RPM - RON'S PRECISION MACHINE, INC.
222 N. Pheasant Dr.
Central, Utah 84722
Engine Rebuild Kit and Parts Online Catalog
|Engine Rebuild & Assembly||Balancing & Blueprinting||Cylinder Heads||About the owner of RPM|
|Engine Rebuild Kits||Engine Start-up||Other Related Web Sites Page 1||Frequently Asked Questions|
|Crankshafts||Degree Cam||Other Related Web Sites Page 2||Purchase warranty & Return Information|
How much is shipping How do I purchase parts Crankshaft Counterweight Clearance Piston Sparkplug/Cylinder Head Clearance
Using 351C flat top pistons in a 400 Rod to Piston Clearance Valve Relief Orientation/Clearance To figure compression ratio
What is detonation How do I figure rod ratio Recommended Automotive Compression Ring Gap Clearances
When should I have my engine balanced How do I figure cu. in. Location of ring gaps for a V8 Chevy engine & other engines
Final compression ratio for super charger What is Cryogenic processing or treatment Cu. In. and Metric conversion formulas
Subject: How much is shipping?
Shipping for engine rebuild kits is $12.50 in the continental U.S. Shipping is extra to Hawaii and Alaska, you will need to get a quote on shipping there.
We no longer ship outside the U.S. and we do not accept credit cards from outside the U.S.
Subject: How do I buy parts or engine
rebuild kits from this site?
Just click on the order form and fill that out or e-mail for pricing or ordering parts. Or click on the Purchase & Return Information page, and read that. You may want to go to the Price engine rebuild kits & Parts page, if you haven't already done so, to see what parts you need. Most kits and parts will have prices already there (more coming soon). If you don't see what you need, then simply fill out the order form to price what you need or e-mail or call toll free to order and purchase at: 1-866-700-5877.
Crankshaft Counterweight Clearance
Always check counterweight to piston clearance at BDC. Recommended minimum is .060".
Piston Sparkplug/Cylinder Head Clearance
Always check for adequate piston to sparkplug/cylinder head clearance. Use clay to measure
clearance with piston installed on rod at TDC. Rock the piston to get minimum clearance.
Minimum clearance for aluminum rods = .060" for steel rods = .040".
Using 351C flat top pistons in a 400
The 400 engine has a compression height of 1.635" and the 351C engine has a compression height of 1.630" but the wrist pin diameter is different between the 400 engine (.9752") and the Cleveland engine (.9122" so the 400 connecting rods would need to be bushed for the smaller wrist pin and the pistons would need to be K/B (Keith Black) or TRW forged flat top Cleveland pistons which has a snap ring groove in the pistons for full float.
Rod to Piston Clearance
Due to the multitude of variations in connecting rod materials and design, piston to rod
clearances need to be checked. The minimum recommended clearance is .050" per side
and .050" from the top of the rod to the underside of the piston. With the piston installed on
the rod, rock the piston side to side, back and forth, checking for adequate clearance.
Valve Relief Orientation/Clearance
Minimum recommended clearance for both intake and exhaust is .100" deep and .050"
Radially (eye brow clearance). Using clay or the cam manufacturer's recommendations, check for clearance. The
cam must be degreed exactly as it will be during operation.
To figure compression ratio
Compression Ratio = (Swept Volume + Top Dead Center Volume) divided by
Top Dead Center Volume . TDC Volume divides into (S.V. + TDC Volume)
o Swept Volume = 3.1416" x Bore x Bore x Stroke ÷ 4 (or .7854 x bore x bore x stroke)
o TDC Volume = Cylinder Head Chamber Volume + Gasket
Volume +Deck Volume + Piston Dome/Dish Volume
o Gasket Volume = 3.1416" x Bore x Bore x Compressed
Gasket Thickness ÷ 4 (or .7854 x bore x bore x stroke)
o Deck Volume = 3.1416" x Bore x Bore x Deck Clearance ÷ 4 (or .7854 x bore x bore x stroke)
o Piston Dome/Dish Volume = listed volume in cc's x .061
(to convert cc's into ci's)
o Cylinder Head Chamber Volume as listed by the MFG
in cc's x .061 (to convert cc's into ci's)
RECOMMENDED AUTOMOTIVE COMPRESSION RING GAP CLEARANCES
CHECKING COMPRESSION RING GAPS
Tolerance Ring Gap
1.0000" to 2.3624" .006 to .014
2.3625" to 2.9524" .008 to .016
2.9525" to 3.5424" .010 to .020
3.5425" to 4.3299" .012 to .022
4.3300" to 5.1174" .014 to .026
5.1175" to 5.9049" .016 to .030
5.9050" to 6.8899" .020 to .035
6.8900" to 8.9999" .024 to .041
An important fact to remember is that these tolerances
are rigidly adhered to by the manufacturers and that the
ring gaps are inspected in gauges accurate to .0001" at
the cylinder diameter the ring is manufactured for. Any
increase in the diameter of the cylinder the ring is being
used in, over the designated size, results in an increase
of approximately .003" in ring gap for each .001"
increase in cylinder diameter.
