Wet Cylinder Liners 5

[m899nyc]

Is there a limit to the number of times you can rebuild an engine if you use wet sleeves? My understanding is that wet sleeves act as the actual cylinder and are held into the block with an o-ring. If you can simply remove the sleeves and overhaul the engine, does this mean an classic engine block could be maintained in running order indefinitely?

 

[dgallup]

You can certainly replace cylinder liners that are not cast in. Frequently there is a press fit or shrink fit. The block is still not going to last forever, even rocks don't last forever.

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[m899nyc]

Is there a limit to the number of times you can replace liners that are not cast in?

What is the lifespan of a cast iron block anyway? Many early engines are around, even Model T's. Heck, even firearms last centuries.

 

[catserveng]

On larger engines with liners fit to counterbores or mated to the top of the block suffer from erosion and wear. There are repair procedures for counterbores, including inserts. Liners mated to top deck surfaces of the block can sometimes have inserts installed, depends on the block and the manufacturers recommended repair procedures.

Low and medium speed engines have longer service lives, smaller lighter high speed engines have lower service lives. Different types of engines are built and rated for long time use, others are built to provide maximum horsepower in as small a footprint as possible.

So really the best answer to your question is, it depends. What kind of engine are you talking about? How is it rated? What kind of service is it in? How many hours a year does it run?

Hope that helps, MikeL

 

[m899nyc]

The engine is a turbocharged 6.75 Rolls Royce V8 in daily service.

Irv Godron kept his engine running 3 million miles with 2 rebuilds. I intend to daily drive this vehicle for as long as possible. I'm here to set a record.

Engine is wet lined, so, if it needs an overhaul, I would simply replace the liners, correct? If those ever needed another change, just repeat the process, correct?

 

[catserveng]

I'm not familiar with that engine, but in general with "wet" liners, the points at which they interface with the block does wear. Most wet liner systems I'm familiar with have both a surface inspection criteria for the area where the liner meets the block, and in many cases a liner protrusion measurement requirement that must fall into manufacturers specs.

There is also the area at lower portion of the liner where the liner seals the cooling jacket, in most cases seal rings are used, and after time the sealing rings can erode the surface in the block, requiring repair as well.

Maybe someone with direct experience on that engine will contribute.

MikeL

 

[tbuelna]

If the materials used for the wet liner and block are dissimilar (say an iron liner in an aluminum block) there can be long term fretting and corrosion issues at the close-tolerance interfaces. This would usually require machining surfaces of the aluminum block oversize to remove any corrosion/fretting damage, and then making a new iron liner to match. Fortunately, it is not too costly to have custom iron liners made.

 

[m899nyc]

"There is also the area at lower portion of the liner where the liner seals the cooling jacket, in most cases seal rings are used, and after time the sealing rings can erode the surface in the block, requiring repair as well."

Interesting. How is this repair performed?

 

[BigClive]

If I remember correctly the Jaguar V12 engines (or at least the earlier ones I am familiar with) did not allow the option of rebores and oversize pistons etc. Oversize pistons were not available - liners and matching pistons only. This made Jag V12 engines very expensive to rebuild.

 

[dgallup]

3 million miles is a long way short of forever. Plenty of diesel engines have gone farther than that.

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[m899nyc]

How many rebuilds did those diesels take?

 

[catserveng]

In the lower liner bores for smaller erosion problems we had a procedure to use Belzona then remachine the lower line bore, this repair usually lasted until the next major overhaul, 30-50,000 hrs. More severely damaged lower bores were cut oversized and sleeves were fitted, we had a number of engines operating with reworked lower liner bores for an additional 100,000 hrs.

I recently did a plant upgrade on older natural gas engines that had been in service since 1983, with an average annual runtime of 8400 hrs/year, so each engine had about 268,000 hrs. Those engines had top end overhauls every year-cylinder heads, turbo's, fuel system repairs, about every three years major overhauls (what we called in frames), that added liners and rings, and crank bearings. Each engine had two shop overhauls down to bare block, that included machining the counterbores, top decks, and line bores in their life. Those engines ran 100% of their rated load all the time.

