Metal Stitching an Engine Block from 1921 in-situ!

1921 Duesenberg Model A

We do a lot of in-situ work. We routinely carry out machining and metal stitching work, among others, on components that are too large to be moved to a workshop or where dismantling work is too time consuming or costly. But repairing a an antique car engine block, in the chassis, in a museum, is still quite special. Even for us.

The engine in question is an in-line, eight cylinder one with a bore of 72 mm and a stroke of 125 mm (2.875″ x 5″). With a swept volume of 4’256 cc, or 260 cubic inches, this early Duesenberg Model A engine is capable of producing up to 88 hp (66 kW) of power.

Repair in progress. The engine remained in the chassis, only the cylinder head was removed.
Repair in progress. The engine remained in the chassis, only the cylinder head was removed.

We got the opportunity to work on this engine as cracks had began to show at the corners of the engine block. The cracks originated from the threaded bores housing the cylinder head studs. They extended towards the outside of the engine block on one side and into the cooling water passage on the other.

The fact that the engine was left inside the chassis made the repair a little more challenging than usual. Our metal stitching expert had to use a mirror for much of the repair work. Without it he could not see, let alone repair the cracks at the rear end of the engine block. In addition to sealing the cracks with stitching pins, our expert also installed Full Torque™ thread inserts at the threaded bores. Unlike conventional thread repair inserts, Full Torque™ inserts do not create spreading forces. They are therefore the perfect solution for cases like this one, where threaded bores close to an edge have to be repaired.

Cracks extending from the cylinder head stud bores to the outside and to the cooling water space
Cracks extending from the cylinder head stud bores to the outside and to the cooling water space
Installation of Castmaster stitching pins.
Installation of Castmaster stitching pins. They are the strongest and most advanced stitching pins on the market today.
Ultrasonic inspection of the casting
Ultrasonic inspection of the casting to determine the wall thickness
Metal stitching in progress. Due to the location of the crack a mirror was used.
Metal stitching in progress. Due to the location of the crack a mirror was used.
The completed repair. Cracks stitched and Full Torque thread inserts installed.
The completed repair. Cracks stitched and Full Torque thread inserts installed.

Links

Metal Stitching

Metal stitching is a very well-established repair method. It is applicable to a wide variety of materials such as cast iron, cast steel and many non-ferrous metals.

View more

Thread Repair

The repair inserts that we use to repair damaged threads are super strong and do not create spreading forces. They are ideal for high-load applications.

View more

Metal Stitching a Fractured Engine Block from 1913

Pierce Arrow

This post describes the repair of a Pierce Arrow engine block from 1913. The Pierce Arrow was the largest production automotive engine at its time. The swept volume of this 6-cylinder, 48 hp (36 kW), engine amounts to a whopping 13’500 cc (824 cu in)!

This engine is of the T-head engine type, which is essentially an early form of crossflow engine. This design is characterized by two separate camshafts, one on either side of the cylinder. One camshaft operates the inlet valves and the other the exhaust valves. This makes this engine design quite complex and expensive to produce.

The main advantage of the T-head engine design is the fact that it is not at all prone to knocking – a condition where the gasoline vapour in the cylinder ignites too early by itself due to compression, before it is lit by the spark plug. Knocking was a big issue especially during the early decades of the 20th century, when gasoline sold typically had a very low Octane rating. T-head engines were therefore popular until about 1920, when better fuel became widely available. At that time, the disadvantages of the design started to outweigh the advantages.

A large piece had broken off the cast iron engine block and had to be reattached
A large piece had broken off the cast iron engine block and had to be reattached

The in-line 6-cylinder Pierce Arrow cast iron engine block that we received for repair at our workshop at Lock-N-Stitch in California, USA, was severely damaged. A large piece of the casting had been broken off at the block’s front (timing belt) end.

Our metal stitching specialists successfully reattached it. In order to do so, they installed about thirty Castmaster™ stitching pins over a total fracture length of 160 mm, in material with a thickness ranging from 12 – 16 mm. For additional strength, they also installed two high-strength locks perpendicular to the fracture line.

The fracture line passed through a hole for a positioning dowel pin. To repair that, our specialists first closed the hole by installing a solid Full Torque™ plug, before drilling it anew in the exact location.