Subject: What is detonation?
Detonation is the rapid and uncontrolled combustion of the air/fuel mixture. Detonation can occur in the cylinder of a spark ignition engine when operating on a fuel of inadequate octane rating, or with ignition too far advanced. It is informally called "pinging".
In discussions on this condition, we will refer to detonation as an abnormal combustion process. Normal combustion is a controlled amount of air/fuel ratio mixture entering each cylinder at the correct operation chamber temperature.
The compressed, "charged" mixture is then ignited at a precise moment by the ignition system that starts a small flame kernel, which is followed by a smooth controlled burning. Anything that alters the air/fuel ratio, chamber temperature, or ignition timing, will effect the combustion process.
The following are items that will usually effect the combustion process: Camshafts that alter valve timing from OEM specs, a different combination of pistons or cylinder heads altering compression ratio, wrong octane gasoline, engines that burn oil, a non-functioning EGR system, vacuum leaks, or restricted exhaust systems.
Listed below are some of the results of an abnormal combustion
process in a gasoline engine:
>Piston, ring land, or piston ring breakage.
>Head gasket armor distortion and burn through.
>Tuliped intake valves.
>Burned, cracked, or distorted exhaust valves.
>Cylinder head cracks in combustion chamber.
>Connecting rod bearing damage on upper shell first; leads to complete engine failure.
Once detonation starts, it propagates with each combustion process. As the temperature and pressure in the cylinder increases, creating a violent uncontrolled burning, the exhaust stroke is no longer capable of evacuating enough temperature from the combustion chamber.
Modern engines have more electronic controls for engine management systems than engines built even 10 years ago. Those modern controls, when operating correctly, prevent detonation by retarding the ignition system. Engines without electronic spark control, rely on drivers to sense detonation, and correct the problem.
If you rebuild your engine, and it had a detonation problem,
then you could damage your newly rebuilt engine. All systems and
sensors, need to be operating properly. The compression ratio
has to be low enough for the type of fuel you run in your engine.
Some after market camshafts build cylinder pressure, more than a stock camshaft; so, compression ratio is even more critical. It is true, that higher compression ratios build more horse power, so be careful of the camshaft choice, if you are raising your compression ratio. Most compression ratios at sea level to approx. 1800 feet, require 9.0 to 1 or less. The higher the elevation, the higher the compression ratio can be. If your compression ratio is higher than stock, for your engine, then you must use a higher octane gas.
How do you figure rod ratio?
Take the length of the connecting rod and divide it by the stroke of the crankshaft.
Example: 5.7 divided by 3.48= 1.64 rod ratio. Rod ratio changes the piston speed at top and bottom dead center.
Usually, the longer the rod ratio, the easier it is on the cylinder walls. But a shorter rod ratio gives more bottom end torque.
When should I balance my engine assembly?
You should balance your engine assembly any time your reciprocating or rotating weight changes. For example: if your pistons don't weigh the same, then your reciprocating weigh is different. The counter weights on your crankshaft must be the right weight, and the weight has to be in the right place. Much like the weights on a tire and rim have to be in the right place to have your wheel in balance. If you are under balanced at all, you will notice the car behind you in your mirror is fuzzy. You can be a little overbalanced, but generally about 12 grams is all. That's less than a half an ounce. Just click on balancing and blueprinting to read more about this subject.
