Recently, one of the interns at work upgraded his K04 Volvo Turbo to a K05. Volvo's are new to me and although not a DSM I can appreciate anyone who is a car and turbo enthusiast. So he got a used K05 to upgrade and was just going to put it on the car as it was until I convinced him to look it over. He bought a very good rebuild kit and we tore the turbo apart together. The K04 and K05 turbos are basically a Volvo modified MHI TDO4.

After a good clean, and inspection I went to assemble and grabbed the hot side oil seal to put on the shaft and found this:



The seal has a step to it to help lock in oil!! I have never seen these before and started doing some research. They are called step or labyrinth oil seals. Such a simple concept but you won't find these in most rebuild kits. I found this company on ebay and although ebay reputation is usually related to Chinese related products, these guys are in the UK. While I have a 14B and 16G apart I may go with this upgrade which for us daily drivers should in theory be worth it.

Anybody have any success or failures on these step oil seals?

Got a link to these guys? Im in the UK so i can call and chat to them about it. Seems like a better idea then the straight cut seals in the kits

http://www.turborebuild.co.uk/

I don't think they necessarily "designed" this but so far has been the only company I found that offers them for a wide variety of turbos.

It just blew my mind when I saw the oil ring in that kit, maybe it's been out for 300 years but its new to me and I couldn't find much info on it so figured I'd share.

Tell them I said Hi if you make contact with them and pour a cup of Earl Grey in my absence!!

Haha, i found it just a minute go and have emailed them asking details. The got the td04/05 option 7mm shaft and td05/06 option 9mm shaft at least i think thats correct. They say they make them in house,

I am awaiting full details as to why this is a better seal but i can see why as it overlaps but im not expert on a seal alone

And i drink earl grey, its nice tea, of subject

So i spoke to them through emails as they seem pretty good. I ended up buying one, it will arrive in a few days so i can post up a pic next to an oem seal aswell to compare.

This is a reply i got from them about these seals

The Standard piston ring has square edges. To allow room for expansion, these two edges do not "butt" together. This means there is always a gap which allows blow by. This is more of an issue where the back pressure is low due to aftermarket exhausts with larger bores and less restriction eg less silencers and decats.

The Staggered seal the ends are stepped. This means that when in the bore and even with the expansion gap, there is not a hole for blow by and the ring overlaps. Similar design/theory to "total closure" engine piston rings

actually that explanation of how the ring works is not true. the ring most definitely buts together when installed. the butting together is necessary as it gives the ring extra tension which is needed to hold the ring in place. there is no gap on a standard ring when its installed.

94awdcoupe said:

actually that explanation of how the ring works is not true. the ring most definitely buts together when installed. the butting together is necessary as it gives the ring extra tension which is needed to hold the ring in place. there is no gap on a standard ring when its installed.

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So if it does BUTT together then surely the blowby as they called it should never get past (ever) but people do complain about it so it must be an issue and not fully seal like they say? I dont know how much it squeeses together by but it must resess back into its groove so it cant 100% touch or it would never close to go in!

At least thats how i see it working.

I have serviced maybe fifty turbos here. I think I know what I am talking about. the ring needs to fit tight or you need to use next longer ring. It butts together.

the staggered ring does nothing but drain your wallet.

Im not saying you dont know what your on about but from the way i see it is it has a clearence over the shaft then once pressed into the chra is closes up but..... As it resesses in the groove again it must open a tad so hence has a small gap otherwise how could it spring closed then open to seal? Thats at least what i saw when i was checking out the seal on my turbo. I will check it out as i got a spare chra and a normal seal so i will out it in and check the gap,

These have been around quite a while. Their intent is for use on worn bearing housings where the surface may allow a standard sealing ring's gap to be larger-than-spec, allowing pressure to seep through the gap in the sealing ring. Basically it keeps you from stocking rings in various oversizes...I keep one or two stagger-gap sealing rings for every brand on stock but only use them if the customer's bearing cartridge is worn- so probably less than 2% of the time.

If all of the parts are new the ring's gap will be .002" or less, so using one of these on a housing that doesn't need it is basically a waste of money unless the parts kits came with it.

