PabloCruise
SILVER Star
Oh, wise guy, eh?
Why I oughta...
Why I oughta...
Aftermarket Performance 2F Cams
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PabloCruise said:
Sorry, I was AFTK for a bit.Mark W said:
The '77-78 carb is a good one for efficiency & throttle response, because it is slightly smaller than other years.
But if you are asking about which intake manifold & cam to use, then I assume you are ekeing out every last bit of performance/efficiency.
In that case I would suggest (in order of preference) 1976, 1975.
They all have 38/40 throttles and 31mm primary venturis, but they also have gianormous 35mm sec. venturi.
77-78 USA and all non-US have 31/33 venturis. Some cali-spec are smaller yet, w/ 28mm pri venturi.
Late model to me is the 81-87 stuff. They are also good carbs, w/ the same basic dimensions as 1976. But installing one on a 1978 FJ40 is more of a hassle. Single feed fuel line, different choke cable, shorter height which leads to air cleaner difficulty, two wire ICS, yadda yadda...
HTH.
Do all these cams fit in the 3FE?
from: http://www.yankeetoys.org/KLF/EPCDiags/1988_FJ62_New_Features.pdf
Somebody smarter than me (Mark maybe?) will have to comment on how the differences between the two cams would affect performance, etc.
Steve
Somebody smarter than me (Mark maybe?) will have to comment on how the differences between the two cams would affect performance, etc.
Steve
Well alrighty then, there has been much ado about cams in our little f, 2f, 3fe tractor motors. I have shamelessly pilfered the following passage from the crane cams website...but I find it easier than re-inventing the wheel. A couple of key things to keep in mind as you peruse this...1.) duration... more is not necissarily better in tractor world...ie moving yourself up the rpm curve to gain HP is somewhat opposed to obtaining more torque down low. Remember it's a tractor motor...anyway read on...2.) so you think your bent on building the ultimate tractor motor...whoo hooo...and you want the "big" cam. Do you have enough compression, valves, flowed heads, exhaust to move all that air around ??? Doubt it..so you risk flogging your flacid member 
and 3.) Just how fast is/was your bottom end designed to spin...trust me it's no Ferrari or even a NASCAR racing taxi cab. Do you really want to run your cruiser at 5 to 6 k ? for what purpose? Believe me, I understand wanting to goose a little more out of any motor....but also realize that there is no substitute for cubic inches. If getting more torque/hp at a reasonable cost is what you seek... save yourself the heartache and $$$'s and get a V8. Anyway, the following gives you the deal re: cams and associated bits. It's a little long but a valuable read.
Cam and Valve Train Questions
What is meant by Basic RPM?
The camshaft's basic RPM is the RPM range within which the engine will produce its best power. The width of this power band is approximately 3000 to 3500 RPM with standard lifter cams, and 3500 to 4000 RPM with roller lifter cams. It is important that you select the camshaft with the "Basic RPM Range" best suited to your application, vehicle gearing and tire diameter. Why is Cruise RPM at 60 MPH important?
When selecting a new camshaft, you can raise or lower the engine's basic RPM range. It is important to be sure the vehicle's drive train is capable of matching your selection. The cruise RPM at 60 MPH is a way of rating your rear end gearing and tire diameter to determine if these components match the RPM potential you are desiring.
What is Camshaft Duration and why is it important?
Duration is the period of time, measured in degrees of crankshaft rotation, that a valve is open. Duration (at .050" lifter rise) is the deciding factor to what the engine's basic RPM range will be. Lower duration cams produce the power in the lower RPM range. Larger duration cams operate at higher RPM, but you will lose bottom end power to gain top end power as the duration is increased. (For each ten degree change in the duration at .050", the power band moves up or down in RPM range by approximately 500 RPM.)
What is the difference in Advertised Duration and Duration at .050" Lifter Rise (Tappet Lift)?
In order for duration to have any merit as a measurement for comparing camshaft size, the method for determining the duration must be the same. There are two key components for measuring duration-- the degrees of crankshaft rotation and at what point of lifter rise the measurements were taken. Advertised durations are not taken at any consistent point of lifter rise, so these numbers can vary greatly. For this reason, advertised duration figures are not good for comparing cams. Duration values expressed at .050" lifter rise state the exact point the measurement was taken. These are the only duration figures that are consistent and can accurately be used to compare camshafts.
How does Valve Lift affect the operation of an engine?
Lift is the distance the valve actually travels. It is created by the cam lobe lift, which is then increased by the rocker arm ratio. The amount of lift you have and the speed at which the valve moves is a key factor in determining the torque the engine will produce.
What is Camshaft Lobe Separation and how does it affect the engine?