Badly fractured engine block
The completed repair.
The completed repair.
Close-up of the fracture line
Close-up of the fracture line
Repair completed. Stitching pins, locks and Full Torque insert installed
Repair completed. Stitching pins, locks and Full Torque insert installed

Repairing a V12 Flathead Engine Block from 1934

Packard Twelve

We routinely work on museum pieces. In this post we introduce a typical case: The repair of a Packard Twelve engine block from 1934, carried out by our colleagues from Lock-N-Stitch in California.

As the name implies, the Packard Twelve is a 12-cylinder engine. It is a flathead engine, sometimes also called side-valve engine, where the intake and exhaust valves are contained within the engine block rather than within the cylinder heads. Flathead engines were very popular until the 1950s and were built in large numbers by automotive manufacturers. Their advantage is their simplicity, compactness, reliability and low cost as the flathead design obviates a complicated valve train. Such engines therefore need far less components than alternative designs such as, for example, single or double overhead camshaft arrangements.

The main disadvantage of the flathead engine is its relatively low efficiency and power output. The Packard Twelve V12 engine has a displacement of 7300 cc (445 cu in) and a maximum output of 119 kW (160 hp).

Engine block received with cracks in both longitudinal side walls and around the valve seats
Engine block received with cracks in both longitudinal side walls and around the valve seats
Repair finished
Repair finished. We stitched about 200 mm (8 inches) of cracks in this engine block.

Repair of cracks in the side walls of the engine block

When the engine block was delivered to us, it contained eleven cracks of various lengths. Some were small, others rather long. Added together, they amounted to a total length of 200 mm. In addition, the block suffered from corrosion and material loss around the camshaft spaces.

The cast iron block had been “repaired” before by arc welding. This has not been a great success – new, fairly large cracks could be seen extending to the left and right of the weld.

As they always so on cast iron parts on which someone has already been attempting a repair by welding, our specialists cut out all material in the vicinity of the weld, in the so-called heat affected zone. This is our standard operating procedure. Whenever cast iron is welded at, the heat from welding burns out the carbon, which constitutes between 2% and 4% of the cast iron. Once the carbon is burnt, the cast iron becomes hard and brittle, looses its structural integrity and becomes worthless.

To replace the cut out material on both longitudinal sides of the block, our specialists installed repair patches made of cast iron. They stitched them firmly in place with Castmaster™ stitching pins. Similar pins of various lengths and diameters were also used to repair the cracks found in various locations on the block, in material ranging from 3 – 10 mm thick. Some of these cracks are visible in the pictures below.

Our specialists also installed five Full Torque™ thread inserts to repair thread holes damaged by corrosion and erosion.

The engine block had been arc welded in the past. As expected, this did not solve the problem but led to further cracks extending left and right.
The engine block has been arc welded in the past. As expected, this did not solve the problem but led to further cracks extending to the left and right of the weld.
Crack extending leftward from the weld, serious corrosion at the edge of the sealing surface.
Crack extending leftward from the weld, serious corrosion at the edge of the sealing surface.
We removed the material that has previously been welded and installed a repair patch.
We removed the material that has previously been welded and installed a repair patch.
Crack extending rightward from the weld. Again, serious corrosion at the sealing surface.
Crack extending rightward from the weld. Again, serious corrosion at the camshaft cover sealing surface.
Installation of stitching pins to seal the crack
Installation of stitching pins to seal the crack
Skimming of cylinder head landing surfaces
Skimming of cylinder head landing surfaces
Left longitudinal side wall completed
Left longitudinal side wall completed
Right longitudinal side wall completed
Right longitudinal side wall completed

Repair of cracks around the valve pockets

A thorough magnetic particle inspection (MPI) of the block revealed hairline cracks between some of the valve seat and cylinder liner bores. We permanently repaired these cracks by installing small size stitching pins.

After completion of the repair, we took the opportunity to skim all cylinder head gasket mating surfaces, on the engine block as well as on the two cylinder heads.

Crack between valve seat and cylinder bore clearly visible during Magnetic Particle Inspection (MPI)
Crack between valve seat and cylinder bore clearly visible during Magnetic Particle Inspection (MPI)
Cracks between valve seat and cylinder bores successfully repaired
Cracks between valve seat and cylinder bores successfully repaired
Another crack
Another crack, seen here under Ultraviolet (UV) light during MPI

Tractor Engine: Stitching Repair in the Combustion Chamber

Ford 1710

This post is about a small metal stitching repair that we carried out on the cylinder head of a Ford 1710 tractor built in 1984.