How do I figure what my cu. in. is?
The formula is: Bore x Bore x Stroke x .7854 x (number of cylinders)
Example: 4.030 x 4.030 x 3.480 x .7854 x 8= 355.1159836 or 355 cu. in
Location of ring gaps for a V8 Chevy engine
And other V8 engines.
No ring gaps can be above the wrist pin on either side. All gaps have to be above the skirt of the pistons on each side.
Left bank #'s 1,3,5,7 (Chevy) top ring gap to lifter galley (above the skirt of the piston), 2nd ring gap to outside of block (above the skirt of the piston), oil ring expander below the top ring gap anywhere above the skirt of the piston, oil ring rails gap opposite skirt (outside of block) on each skirt edge.
Right bank #'s 2,4,6,8 (Chevy) top ring gap to outside of block, 2nd ring gap to lifter galley, oil ring expander to outside of block and oil ring rail gaps to lifter galley on each side above the skirt.
Four cylinder and inline 6 cyl. engine just use the left bank locations.
How do you figure final compression ratio for supercharger
The formula is: FCR= (Boost/14.7)/1xCR FCR: Final Compression Ratio CR: Compression Ratio
Final compression ratios above 12.4:1 are not recommended for
use with "premium pump gasoline."
The higher the final compression ratio, the higher the octane rating of the gasoline must be, in order to avoid detonation and serious engine damage.
Subject: What is Cryogenic processing? Also go to http://www.metal-wear.com/
Racing pushes engine and drive train components to the absolute
limits of their durability. Extending those limits
means more speed, better safety, and more races won. For this reason Cryogenic processing is becoming a
necessary part of the manufacturing process for racing components. This racing experience will serve as an
example to manufacturing industries---now similarly engaged in there own competition against manufacturing
costs and waste, and the challenge to provide high quality products with superior performance.
Using extremely low temperatures to make permanent changes
in metal and plastic components, cryogenic
processing is not the typical 84 degrees C (-120 degrees F) cold treatment most heat treaters use. It essentially
involves exposing materials to temperatures below 184 degrees C (-300 degrees F). If done correctly, it creates a
permanent change to the material that alters many wear characteristics.
The concept of changing metal through the use of low temperatures
is relatively new and not well understood. Yet it
is certain that exposure to very low temperatures does make permanent changes in virtually all metals and to some
plastics. Observed changes include:
*Increased resistance to abrasion
*Increased resistance to fatigue
*Precipitation of very fine carbides in ferrous metals that contain carbide forming elements.
*Transformation of austenite to martensite in ferrous metals.
*Change in vibrational damping.
*Increased electrical conductivity.
*Anecdotal evidence of changes in heat transfer.
*Stabilization of metals to reduce warping under heat, stress, and vibration.
In practice, cryogenic processing affects the entire mass
of the part. It is not a coating. This means that parts can be
machined after treatment without losing the benefit of the process. Additionally, cryogenics apply to metals in
general, not just ferrous metals. For many years, it was assumed the only change caused by extreme cold was the
transformation of retained austenite to martensite in steel and iron. Because of this, many misinformed engineers
still believe that cryogenic processing is "just a fix for bad heat treat." It is not known that cryogenic processing has
a definite affect on copper, titanium, carbide, silver, brass, bronze, aluminum, both austenitic and martensitic
stainless steel, mild steel and others. It is also known that plastics such as nylon and phenolics show property
Cryogenic processing is currently in use in every form of
racing imaginable. It is used in virtually every class of
NASCAR racing, IRL, CART, NHRA, IHRA, SCCA, IMSA and ARCA, not to mention tractor pulls, go-karts,
motorcycles, boats, and even lawn mower racing. Controlled Thermal Processing (CTP) has even done a fair
number of axles for soap- box derby cars. Over half of the cars competing at any given NASCAR Winston Cup race
run parts that are cryogenically treated by CTP alone. Cryogenic processing can have a positive affect on virtually
every engine, transmission, and drive line part, as well as many chassis parts.
