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neal

Turbo damage and oil catch tank(s)

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Four years ago I needed to have both my turbos refurbished due to oil leaks. A couple of years the ago the engine lost boost due to compellor wheel damage to both turbos:

I sent these pictures off to Turbo Technics and they replied saying that this was indicative of foreign material damage, i.e. fine particles hitting the blades.

Being a bit miffed that this had happened so soon after the rebuilds I replaced the turbos with new old stock ones from Lotus (in case the rebuilds had used sub-standard compellors) and replaced my K&N filters with the Lotus OEM paper filters (in case the K&Ns weren't providing sufficient filtration).

However looking at the turbos today the same thing is starting to happen (look for the pitting on the leading edges of the blades):

Now I'm still getting full boost but I think there's a bit more lag. Obviously I don't want to replace another set of turbos without finding the cause. There could be a hole in the ducting or a poor seal somewhere but it's a bit improbable to have the same problem on both sides.

So I'm leaning towards the crankcase breathers. On the V8 these feed into the airbox on each side after the air filter so the oil vapour flows directly into the turbo. If there were any fine particles (e.g. bits of metal or carbon from the engine) in the oil vapour, which were not picked up by the engine oil filter, that could be the cause. And because I do a lot of trackdays the crackcase breathers get a lot of use: high rpm, high oil temperature, high oil pressure = lots of oil vapour.

Does this sound reasonable?

If so I've a few options:

1. I could just block the breather inlets on the air box and route the pipes from the crankcase down onto the road. But that is a bit rude on the track!

2. I've seen inline crankcase breather filters which go between the crankcase and the airbox. Any experience of these?

3. I could fit one (or two) oil catch tanks. But I can't think of any space in the engine bay large enough and an oil catch tank's not the sort of thing you want to mount in the boot! Has anyone else installed one in a V8?

Thanks,

Neal

Edited by neal

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Thats nasty.

I'd sure look at breather filters, but even so, you shouldn't be getting debris like that though your breather, something doesnt seem right. Are the air filter boxes sealing correctly?

As you say, your going to have to check for any holes anywhere in the pipework.

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Neal, I don't know here you are located (Brentwood) venting the crankcase to the atmosphere isn't legal, in the U.S. Of your choices a catch can vented, via a filter, to the atmosphere is the best approach, as nothing could then find it's way into the intake system. This is the way it's done on race cars. I do find it some what strange that particles are being blown into the airbox.

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Are you running standard boost levels and the standard blow-off valve? Over-boosting or not relieving the boost on overrun could lead to the compressors stalling and some nasty shock waves on the edge of the blades.

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Thats why I ditched mine - I vent mine to atmosphere via a long downward pipe unto the engine undertray.

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If it's happening with both turbos, you're looking for the common denominator, I have no idea on a V8 what that is, but it's unlikely that independant feeds would cause a common problem. I'd be inspecting and cleaning the air feed pipes or replacing them.

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Hi Neal,

Something has definately made contact with those impellors.

I fitted a catch tank on my last project Esprit but had the fortune of a non-standard rear deck

f_158irgwgsrdm_af466da.jpg

On the standard car, I think that you´d need two small ones located in the front corners of engine bay - ahead of the timing belt covers.

As Roger suggests, another alternative could be material from the air ducts themselves. As you know, they are a reinforced woven type duct, so maybe they are deteriorating inside?....

Cheers,

Mike S

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Could also check the metal bands inside the pipes oming from the air filters. I have one in the garage thats badly corroded and I'd expect it to cause considerable damage if fitted to the car.

A Long shot, but thought I'd throw it in there.

Mikes setup is probably the best solution for your breathers.

Vent to catch tank, catch tank filtered to atmosphere. Then block up the connector to the air box and eliminate them from the system for good.

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Thanks for all the advice guys, some interesting points.

I had thought it unlikely to be a problem with the ducting (such as a tear) since both side are affected. But it could just be general deterioration on both sides. The car's a 98 with 60k miles and has been used in all weathers. So the metal spiralling in the ducting could be corroding or the fabric disintigrating on both sides.

How much hassle do you think it is to replace the ducting? Looking at the parts list I'm guessing the main headache is going to be removing the sidewall panels to which the top of the duct attaches?

Also, what are your thoughts on using the Lotus OEM parts? Each side duct is made up of three pieces and a load of jubilee clips, which no doubt will cost a fortune for both sides, if available at all. I could just run a single piece dual layer silicone spiralled hose on each side, which while not as neat would be a lot easier to fit and inspect in future (not to mention cheaper). Although no doubt Lotus won't have made it that simple and the airbox take off diameter will be different to the turbo inlet diameter...

On the breather front I was thinking about it last night and I reckon you could mount a catch tank against the chassis rails on either side of the gearbox ahead of the driveshafts. Though I'll probably start off going with the old chestnut of an empty oil bottle and lots of cable ties, then take it on a track to see how much oil we're talking about :)

Edited by neal

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Neal, undo your carpeted quarter-panels , to see how much space is there behind every for a catch tank on at least one side. And even how simple the airducting is concepted. If you want to undo the big side-panels on the engine bay , keep in mind that on older cars the 3 srews on the basis on each side of the body part are heavily corroded for sure. what means you need to cut the heads of and drill the rest out -or the nut inserts in thelaminated body simply turn over for nothing.. .

sidenote: If you *gogle* Garett and/or Honeywell turbo refurbish you will find an document illustrating an story with unequaly and not specified materials on some charges of re-production/refurbished turbo internals. There was something with 'non-approved' companies on turbo refurbing & parts sources.. .