The cylinder head of this 3-cylinder, 1’400 cc (85 cu in), 84 mm bore and 84 mm stroke engine suffered from a crack close to one of the fuel injectors. The crack led to cooling water leaking into the combustion chamber. The cylinder head had been repaired before, by metal stitching, but not by us.

3-cylinder, 26 hp (19.4 kW), Ford 1710 tractor cylinder head
3-cylinder, 26 hp (19.4 kW), Ford 1710 tractor cylinder head

To permanently repair it, we carried out the following work on the cylinder head of this 19.4 kW (26 hp) engine:

  • Dismantling
  • Visual and Magnetic Particle Inspection (MPI)
  • Metal stitching of two cracks
  • Milling of the landing surface
  • Reassembly
  • Pressure testing

Metal stitching cracks inside various engines’ combustion chambers is something that we routinely do with excellent results. Our repairs are well able to withstand the challenging environment of up to 200 bars (2’900 psi) pressure and 350° C temperature that exists there. This time, the repair will last (unlike the earlier one, not done by us).

Magnetic Particle Inspection (MPI) reveals two cracks, extending from the earlier repair into the valve seat bores
Magnetic Particle Inspection (MPI) reveals two cracks, extending from the earlier repair into the valve seat bores
Cracks repaired, valve seat rings reinstalled
Cracks repaired, valve seat rings reinstalled
After skimming of the landing surface
After pressure testing and skimming of the landing surface
The reassembled cylinder head prior to return to the customer
The reassembled cylinder head prior to returning it to its owner

Metal Stitching Repair on a Small Diesel Engine Bed Plate

A customer reached out to us in May 2022 in Singapore, asking for our help in repairing a damaged two-stroke engine bed plate. The cast iron bed plate suffered from cracks and missing material, inflicted as consequential damage following a connecting rod failure.

Our experts immediately carried out an inspection on board. They found this main engine bed plate to be repairable, but determined that the damage area could not be accessed properly without removing the engine’s A-frame. The shipowner therefore decided to bring the 19-year old, 100 m long asphalt carrier alongside a ship repair yard in Singapore.

“We are very satisfied with your service.”

Customer’s Technical Superintendent, by email, August 2022

Damage location
Damage location

While the shipyard’s personnel dismantled the ø 38 cm bore, japanese-made engine, our specialists prepared a repair plan and discussed it with the customer and classification society. Simultaneously, they arranged for a tailor-made repair patch to be made, including a set of accompanying classification certificates.

In late June 2022, once the engine had been suitable dismantled, three metal stitching specialists from QuantiServ Singapore carried out the bed plate repair. They first removed all damaged and deformed material and dressed up the facture. They then installed the newly fabricated cast iron repair patch with Castmaster™ stitching pins. They repaired all cracks in the same manner, including a 150 mm long one that had not been visible until the deformed material had been removed.

Once all stitching pins had been installed, our specialists then added high-strength locks, made of heat treated steel. These are always installed perpendicular to the fracture line and serve to distribute stresses over a wider area. They also add additional strength to the repair.

The completed repair was thoroughly checked by Magnetic Particle Inspection (MPI). The attending classification surveyor witnessed this. And last but not least, our in-situ team carried out a laser alignment check of the main bearing pockets. This was done to rule out any deformation in the bedplate due to the impact forces exerted upon it by the broken connecting rod.

Damaged bed plate prior to repair
Damaged bed plate prior to repair
Damage area prepared for stitching repairs
Damage area prepared for stitching repairs
Classification surveyor attending the Magnetic Particle Inspection (MPI)
Class surveyor witnessing Magnetic Particle Inspection
Installation of stitching pins along the crack line
Installation of stitching pins along the crack line
Stitching in the repair patch
Stitching in the repair patch
Magnetic Particle Inspection (MPI) of the completed repair
Magnetic Particle Inspection (MPI) of the completed repair
Magnetic Particle Inspection (MPI) of the completed repair
Magnetic Particle Inspection (MPI) of the completed repair
Preparing the repaired bed plate for laser alignment check of the main bearing pockets
Preparing the repaired bed plate for laser alignment check of the main bearing pockets

Metal Stitching and Line Boring on a Japanese Auxiliary Engine Block

In late 2021, a Greek owner of a 4250 TEU container vessel approached us for the repair of an auxiliary engine. The 26-bore, japanese-made engine had suffered from a so-called “side kick” – the connecting rod had smashed a hole in the engine block, above cylinder #2.

