If you ever wanted to know what made a C5R block better... Step inside.
04-25-2005, 08:04 AM
#1
Melting Slicks
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If you ever wanted to know what made a C5R block better... Step inside.
Nicky Fowler from SDPC posted a very imformative thread on this over on ls1tech that many of you might be interested in...
http://www.ls1tech.com/forums/showthread.php?t=310618
12480030 C5R Blocks
Lots of discussion and little truth! So let’s clear the air about these blocks.
Number 1 - They are expensive for a reason and not because GM wants to bend you over and make you pay! Below is an abbreviated version of the C5R block process.
Several years ago I made a post that stated the differences between parts made and distributed by GM Service Parts, GM Performance Parts, and GM Racing. This block comes from the GM Racing program and as such the original intent was never to resale this part to the public to meet the demand for a “reasonably priced” big bore block to build GEN3 engines. In fact, if I and another employee of GM Racing had not asked and continually pleaded with Jim Spaulding (GM Racing - Program Parts Manager at that time) for the block to be made available to the public, then we would never have known about it to begin with!
It was developed for one purpose and one purpose only; to win races and World Championships for the C5R racing program under the required engine rules.
Bottom line, this block is not a “reverse engineered” piece. In-fact GM Racing made some developmental siamese-bore castings by modifying the stock cores from the factory production blocks. These developmental blocks failed the durability test! That is why the C5R block was designed!!!! The original production LS1/LS6 design would not hold up to the 24hr durability testing at the HP levels required to win the 24 hours of Le Man. The new LS7 block (soon to be released!) was designed from the continuation of lessons learned from the C5R racing program, -- good news for me and you! A production big bore block with a racing influence.
The requirements were determined and standards were set, the least of which was that the block had to meet the demands of the 24-Hours of Le Man. GM Racing worked with their in-house designers and engineers, they made 3D Models, tightened production engineering tolerances, defined casting requirements and detailed the heat treating processes before the first prototype block was ever made. The first blocks were cut into sections, X-rayed, inspected, tested for material hardness, etc --- before one engine was ever assembled. Then durability testing was started to determine any shortcomings and make improvements if necessary. The requirements to become a C5R block are way beyond any other standards that current block manufacturers use today.
The block is cast from premium 356M aluminum. It is a modified form of virgin 356 aluminum material specifically developed from the GM Racing programs. Each batch of blocks has several sample test bars cast for material specification testing at the foundry. They must have the correct “356M Recipe” or the batch is rejected. It is not just another 356 aluminum block as some people have stated!
It is then taken to a facility for heat treating requirements and a special cleaning process to remove the sand from the casting procedure.
From here it is taken to another facility to be “hipped”, also known as the “HIP” process. HIP is the acronym for Hot Isostatic Pressure. An expensive procedure that is demanded in industries where there is no room for error (Aerospace, NASA, etc) and where the end product must be a representation of the highest degree of strength and integrity possible from the material in use. This process puts the blocks in a sealed vessel where a vacuum is first used to remove the room air and any possible contaminants. The vessel is then filled with high pressure Nitrogen (up to 30,000-psi) and then heated to the required temperature and sustained for a determined amount time. The cooling process is also a controlled procedure to insure maximum strength and proper heat treat. This extreme high pressure and heat removes almost 100% of the internal porosities that are generated during the casting process. The hipping procedure will clearly show defects that might not have been caught until the block had been subjected to actual race applications under high stress and heat. The material integrity is greatly enhanced because of hipping and the material strength and fatigue life will increase significantly. Any block that exhibits an exterior surface hole after hipping is considered a defect. Most manufacturers will weld and re-sandblast any small defect or holes to cover up the imperfection. Not GM Racing! Actually, I do not know of any aluminum blocks made by other manufacturers that use the HIP process – it is too expensive and time consuming! Not to say that this does not exist, I am just not aware of any.
The blocks that passed the hipping process are then taken for an X-ray to determine if there are any internal voids, cracks, imperfections or flaws that could lead to a block failure.
