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Stripping and rebuilding a turbo


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I know that Les has already done an article on the subject in Tech Archives, but for some reason that forum is not accepting ''replies'' or ''New Topics'' today.

I have a Turbocharger from a friends LandRover that I brought back from Vietnam to have rebuilt here in OZ as apparently their is no firm over there willing or capable of doing the job .

The problem with this turbo is that it leaks oil into the exaust turbine housing. The bearings/bushings felt ok with a slight amount of play which is normal, because like most other turbos, these have what are called hydrodynamic bearings which take up the freeplay with engine oil pressure once the engine starts. The turbine blades appear to be in good condition too, with nice sharp edges and corners on the vanes,so I thought ''it has to be stripped at the turbo rebuilders anyway, so what have I got to lose by stripping it myself to see what makes them tick?'' Upon disassembly everything appears to be in good order with the exception of a small split ring similar in design to a piston compression ring which is the cause of engine oil escaping into the exhaust turbine area. This oil ring appears to be worth not much more than a shilling but the local Turbo shop wants $800 to rebuild the unit, stating that a full overhaul kit will need to be fitted and the unit balanced after assembly, and as they will not be fitting the rebuilt unit to the vehicle themselves there is no Warranty.

Before stripping the unit I carefully looked for areas where metal would have been removed to balance the unit after original assembly. there were none. The only areas that metal was removed were on the back of the turbines, that can only be accessed by dismantling the turbo assembly. I also took the precaution of putting ''timing marks'' on each turbine and bearing housing to insure that the correct relationship if any would be maintained upon reassembly.

Some research on the Net has revealed that all turbo components are individually balanced before assembly and then rebalanced once assembled. As I mentioned earlier ,I do not see any ''post assembly'' balance marks so I am tempted to try to get hold of an oil sealing ring, reassemble the unit and ship it back to my friend. Any words of encouragement or otherwise from forum members ?

And any ideas on where I may be able to get hold of the sealing ring ?

Bill.

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AR turbo rebuilt mine they may be able to provide spares

ct 01924477747.

ps the tech archive doesn't allow posting at any time it is only added to by the moderator if a member wants a topic created /added to

May I request that my first posting be added to Les's thread then ?Members interest in that particular article fizzled out on the question of balance, and aside from that possible question mark there is nothing in the mechanical make up of a turbocharger that is rocket science. People in ''the trade'' seem very reluctant to share their secrets so further discussion on this subject among interested forumers may prove beneficial.

Bill.

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As I mentioned earlier ,I do not see any ''post assembly'' balance marks so I am tempted to try to get hold of an oil sealing ring, reassemble the unit and ship it back to my friend. Any words of encouragement or otherwise from forum members ?

And any ideas on where I may be able to get hold of the sealing ring ?

Bill.

IIRC they file/machine the nut on the shaft for any 'post assembly' balancing.

Andy

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There is a company on e-bay selling genuine turbo rebuild kits - I posted acouple of weeks ago about this - looking on the net it appears that its the shaft/impellors that are balanced and as long as you dont take these apart you are ok, if you do take tham apart remember to line everything up again afterwords.

do a search on the net under diy turbo rebuild or something like that. I am probobly going to go the re-con route but if you are stuck a kit may be the answer?

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There is a company on e-bay selling genuine turbo rebuild kits - I posted acouple of weeks ago about this - looking on the net it appears that its the shaft/impellors that are balanced and as long as you dont take these apart you are ok, if you do take tham apart remember to line everything up again afterwords.

do a search on the net under diy turbo rebuild or something like that. I am probobly going to go the re-con route but if you are stuck a kit may be the answer?

Thanks for that information, I will look for your post.

The only way that one can get at the bearing bushes and oil sealing ring is to undo the compressor impellor retaining nut(left hand thread) and remove compressor impellor from the shaft. The exhaust turbine can then be withdrawn together with the shaft and bearing bushings.

From studying the components I can't see how a bunch of individually balanced parts when assembled together won't remain balanced, but at any rate my ''timing'' marks should ensure that is the case, assuming I can get hold of a sealing ring without having to purchase a complete rebuild kit.

Bill.

Edit. Selectcase,I checked your thread. Do you have any links to the articles on the net with guide on how to rebuild turbos?

It took me hours of frustrating searching before I came across the article mentioning that all turbines, shafts, nuts etc are individually balanced before assembly.

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Im not sure about balancing nuts Bill,

I can see the merit of a dynamic balance of the whole assembly but balancing the components doesnt make sense, trimming impellor blades would have a more pronounced effect?

It was the impellor retaining nuts I was refering to Jez.A place I took the unit to in Hanoi declined the job because the compressor turbine retaining nut was ever so slightly chewed and would ''throw the unit out of balance'' I have since obtained an undamaged nut.