Are there definite tests and data on racing and cryogenic
processing that we can point you to? Not yet. Racers do
most of their testing on the race- track or on the dynamometer. These are not controlled experiments in the
classical sense, and in most cases they do not allow the results to be published because of the risk of losing
competitive advantages. We do know that the use of cryogenic processing is on the upswing. Its use by
manufacturers of racing components has been growing sharply. We also know that very experienced racing experts
have examined the effects of cryogenic processing and have been very impressed.
Increasing the durability of components in the vehicles
is the main reason for using cryogenic processing. Racing
continually presents the engineer with the challenge of designing engine and chassis components that will survive
long enough to win a race, but will not have any excess weight as a consequence. Put in too much mass, and a car
will be slow and handle poorly. Make components too light, and they will not survive the race. There is always this
delicate balance: weight versus reliability. The great thing about cryogenic processing is that it allows an increase
in durability without an increase in weight or major modifications to component design. In addition, the use of
cryogenic processing has helped some racing teams reduce costs, enabling some expensive parts to survive the
stresses of racing for use in subsequent races.
Cryogenic processing has become an integral part of the
production process for many racing components. Many
top racing teams have the process done if the manufacturer does not provide it. They do so because cryogenic
processing has proven its worth time and again under extremely competitive conditions. Racers are generally
people in a big hurry and would not take the time for cryogenic processing if there was no advantage to it.
Applications that benefit from cryogenic treatment probably number more than anyone expects.
Brakes and Clutches. Brakes of a racing car take a real
beating. It is not unusual for a racing vehicle to finish a
race with the brakes totally worn out. This is especially true during road races and endurance racing, where brake
rotors can get so hot they glow visibly at night. Cryogenic processing can be applied to both rotors and pads. The
net result is two to three times the life of untreated components even under severe racing conditions. As a side
benefit, the rotors are less prone to crack or warp. It is interesting that drivers report better braking action and feel.
Some drivers are so sold on the concept that they have their street vehicles equipped with treated brakes.
Clutches are a form of brake, and the results are very similar.
Drag racers have been doing some work on clutch
plates to measure the coefficient of friction in highly instrumented cars. They find that treated clutch facings will
develop a higher coefficient of friction but exhibit significantly less wear.
As an offshoot of racing development, cryogenically treated
rotors and pads are making their way into fleet
operations on the road. The U.S. postal service specifies cryogenic processing for their rotors and is experiencing
up to three times as many miles as they were getting on the unprocessed rotors. Similarly, many police fleets are
starting to adopt treating rotors and pads. They, too, are experiencing large maintenance savings on both parts
and labor. What is metallurgically interesting is that the brakes are a gray cast iron that has a pearlitic structure.
This rules out the austenite to martensite transformation as the mechanism for increase life.
Springs fail in one or two modes. They either break or their
spring constant starts to decline. Either way, it can
have catastrophic effects on the performance of the vehicle. Most valve springs are made of specially made chrome
silicon steel. The automotive valve spring is a fatigue failure waiting to happen. It typically can lose up to one third
of its spring constant during a long race. In some forms of racing, it is just hoped that the valve springs will last
through the race. Some drag racers routinely change the valve springs before every run down the drag strip to
insure consistent performance. Typically valve springs exhibit a longer life after cryogenic processing. How much
depends on the type of racing, the type of spring, the manufacturing lot of the spring and the criterion for a failure.
Cryogenic processing of springs will usually triple the
life before fatigue failure occurs, and it will reduce the
amount of spring constant lost from 20-30% down to about 7%. This makes it easier to set up the engine, as there is
not such a wide variation in the spring performance. It is difficult to determine absolute spring life increases,
because the racers typically discard them long before they break. We do no one drag racer who use to change
springs after each run: He now makes seven runs before changes. There is a caveat. Occasionally we come across
groups of springs that will not respond to cryogenics. Analysis of these springs usually discloses large inclusions in
the wire, which become stress concentrators, causing failures at these locations.
Further advantage for cryogenic processing of springs is
that the process seems to eliminate or reduce harmonic
vibrations. If you have ever seen a high-speed movie of a valve spring at high engine rpm, you will notice that the
springs do not simply move up and down. It does a very complex hula dance because of the harmonic vibrations.
Racers typically have to design the spring and valve trains so that harmonics do not interfere with the valve action.
