Why do Cylinder Sleeves Drop? | Darton Sleeves [TECH TALK]

Why do Cylinder Sleeves Drop? | Darton Sleeves [TECH TALK]

– As we’ve seen power levels rise
with high performance turbo charged aluminium block engines,
the actual strength of the engine block can become a limiting factor in to
how much boost and hence how much horsepower that engine
block can survive with. It’s become a common option
with these engines to fit aftermarket ductile iron sleeves
in place of the factory liners in order to improve strength. We’re here with John from Darton Sleeves
to talk about what goes into that technology. So John for a start,
let’s talk about those factory alloy blocks, what are the weaknesses
with those blocks, and why are the factory alloy
blocks a limiting factor in terms of power and boost? – The biggest issue with the OEM
setups is pretty much all of them, 90% of them come with a stock
cast iron sleeve in them. Issue with that is it’s a lower
grade material, they just do it primarily for
cost effectiveness. Their sleeves are only about probably
30, at the max 40000 tensile strength. Not a lot of strength in that sleeve,
and then they’re also cast thin because they’re not trying to go
bigger bore, they’re pretty much making that block
that bore size and that’s all it’s gonna do. So you’re limited on how much power
that can actually take because there’s also zero ductility
with cast iron. Any type of movement or flex
in that cylinder, since it is only cast iron,
it will end up cracking and stuff and that’s gonna be a real big limitation. Especially when you’re trying to take
a stock block and increase the power, add more boost, go much higher
compression pistons and stuff, so adding any more power than what
the OEM manufacture intended to, it will lead to eventual of failure
’cause that cast iron sleeve it’s in the ** – Now another problem with a lot
of the alloy blocks that we see are what’s referred to as an open deck design
where the sleeves and the cylinders themselves are really not connected
to the outside of the block so this also presents some other
problems even aside from actual sleeve strength with the sleeves
moving around and causing problems with head gasket failure,
is that a sort of a common scenario? – It is ’cause same issue with
the standard aluminium, they still come with the stock
cast iron sleeve, it’s not as much support. And then added to that,
the biggest issue with that, that goes hand in hand is since
there’s open deck configuration block, problem is there’s no upper structure
or any support. So what happens under say a high
horsepower application, is you end up getting sleeve walk. So the cylinders start rocking
under a high boost, the higher horsepower applications. So as soon as you get any type of movement
that cast iron ends up cracking, and it’ll crack all the way out
to the aluminium, ends up blowing head gaskets
or cracking the cast iron. – Even if we’re getting to a scenario
where we aren’t exceeding the strength of that cast iron sleeve and it’s
not actually cracking, with that open deck design,
the sleeves will still tend to flex a little bit at very high boost levels,
and ultimately distort slightly, and that’s going to still even affect
our ring seal and hence the power of the engine,
even if we aren’t cracking the sleeves, is that correct? – Correct, there’s still your limiting
factor of being cast iron. Having that open deck is just weakening
the support. Like I said any type of movement with that
then you’re gonna see a failure, or it’s gonna go distort and just
completely go out of round anyway, it’s not gonna maintain its figure and
stuff throughout the higher horsepower applications. – OK so let’s talk about Darton’s solution
to this. So you’ve produced a range of ductile
iron sleeves. In particular the product that I want to
talk about here is your MID sleeves that are used to replace the factory
cast sleeves on a lot of those open deck design blocks. So can you tell us what those
ductile iron sleeves are, and how they work? – Our MID sleeve, it’s made from our
proprietary material which is ductile iron It’s based on an ASTM spec for ductile
iron but we actually tweaked that metallurgy to be able to work
with a piston ring better than you know what the standard
ductile iron actually is. So what it is, it’s taking say your
30000 tensile strength cast iron that’s in a block and we’re replacing
it with a much thicker wet sleeve, and then it’s gonna end up
100000 to 130000 tensile strength. But at the same time still be ductile
to where if there say if there is real high horsepower application,
where there may be any distortion or flex in the bore, it’ll flex
and not end up cracking, but it’ll still kinda have a memory effect
and still go back to its original shape once the horsepower actually drops
back down. – Now there’s two aspects that I wanna
talk about there. So first of all, you’ve talked about the
improved strength of your proprietary material but on top of the improved
strength you’re also now, because you’re removing that factory
cast iron sleeve plus the alloy that surrounds it, you’ve also got
a much thicker wall to your ductile lined sleeve, correct? – Correct yeah i mean you’re looking
at say minimum, you’re going from usually stock cast iron,
which is only maybe 30000, 40000 thickness in the actual stock
and about another 100000 in the ** of the aluminium, we’re
eliminating all of that and replacing it with a full wet sleeve design,
which will completely take down the weakest part of that block
and replace it with a sleeve that’s gonna be 150000 to 250000 thick. And a material that’s also two to three
times stronger, and then giving you full support
at the top so you don’t have a problem with that sleeve walk
or the cylinders actually moving on you under the high horsepower
application. – OK so now just to talk about that
ductility because I know you showed me before, you’ve got a sleeve out
of a top fuel engine made out of that ductile iron material,
and you pressed that almost completely flat in a press and yet it still
hasn’t cracked correct? – Correct yeah I mean I’ll show
the material. I’m actually able to take our material,
this is a top fuel sleeve, let’s say John Force, Schumacher
or ** racing would use, and we’re able to actually take
this sleeve and crush it down probably to roughly about little
over an inch and the sleeve actually its memory
effect actually allowed it to spring back without cracking
without any signs of wear just because of the ductility
and strength of the material. – So obviously if your sleeve crushes
to that sort of diameter in operation you’ve probably got bigger things
to worry about than your sleeve cracking but it’s
a good indication or demonstration of exactly how flexible that material is. Now the other thing I wanna talk about
here is the way those MID sleeves convert an open deck design block
to effectively a closed deck, so can you tell us how that works? – Yeah effectively what we’re doing
is we’re eliminating all of that freestanding wall which is technically
the weakest part of the block anyway so using that kind of limits what you
are able to do size wise and power wise. So we’re eliminating that process
and then installing our wet sleeve so then that’s allowing you