Lobe separation is the distance (in camshaft degrees) that the intake and exhaust lobe centerlines (for a given cylinder) are spread apart. Lobe separation is a physical characteristic of the camshaft and cannot be changed without regrinding the lobes.
This separation determines where peak torque will occur within the engine's power range. Tight lobe separations (such as 106°) cause the peak torque to build early in basic RPM range of the cam. The torque will be concentrated, build quickly and peak out. Broader lobe separations (such as 112°) allow the torque to be spread over a broader portion of the basic RPM range and shows better power through the upper RPM.
What are Intake and Exhaust Centerlines?
The centerline of either the intake or exhaust lobe is the theoretical maximum lift point of the lobe in relationship to Top Dead Center in degrees of crankshaft rotation. (They are shown at the bottom of the camshaft specification card as "MAX LIFT.") The centerline of the cam can be moved by installing the camshaft in the engine to an advanced or a retarded position.
How does Advancing or Retarding the camshaft's position in the engine affect performance?
Advancing the cam will shift the basic RPM range downward. Four degrees of advance (from the original position) will cause the power range to start approximately 200 RPM sooner. Retarding it this same amount will move the power upward approximately 200 RPM. This can be helpful for tuning the power range to match your situation. If the correct cam has been selected for a particular application, installing it in the normal "straight up" position (per the opening and closing events at .050" lifter rise on the spec card) is the best starting point.
Why is it necessary to know the Compression Ratio of an engine in order to choose the correct cam?
The compression ratio of the engine is one of three key factors in determining the engine's cylinder pressure. The other two are the duration of the camshaft (at .050" lifter rise) and the position of the cam in the engine (advanced or retarded). The result of how these three factors interact with one another is the amount of cylinder pressure the engine will generate. (This is usually expressed as the "cranking pressure" that can be measured with a gauge installed in the spark plug hole.)
It is important to be sure that the engine's compression ratio matches the recommended ratio for the cam you are selecting. Too little compression ratio (or too much duration) will cause the cylinder pressure to drop. This will lower the power output of the engine.
With too much compression ratio (or too little duration) the cylinder pressure will be too high, causing pre-ignition and detonation. This condition could severely damage engine components.
How does Cylinder Pressure relate to the octane rating of today's unleaded fuel?
In very basic terms, the more cylinder pressure we make the more power the engine will produce. But look out for the fuel! Today's pump gas is too volatile and cannot tolerate high compression ratio (above 10.5:1) and high cylinder pressure (above approximately 165 PSI) without risking detonation. Fuel octane boosters or expensive racing gasoline will be necessary if too much cylinder pressure is generated.
How does an increase in Rocker Arm Ratio improve the engine's performance?
The lobe lift of the cam is increased by the ratio of the rocker arm to produce the final amount of valve lift. A cam with a .320" lobe lift using a 1.50:1 ratio rocker arm will have a .480" valve lift (.320" x 1.50 = .480"). If you install rocker arms with an increased ratio of 1.60:1, with the same cam, the lift would increase to .512" (.320" x 1.60 = .512"). The engine reacts to the movement of the valve. It doesn't know how the increased lift was generated. It responds the same way it would as if a slightly larger lift cam had been installed. In fact, since the speed of the valve is increased with the higher rocker arm ratio, the engine thinks it has also gained 2° to 4° of camshaft duration.
The end result is an easy and quick way to improve the performance of the existing cam without having to install a new one. See the Buyers Guide section for availability of increased ratio rocker arms. Remember, whenever you increase the valve lift, with either a bigger cam or larger rocker arm ratio, you must check for valve spring coil bind and for other mechanical interference. Please review the previous sections concerning these matters.
Must new (Standard Design) lifters always be installed on a new camshaft?
YES! All new standard hydraulic and mechanical camshafts must have new lifters installed. The face of these lifters have a slight crown, and the mating lobe surface they ride on has been ground with a slight taper. The purpose of this is to create a "spinning" of the lifter as it rides on the lobe. This is necessary to prevent premature wear of the lifter and lobe.
Therefore, these parts will be mated to one another during the initial break-in period. Used lifters will not mate properly, causing the lobe to fail. If you are rebuilding an engine and plan to re-use the existing cam and lifters (in the same block) it can be done, as long as the lifter goes back on the same lobe it is mated to. To keep your components in order, a Crane Cams "Organizer Tray" part number 99015-1 would be helpful. If the lifters get mixed up, they cannot be used, and a new set will be required. The new lifters would also have to go through the break-in procedure to mate to the old cam.
Can used Roller Lifters be installed on a new camshaft?