Not unexpectedly, chassis springs are also affected by cryogenic
processing. Chassis springs lose their spring
constant during a race. This can cause the chassis to lose its cornering ability, which drastically slows the car. Loss
of spring constant also alters the height or road clearance of the vehicle. The vehicle height is critical at high
speeds because it has a big affect on the aerodynamics of the car, and hence on the handling and the top speed of
Other ramifications of springs sagging are evident. Watch
the pit crew after a Winston Cup race as the car is
pushed up onto a plate form for inspection. If the springs have settled too much, the car maybe disqualified. So the
pit crew will often be lifting on the chassis as they roll it along to set it up a little higher.
When they get the car to measuring surface, they generally
let it down so it does not bounce and settle farther than
necessary. You have to know the tricks if you dont want to lose.
The chassis itself is basically a very large, complex spring,
having numerous welds and using not very precise
tubing. The metals used here vary, depending on the type of racing. NASCAR frames are made from 10/20 steel;
other forms of racing use 4140 steel. Of course, other high strength, lightweight materials are also used.
As the chassis experiences vibration during the race, residual
stresses in the welds and the tubing can start to
relieve. This causes the chassis to change shape during the race, effecting the handling of the vehicle and therefore
its speed. We are now working with several teams to do a heat stress relief on the chassis followed by a cryogenic
Gears, shafts, and assemblies. A study for the U.S. Army
Aviation and Missile Command, by the Illinois Institute of
Technology Research Institute concluded that cryogenic processing of the carburized 93/10 steel increase the gear
contact fatigue life by 100%, and the ability of the gear to handle load by 10% over the same material that had
under gone a 84 degrees C (-120F) cold treatment per Military specification. They also found that the conversion
of retained austensite is only part of the effect on the gear. Most racing gears are 93/10 carburized steel, although
8620 is also used. It is interesting to notice that there is an experimental gear material under test that specifies
cryogenic processing as part of its heat treat.
One major racing transmission maker, after inspecting numerous
gearboxes after races, have asserted that
cryogenic processing cuts the gear wear dramatically.
This also holds true for road racers of Porsches and BMWs
and other SCCA race cars who are now getting about
three times the life on their gearboxes. The major problem of all these racers see is wear on the pitch line of the
gear. Breakage is sometimes a problem, but that can usually be traced to driver error, bad heat treatment, or
inferior material. Jerico Performance Products, a well know producer of Racing Transmissions, supplies gearboxes
to over 50% of the racers in Winston Cup, and to many other racers. The company currently has all of its gears and
shafts cryogenically processed.
Cryogenic processing also increases the other heavily loaded
gears. We are doubling the life of ring and pinion
gears and differentials, even under such severe usage as tractor pulls. Quick-change gears also show dramatic
increases in life. Axle shafts, universal joints, and CV joints all show dramatic increases in durability. As the racing
of front wheel drive cars becomes more popular, we begin to see more and more CV joints being processed, as this
is one of the weak points of the drive line. Axles are treated to stave off fatigue failures in the splines.
Virtually every part of an engine will respond to cryogenic
processing, with all components exhibiting life
increases. Several component manufactures are starting to take advantage of this and are treating their racing
components as part of their production. Some of the main applications are:
Connecting rods usually fail in fatigue. This occurs because
of the high "g" loading of the piston and pin. Winston
Cup engines currently run around 9300 rpm. They have a stroke of around 86mm (3.375 in). Pistons and pins
typically have a mass of around 650 grams. Given these figures, it can be calculated that the upward force of the
piston and Wrist pins exerts on the connecting rod during the exhaust stroke is over 4800 gs. Although this
calculation ignores the weight of the small end of the connecting rod, it can be seen that there is a repeated stress
on the rod, which has a cross sectional area of under 230 MM2 (0.35 IN2). Cryogenic processing increases the
fatigue life of connecting rods considerably. Dyers Top rods in Forrest, IL, claims that they would not release a
rod from their shop without cryogenic processing. We process steel, titanium and aluminum rods. The steel rods are
generally AISI 4340 or 300 M steel, aluminum rods are usually 7075 T6.