20% of the castings will have been eliminated by this time! Note; the hipping process is so extreme that most castings will exhibit some shrinkage from the high pressure. Therefore, one must take this into account during the initial design phase! Raw castings may need to be dimensionally increased from 1% to 2% if hipping is to be applied.
The qualified blocks are now taken to a final heat treating process to arrive at the T6 designation. After the final heat treat, the blocks are blasted, cleaned, inspected, and packaged for shipment to the machining center. You now have a hipped and X-rayed 356M-T6 premium aluminum qualified casting.
At the machining source, the casting is inspected and set-up on a qualifying fixture. The water jacket is probed to center the bores to eliminate any thin sections. GM Racing stipulates the requirement for a uniform bore wall thickness. If a block can not meet this requirement then you will not be able to buy it! The castings are qualified and the machining process starts. Keep in mind, the most critical tolerances are held to 0.0005”. The relative positions of the deck in relation to the cam, crank, and cylinder bores is held to a tolerance of 0.001”, therefore you receive a true blueprinted and “squared” block! For the layman, a typical sheet of paper is 0.003”. Try and slice it into 3-pcs if you can? Each block is 100% inspected throughout the machining process and fully 100% CMM(Coordinate Measuring Machine) measured on every dimension. In addition, the machinists are required to check all dimensional tolerances during the process and document all numbers. All the data is on file for GM Engineers to review at anytime!!!!
Special liners are made from a material that GM Racing has developed from its NASCAR & Indy Racing programs. This is not just another cast iron liner as some people have stated! The liners are installed with a special process developed in racing programs and then machined to size for a true and straight bore. Some of the other aftermarket aluminum block manufacturers install liners that are pre-machined. The block includes premium head studs made from 4340 material with rolled threads - not cut. The blocks come with special screw-in AN-style water jacket plugs with o-ring seals in all locations including the oil galleries. Also included is a tube of special lube for assembly which GM Racing tested against all the other lubes and oils on the market for accurate and repeatable torque readings. Main caps are made from premium 8620 material. The caps are coated with black oxide and laser etched with the GM Racing logo and part number.
The blocks are leak tested and packaged for shipment in special high quality wooden boxes so the block is not damaged. Each serial numbered block contains a documented sheet showing the critical dimensions for that block. Have you ever seen the boxes the C5R blocks come in? They are made from 5-layer Birch plywood! You can make cabinets for your house with this plywood! I do not why they did this! It is certainly overkill, but at least the block is protected. When you open the box and look at the GM Racing C5R block, you know it is a premium part. Look at the micro finish on the machined surfaces. The machined finish is like a mirror. Compare that and the other features described here with other manufacturers and not just the price. GM Racing has invested the time and money to make sure this block will meet the requirements it was intended to fulfill, which should far exceed most any application that you and I will ever try to use this block for.
And people want to claim that a machined LS1/LS6 block with the Darton sleeve system has the same structural integrity and capabilities as the C5R block??? Sorry, I beg to differ. The LS1/LS6 block was already lacking before you cut it up. The Darton sleeve system is not going to make up for the differences in block material, heat treating, hipping, main web strengthening and other features that GM Racing designed into the block.
Could GM have produced a cheaper block that would have met our needs? Sure! But they didn’t because that was not the intent of the C5R block. As most always is the case, you get what you pay for! Now we all know what we are paying for!
Not to say that the LS1/LS6 Darton MID blocks do not fit a need, they do! And they are appropriately priced for what you get, but it is not the same as a C5R block by any means. Do I want cheaper big bore blocks that will meet high HP needs? Absolutley!
In closing – big bore blocks are coming! And they are not Darton sleeved LS1/LS6 blocks. The LS7 will be here before the years end and I have already seen a big bore block from another manufacturer (not Dart and not World!). Both will be priced appropriately! Things will change and products will improve! They say in the fashion business that things are on a 25 to 30-year cycle. Seems to be true for the Small Block Chevrolet also! The future holds some big horsepower for gearheads like me and it will be affordable!
