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Discussion Starter #1
Want to take a look inside an LT engine? I've got a few pics in my Gallery but here is a couple to click on:

Timing chain and guides here

Valve Spring Compressor (I built this tool from pics in the manual and it did a good job for me) check it out here

More pictures to come in the next few weeks as I rebuild the engine on my friends 2005. Next up will be the timing chain guides and possible cylinder head rebuild on our 2002 with over 191k (and no engine work other than valve adjusts).

The pictures are a little large and the preview is not coming up in the gallery. If you have any questions get the photo number, to paste it into a PM or on this thread, and I will interpret what the picture is trying to show you.

Regards,
 

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What prompted this work? Is this yours, a spare or??? And what gets done to it?
Inquiring minds want to know.
 

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I would love to find a dead LT engine just to tear it apart. Trouble is that shipping is so expensive the darn thing has to be local.

Thanks for the pics!

Loren
 

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I have disassembled my engine (01LT with 94K) for new clutch, replacement of valve stem seals and new (acually used) piston rings. Engine block and cylinder head is with my mechanic now. For disassembly pictues, see http://picasaweb.google.com/sully2028/01LTDisassembly#

Expect to start reassembly in a week or two when I get parts back from my mechanic.
 

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Discussion Starter #6
fpmlt said:
What prompted this work? Is this yours, a spare or??? And what gets done to it?
Inquiring minds want to know.
The engine is a replacement for the original that threw a connecting rod through the case. The analysis of the thrown rod is incomplete and will not be fully known until after the replacement "used" engine is rebuilt and installed. I'll tear down the original engine and post my theory at that time; that is if a theory can be determined.

As I stated in my original post this cylinder head and engine belong to a friends bike and my 2002 is going to be my next project since it has a fair amount of miles on it. I was going to wait for the 200k mark to tear it down but I fell short of the miles prior to winter by 8.4k.
 

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Those cross hatch hone marks in the cylinder look to me like it was honed with a very coarse stone. Not what I would expect to see.
 

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2005 K1200LT
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RealWing said:
Those cross hatch hone marks in the cylinder look to me like it was honed with a very coarse stone. Not what I would expect to see.
Guess it does not really matter Jim as they are still there after 100K. Only the rings wear in this engine.
 

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RealWing said:
Those cross hatch hone marks in the cylinder look to me like it was honed with a very coarse stone. Not what I would expect to see.
The way NikaSil is done is to hone the aluminum bore first, then electroplate the cylinder with Nickle. There is very fine Silicon Carbide powder in the nickle plating bath, so fine particles are embeded in the nickle plating. Silicon Carbide is extremely hard (used as an abrasive for very hard stuff). Then a very fine diamond hone is used briefly to smooth the surface so that sharp points of SC are not sticking up beyond the surface.

The hone marks you see are from the original hone of the aluminum, and are coarse enough to insure oil retention on the surface. That is what honing of any cylinder is really for, oil retention. If too smooth, not enough oil is retained, and the rings will wear fast, along with the cylinder surface on cast iron. The NickaSil "liner" is so hard it will outlast just about everything else in the engine.It is also very thin, only a couple thousandths of an inch thick.
 

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dshealey said:
The way NikaSil is done is to hone the aluminum bore first, then electroplate the cylinder with Nickle. There is very fine Silicon Carbide powder in the nickle plating bath, so fine particles are embeded in the nickle plating. Silicon Carbide is extremely hard (used as an abrasive for very hard stuff). Then a very fine diamond hone is used briefly to smooth the surface so that sharp points of SC are not sticking up beyond the surface.

The hone marks you see are from the original hone of the aluminum, and are coarse enough to insure oil retention on the surface. That is what honing of any cylinder is really for, oil retention. If too smooth, not enough oil is retained, and the rings will wear fast, along with the cylinder surface on cast iron. The NickaSil "liner" is so hard it will outlast just about everything else in the engine.It is also very thin, only a couple thousandths of an inch thick.
Nice description of the Nikasil process, but I have to disagree with you somewhat on the honing description.

Most honed finishes have average surface roughness values in the 0.1 to 1.5 micron range (see reference below). Given that a micron is 0.00004 and thus WAY less than a thousandth of an inch, a honed surface would be almost completely obscured by even one thousandth of an inch of Nikasil.

I am no expert on Nikasil, but I would be surprised if the cylinder is honed prior to Nikasil application. I would not be surprised if BMW just bores the cylinders and then applies the Nikasil. I suspect the boring is close enough roughness-wise to hold the Nikasil well and allow the Nikasil hone to provide the correct final surface roughness to allow for good oil distribution and control.

I suspect the marks in the picture are the machining marks from the boring operation or possibly a very amateurish attempt to hone the cylinder after it was plated, but I suspect the former more than the latter.


http://www.tomorrowstechnician.com/Content/Site301/SmartProducts/CommonPractices_00000000930.pdf
 

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Voyager said:
Nice description of the Nikasil process, but I have to disagree with you somewhat on the honing description.

Most honed finishes have average surface roughness values in the 0.1 to 1.5 micron range (see reference below). Given that a micron is 0.00004 and thus WAY less than a thousandth of an inch, a honed surface would be almost completely obscured by even one thousandth of an inch of Nikasil.

I am no expert on Nikasil, but I would be surprised if the cylinder is honed prior to Nikasil application. I would not be surprised if BMW just bores the cylinders and then applies the Nikasil. I suspect the boring is close enough roughness-wise to hold the Nikasil well and allow the Nikasil hone to provide the correct final surface roughness to allow for good oil distribution and control.