to get full support at the upper deck of the block
so you have zero movement and then at the same time since
the material’s so much stronger than what the stock casting is,
and it is thicker, it also allows you to increase
displacement safely and still be able to push a safe amount
of boost through it, but increase the displacement
and adding more rigidity to the block. – Now I know that a lot of people
have trouble with the installation of sleeves and obviously with your
MID sleeves there is a significatnt amount of machine work required
to the block in order to correctly fit them. But a common complaint I hear
about sleeves in the aftermarket is that in operation they can drop. So what causes this dropping
and how can that be circumvented during the installation process? – Majority of the time it’s pure
installation error. The way the sleeves are designed,
they have a larger register on them, it’s a solid piece of metal,
there’s no moving parts, nothing moves, it maintains its shape,
maintains its form once it’s installed properly. Biggest issue with installation,
if the sleeves are gonna move it’s because you’re giving it somewhere
to go. A lot of times you have problems
where they’re decking a block, and the sleeves aren’t completely seated,
or they’re just not following, we have specific installation manuals
that show you the process step by step from setting up the block
measuring, checking where your registers gonna be,
gives you the tolerances. If you’re not able to hold those
tolerances, you’re gonna have problems with installing the sleeve,
the sleeve’s gonna move at that point because the tolerances
aren’t held to spec, or the machining is just not
exact as it could be. If you’re not using like I say
a three or four axle CNC, that would be your minimum basis
upon being able to machine the block properly is it’s gonna
be a CNC machine. – So what you’re saying there really
is this installation, to do it properly you’re getting
beyond the capability of actually doing a good job
within your tolerances using manual equipment? – Correct, I mean everything’s gonna
have tolerances to it. And when you are working with
say a half a thou with our stuff, it’s gonna be a half a to a thou
tolerances, a lot of the times without a CNC
that’s gonna be difficult to maintain, especially trying to maintain
bore centre where that’s critical. Because a lot of blocks have,
they’re thinner on one side than the other. Some of them need an interpolated cut
in order to put the sleeves in. You’re not able to do that with
a standard boring bar, or a standard bridge bore without having
digitals on it at least, to be able to maintain that bore centre. So that three to four axle CNC
will give you a lot more accuracy so that’ll eliminate the process of
you know taking guess work out, being able to machine the block
properly and get the sleeves in. ‘Cause once the sleeves are in,
they’re seated, there’s a large register on the bottom,
heads go onto the top, everything’s held in compression
with each other. So certainly if everything’s machined
properly, everything’s held in with tolerance,
everything’s measured exactly where it should be,
there’s nowhere for the sleeve to go. – Now in terms of the installation as well
I know there’s multiple schools of thought on whether
the sleeves should sit proud of the deck surface of the block
once everything’s been machined ready for assembly, or whether the sleeves should be
flush with the deck. Is there any recommendations from Darton
on that particular aspect? – It comes down to preference
and also application. Standard street cars where you’re
just trying to freshen up a block, you just need to get running again,
it’s gonna be standard horsepower, nothing too elaborate,
you generally can flat deck the block, that’s gonna be a problem,
let the MLS do its job. A lot of the times when you get
to the higher horsepower applications, some people either prefer to step deck,
where they’re leaving up the compression area two to three thou,
or running a seal wire in the sleeves. It comes down to number one,
how much power you’re planning on running, is this a street car or is it a drag car,
is it a road race a car? It depends on the power you’re making, how big a bore you’re going. Cause a lot of times when you go
to the max bore size on a sleeve, there’s not enough room for a seal
wire so you have to step deck instead to get the better crush
on the head gasket. Or some people with the really high
horsepower applications, they’re step decking an running
an o ring to get even more crush on the head gasket. So it depends on application
and certain machinists have their preferences on which way
they’re gonna do it. But a lot of it comes down to,
is what the applications gonna be, street, race, drag race,
really high horsepower, or street strip cars. – Now the other thing with these
MID sleeves or sleeves in general is if you do have a problem
with the engine in operation, maybe you torch a piston
and end up damaging one particular cylinder,
you’ve got the ability to replace and individual sleeve? – Correct, all of our sleeves,
our sleeve designs, they’re all replaceable individually
or full as a set. The technology that we based
these sleeves upon was basically the same thing
that diesel motors, tractor motors, ever since they’ve been in existence
that’s how they were, they were generally a ** design. So what we did is we took
that same concept and just changed the application for it. So by putting o rings,
sealing them along the bottom of the sleeves, what that essentially does
is makes the sleeves completely replaceable without distorting
or bothering the cylinders next to it. You can take out one cylinder
put a new cylinder it, redeck, rehone and reuse that
block over again. Or if you have a problem,
say you go to a max bore size of a kit, like say on a ** Honda,
you go to 90 millimetre, biggest you can go,
you can take all four sleeves out, put a whole new fresh set it,
redeck, rehone, start it back to 86 or 87 millimetre bore,
use that whole block over again. Since the cylinders are just put in
with an o ring, they don’t distort the cylinders next to
it because everything’s all individually held in separate from
each other. – Look John it’s been really interesting. Good to get some accurate information
behind that sleeving technology, get some answers to those questions. If our viewers wanna find out more
about Darton Sleeves, how can they get in touch? – You can email Darton Sleeves
at [email protected] Or go to dartonsleeves.com
all of our information’s right there, how to contact us,
and we have a lot of technical information on there also
that you can look up. And also download our catalog. Same thing it has a lot of technical
information in our catalog. – Perfect thanks a lot for your
time there John. – No problem, thank you for coming by. – If you liked that video,
make sure you give it a thumbs up, and if you’re not already a subscriber,
make sure you’re subscribed. We release a new video every week. And if you like free stuff,
we’ve got a great deal for you. Click the link in the description
to claim your free spot to our next live lesson. You’ll learn about performance engine
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About the Author: Michael Flood