As the vessel was about to call Singapore, QuantiServ Singapore arranged for one of its metal stitching specialists to go on board to conduct a comprehensive damage assessment.

As is nowadays almost always the case, our specialist deemed the engine block damage to be repairable. We engineered a repair proposal, consisting of metal stitching and in-situ machining to be carried out in our workshop in Singapore. The customer gladly accepted our repair proposal due to the obvious time and cost savings compared to replacing the engine block. He made arrangements for the 12-year old engine block to be sent to our Singapore workshop for repair.

The block arrived at our workshop in March 2022 and was immediately attended to. The repair work carried out included the following main steps:

  • We arranged for a tailor-made cast iron repair patch to be cast in a certified partner foundry. The repair patch was then stitched in place using Castmaster™ stitching pins and matching locks. This provides for a permanent, very strong repair.
  • As the damage extended into the lower cylinder liner bore, a repair sleeve was installed there. The repair sleeve guarantees a good fit with the cylinder liner o-rings, preventing water leaks.
  • The ovality of seven out of nine main bearing pockets was found to be excessive. This finding was independent of the accident but needed attention too. We corrected the ovality with in-situ line boring.
  • All eight cylinder liner landing surfaces in the engine block were machined to clear them from corrosion and cavitation damage.

A Magnetic Particle Inspection (MPI) was carried out on the completed repair to the satisfaction of the customer and attending class surveyor.

From start to finish, the repair work took approximately four weeks to complete, well in time for the engine block to be sent back to the vessel during her next routine call to Singapore.

Engine block damage at cylinder number 2
Damaged engine block
Installation of stitching pins
Installation of stitching pins
Machining of the cylinder liner landing surface
Machining of the cylinder liner landing surface
Engine block debris
Engine block debris
Repair patch installed
Repair patch installed
Cylinder liner landing surface after machining
Cylinder liner landing surface after machining
Newly casted repair patch
Newly casted repair patch
MPI inspection after stitching
MPI inspection after stitching
Another job well done
After completion. Another repair job well done!

Upcopming Webinar: Repairing the Irreparable

Advanced in-situ machining and metal-stitching repair solutions

 

In the marine sector, every time a machinery component is worn out or damaged, an important decision needs to be made: To either repair or replace the component with a new one.

Factors such as technical or operating possibilities, lead time for a replacement component, size or weight of the damaged component, the downtime required for the replacement works, loss of revenue, cost of the repairs etc need to be carefully evaluated before deciding to repair or replace a key component with a new one.

Join QuantiServ and Wärtsilä on the 7th of July 2021 at 14:00SGT to explore:

  • Possibilities and benefits of repairing a damaged machinery component with advanced in-situ machining, instead of replacing it.
  • Possibilities and benefits of repairing a damaged machinery component with metal stitching, instead of replacing it.
  • Reference cases

Naeem Arshad Zubair

Sales Development Manager, Specialized Services, Wärtsilä

Moderator

Peter Schwiecker

Technical Manager,
QuantiServ

Presenter

Jeff Reed

Sales Manager,
Lock-N-Stitch, QuantiServ

Presenter

Key Data 2020 – Number of Customers and Orders Increased

We have steadily grown our reach and our customer base during recent years. In 2020, our 356 staff have successfully processed close to 3’000 Reconditioning, In-situ Machining, Metal Stitching, Epoxy Resin or Mobile Team orders from nearly 700 individual customers.

We carried out 70% of these orders in one of our 14 workshops. The remaining 30% of orders we processed on board ships or in customers’ plants.

The customers that we served stem from a wide range of industries. On average, we commenced a new in-situ machining assignment every three hours, anywhere in the world.

Key Data 2020:

Metal Stitching on Historic Bridge in Washington DC, United States

Our American colleagues have just completed metal stitching repairs on a historic bridge crossing the Chesapeake and Ohio Canal.

The Canal

The Chesapeake and Ohio Canal stretches over a distance of 297 km (184.5 miles) from Cumberland, Maryland, to Georgetown, DC on the US East Coast. It was constructed between 1828 and 1850 by approximately 35’000 labourers, mostly immigrants from Europe. Its purpose was to enable the shipment of coal from the rural but coal rich Allegheny Mountains to the much more densely populated regions and sea ports along the Atlantic coast.

The canal was operated from 1831 until 1924. While originally built for the transportation of coal, it quickly became an important lifeline for communities along its way.