If ultra precise balance is as important as people say, what effect does a slightly uneven buildup of exhaust soot on the turbine vanes have upon balance? The exhaust turbine on this unit, although in good condition was unevenly loaded with carbon.

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Have a look here http://www.turbotechnics.co.uk/docs/vsr/balance.htm probably the best known turbo company in the UK.

Site generally is worth a look.

Andy

I spent an hour or so on their website last week. Quite informative and they do know their stuff, but not much there to encourage us DIY (cheapskate, skint) types .

Bill.

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its an interesting game - I'd never really thought about it, we used to send off turbos and s/chargers and pay the bill in days gone by without really wondering what the balancing process was, one of the lads re-conned a japanese turbo (shogun I think) with a seal kit from ebay and its still slugging about to this day but I do remember him saying it was a ***king a*s*ho** of a ****ing job and he would rather eat glass than do it again. can you ping some pics up when you do it please Bill?

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I reckon a lot of it is smoke and mirrors. Surely providing you are using the same turbine, compressor, shaft etc, and you put it back together exactly as it came apart (having marked it all first) I would have thought it would be fine. There are so few components, and I would have thought the only things that would affect the balance are the two 'fans' and the shaft joining them. So, if you put them together the same, surely they'd be balanced?

I suppose the difficult bits would probably be getting some of the corroded bolts out and it is probably easy to tweak it out of balance if you can't hold things properly to remove the compressor centre nut.

Regards,

Diff

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I remember my old man rebuilding many a turbo from Saab cars in days gone past, he knew his stuff with such things, having spent years on steam turbines, big marine diesels, nuclear submarines and so on. I don't recall him ever worrying about balancing car turbos, although I know that Rosyth Dockyard did have vibration analysis facilities, but that was used on big stuff, turbine blades, hush propellors etc. Most of the work I remember him doing on car sized turbos was cleaning, replacing seals and alpping in the wastegate valve.

I'll give the old duffer a ring and see if he can remember anything useful.

EDIT: Rang the old f@rt, he reckons it won't need rebalancing, on all the ones he rebuilt over the years he didn't bother, save for on which had sucked in some foreign objects (washers!) and dinged the blades about a bit.

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I remember my old man rebuilding many a turbo from Saab cars in days gone past, he knew his stuff with such things, having spent years on steam turbines, big marine diesels, nuclear submarines and so on. I don't recall him ever worrying about balancing car turbos, although I know that Rosyth Dockyard did have vibration analysis facilities, but that was used on big stuff, turbine blades, hush propellors etc. Most of the work I remember him doing on car sized turbos was cleaning, replacing seals and alpping in the wastegate valve.

I'll give the old duffer a ring and see if he can remember anything useful.

EDIT: Rang the old f@rt, he reckons it won't need rebalancing, on all the ones he rebuilt over the years he didn't bother, save for on which had sucked in some foreign objects (washers!) and dinged the blades about a bit.

Thanks for that info. I feel confident enough to wack an oil ring in it and send it back. I read the other day that the shaft and bearings/bushes float on a relatively thick film of oil (hydrodynamic) which cushions and absorbs minor inbalance forces.

Bill.

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here are a couple of links on rebuilding a turvo i found on the net. they are usa based as suppliers must me more forthcoming over there

Garrett rebuild

general rebuild info

A honda based forum where someone is doing it with picsanother site

there are lods more sites as well just keep looking - I think its an interesting subject a although I appriciate the balance thing I cant help but wonder why we cant replace seals etc ourselves.

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here are a couple of links on rebuilding a turvo i found on the net. they are usa based as suppliers must me more forthcoming over there

Garrett rebuild

general rebuild info

A honda based forum where someone is doing it with picsanother site

there are lods more sites as well just keep looking - I think its an interesting subject a although I appriciate the balance thing I cant help but wonder why we cant replace seals etc ourselves.

Thanks again for the information and links Selectcase. That was interesting reading. Now to find some company over here that will just sell an oil ring or rebuild kit.

Bill.

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Thanks again for the information and links Selectcase. That was interesting reading. Now to find some company over here that will just sell an oil ring or rebuild kit.

Bill.

there is a company on ebay that sells them - I cant remember thier name now but i posted it in a thread about rebuilding turbos about a month ago

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there is a company on ebay that sells them - I cant remember thier name now but i posted it in a thread about rebuilding turbos about a month ago

Thanks but, I just re read my first post and noticed a typo. It was meant to read LandCruiser not LandRover, so the Ebay kits probably won't suit. The local turbo shop will not sell me a ring or rebuild kit. I'll try other shops next week.

bill.

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