  1. Another one of those times when Andre is heaps smarter than the poor bloke he's interviewing but always professional always a gentleman you walked him through it and made more good content …

  2. Sleeving aluminum blocks, especially open deck types is an absolute must, even if one is just going for a mere refreshing of the engine running stockish power. One might get away with not sleeving a stock aluminum block when refreshing it, or even removing material due to minor cylinder damage if the block has the thickness, but he will not get the longevity an iron alloy sleeve offers. Using high quality sleeves of a properly balanced iron alloy between durability, rigidity and ductility is also another must, poor sleeve design and alloy will net you more problems than just re-boring/honing the stock sleeves most of the times. The last must is correct and precise installation as stressed on this interview, get it wrong or do a sloppy job and get ready for a cracked block. High quality iron alloy sleeves, are low in silicon and higher in nickel. Darton sleeves for us gearheads, are considered high quality sleeves and are well known and proven for high performance in the motorsport field. Nice interview as always, and proper info from Darton.

  3. If you can't maintain 0.001 to 0.0005 tolerance with a non cnc machine then you shouldn't be claiming to be a machine shop. This guy doesn't know what the hell he is talking about as far as minimum tolerances go with non cnc equipment. Quality machine shops and machinist have been maintaining 0.0005 and much higher tolerances than that since WWII.