The bridge we assisted restoring. Visible in the foreground is one of the canal's 74 lifting locks
The bridge we assisted restoring. Visible in the foreground is one of the canal's 74 lifting locks

Boats were used to ship agricultural produce and lumber to markets downstreams. They then returned loaded with manufactured goods. These boats typically did not have their own means of propulsion, but were pulled along by mules walking on towpaths located at either side of the canal.

One end of the canal, Cumberland, lies at an altitude 184 m (605 feet) higher than the other end, Georgetown.  This meant that lift locks were needed – in total 74 of them were constructed. One of them is visible in the picture above, in front of the bridge.

In addition to the 74 locks, the canal also featured many other feats of early engineering. There were seven dams, about 240 culverts, a few aqueducts, a tunnel 950 meters (3’120 feet) long and, of course, bridges. A few of these bridges still exist today, such as the one that our metal stitching specialists proudly helped to restore.

Metal Stitching Work Performed

Exposure to the elements for over 150 years took its toll on the bridge structure. Cracks had developed in many of the vertical cast iron columns carrying the bridge deck. In all likelyhood, the cracks that were found were freeze cracks. Freezing temperatures are common in Georgetown from the middle of December until early March. If water enters one of the exposed, hollow columns and gets trapped there, then it very likely freezes during a cold winter night. Over time, the freeze/thaw cycles led to cracks.

All of the cracks ran in vertical direction. They had a cumulative lenght of 7’400 mm (25 feet). Our specialists sealed them with stitching pins and added perpendicular locks for extra strength. They then ground the locks and pins flush and made them blend in well with the weathered surface texture of the antique columns.

For the work to be carried out, a section of the canal had to be drained
For the work to be carried out, a section of the canal had to be drained
The width of the cracks required pins with a large diameter to length ratio
The width of the cracks required pins with a large diameter to length ratio
Installation of stitching pins
Installation of stitching pins: Close to 1'000 were used for this project
In many locations, the cracks were wide open
On some of the columns, the cracks had caused a gap of up to 12 mm
Our specialists stitched over 7 meters of cracks
On this restoration project, our specialists stitched over 7.4 meters (25 feet) of cracks
Once completed, the repair blends in very well
The completed repair blends in very well
Stitching in progress
Metal stitching in progress: Stitching pins installed in an overlapping pattern
Locks were added for extra strength
Metal stitching in progress: Adding of locks, perpendicularly to the crack, for extra strength

15 Years Service Experience With Metal Stitched 2-S Engine Columns

In October 2020, kindly acting upon our request, the crew of a 53’000 DWT bulk carrier checked the condition of the guide rails on their main engine. Specifically, they checked whether a metal stitching repair that was done in 2005 is still in good condition. Besides a periodical visual inspection, the crew carried out liquid penetrant testing (PT) to check for the presence of cracks.

The inspection revealed that the repair is still in perfect condition. No abnormalities such as cracks or loose stitching components were found.

At the time of writing, this engine had accumulated over 77’000 running hours / 15 years in service since the said metal stitching repair was carried out in October 2005 in Kure, Japan.

Location of the 660 mm long crack that was repaired in 2005
Location of the 660 mm long crack in the gear column, repaired in October 2005

At that time, the engine had 27’000 hours on the counter. Meanwhile, until October 2020, the engine has accumulated 103’000 running hours,  77’000 of them were with repaired guide rails.

To the best of our knowledge, this makes this engine the longest-running one with structural repair to the columns (A-frame) or bedplate carried out by metal stitching.

The permanent repair done in 2006 involved the installation of stitching pins and locks from Lock-N-Stitch to repair a 660 mm long crack. The crack was located in a 13 mm thick steel plate in the gear column of the 6-cylinder, 48-bore two-stroke engine.

The vessel remains in service and we continue to monitor it. Not because we have even the slightest doubt about the quality or durability of the repair, but because she is a living testament to the permanence of our metal stitching repairs.

Area repaired at the side of the intermediate gear wheel boss
Area repaired at the side of the intermediate gear wheel boss
The general area where the crack was repaired
The general area where the crack was repaired
Close up of the repaired area
A close-up view of the repaired area
After application of dye penetrant
Non-destructive examination: Application of dye penetrant
Red dye cleaned, developer about to be applied
Non-destructive examination: Dye penetrant removed
Developer applied - no defects visible
Non-destructive examination: Developer applied
Non-destructive examination: Outline of locks and stitching pins just barely visible
Non-destructive examination: Outline of locks and stitching pins just barely visible

Metal Stitching Repair of Two-stroke Engine Bedplates

This post introduces metal stitching as an attractive solution to repair cracks in two-stroke engine bed plates.

