200 down!!
So, you've still got the balls to try it? Well having ensured that all the parts in the kit are correct, and you have given the vendor the correct serial numbers for your turbo, and you've got the tools you can start. (Or you can dive straight in there and make an arse of it)
1. Remove the turbo from the car
2. wire brush any crap and rust off it
3. Mark the orientation of all the mating faces (as the housings can be rotated 360deg)
4. Use a good fitting spanner to remover the clamps from round the exhaust turbine side.
5. Use a copper mallet or a hammer and piece of wood to knock the casting squarely off the bearing housing. (You can see here, my good fortune has left me with a sheared bolt ACE!)
6. now do the same for the compressor housing (aluminium side)
Now at this point be VERY aware of the fact that the impellor and turbine are delicate and that you probably didn't get spares with your kit ;) so don't up-end it and dump it on the tips of the blades or you will wreck it completely! Use blocks of wood to support it on its end
7. Get a spanner on the nut of the compressor side and hold the turbine side of the shaft. It might look like you need a special spline driver, but you'll find a star ring key or socket will be fine, if it isn't then make sure there's no carbon build up that's causing it to foul.
8. Slide off the impellor and keep it safe.
9. You will now see a cover with about 3 screws on it (it's the actual compressor side seal assembly). Not pictured here is the small seal cartridge that runs in the hole but il try and point it out on the exploded diagram later. Note the orientation because your kit will not come with instructions!! Using a spline driver, remove them all. Or as my good fortune allows, shear your spline driver in the process and resort to drilling the heads off (told you the job might turn to shit!) The cover might be stiff to come out because it's machined to a tight tolerance. So stick at it but don't damage it, and I'll say it again: DON'T FORGET WHAT ORDER THE SEALS AND THRUST COLLAR COME IN!! You have been warned. The exhaust turbine and shaft should pull through now.
10. The flange that is visible now is the thrust bearing, the new one will be coated in white metal so don't scratch it or its wrecked! The above picture actually shows the new one in place after I drilled out more fucking screws
11. Pull out the bearing and remove the internal circlip (this stops the bearing sliding down the housing
12. Now flip it over so you can work on the exhaust turbine side. Remove the oil deflector plate (you'll see it on the exploded picture later) and scrape the carbon off it. And give it a good wire brush!
13. Down the hole, there will be a circlip. Remove it and pull the bearing out (it might be coked in so give it a good dig with a scribe or nail) there's another circlip on the other side. So pull it out as well, the heat buggers the spring steel on the circlip so it might just bend or break out, don't worry there should be new ones in the kit.
14. Now that everything is stripped off, scrape all the carbon off the inside especially on the exhaust side because its warmest. And get right down in to the oil drains. Wash the bits in kerosene or diesel or whatever, and make sure that the small oil holes are clear. Blow the crap out with an airline to ensure there is no shit left in it. (note the use of old frying pan nothing but the best for my wee Charade!)
15. Set out all the bits in order and compare them to your new bits. Try doing it before you burst the packet open. I got 2 extra bearings in mine but they were not the right size, I also got one or two extra screws so don't panic straight away! As long as the bits are all there
16.
17. If you've made it this far, then you will probably manage no problem getting it back together. It really is the reverse of how it came apart. The only other thing worth remembering is that the compressor nut is a LEFT HAND THREAD! So its anti clockwise to tighten. Don't over tighten it because it will shear and now you'll be fucked good and proper! But failure to tighten it enough will result in it coming off and lodging its self in your inter cooler. So be careful. I'm sure there's a correct torque setting out there, but I didn't use it. The turbo should run freely, it shouldn't be at all tight or stiff, if it is then something's gone to fuck, stop and check before going any further. Use a clean oil-can and oil to purge the oil ways and pre-lube the bearing. When you start the car DO NOT REV IT. Give it a chance! The oil will need to flow thru and settle into the seals. Any smoke coming off is probably oil from the surface. If it doesn't stop, then check all the copper washers and the gaskets for leaks. If smoke billows out the exhaust after is first run then you've fucked up somewhere and the exhaust seal is likely goosed. If it's blue smoke then it's likely the compressor side, although there is no real way of telling.
Fraser McDougall
Note1. To remove diffuser plate screws try giving them a sharp rap with a ballpein hammer and suitable drift. This will break the thread sealer grip.