Not sure that this was in case on your first turbos/refurbing ??

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And even how simple the airducting is concepted. If you want to undo the big side-panels on the engine bay , keep in mind that on older cars the 3 srews on the basis on each side of the body part are heavily corroded for sure. what means you need to cut the heads of and drill the rest out -or the nut inserts in thelaminated body simply turn over for nothing.. .

Yeah, I've been looking at those bolts. They're caked in oil/grease so might not be badly corroded. That said, one is missing from the RHS so it's possible it's already had to be drilled during a previous repair.

sidenote: If you *gogle* Garett and/or Honeywell turbo refurbish you will find an document illustrating an story with unequaly and not specified materials on some charges of re-production/refurbished turbo internals. There was something with 'non-approved' companies on turbo refurbing & parts sources.. .

Not sure that this was in case on your first turbos/refurbing ??

That was my concern first time round. However, the company that refurbed them were pretty reputable. But as I said, to be on the side I replaced them with new old stock turbos from Lotus - shiny, unused, even had the original part number labels, and the same thing is happening to them in the space of 24 months/8k miles.

Edited by neal

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I recently sold an oil catch tank to a V8 owner last month. I queried why they were installing on a V8? They were going to install I think opposite side to header tank. The oil catch tank looks pretty enough to leave on view. As for ducting, I recently broke a V8 but didn't sell the ducting. I threw some of it away but the rest I gave to Pete at PNM. He definately has the side walls. You could try him to see if he has the ducting? From what I recall, it was same diameter all the way from turbo to first connector. Not sure if it changes diameter after then but it certainly doesn't taper part way through.

IMG_2037.jpg

Regards,

David Walters

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Hi Neal,

Replacing the OE air hose is not so difficult as it runs down adjacent to the fuel tanks. You will probably need to undo the side walls to ease access - but you shouldn´t need to remove them completely. There is a small change in diameter when transitioning from the reinforced air hose to the flexible plastic duct that in turn connects to the rubber intake elbow on the turbo.

Cheers,

Mike S

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David, this shiny boy-toy looks as if it belongt to a pub or kitchen :)

Neal, as Mike mentioned some time ago in an other topic (see his documentation of the s350 builds..) -there is an point on the sidewall opening were the aircleaner element is fitted. Some sidewalls (or as we could think *all*) have loose segments on that hole. What do you think, can broken pieces of this reinforced GRP together with oil pass along all the way up to the turbos ..??? It is the only 'hard' element I can imagine in the whole induction system (apart from the aircleaner-element foritself..)

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That oil catch tank looks nice but remarkably similar to the one I fitted to my car (carb turbo) which then blew out the oil dipstick and showered my engine in oil. There is quite a lot of pressure coming out of the breather (mostly water vapour) so any catch tank must have a pressure valve with filter. I simply scrapped it and dangled the tubing under my tray. No trouble since - if you buy one don't go anywhere near ebay.

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Was looking at the this again today and the airboxes are pretty concerning:

All those cracks can't be from a poorly finished casting? From the outside they look fine but knowing where to look I did find a crack all the way through on the RHS when flexing the casting. Because of the large vacuum the airbox would be flexed inwards so stress cracks would appear on the inside.

Also if you look at the the duct ends, there are scratches which indicate something hard is travelling along the airbox and bouncing off the bend before pulled through into the ducts to the turbos:

Does anyone have or recently fitted an airbox and know what they should look like on the inside?

On the breather front there is a fair bit of oil throughout and it feels a bit gritty when you rub it between your finger and thumb so I think a catch tank will be in order too.

Edited by neal

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first view is -it looks a little like 'delamination' as for the track-use and hot oil fumes passing along all the time. But not as much as expected. The handlayed lamination is not precise, so what looks like several cracks could also be just steps an inconsistences in the lamination/gray-gelcoat layer ?!

What wounders me is -wow...that much oil?!

I know you said that car is tracked from time to time, bud have you ever cleand (wiped out) the airboxes before ? I do it regularly, maybe that's why there wasn't that much even prior to my engine work. And of course, my engine still runs with the old valve-stem seals... .

Inspect the hole in the sidewall, where the turbo duct is connected -anything broken off ? (see the picture on mikes S350 Nb.32 'rebuild')

sidenote: have you undone the sealings for the pictures ? Or was it fitted without (as the oil is insde and out..)

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first view is -it looks a little like 'delamination' as for the track-use and hot oil fumes passing along all the time. But not as much as expected. The handlayed lamination is not precise, so what looks like several cracks could also be just steps an inconsistences in the lamination/gray-gelcoat layer ?!

Well that's the question. But as I side, on the RHS one of the cracks is completely through the box. However, that's a good point that the hot breather which gets a lot of use on the track could be weakening the airbox, making it more prone to delaminating/cracking.

What wounders me is -wow...that much oil?!

I know you said that car is tracked from time to time, bud have you ever cleand (wiped out) the airboxes before ? I do it regularly, maybe that's why there wasn't that much even prior to my engine work. And of course, my engine still runs with the old valve-stem seals... .

Inspect the hole in the sidewall, where the turbo duct is connected -anything broken off ? (see the picture on mikes S350 Nb.32 'rebuild')

sidenote: have you undone the sealings for the pictures ? Or was it fitted without (as the oil is insde and out..)

I track the car every other month. Last time the boxes would have been cleaned is two years ago, when the filters were replaced. The sidewall is fine - the duct connections are completely intact. And yes, the seals were present, just removed for the photos :)

Edited by neal

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