Nicky Fowler
GM Performance Guru &
Chief Gearhead @ SDPC
http://www.ls1tech.com/forums/showthread.php?t=310618
12480030 C5R Blocks
Lots of discussion and little truth! So let’s clear the air about these blocks.
Number 1 - They are expensive for a reason and not because GM wants to bend you over and make you pay! Below is an abbreviated version of the C5R block process.
Several years ago I made a post that stated the differences between parts made and distributed by GM Service Parts, GM Performance Parts, and GM Racing. This block comes from the GM Racing program and as such the original intent was never to resale this part to the public to meet the demand for a “reasonably priced” big bore block to build GEN3 engines. In fact, if I and another employee of GM Racing had not asked and continually pleaded with Jim Spaulding (GM Racing - Program Parts Manager at that time) for the block to be made available to the public, then we would never have known about it to begin with!
It was developed for one purpose and one purpose only; to win races and World Championships for the C5R racing program under the required engine rules.
Bottom line, this block is not a “reverse engineered” piece. In-fact GM Racing made some developmental siamese-bore castings by modifying the stock cores from the factory production blocks. These developmental blocks failed the durability test! That is why the C5R block was designed!!!! The original production LS1/LS6 design would not hold up to the 24hr durability testing at the HP levels required to win the 24 hours of Le Man. The new LS7 block (soon to be released!) was designed from the continuation of lessons learned from the C5R racing program, -- good news for me and you! A production big bore block with a racing influence.
The requirements were determined and standards were set, the least of which was that the block had to meet the demands of the 24-Hours of Le Man. GM Racing worked with their in-house designers and engineers, they made 3D Models, tightened production engineering tolerances, defined casting requirements and detailed the heat treating processes before the first prototype block was ever made. The first blocks were cut into sections, X-rayed, inspected, tested for material hardness, etc --- before one engine was ever assembled. Then durability testing was started to determine any shortcomings and make improvements if necessary. The requirements to become a C5R block are way beyond any other standards that current block manufacturers use today.
The block is cast from premium 356M aluminum. It is a modified form of virgin 356 aluminum material specifically developed from the GM Racing programs. Each batch of blocks has several sample test bars cast for material specification testing at the foundry. They must have the correct “356M Recipe” or the batch is rejected. It is not just another 356 aluminum block as some people have stated!
It is then taken to a facility for heat treating requirements and a special cleaning process to remove the sand from the casting procedure.
From here it is taken to another facility to be “hipped”, also known as the “HIP” process. HIP is the acronym for Hot Isostatic Pressure. An expensive procedure that is demanded in industries where there is no room for error (Aerospace, NASA, etc) and where the end product must be a representation of the highest degree of strength and integrity possible from the material in use. This process puts the blocks in a sealed vessel where a vacuum is first used to remove the room air and any possible contaminants. The vessel is then filled with high pressure Nitrogen (up to 30,000-psi) and then heated to the required temperature and sustained for a determined amount time. The cooling process is also a controlled procedure to insure maximum strength and proper heat treat. This extreme high pressure and heat removes almost 100% of the internal porosities that are generated during the casting process. The hipping procedure will clearly show defects that might not have been caught until the block had been subjected to actual race applications under high stress and heat. The material integrity is greatly enhanced because of hipping and the material strength and fatigue life will increase significantly. Any block that exhibits an exterior surface hole after hipping is considered a defect. Most manufacturers will weld and re-sandblast any small defect or holes to cover up the imperfection. Not GM Racing! Actually, I do not know of any aluminum blocks made by other manufacturers that use the HIP process – it is too expensive and time consuming! Not to say that this does not exist, I am just not aware of any.
The blocks that passed the hipping process are then taken for an X-ray to determine if there are any internal voids, cracks, imperfections or flaws that could lead to a block failure.
