Rover 1.8T turbocharger rebuild

[good_mojo]

I’ve finally got round to investigating my 1.8t that I bought last year. I have not driven it other than backing the car onto my drive after it was delivered on the back of a recovery truck. It starts and runs but produces incredible amounts of smoke. The smoke is mainly white, but there is also lots of blue / black there too. The exhaust gas stinks and catches you at the back of the throat so you don’t want to be around it for too long.

Usually, white smoke results from coolant or water; black smoke is an overly rich fuel mix; and blue smoke is oil. At first I suspected HGF because there is a lot of white smoke. However, Marinabrian, gave me tip to check the turbo compressor wheel for play so I took off the hose to the centre of the aluminium compressor housing, aka ‘snail shell’. When I looked and felt the wheel, it did not take a mechanical genius to see that in my case, the turbo had excessive play in the bearings and the seals had failed.

This image from dieselnet shows a sectional view of turbocharger. The turbocharger has journal bearings in the middle of the turbocharger, between the intake and exhaust sides. The bearing supports the shaft on a thin layer of oil that is constantly pumped around the shaft. The shaft is lubricated by oil under high pressure from the engine's oil pump. There are oil seals on the intake side and the exhaust side that keep oil from escaping from the bearing. If the exhaust side oil seal fails then oil will leak into the exhaust system, where it may, or may not, burn if the exhaust temperature is hot enough. This will give different smoke colours, depending on if, or how much, the oil is burnt. The smoke is only blue if the oil is burning. If the oil that gets into the exhaust is not burnt but is vaporised by the heat instead then there is white smoke. If the intake side oil seal fails then oil will leak into the intake system, where it is drawn into the engine and burnt along with the fuel, creating blue smoke.

My turbo was clearly very poorly so I considered the following three options.
1. Replace turbo
2. Buy a ‘turbo fix kit’ from eBay. These can be an el-cheapo few washers and seals in a bag or more expensive, fairly comprehensive looking kits with axles, new compressor wheels and turbine wheels.
3. Install a replacement, fully balanced, centre part of the turbo with all the moving parts. This is known as a Centre Hub Rotating Assembly (CHRA) cartridge.

I discounted the eBay turbo fix kits because it is essential that the assembly is fully balanced and I cannot see how anyone at home can achieve this with one of these kits. Turbochargers spin exceptionally quickly and any unbalance would quickly lead to destruction. Videos on YouTube suggest carefully marking the wheels to replace them in the same position. I was too sceptical to seriously consider this.

I did not want the hassle of fitting a second hand turbo, as it could be trouble in the future. I rang Midland Turbo who was very helpful and gave me an exceptionally good price for a replacement turbo they had on the shelf – and that was very tempting.

In my research I had come across CHRAs and it looked to me like it was possible to replace the CHRA without removing the complete turbo unit from the car. This would save considerable time and aggravation removing stubborn nuts, bolts or studs on the exhaust manifold and the exhaust side of the turbo.

[Marinabrian reassured me that the whole turbo would come out easily but I’m lazy and I figured that if I don’t have to take it all out then it makes my life easier].

Midland turbo would have to make up a CHRA for me, which would take a few days and the price was not as attractive, so I identified one on eBay from Turbocharger Solutions which was £95, manufactured in the UK and comes with a balance test sheet.

I stripped out the compressor side of the turbo from the car before ordering the CHRA so that I could be sure that it could be done without removing the whole turbo. I will put the details of the turbo strip down and rebuild in my next post…