Cylinder heads. Both aluminum and cast iron heads usually
fail by cracking, which results from both thermal cycle
fatigue and the flexing of the head under combustion pressures. Further, the heads are often subjected to the
extreme pressures created when the fuel mixture detonates. All these pressures can cause the head to flex so much
that it is not unusual to find debris such as piston coatings under the head gasket, blown there during a combustion
Several Winston Cup teams have concluded that 356 T6 aluminum
heads yield about double the life after
cryogenic processing. Other racers have the heads (both aluminum and cast iron) treated as a matter of routine. Of
course, treating the heads increases the life of the valve seats and valve guides. It is interesting to note that the
heads can be treated with the valve guides and seats installed.
Camshafts and lifters. Roller lifters usually fail by breaking,
some of which is just poor design with sharp edges and
stress risers all over. Even so, one customer reports that he gets about five runs down the drag strip and unless he
cryogenically processes his lifters. After cryogenic processing, he typically gets over 100 runs.
Winston Cup rules specify solid lifters. These cars are
turning around 9300 rpm. So valve spring pressure have to
be very high to slam the valve shut. The current practice is to create a cam profile that will actually loft the lifter.
The lifter is thrown up in the air, forcing the valve to open very fast and then the spring slams the lifter down back
against the cam. This creates extreme wear, but it gets the valve wide open as quickly as possible and leaves it wide
open to the last possible microsecond.
The lifters start with a slightly convex surface and wear
into a concave configuration. Typically, they are cast iron
and heat treated to the mid 50s HRC. In use, any wear increases the valve lash and delays valve lift, creating a loss
of power. It also leaves a lot of wear particles in the oil. It can take up to three sets of lifters to get an engine
through dyno testing and the race due to the extreme wear caused by these radical cam profiles and high spring
pressures. Cryogenic processing reduces this wear by about half.
Camshaft wear is also a problem. Camshafts are generally
carburized 8620 steel, but typical Winston Cup
camshafts are 8620, with a layer of stellite welded or spray coated onto the lobes to help reduce wear. The stellite
has a hardness of about 52 HRC. It wears and chips badly during a race, changing the valve lash and also the valve
timing. In other forms of racing, camshaft wear is not as drastic, but still a definite problem, especially for racers
who cannot afford a tear down after each race. Cryogenic processing has proven a boon to these racers because it
reduces wear and therefore reduces camshaft replacement costs.
At least one bearing manufacture cryogenically treats babbited
bearings as part of their production process. They
found it increased the life of the bearings and also of the steel backing, which tend to fail in fatigue. It is interesting
that cryogenic processing has an effect on the babbit metal of the bearings. Similarly, bronze bushings used on
wrist pins also wear considerably less when treated.
Many racers are processing ball bearings and roller bearings
(typically 52100 steel) because they get a three to five
fold increase in life. Rod ends used in steering and suspension systems get the same treatment and performance
Cylinders, Pistons & Rings
Cryogenic processing of piston rings and cylinder walls
has been shown to reduce wear substantially. One go-kart
racing customer claimed he got a five fold increase in engine life before he had to freshen the engine. Better ring
seal was born out in pressure readings on a dynamometer. Apparently, this happens because the parts machine and
hone better after treatment as a consequence of a more uniformed hardness distribution over the surface of the part.
(This fellow was a national champion, so he must know his business.) CTP has done tests that show a significant
reduction in the standard deviation of hardness readings taken before and after cryogenic processing. In some
cases, the standard deviation is 1/3 of what is was before the process.
Processed piston rings typically wear both less and more
evenly than untreated rings. More tribologically
compatible with the cylinder walls, they tend to flutter less due to the vibrational dampening the process imparts
into the material and due to the more even hardness of both the rings and the cylinder walls. All these factors
combined to give better ring sealing, and therefore more power.
Cryogenic processing of engine blocks also stabilize the
blocks and reduces warping and distortion due to
vibration and heat during use. The same is true for pistons.
Several engine builders, who specify the process, have taken
careful measurements of pistons before and after use,
finding that cryogenically processed pistons distort less after use.
Cryogenics plays a vital role in a process developed by
CTP to induction harden the bores of cast iron blocks. This
process reduces friction and wear. Here initial reports indicate substantial horsepower gains from this process.