Background

The term “metal stiching” is most commonly associated with the repair of cast iron parts, as an alternative to welding, to which cast iron does not lend itself easily. Due to its brittle nature, cast iron tends to fail again rapidly after welding, unless the welding takes place at very elevated and uniform temperatures. These conditions are hard, if not impossible, to achieve in most workshops, let alone at site.

It is less commonly known that metal stitching is also an increasingly often used process for the repair of steel parts, where welding actually would be possible. There are good reasons for chosing stitching over welding, even in steel.

First and foremost, metal stitching is a cold process and thus does not lead to deformation or latent heat-induced stresses in the part being repaired. Post-repair (in-situ) machining to correct these deformations is therefore rarely required.

Second, as we have shown through independent labaratory testing, a metal stitched junction that has been made by a qualified operator using Lock-N-Stitch tools and stitching components, exhibits a tensile and fatigue strength that is equal to, or better, than that of a welded junction.

During the last few years, QuantiServ have gained extensive experience in applying the metal stitching process to crack repairs in two-stroke engine bedplates and columns. Two instructive cases are discussed below, both involving container ships with 96-bore engines.

On the first vessel, the stitching was carried out in stages, during successive port stays. On the second, the repair was carried out during a regularly scheduled dry docking in China.

Case 1: Bed Plate Metal Stitching During Successive Port Stays

In the course of a crank case inspection, a 800 mm long crack was found in the main engine bedplate on board a 15,500 TEU container vessel in 2019. Contacted by the ship owner, we carried out an assessment. It revealed that the crack would propagate quickly if the engine, a 14-cylinder, 96-bore one, would continue to operate at, or near, its nominal speed.

We proposed to the customer to carry out the repair while the ship remained in service. As the thirteen year old vessel was engaged in a “high-rate/less-time” trade, the customer of course jumped at the opportunity to get the crack repaired without any vessel off-hire. Following a review of the vessel’s trading pattern, we decided to carry out the repair during successive port stays during the vessel’s Northern European loop.

Our specialists commenced their work as soon as the vessel was alongside in port and did not stop anymore until the engine had to be restarted. They then rested during the short voyage to the next port, where they continued in the same manner.

While working, our specialists discovered that the crack in fact was about 300 mm longer than had previously been reported by the crew. This meant that the time in Europe was insufficient to repair the crack in its entirety.

Our specialists revisited the vessel a few months later, again in Europe, to repair the previously unreported section of the crack. All in all, it took seven port stays of a few hours each to repair the bedplate.

Attendance Voyage Number of port stays
First Antwerp – London 4
Second Bremerhaven – Antwerp 3

In total, we repaired on this bed plate over 800 mm of crack in steel plates with thickness ranging from 18 – 50 mm, without a single day of off-hire or otherwise interfering into the vessel schedule.

To repair this bed plate, metal stitching was chosen over welding because it has the following advantages:

  • The vessel stayed in operation throughout the repair. The stitching was done in stages during port stays, a few centimeters at a time. With welding, this would not have been possible. The vessel would have had to be taken out of operation for around three weeks.
  • Lower costs, compared to welding. A competitor proposed to carry out repair by welding in 20 days. We repaired it by stitching in 12 days. Less time spent means less costs.
  • For metal stitching, a hot work permit is not normally required. Such a permit would be very difficult to get in container terminals, meaning that welding would not have been possible from a safety point of view.
Crack runs from the girder side plate down into the oil sump
The crack runs from girder side plate down into the oil sump
Metal stitching repair in progress
Crack without the sealing compound that was temporarily applied
View of the crack without the sealing compound that was temporarily applied
The completed repair, prior to cleaning and painting
The completed repair, prior to cleaning and painting

Case 2: Bedplate Stitching During Dry Docking

The second case discussed here concerns an 8-year old, 13,000 TEU container vessel with a 12-cylinder, 96-bore main engine. The crack discovered on this engine was quite similar to the one described above.

Since the crack was discovered shortly before the vessel was scheduled to undergo a routine dry docking, it was decided to repair it during the docking period in China in 2020.

The crack extended over a length of 750 mm in steel plates with thickness ranging from 18 – 50 mm. Repairing it took our specialists eight days, working in single shifts.