I think the longest running plant I worked on was in Australia, with the engines installed in 1947, they were gradually replaced from 2009 to 2012, the oldest engine had about 425,000 hours on it, as I remember those engines averaged about 6500 hrs/year at an average load factor of about 60%.

I'm sure someone else here has had contact with longer running engines, I know some manufacturers have cited 500,000 hours on some of their engines. So well built properly maintained heavy duty engines can last many years and rebuilt many times, virtually all I know of using wet liner type technology. Some industrial diesels did use dry sleeves but usually higher speed smaller units used in boats and standby generators.

We used to use a formula that CAT came up with for "equivalent miles" I'm sure some sales guy thought it up for our engines that were used in both industrial and on hiway trucks, they used 1 engine hour equaled 40 miles, which actually seemed to work out pretty close for one of our most popular models. So if I apply that to my two old gassers 268,000 X 40 = 10,720,000 miles (at or near full load all the time).

Not really a good comparison to your car engine, but wet liner technology has been around a long time and used in engines that easily go beyond your 3 million mark all the time. Like everything else, I'd say it's not just the liner, but how well the block supports the liner and other moving parts (like the crank) that provides the overall longevity to the engine.

MikeL.

 

[Overrun]

The 1300 Alfa engine I raced way back underwent many rebuilds with the same wet liners, though the time between rebuilds was maybe 20 hours run time. With electrolytic problems aside and using a torque plate when honing to tidy up the cylinder surface, no problems at all.

 

[JayMaechtlen]

My sister and her husband are long haul truck owner-operators, working out of the NW US.
They bought their first truck with ? 800k miles on it, and it suffered a failure at about 1.3 million and got an overhaul at that point.
They've since upgraded to new rigs that meet the Calif emissions, so the old beasts have moved to other owners. (They have his and hers rigs)
But, that's over a million miles on the original engine. If overhauled properly, you'd expect a similar time of service.
So, 3 million miles should require only two overhauls.
ymmv.



Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[Panther140]

IIRC you can get over sized pistons from niche manufacturers as long as you have them make X amount for you

"Formal education is a weapon, whose effect depends on who holds it in his hands and at whom it is aimed." ~ Joseph Stalin

 

[Mitsos1]

A second comment regarding Alfa engines... The prevalent type since late 50's -early 60's has aluminum alloy block with drop-in cast iron wet liners, sealing with a thin rubber ring sandwiched between liner/block seat. Liner protrusion from top of block is .01-.05mm. We have opened countless 40-45 year old engines and those maintained with suitable coolants (not just water) had almost no wear/pitting on the critical block/liner interface, allowing simple no-hassle liner replacement. I can see someone doing this several times without problems provided the block is not distorted because of overheating etc. Engines with water as coolant present pronounced block seat pitting and even worse head surface pitting -that is, IF the head can be pulled off to see below! Head pitting can be easily welded and re-surfaced but block seat defects are not that easy to repair. Most of the time its simpler/cheaper to source another 'clean' block.

 

[PackardV8]

The engine is a turbocharged 6.75 Rolls Royce V8 in daily service.

IIRC, that engine has been used in RR/Bentley for many years and continually improved. What year is yours?

Today's petrol engines with thin low tension moly rings, computer controls of fuel, ignition and warmup and double overdrive automatic gearboxes will vastly outlast the previous generations. We've been rebuilding engines for fifty years and are continually amazed that many of the late models exhibit no cylinder bore wear after 150,000 - 250,000 miles. The last century designs at 100,000 miles would have .020" or greater cylinder taper, coked and burned valves, worn valve guides.

FWIW, we've doubled the effective life of some obsolete engines by converting them to better piston and ring materials, more accurate machining and assembly, and electronic controls.

jack vines