20% of the castings will have been eliminated by this time! Note; the hipping process is so extreme that most castings will exhibit some shrinkage from the high pressure. Therefore, one must take this into account during the initial design phase! Raw castings may need to be dimensionally increased from 1% to 2% if hipping is to be applied.
The qualified blocks are now taken to a final heat treating process to arrive at the T6 designation. After the final heat treat, the blocks are blasted, cleaned, inspected, and packaged for shipment to the machining center. You now have a hipped and X-rayed 356M-T6 premium aluminum qualified casting.
At the machining source, the casting is inspected and set-up on a qualifying fixture. The water jacket is probed to center the bores to eliminate any thin sections. GM Racing stipulates the requirement for a uniform bore wall thickness. If a block can not meet this requirement then you will not be able to buy it! The castings are qualified and the machining process starts. Keep in mind, the most critical tolerances are held to 0.0005”. The relative positions of the deck in relation to the cam, crank, and cylinder bores is held to a tolerance of 0.001”, therefore you receive a true blueprinted and “squared” block! For the layman, a typical sheet of paper is 0.003”. Try and slice it into 3-pcs if you can? Each block is 100% inspected throughout the machining process and fully 100% CMM(Coordinate Measuring Machine) measured on every dimension. In addition, the machinists are required to check all dimensional tolerances during the process and document all numbers. All the data is on file for GM Engineers to review at anytime!!!!
Special liners are made from a material that GM Racing has developed from its NASCAR & Indy Racing programs. This is not just another cast iron liner as some people have stated! The liners are installed with a special process developed in racing programs and then machined to size for a true and straight bore. Some of the other aftermarket aluminum block manufacturers install liners that are pre-machined. The block includes premium head studs made from 4340 material with rolled threads - not cut. The blocks come with special screw-in AN-style water jacket plugs with o-ring seals in all locations including the oil galleries. Also included is a tube of special lube for assembly which GM Racing tested against all the other lubes and oils on the market for accurate and repeatable torque readings. Main caps are made from premium 8620 material. The caps are coated with black oxide and laser etched with the GM Racing logo and part number.
The blocks are leak tested and packaged for shipment in special high quality wooden boxes so the block is not damaged. Each serial numbered block contains a documented sheet showing the critical dimensions for that block. Have you ever seen the boxes the C5R blocks come in? They are made from 5-layer Birch plywood! You can make cabinets for your house with this plywood! I do not why they did this! It is certainly overkill, but at least the block is protected. When you open the box and look at the GM Racing C5R block, you know it is a premium part. Look at the micro finish on the machined surfaces. The machined finish is like a mirror. Compare that and the other features described here with other manufacturers and not just the price. GM Racing has invested the time and money to make sure this block will meet the requirements it was intended to fulfill, which should far exceed most any application that you and I will ever try to use this block for.
And people want to claim that a machined LS1/LS6 block with the Darton sleeve system has the same structural integrity and capabilities as the C5R block??? Sorry, I beg to differ. The LS1/LS6 block was already lacking before you cut it up. The Darton sleeve system is not going to make up for the differences in block material, heat treating, hipping, main web strengthening and other features that GM Racing designed into the block.
Could GM have produced a cheaper block that would have met our needs? Sure! But they didn’t because that was not the intent of the C5R block. As most always is the case, you get what you pay for! Now we all know what we are paying for!
Not to say that the LS1/LS6 Darton MID blocks do not fit a need, they do! And they are appropriately priced for what you get, but it is not the same as a C5R block by any means. Do I want cheaper big bore blocks that will meet high HP needs? Absolutley!
In closing – big bore blocks are coming! And they are not Darton sleeved LS1/LS6 blocks. The LS7 will be here before the years end and I have already seen a big bore block from another manufacturer (not Dart and not World!). Both will be priced appropriately! Things will change and products will improve! They say in the fashion business that things are on a 25 to 30-year cycle. Seems to be true for the Small Block Chevrolet also! The future holds some big horsepower for gearheads like me and it will be affordable!