Crack runs from girder side plate down to oil sump
The crack runs from the girder side plate down into the oil sump
Stitching of the crack in progress
Metal stitching of the crack in progress
The completed repair prior to repainting
The completed repair prior to repainting

The first two-stroke diesel engine that we have metal stitched has meanwhile accumulated 77,000 hours. We repaired a 600 mm long crack in the gear column (A-frame), in 2006. The repair is still in perfect condition today.

04 January 2021

Read more

The two repairs presented above were carried out using stitching components from the American company Lock-N-Stitch. We would like to stress that we have labaratory-tested other products available in the market and that we have found their strength to be insufficient for demanding applications like these.

Read more about metal stitching

Four-stroke Engine Block Metal Stitching and Crankshaft Machining

Over the years, medium-speed diesel engines have become very popular for a variety of applications, most notably in ship propulsion and in power generation. Accordingly, the number of such engines in service is very large.

Due to their large number and to the relatively high nominal speeds, combined with significant mass inertias, one would from a theoretical stand point expect more fequent and more severe damages on medium-speed, four-stroke diesel engines than on low-speed, two-stroke ones. That this is indeed the case in practice is evidenced be the fact that we are frequently contacted and subsequently repair a few dozen cases of severe engine damage every year.

Here is a typical example, one of many:

A Korean-made auxilliary engine with eight cylinders, 210 mm bore and 320 mm stroke suffered a serious bearing failure on crankpin #1. The engine block and crankshaft both got severely damaged, due to the connecting rod impacting both. The accident happened while the vessel, a Ro-Ro ship, was trading in East Africa.

Her next port of call was in Florida, United States, where our technicians went on board for a thorough inspection. They determined that both the crankshaft and engine block were repairable. As in addition to crankpin #1, which was badly damaged, all other pins were found with corrosion and scratch marks, we suggeted to the customer to offload the engine and to sail a few weeks without it. The customer agreed.

The engine was offloaded in Freeport, Texas, for repair and was delivered back to the vessel 46 days later in the same port. In the meantime, the vessel continued to sail with one engine less. The duration of the voyage, 46 days, was more than sufficient for our specialists to repair the crankshaft and engine block according to our very exacting standards.

Repair of the crankshaft

Due to the damage sustained by the accident, crankpin #1 had to be machined to – 3.00 mm. This was necessary to clear all dent marks. And as the other seven crankpins were suffering from scratches and/or corrosion, it was decided to machine them all to – 0.50 mm.

Repair of the engine block

Repair of engine block before and after

The cavity in the block caused by the accident was fairly substantial. A total volume of about 6’000 cm³ (366 in³) of material was missing and cast iron plates with a thickness of 19 – 51 mm (0.75 – 2 in) had to be repaired.

Our cast iron repair specialists scanned the damage with a 3D scanner. The data thus acquired was then used to fabricate a perfectly-fitting cast iron repair patch. The repair patch was stitched in place with stitching components, chiefly Castmaster stitching pins and locks, that are sold by Lock-N-Stitch.

After the repair was completed, it was hardly visible and the customer was very pleased with the outcome.

Here is a step-by-step description of how the block repair work was carried out:

 

Flywheel In-situ Repair on the US East Coast

Starting up a handymax bulk carrier’s 48-bore, two-stroke main engine with its turning gear engaged resulted in the turning gear shattered and in damage to 12 consecutive teeth on the flywheel.

The turning gear was damaged beyond repair and had to be replaced. Not only was its housing shattered but the planetary gears were completely destroyed too.

Faced with the costly and unpalatable reality of most likely having to replace the flywheel as well, the ship management company turned to QuantiServ for help. Always liking a challenge when we see one, we engineered and delivered a comprehensive solution that consisted of the following:

  • Inspection on board
  • CAD and FEA modeling to engineer an economical yet structurally very strong solution
  • CNC machining of repair inserts in our workshop
  • In-situ machining of the flywheel on board
  • Stitching the repair inserts in place

Our in-situ machining and metal stitching specialists carried out the work in February 2019, during the vessel’s port stay in Florida, without interfering in her schedule.

QuantiServ carries out a number of gearwheel repair assignments every year, mostly for industrial, marine and mining customers.

Metal Stitching: Why we Use the Best Stitching Pins in Existence Today

The Castmaster stitching pins that we use for our metal stitching repairs are manufactured by Lock-N-Stitch in the United States. They feature the patented Spiralhook thread, which makes them the best choice to carry out very strong, permanent metal stitching repairs.