I suspect the marks in the picture are the machining marks from the boring operation or possibly a very amateurish attempt to hone the cylinder after it was plated, but I suspect the former more than the latter.


http://www.tomorrowstechnician.com/Content/Site301/SmartProducts/CommonPractices_00000000930.pdf
I cannot say how every cylinder surface operation is done, but it was very common in the past to use a very coarse hone on the aluminum cylinder liner, then plate it up to just undersize, then diamond hone it lightly to smooth out the surface. The coarse original honing would not be "filled in" by the plating, as the plating follows the surface profile closely. The rather large grooves from the original hole would be closed in some, but there would still be the ridges and valleys left. I have seen this process written up on more than one occasion, but will have to research it again.

Nickasil has been used for some time in aircraft engine cylinders, but most of those are still on iron liners, and used for wear resistance.
 

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dshealey said:
I cannot say how every cylinder surface operation is done, but it was very common in the past to use a very coarse hone on the aluminum cylinder liner, then plate it up to just undersize, then diamond hone it lightly to smooth out the surface. The coarse original honing would not be "filled in" by the plating, as the plating follows the surface profile closely. The rather large grooves from the original hole would be closed in some, but there would still be the ridges and valleys left. I have seen this process written up on more than one occasion, but will have to research it again.

Nickasil has been used for some time in aircraft engine cylinders, but most of those are still on iron liners, and used for wear resistance.
Which engine makers? I have been a pilot since 1978 and I don't recall either Lycoming or Continental using Nikasil. I believe Lycoming has used hard chrome in the past and now uses nitriding as does Continental. Just don't recall them using Nikasil and can't really see why you would on steel liners as you have other means to get hardness and wear resistance that aren't available with aluminum.

I know at least one maker of experimental engines (AeroVee) uses Nikasil on they VW conversions. I don't know much about the Rotax line, but maybe they use Nikasil.
 

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Voyager said:
Which engine makers? I have been a pilot since 1978 and I don't recall either Lycoming or Continental using Nikasil. I believe Lycoming has used hard chrome in the past and now uses nitriding as does Continental. Just don't recall them using Nikasil and can't really see why you would on steel liners as you have other means to get hardness and wear resistance that aren't available with aluminum.

I know at least one maker of experimental engines (AeroVee) uses Nikasil on they VW conversions. I don't know much about the Rotax line, but maybe they use Nikasil.
It was not Nikasil as I said, but Cerminil (very similar, if not just another name for the same process). Cylinder rebuilders were using it, and I think Superior was using it in their new replacement cylinders.

Here is an article on cylinder options from AVWEB, there are quite a few options that have been used.
http://www.avweb.com/news/maint/182902-1.html
 

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dshealey said:
It was not Nikasil as I said, but Cerminil (very similar, if not just another name for the same process). Cylinder rebuilders were using it, and I think Superior was using it in their new replacement cylinders.

Here is an article on cylinder options from AVWEB, there are quite a few options that have been used.
http://www.avweb.com/news/maint/182902-1.html
Well, given the Cermichrome experience, I think I'll wait for the Cerminil movie... :)

Personally, I'll take a nitrided steel cylinder over a Cerminil plated cylinder any day. With an aluminum sleeveless engine, that isn't an option and it appears that Nikasil is a very good alternative.
 

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Discussion Starter #17
Randi's Trike Engine Exchange (The Cylinder Head)

The engine block is the next to come out now that we have the front end back together and the trike is stable on the bike bench. The blown engine is lightened up with the crank and pistons removed. Next I'm building a hoist for lifting the frame up to facilitate removing the transmission and engine block. The trike rear section had to be separated from the original LT subframe for this next step in the process. In the mean time I rebuilt the cylinder head off the original engine. After glass beading the head and lapping the valves I built a better tool for compressing the valve springs. With the head now complete we are ready for the old engine removal and start on the replacement rebuild.
 

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Couple'a things: that front end looks real nice. Is that powder coating? Looks good Randi.
Earnie, any idea or thoughts as to why the bottom end blew? That there's some impressive damage.
 

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Discussion Starter #19
fpmlt said:
Couple'a things: that front end looks real nice. Is that powder coating? Looks good Randi.
Earnie, any idea or thoughts as to why the bottom end blew? That there's some impressive damage.
The front end and wheels are powder coated. The work is done very well BTW. The company that did the work is in Bend, and if you want the contact info drop me or Randi a line.

The cause of the bearing failure is not clear. It could be for a number of reasons, but for for one it was not for a lack of lubricant at the time of failure. Randi bought this bike used and had the trike conversion completed. There might have been some damage done prior to his purchase. Who knows for sure?
 

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Discussion Starter #20
Re: Inside Your Engine (aka Randi's Trike)

It's been a long haul putting this project together. The used engine was quite a bit worn in some areas and others showed some quality maintainence. For instance, the pistons were shot (two had broken ring lands) and the oil sump was full of gunk from non-to-frequent oil changes, while the water/oil pump was just rebuilt as well as the timing chains and guides. The best course of action was to completely rebuild the engine.


What we started with (Randi's blown '05 engine)


What we have now (The rebuilt '02 engine with '05 upgrade parts)

I've posted quite a few pictures on my gallery if you are interested. Have fun looking inside an LT engine.
:bmw:
 
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