Project #3...Oh no, not another Nissan Figaro!!!!!!

[Ruffian]

Funny...spent hours trying to get this off last night. Took me 5 minutes this morning with fresh eyes and fresh hands.

By the looks of this exhaust gasket I think the person who fitted the turbo also struggled with this. Me thinks I've located the source of the exhaust blow. These things happen to the best of us I guess!!

Yep that be kerknackered.

 

[Gareth_16V]

While I wait for the garage to become available (still waiting for Project #2 to be finished) I figured I would make a list of bits I need. First thing that needs sorting is oil coming out of the exhaust....and I don't mean just a little either!!!!

for some reason knackered ringlands like to kill turbos.

Is that oil coming out of the exhaust, or is the car running really rich? If it's rich, oil dilution can cause turbo bearing damage - especially if the car is never allowed to warm up to evaporate the fuel out (>70°C oil temp).

The exhaust ports don't look wet with oil - is there oil residue in the exhaust downpipe? If it is oil, knackered rings or a high level of blowby (valve guides, etc) can pressurise the crankcase, meaning that instead of being drawn back into the sump the oil from the turbo decides to follow other routes of lower pressure, such as out of the exhaust at idle. The compressor outlet on that turbo looks very clean, suggesting the compressor side oil sealing is good. The fact that the oil drain tube is clear is also a good sign.

Might be worth cranking the engine over without starting it and seeing how long it takes for oil to reach the turbo inlet banjo.

 

[Pigeon_Droppings2]

Few more pics...I'm pretty sure there was liquid coming out of the exhaust but now I'm wondering whether it was just soot being blown out the back. It's dry but it's pretty thick all over the outlet components.

I think with a torn connector between the turbo and the inlet it would definitely have been running rich as (I think) the air flow sensor is before the turbo.

I've ordered an oil pressure gauge so am going to start by checking the oil pressure. If the oil feed is OK then I'll fit the second hand turbo that I picked up followed by a new set of ignition components (leads, dizzy, plugs etc).

Once it's back together I'll see how it runs...the plan is actually to remove the engine anyway as part of this build and strip it down but I'll do a compression test I think just to get an idea of where we are.

To me it looks like there was oil being forced out of the turbo....the housing is covered in it too. I wonder if the oil return pipe that is attached to the turbo itself has a problem.....I might take that off and have a good look.

 

[jpmillermatic]

compression test. yep....

process of elimination, I guess.....I guess small mishaps like that gasket can happen to anyone....I wont tell you who put my inner brake pad in place but didnt align it quite right!....found that last week!




JP

 

[Pigeon_Droppings2]

Decided to pull the turbo to bits...well into its main parts.

So far there is evidence of oil and coolant in the mail seals. End float is about 1mm...i don't know alot about turbos but I'm guessing for something doing 100k rpm this sounds alot.

Other observations...the main casting is stamped HT (Hitachi) but this to me looks like some kind of rebuild. The nuts and bolts and adaptor ring suggest perhaps this is some sort of rebuild which has been refitted to the original Hitachi casing (anyone out there confirm this?)

Also the fan blade looks like it was balanced separately (see the grind is under the nut)....I think probably means its reasonably safe to mark the relative positions of everything and have a look inside? The original Hitachi turbo has the nut itself grand which I think means the turbo was assembled and then the whole assembly was balanced. This is all gets work of corse...this is the first turbo I've taken apart but I do happen to know quite a bit about the physics and mathematics involved (although it's been a very long time indeed since I did any of this stuff!!!)

I have a used turbo from a low mileage car in stand by so this investigation is more about working out what might have cased the failure. I doubt I'd be able to find a new seal kit for this without knowing who made the fan assembly.

 

[Pigeon_Droppings2]

Well it took all of about 30 seconds to find an identical turbo...so I'm guessing they start with an exchanged unit and then fit an adaptor blate to allow them to recore the compressor fan. The up side is that spares may be available unlike the original Hitachi units. It is literally an exact match

 

[jpmillermatic]

I love investigating the cause and effect of equipment failures, or longevity for that matter. you gotta take it all apart now! There are plenty of turbo related vids on youtube, ect....and some good ones that mention run out specs, reassembly tips, ect. some kits require welding, some do not.

(BMW E60 twin turbo rebuilds, the DIY kind anyway, require welding)

JP

 

[Ruffian]

Just bite the bullet and do what we have done, remove the standard turbo and chuck it in the scrap bin.

Then buy a borg Warner efr and smile.
(Picture added for size difference)

But the figaro is just essencially a micra turbo so parts should be able to be sourced/ reconed easy enough.

Oil pressure and feed must be correct. Both pressures and flow rates. Would be interested in dropping the sump and checking he condition of the pick up also.
Especially if it has gone through multiple turbos.

 

[Pigeon_Droppings2]

Yea JP am definitely going to strip it down....we all knew it was going to happen of course . Cheers Ruffian....that one on the left looks like a lot of fun....I may hunt around and see what upgrades other people have done.