This animation shows the working principle of the Spiralhook thread and explains why, unlike other products, these stitching pins do not create a radial spreading force during tightening.

 

These stitching pins are available in various diameters and lengths and are suitable to repair cast iron, steel, aluminium and bronze parts that are from 4 to 200 mm (1/6 to 8 inches) thick.

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Our Brand-new Case Study Page is now Online!

The new QuantiServ Case Study page is now online. It introduces recent work that we have done for customers coming from a variety of industries ranging from Marine, Mining, Hydro and Thermal Power Plants to Oil & Gas.

The cases are sortable by industry and cover services such as in-situ machining, metal stitching, reconditioning and many more. They each include a short description of the problem that the customer was facing, the solution and include many before/after and in-process pictures.

Case Studies

 

QuantiServ at the Norshipping 2017 Exhibition in Oslo

Our participation at the recently held Norshipping 2017 exhibition in Oslo, Norway, was very successful. We displayed our exciting metal stitching, in-situ machining and reconditioning solutions. These solutions created quite a lot of customer interest and led to many interesting discussions. It was also nice to meet many existing customers again and to know some new ones too.

Our next stop will be the Philmarine 2017 exhibition, which will be held from 12 – 14 July 2017 at the SMX Convention Center in Manila. We will be at booth 111/118. Come and visit us there.

QuantiServ at the Sea Asia 2017 Exhibition in Singapore

Sea Asia Exhibition 4Our participation at the recently held Sea Asia 2017 in Singapore was a big success. We displayed our metal stitching and in-situ machining solutions, as well as the refurbishment of four-stroke cylinder covers by furnace brazing, which we are particularly proud of. These solutions created quite a lot of customer interest and led to many interesting discussions.

Our next stop will be the Norshipping Exhibition in Oslo, 30 May – 02 June 2017, where we will be at booth D 05-34. Come and visit us there.

Crank pin machining mock-up

Crank pin in-situ machining mock-up

Furnace brazed 32-bore 4-stroke cylinder cover

Furnace brazed 32-bore 4-stroke cylinder cover

Fully reconditioned 35-bore 2-stroke cylinder cover

Fully reconditioned 35-bore 2-stroke cylinder cover

Metal Stitching of an Engine Block in Tehran, Iran

 

Metal stitching on an auxiliary engine block

Our metal stitching expert traveled to Tehran, Iran, last week to repair a four-stroke main engine block on board a tug boat. It had a crack between the charge air space duct and the cooling water space around one of the cylinder liners, as well as some dents. Cooling water was leaking into the charge air space.

To repair the damage took our expert just one full day of work. The customer was very pleased with the result and was impressed by how fast the repair was being carried out.

Once again it was proved that metal stitching is a quick and reliable solution for cast iron repairs – for jobs big and small!

 

 

Enjoying a cup of tea in the engine room after a job well done

Enjoying a cup of tea in the engine room after a job well done

Metal stitching

A very happy customer

Metal stitching test piece resists water pressure of 12 bars

Metal stitching test piece resists water pressure of 12 bars

Metal stitching, as long as it is carefully and properly carried out by trained technicians, is tight against gases and liquids. To demonstrate this, QuantiServ has manufactured two cast iron half-shells and has joined them together by metal stitching. The resulting container was successfully pressurized to 12 bars (175 psi) and no leak was observed.

This proves that there is no issue to repair cooling water spaces in for example engine blocks, where the cooling water pressure typically lies around 3 – 4 bars (44 – 58 psi), by metal stitching. In fact we knew this well, because we have done it successfully many times. But that the stitching could easily withstand 12 bars impressed even us.

 

 

No job too small – if it solves the customer’s problem

No job too small – if is solves the customer’s problem

A ship’s crew received a new cylinder liner in a mid-eastern port. Unfortunately, while lifting it onto the vessel, a sling came lose and the liner crashed hard on to the deck. Luckily no one was injured, but it caused a piece of cast iron at the circumference to be chipped off, rendering the liner unusable.

Instead of scrapping the liner, the Superintendent contacted QuantiServ and sent us pictures. After we confirmed that we could salvage the liner, he shipped it to our workshop in the Netherlands.

repair-mill

There our skilled machinists milled off a section of the liner and confirmed that there were no further cracks in the material. They then produced on a CNC milling machine a new piece that perfectly resembled the size and shape of the missing material. This they locked in place with glue and screws, thus saving a liner that otherwise would had to be scrapped.