  4. I wish he would enunciate "deck" with more of an american accent. Sounds like he keeps saying dick surface lolol

  5. I agree Ductile Iron is far superior in tension than plain grey cast iron but please remember the material they are using is still a cast iron based material with additional flow, strength and casting additives that allows increased base tension strength due to the forming of the carbon (graphite) in more uniform formed rounder shapes (nodules) rather than the flakes normal grey cast iron has, this increases the bonding strength between the molecules and the reduction of sharp edged graphite (that causes stress raisers) and long thin graphite with high surface area and very low tensile strengths compared to the nodules shape.
    These materials in conjunction with the casting method and the following heat treatment allows the normal cast ion to be formed as Ductile (cast) iron. Yes I know its is a different final produce but the interview could lead to some people thinking its not a cast iron based produce, and no the guy was not wrong, every thing he said (except for the machining, how did we old tradesmen manage to produce high quality Areo and ship engines, diesel and turbines etc before cnc machines which do give a much higher consistency) is correct and Ductile iron liners are certainly a lot lot stronger than plain normal grey cast iron liners.
    A couple of things to remember.
    1/ Cast iron is very very high strength in compression, moderate strength in sheer but very low strength in tension (pressure in the cylinder cast iron liner into tension).
    2/ Grey Cast iron is still the best material for normal liners in the standard designed engine where the wall thickness is correct to prevent the tension failures. This is due to porous nature of grey cast iron that allows oil to impregnate the top layers and in conjunction with the flakes of graphite provide better lubrication and reduced friction for better. long term wear. This is why we generally don't use steel liners that could be made a lot lot stronger and lighter in weight, they just wear out to quick and have a lot higher friction losses without excessive lubrication and burning oil.
    3/ Ductile Iron liners are the best solution as a compromise between liner lubrication, slight increase in friction, good life expectancy and the need for higher internal cylinder pressures for higher non standard/performance engines.
    I'm not critical on this guy or your channel (I like it and your style) but the main reason I raise this is that i'm constantly hearing miss information and old wives tales in auto industry and if more people knew the details it would help, reduce fake costs, better tailored to suit the need outcomes and allow the good providers to get paid for what they are worth. (no not me I'm not in this industry just a poor old fitter and turner and fully qualified Marine Engineer who is semi retired and has far to much time on his hands, eg writing this long winded stuff)
    Ps. open deck blocks and liner support/flex can be addressed with recessed cylinder heads and a combination of head gasket to control fluids and movement wear and inserted firing/compression rings to retain the cylinder sealing but its out of the realm of most machine shops and a lot higher cost but very effective solution.
    P.sssss. the suppler site does discuss most of the technical stuff i crap on about above so looks to be a open and honest suppler.

  6. Not gonna lie didn't see his left arm for the first 90 seconds of the video and came to the conclusion he was a amputee then bam out it came to my disbelief

  7. thats not true..darton do there sleeve job not like there datasheet on download. honda blocks have so much sink sleeve.

  8. Hi Andre. Thank you for sharing this high quality content. I just want to drop a mention of the rover KV6 for your viewers who are likely interested in internal engine design. The KV6 is one of the biggest lemon engines in modern history. Absolutely notorious for head gasket failures due to dropping the sleeves which scraps the whole engine. Rover used an extremely unconventional design – interesting to research and see "what not to do" for a performance build. Basically they used an alloy block with extreme open deck design, with the floating IRON liners only held in place by clamping force from long thru bolts sandwiching the block between the head and main bearings. Not the sturdiest design and then you add the usual mix of british insanity, ie wrong thermostat placement, sloppy production tolerances, plastic head dowels(!), and bad gasket technology… the result was exactly as bad as what you would expect.

    The K engine caused massive headaches for landrover freelander owners, then after all the bad publicity, kia bought the licence cheap cheap and fitted it to their first generation carnival/sedona minivans. Something like 40% of their carnivals had engine blocks replaced under the 3 year warranty due to head gasket/sleeve failure and kia was still forced to offer goodwill engine replacements for vehicles well out of warranty. Anyway storytime over, keep up the good videos mate!

  9. I have the MID sleeves in a Noonan Block for a 427 build. It's still waiting for a suitable builder to finish it, but I recently heard a rumor that MID's are not suitable for a street build as the MID's could 'move around' and/or leak coolant. This video seems to point to installation errors for this to happen, but I was hoping to hear from other's that may have firsthand accounts.

  10. I would have liked to hear them discuss sleeving an Alusil engine that doesn't actually come with steel sleeves from the factory.

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