Crankshafts benefit greatly from cryogenics. Several of
the most recent names in the crankshaft business used
cryogenics as a part of their thermal treatment.
Cryogenic processing greatly decreases wear on crankshaft
journals and stabilizes the crankshaft. We have treated
everything from stock cranks through special racing nodular iron cranks and racing cranks made from 4340 steel.
Virtually all parts that are subject to stress or abrasion
can benefit from cryogenic processing. Even head gaskets
benefit because the armor around the combustion chamber is subject to both thermal cycle fatigue and to flexing
Keys to the process
Success of cryogenic processing is critically dependent
on the equipment in which the processing is done. The
quality and function of the machines available varies from poor to excellent. So does the ability of cryoprocessor
manufactures to support their machines with technical and processing advice. (More details on the equipment will
appear in the up coming HTP articles.)
Cryogenic processing use to be simple. Bring the part down
to 184 C (-320F) typically over an eight hour period.
Hold the part at this temperature for eight to twenty hours, and bring it back to ambient temperature over a fifteen
hour period, followed by tempering at 149C (300F). This general formula can be used to good effect for many
components, especially when all the previous thermal treatment spec.s are not known. The actual practice is
harder than it looks. There are several large companies that have spent a lot of time trying to develop the process
unsuccessfully. In fact, the idea that almost anyone can buy a cryogenic processing machine and set up a viable,
reliable business is absurd. Metallurgical knowledge is not only helpful, but it is a requirement to achieve effective
The optimum process for any given part varies according
to the metallurgy and the failure modes of the piece.
Although "standard" processes will greatly improve components that are sent to us for processing, better results
are achieved when the cryogenic process is part of an optimum package of material selection, production methods,
heat treat and cryogenic processing. We even spend time analyzing component failures to allow us to optimize all
factors in thermal treatment of the part. This approach yields excellent results, especially for companies that do not
have their own metallurgical staff.
Cryogenic processing is destined to become part of the standard
production process as opposed to being an add-on
process as it now exists. CTP selected Midwest Thermal Vac Inc., Kenosha, Wisc. For their unflagging attention to
customers needs and their quest for doing things right. MTVs president, Frederick Otto states, "It is becoming
more and more obvious that cryogenic processing is a necessary and integral part of the thermal treatment of a
By helping customers set up realistic standards and specifications,
we have allowed them to develop sophisticated
metallurgical standards to ensure the metallurgical performance of their product. According to roger Friedman of
Dyers Top Rods, "Integrating cryogenic processing with out materials selection, heat treat, and manufacturing
methods has allowed us to make connecting rods that are both light and have a long service life under extreme
racing conditions. The result? At the Eldora million race, where there was a one million dollar prize for the winner,
seven out of the first ten finishers used our rods, including the winner."
The use of cryogenic processing is now starting to extend
into the production processes of companies. Racing
component manufacturers are beginning to treat their tooling and theyre cutting tools. This is reducing their
tooling costs considerably. One firearms manufacturer currently saves over $3,000,000 annually by treating its
The cryo future
More research into cryogenic processing is a certainty.
When Illinois Institute of Technology created its Thermal
Processing Technology Center in conjunction with the National Science Foundation earlier this year, it purposely
used the term "Thermal Processing" in the name because elevated temperatures are no longer the only means of
thermal processing. One of the first proposed projects for this center is to study cryogenic processing to determine
what factors cryogenic processing changed in metals. There is a current interest in the use of the process on H13
Los Alamos National Laboratory, too, is very interested
in doing more work on the subject. Their testing revealed
that there were interesting things happening with steels that were cryogenically processed. They are eager to find
industrial partners to help fund the research to delve into the process even further.
You may also want to visit http://www.metal-wear.com/
Cu. In. and Metric Conversion
FRACTIONS OF INCH TO DECIMAL EQUIVALENTS
Multiply 25.4 to obtain Millimeters (25.4 x .020" = .508mm
Divide Millimeters by 25.4 to obtain inches (.50mm Divided by 25.4 = .0197") or (.50mm x .03937 = .197").
Inches 25.4 Millimeters
Millimeters .03937 Inches
MULTIPLY BY TO OBTAIN
Cubic Inches 16.38716 Cubic Centimeters
Liters 61.023 Cubic Inches