Nicky Fowler
GM Performance Guru &
Chief Gearhead @ SDPC
04-25-2005, 08:45 AM
#3
Drifting
Very 
, thanks alot for posting that!
SDPC is a great place to deal with when you don't already have all the answers yourself. Be nice if they were a forum vendor so I could recommend them on CF more often.
, thanks alot for posting that!SDPC is a great place to deal with when you don't already have all the answers yourself. Be nice if they were a forum vendor so I could recommend them on CF more often.
04-25-2005, 03:34 PM
#14
NCM, WSCC &amp;amp; SCC Member
C5R vs. Darton...Information for discussion
I not endorsing either product. As, I think they are both good. Darton does guarantee its sleeves now.
http://ls1tech.com/forums/showthread.php?t=308555
The Darton.
Howard is my first Block Pro CNC machine customer, was trained by me and knows the process well. He also has a stress relief machine. His info sheet will answer many questions.
Those of you with new blocks (sleeved or not) or heads should get your stuff stress relieved before putting your engine together if you want flat surfaces and round cylinder bores in service. For you fellows on the East Coast, especially those down south, Howard is the one to see about getting your block resleeved and your parts stress relieved.
I'd like to respond to the strengths, weaknesses of a sleeved block as compared to the C5R. Actually, we examined the C5R prior to finalizing the design of the Darton MID sleeve. At the time there were two options for a large bore LS1. Dry sleeve the block with it's inherent problems of dropped sleeves, out of round sleeves, cracked walls behind the sleeves with resultant leaking into the crankcase, or the expensive C5R which solved most of the above problems.
The C5R has pressed in dry liners in a block with heavy walls similar to the LS2 block in terms of aluminum behind the sleeve. The sleeves extend into the crankcase to provide some additional piston support for long stroke engines. The sleeves are gray iron, not high strength ductile iron. The C5R also includes steel main caps and studs from the factory replacing the stock powdered metal caps. Block is cast in 356 alloy where the stock blocks are cast in 319 alloy. Material strengths of these two alloys are very similar by the way.
We looked into extending the MID sleeves into the crankcase but decided against it. An unsupported sleeve section hanging in thin air is very difficult to hone. Lack of overstroke during honing makes it even more difficult.
There have been cases of the C5R splitting cylinder sleeves under high boost or nitrous. This happens with gray iron which is quite brittle compared to ductile iron. Gray iron has less than half the strength of the specially modified A356 ductile iron Darton uses.
Steel main caps and studs are a good idea on any high output engine. One can add steel caps to any of the LSX blocks. They are available from several tuner shops including Cartek and are also sold by Pro Gram Engineering for those wanting to do their own work.
I truly do not believe there is any inherent weakness in a properly machined MID block. The first blocks were indeed problematic but this has long since been resolved. There are however a couple of items that need attention. Coolant, and proper head gaskets. An MID block requires special MID specific Cometic head gaskets and Evans coolant. One can run water with wetter for racing but for street use (long life) you need Evans coolant to protect the sleeves from cavitation damage.
Regarding pricing. Most of you know what a C5R block costs. One can do an MID block with steel caps, ARP hardware for at least three grand less. Darton, by the way, guarantees the sleeves to be free from defects for a year after purchase.
I believe an aftermarket aluminum block would still be out of reach price wise for most guys. Should be lower than a C5R for sure. Hopefully an aftermarket block will have ductile iron liners.
We are currently working (will be available in a couple of weeks) on a large bore dry sleeve liner for the LS2 block to offer a less expensive alternative to the MID wet liner, and C5R. We will incorporate some special design features on the sleeves. Large diameter flanges will keep them in place. Pricing should be such that everyone will be able to afford a large bore LS2 engine. Conventional coolants can be used with dry liners but I still recommend Evans coolant for best protection against detonation related damage on any engine sleeved or not.
Note that the new LS2 dry sleeved blocks are not a replacement for an MID sleeved block for high output applications. The MID sleeves are much stronger than anything else on the market.