In 94awdcoupe's defense, you were most-definitely fed a line of bullshit...there will always be a gap somewhere in the system, whether it be between the ends of the ring, between the ring and turbine groove at the sides, or underneath the sealing ring between it and the shaft. Dynamic seals do not seal 100% by design...older carbon seals would seal nearly 100% on the compressor-side (hence the reason they're the only type that will work in a draw-thru carbureted application- otherwise the carb would suck all the oil out of the engine through the turbocharger), but they also caused excessive drag on the shaft.

So in a working turbo with a proper-gapped sealing ring, you stand more of a chance losing oil between the shaft and sealing ring than between the gap in the sealing ring itself. Nothing can remedy this.

there is no groove in the housing where the gap would open back up. if your used housing has a groove then it is worn from the ring spinning. there is a raised edge that keeps ring from sliding too far in. but no groove.

I'll Throw my 2 cents in on this one as I have also rebuilt many a turbo. If the conventional style flat end seals had no clearance they would fail when the turbo gets hot. There HAS to be a gap otherwise the tension plus heat tension will snap the ring since they are hard but brittle. This is very common on haggard turbos with excess carbon build up. The blow by oil will slowly turn to carbon and build up under the seal on the shaft expanding the seal. Eventually they snap and when disassembled literally crumble and fall apart. I just had one do that on a 13G I took apart. The oil seal snapped and fell in 2 pieces on the work bench. The shaft grooves were almost completely packed full of hard carbon.

Also every MHI turbo I ever took apart has an oil groove on the hot side housing, it is critical for lubrication and needs to be cleaned before re-assembly.

So I respectfully disagree, I think these are well worth the cost and wouldn't be surprised if all the rebuild kits in the near future started to include them. I'm ordering them and will monitor the Volvo K05 turbo to see how it holds.

Also, my end of rebuilding turbos is the complete opposite of Jus. I literally am pulling turbos out of the trash and trying to salvage them (within reason). So 98% of the turbo's I will ever see are guaranteed to be worn and will be used on DD cars. So the extra $15 will let me sleep better, especially after a cup of Earl Grey!!

I have just checked with my spare chra and a traders greg seal and its damn close yes i agree, touching as in 100% butting most likely not. There is a ring groove in there, 16g at least im checking on. All my chra's are well within spec as they got tested before i decided to rebuild 2 of them, even if it was 100% touching there is still a straight path for weapage to go through. I mean the stepped ring will contain more as it will need to go sideways, it will find its way past but will be later rather then sooner then the non stepped ring.

YUPOK said:

Also every MHI turbo I ever took apart has an oil groove on the hot side housing, it is critical for lubrication and needs to be cleaned before re-assembly.

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The groove in the shaft as well as the groove in the housing need to be cleaned to allow the hydrodynamic seal to work as intended.

YUPOK said:

So I respectfully disagree, I think these are well worth the cost and wouldn't be surprised if all the rebuild kits in the near future started to include them.

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...and I'll respectfully disagree again, on the grounds that if it truly were a better design the manufacturer would utilize it when the turbo was built. I'm sure Garrett, Holset, and Schwitzer/Borg with maybe a billion units in operation between the three pay their R&D team great salaries to build their turbos the "best" it can possibly be...there's no way they'd overlook something as simple as a step-gap sealing ring if it gave them even a slight advantage over the competition.

I've seen turbos with these sealing rings installed come to me with oil puking out of both ends from a faulty PCV system or kinked oil drain...I'll rebuild it with a standard non-stepped sealing ring because the gap is within spec, and it works fine. They're not a cure-all for an underlying issue by any means...like I said before you have a better chance of losing oil between the seal and shaft than between the tiny .002" gap in the sealing ring.

For those of you reading this, Jus and I are actually brothers. We hang out every weekend and buy gifts at Christmas. He's mom's favorite though and he's older so he always needs to point out when I'm wrong, but I still love him!!

I'll always be mom's favorite, b!tch. Don't forget it.

Brotherly love, haha, be nice and agree whats right

I'm gonna buy him one of these for his birthday and bend it into a heart shape.

You just missed it, so you'll have a year to get the masterpiece finished. May want to start right away...I know how long it takes you to get shit done.

well I just checked a bunch of used housings with new rings. most of them butt solid with zero light getting through the gap. I always make sure there is no gap when I build a turbo. the ring and housing expand together as one. its not gonna crack when it gets hot. thats just silly. I am for new things that actually improve things. this just doesnt qualify for me. just not needed.