YES. "Roller" lifters are the only ones that can be re-used. This design lifter has a wheel (supported by needle bearings) attached to the bottom of it. The lobe the roller lifter rides on does not have any taper. This is a very low friction design and does not require the lifter to mate to the cam. As long as the wheel shows no wear, and the needle bearings are in good condition, the "hydraulic roller" or "mechanical roller" lifter can be re-used.
What Engine Oil and Lubricants should I use?
Crane Cams does not recommend the use of synthetic oils during the initial break-in period for a new camshaft. Use a good quality grade of naturally formulated motor oil during this period. If you choose to use synthetic oil after the engine has been broken in, change the oil filter and follow the oil manufacturer's instructions.
When using either regular oil or synthetic it is important to pick the weight oil that best matches your engine bearing clearances, the engine's operating temperature, and the climate the vehicle will be operating in. Use the oil manufacturer's recommendation to satisfy these conditions. Crane Cams offers lubricants to aid during the critical break-in procedure, and to prolong the engine's life.
Should I use "Oil Restrictors" in my engine?
No, Crane Cams does not recommend the use of oil restrictors. The oil is the life blood of the engine, not only lubricating but cooling the engine components as well. For example, a valve spring builds in temperature as it compresses and relaxes. This increase of temperature affects the characteristics of the spring material, and if excessive, will shorten the life of the spring. Oil is the only means the spring has for cooling.
How do I prime the engine's oiling system?
It is critical that the engine's oiling system be primed before starting the newly built, or rebuilt, engine for the first time. This must be done by turning the oil pump with a drill motor to supply oil throughout the engine. If this is done with the valve covers off, you will be able to see that the oil is being delivered to the top of the engine and to all the valve train components.
What is the Most Important thing to remember?
Reading and following the instructions supplied to you is most important. If there is something you don't understand, contact the people who supplied you the parts, or call one of the Crane Cams Technical Consultants. Get answers to your questions before proceeding. Any non-roller camshaft and lifters must be pre-lubricated before installation. Use Crane Cams Assembly Lube, part number 99002-1, and Crane Cams Super-Lube, part number 99003-1.
What is Valve Spring Installed Height?
Installed height is the dimension measured from the bottom of the valve spring retainer, where the outer valve spring locates, to the spring pocket in the cylinder head, when the valve is closed.
How Does Installed Height Affect the Spring Tension?
Installed height is the determining factor of what the valve spring “Closed Tension” will be. The camshaft specification card, and the spring section of the catalog both show what the approximate tension a particular valve spring will exert if installed at a specific height. For example, spring part no. 99848 shows 105# @ 1.700”. This means that if this spring is installed at a height of 1.700” it should exert 105 pounds of tension with the valve closed.
How Do You Change Installed Height, and What Effect Does it Have?
The easiest way to lessen installed height is to insert a shim in the spring pocket below the valve spring. Another method is to use a different design valve spring retainer. Retainers with a deeper dish will have more installed height; with a shallower dish, less installed height. You can also use a valve lock that is designed to change the location where the retainer is positioned on the valve stem. Longer length valves can also be used.
The shorter the installed height, the higher the valve spring tension will be, and the less distance the spring can travel before reaching coil bind.
The taller the installed height, the less the valve spring tension and the further the spring can travel before coil bind occurs.
What is Valve Spring Coil Bind and How Does it Relate to Spring Travel and Valve Lift?
When the valve spring is compressed until its coils touch one another and can travel no further, it is said to be in coil bind. To measure this you must install the retainer in the valve spring, then compress the spring until it coil binds. Now measure from the bottom side of the retainer to the bottom of the spring. This measurement is the coil bind height. This can be done on the cylinder head with a spring compression tool (part number 99417-1), in a bench vise, or in a professional valve spring tester.
Using Figure 5, subtract the coil bind height “B” from the valve spring installed height “A”. The difference “C” is the maximum spring travel. The spring travel must always be at least .060” greater than the full lift of the valve. This safety margin of .060” (or more) is necessary to avoid the dangers of coil bind and over-stressing the spring.
If coil bind occurs, the resulting mechanical interference will severely damage the camshaft and valve train components.
How Do You Increase the Spring Travel?
The valve spring must have sufficient travel (plus .060” safety margin) to accommodate the amount of valve lift created by the camshaft and/or an increase in rocker arm ratio. To increase spring travel you can either raise the installed height (but this will lessen the spring tension), or change to a spring with additional travel. If there is not a standard diameter spring available with enough travel, then the cylinder heads will have to be machined and a larger spring installed.
Crane Cams offers some special valve springs in standard diameters which saves you from having to machine the cylinder heads. For example, a small block Chevrolet engine can use spring kit part no. 11309-1 to handle .550” to .600” valve lift. The 85-95 302 Ford hydraulic roller engines can use spring kit part no. 44308-1 to handle .550” lift.