 

[Ruffian]

Left is huge, capible of 800bhp
Mine is the centre one, up to 650bhp
The right is good for about 300bhp

(All on subaru ej engines

 

[Pigeon_Droppings2]

So I cracked open the turbo today...the bad news is I snapped the top of the shaft...I think it was on there pretty tight.

The better news is I think the innards have been "borrowed" from a fairly standard Garrett turbo used on Peugeot/Citroen diesel engines.

I worked this out by looking for repair kits and then matching up the parts. I'm half tempted just to buy a Garrett turbo cartridge and take it apart...there is of course a risk that I'm wrong which would flush £70 down the toilet.

I'm officially a complete idiot....the nut is a left hand nut...why on earth didn't I see that!!!!!!! The last time I made that mistake I was 12 years old...spent a whole day bashing my bike trying to get the pedals off!!

 

[jpmillermatic]

left hand thread!...of course....only other reason would be thread locker....

JP

 

[Pigeon_Droppings2]

I've been reading about turbo balancing for the last couple of days. I reckon this small bit of damage could have ultimately caused my oil leak. Turbo balancing is measured in milligramme ofweigh deviation from the axis of rotation. Shame this chunk is right on the edge. On the up side at least the turbine didn't break up and get sucked into the engine!!

 

[gaz_moose]

what on earth has damaged it like that? are your sure its not been ground to balance it?

 

[Pigeon_Droppings2]

Dunno...most that I've seen are ground on the back? I was thinking the same but there is a grind on the top near the spindle so I figured that was for the balance but guess there is no reason not to have 2 grind marks. Looks like someone hit it with a blunt nail to me!

I've decided to dig deep and go all out for a new spindle and compressor turbine. Managed to find a cheap spindle on eBay so fingers crossed its actually the right one when it arrives. Found a place on line that will balance the spindle with the turbine and nut attached so think I'll go that route...it's £50 though!

My maths is a bit rusty...I worked out that 1 gram at a distance of 1cm doing 100k RPM would have a centrifugal force of about 1,000KG. That just sounds totally wrong...anyone care to have a go at the calculations and correct me.....just sounds a bit wrong to me.

 

[Gareth_16V]

It looks like a balance cut. Individual parts are balanced separately, and then "group balanced" once assembled. It's why re-assembling them isn't simple. You'd also need to know the torquing method (shaft stretch, torque or torque + angle) for the nose nut.

 

[Pigeon_Droppings2]

Could be Gareth...I'm going to check the inside of the casing for damage...no damage I think means you're correct that it's a balance mark....anything hitting the spinning turbine would have been deflected into the casing for sure. The down side....I've just spent £20 on a new compressor wheel that maybe I didn't need!

But on a positive note....my guess of the internals being from the Garrett GT15 turbo turned out to be spot on...all the internals are an exact match to the kit I purchased. I trial fitted the brass central bearing...there is definitely a lot less wear vs the original one.

Gareth....I think you may have just answered my next question...I was thinking that if the shaft is balanced and the compressor is balanced then the "assembled re-balance" is pretty much just compensating for the nut (which is unbalanced)?

My plan was to confirm that the turbo is the GT15 (by ordering and matching up the internals...now confirmed!)....then I was going to go with the GT15 torque setting for the end nut.

Lastly....I still cannot decide whether to just assemble the balanced components and hope it's OK, send the shaft + compressor and nut off to be balanced (mark, disassemble and then fit to the cartridge)....or assemble the entire cartridge and then get that balanced. I think the last option is probably the best...anyone done this before?

Running the components without a final balance will definitely shorten their life....but we are talking about a total spend of around £60 for all the bits in the picture including a new shaft too! The shaft and the compressor are supplied by Melett and have been "component" balanced.

Update...just checked and the casing is clean as a whistle so I reckon Gareth you are correct this was a balance mark when they did the final balancing of the assembled turbo.

 

[Gareth_16V]

The assembled balance is to correct for imbalances of the components when assembled all together. This does of course have an effect on bearing wear and longevity at the extreme cases, but also noise generated by the unit.

 

[Pigeon_Droppings2]

Just checked the pile of paperwork that came with the car...the turbo was swapped in 2011 when the car had 230k km on the clock (now has 260k km on the clock). Seems very odd that this has failed so soon....they even fitted a new oil feed hose too as a precaution! I'm wondering if this is just something really random like someone dropped it when fitting it and then didn't notice the damage to the compressor! This turbo cost over £800 back in 2011.....wow!!

My oil pressure kit arrived so that'll be the next place I investigate...no point repairing the turbo if there is an oil feed issue.

Gareth...still deciding what to do about the balancing. The problem is the innards are so cheap that it's almost worth just taking the risk and accepting that it might need a rebuild in 50k km!...the inner bearings, seals, compressor and shaft cost the same as the rebalance!!

Good point on the noise though...I'd hate to have something that sounds like a bag of spanners!

 

[Pigeon_Droppings2]

Was a nice sunny day today so I refitted the second hand turbo that I bought...then did a little service. This car ran surprisingly well given what the air filter looked like!!