Steve
Quote:
Originally Posted by sb427f-car
Does it also have details about strenghts as well as advantages / disadvantages to going the resleave route vs. say a C5R block? All I can say is, I wish world would hurry up and do an aftermarket LSx block to help drop the prices on all the other stuff.
__________________
Steve Demirjian
sponsor
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
http://ls1tech.com/forums/showthread.php?t=308555
The Darton.
Howard is my first Block Pro CNC machine customer, was trained by me and knows the process well. He also has a stress relief machine. His info sheet will answer many questions.
Those of you with new blocks (sleeved or not) or heads should get your stuff stress relieved before putting your engine together if you want flat surfaces and round cylinder bores in service. For you fellows on the East Coast, especially those down south, Howard is the one to see about getting your block resleeved and your parts stress relieved.
I'd like to respond to the strengths, weaknesses of a sleeved block as compared to the C5R. Actually, we examined the C5R prior to finalizing the design of the Darton MID sleeve. At the time there were two options for a large bore LS1. Dry sleeve the block with it's inherent problems of dropped sleeves, out of round sleeves, cracked walls behind the sleeves with resultant leaking into the crankcase, or the expensive C5R which solved most of the above problems.
The C5R has pressed in dry liners in a block with heavy walls similar to the LS2 block in terms of aluminum behind the sleeve. The sleeves extend into the crankcase to provide some additional piston support for long stroke engines. The sleeves are gray iron, not high strength ductile iron. The C5R also includes steel main caps and studs from the factory replacing the stock powdered metal caps. Block is cast in 356 alloy where the stock blocks are cast in 319 alloy. Material strengths of these two alloys are very similar by the way.
We looked into extending the MID sleeves into the crankcase but decided against it. An unsupported sleeve section hanging in thin air is very difficult to hone. Lack of overstroke during honing makes it even more difficult.
There have been cases of the C5R splitting cylinder sleeves under high boost or nitrous. This happens with gray iron which is quite brittle compared to ductile iron. Gray iron has less than half the strength of the specially modified A356 ductile iron Darton uses.
Steel main caps and studs are a good idea on any high output engine. One can add steel caps to any of the LSX blocks. They are available from several tuner shops including Cartek and are also sold by Pro Gram Engineering for those wanting to do their own work.
I truly do not believe there is any inherent weakness in a properly machined MID block. The first blocks were indeed problematic but this has long since been resolved. There are however a couple of items that need attention. Coolant, and proper head gaskets. An MID block requires special MID specific Cometic head gaskets and Evans coolant. One can run water with wetter for racing but for street use (long life) you need Evans coolant to protect the sleeves from cavitation damage.
Regarding pricing. Most of you know what a C5R block costs. One can do an MID block with steel caps, ARP hardware for at least three grand less. Darton, by the way, guarantees the sleeves to be free from defects for a year after purchase.
I believe an aftermarket aluminum block would still be out of reach price wise for most guys. Should be lower than a C5R for sure. Hopefully an aftermarket block will have ductile iron liners.
We are currently working (will be available in a couple of weeks) on a large bore dry sleeve liner for the LS2 block to offer a less expensive alternative to the MID wet liner, and C5R. We will incorporate some special design features on the sleeves. Large diameter flanges will keep them in place. Pricing should be such that everyone will be able to afford a large bore LS2 engine. Conventional coolants can be used with dry liners but I still recommend Evans coolant for best protection against detonation related damage on any engine sleeved or not.
Note that the new LS2 dry sleeved blocks are not a replacement for an MID sleeved block for high output applications. The MID sleeves are much stronger than anything else on the market.
Steve
Quote:
Originally Posted by sb427f-car
Does it also have details about strenghts as well as advantages / disadvantages to going the resleave route vs. say a C5R block? All I can say is, I wish world would hurry up and do an aftermarket LSx block to help drop the prices on all the other stuff.
__________________
Steve Demirjian
sponsor
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