Besides Coil Bind, What Other Types of Mechanical Interference Should You Look Out For?
When you increase the valve lift with a bigger cam or increased rocker arm ratio you must be sure that there is no interference between any of the moving parts. Some of the components that must be inspected for clearance are:
1. The distance from the bottom of the valve spring retainer and the top of the valve stem guide, or the top of the valve stem seal must be equal to the net valve lift of the valve plus at least .060” more for clearance.
2. When using rocker arms mounted on a stud, the length of the slot in the rocker arm body must be inspected to be sure it is long enough to avoid binding on the stud. The ends of the slot must be at least .060” away from the stud when the rocker is at full valve lift and when the valve is closed. – Crane Cams offers steel long slot and extra long slot rocker arms to relieve this interference problem. Aluminum roller rocker arms may be required to provide sufficient travel on larger lift camshafts.
3. The underside of the rocker arm body cannot touch the valve spring retainer. You will need at least .040” clearance to the retainer throughout the full movement of the rocker arm. If necessary, a different shape retainer or rocker arm design will be required. In some cases, installing a lash cap on the tip of the valve stem can provide the clearance required.
4. Valve to piston clearance must be checked to be sure there is sufficient clearance. The intake valve must have at least .100” clearance to the piston and at least .120” clearance on the exhaust valve.
What is a Quick Way to Check Valve to Piston Clearance on an Assembled Engine?
Low tension checking springs, Part Number 99881-2, must be used (instead of your normal spring) to mock up your valve train and to check the piston to valve clearance on the engine. Assemble the valve train and verify correct lifter preload or valve lash. By mounting a dial indicator on the cylinder head with the plunger’s tip on the valve spring retainer, you can quickly check the clearance.
Hand rotate the engine through a complete cycle (two rotations of the crankshaft), stopping at several points before and after Top Dead Center (T.D.C.) to check the valve clearance. The least amount of clearance will usually occur between 15 degrees before T.D.C. and 15 degrees after T.D.C. This also provides a graphic illustration that gross valve lift does not determine piston to valve clearance, as the piston is fairly far down in the cylinder when maximum valve lift is reached.
By pushing the rocker arm down with your finger, the valve will contact the piston. The amount of movement shown on the dial indicator is the valve clearance at that point of engine rotation. Rotate the crankshaft a few degrees and re-check the clearance. As the piston moves through this area, the dial indicator reading will lessen, then become larger as you rotate the engine past the critical point. The shortest reading you get is the actual valve to piston clearance.
What is the Critical Point of Crankshaft Rotation for Checking Valve to Piston Clearance?
The critical point for both valves is the “Overlap Period” as the exhaust cycle is ending and the intake cycle is beginning. You must start checking the clearance before and continue after T.D.C. on both the intake and exhaust to be sure you have the correct readings through the overlap period.
You can find all the tools required for checking valve to piston clearance (as well as degreeing a cam) in Crane Cams’ Tune-A-Cam Kit, Part Number 99030-1.
and 3.) Just how fast is/was your bottom end designed to spin...trust me it's no Ferrari or even a NASCAR racing taxi cab. Do you really want to run your cruiser at 5 to 6 k ? for what purpose? Believe me, I understand wanting to goose a little more out of any motor....but also realize that there is no substitute for cubic inches. If getting more torque/hp at a reasonable cost is what you seek... save yourself the heartache and $$$'s and get a V8. Anyway, the following gives you the deal re: cams and associated bits. It's a little long but a valuable read.Cam and Valve Train Questions
What is meant by Basic RPM?
The camshaft's basic RPM is the RPM range within which the engine will produce its best power. The width of this power band is approximately 3000 to 3500 RPM with standard lifter cams, and 3500 to 4000 RPM with roller lifter cams. It is important that you select the camshaft with the "Basic RPM Range" best suited to your application, vehicle gearing and tire diameter. Why is Cruise RPM at 60 MPH important?
When selecting a new camshaft, you can raise or lower the engine's basic RPM range. It is important to be sure the vehicle's drive train is capable of matching your selection. The cruise RPM at 60 MPH is a way of rating your rear end gearing and tire diameter to determine if these components match the RPM potential you are desiring.
What is Camshaft Duration and why is it important?
Duration is the period of time, measured in degrees of crankshaft rotation, that a valve is open. Duration (at .050" lifter rise) is the deciding factor to what the engine's basic RPM range will be. Lower duration cams produce the power in the lower RPM range. Larger duration cams operate at higher RPM, but you will lose bottom end power to gain top end power as the duration is increased. (For each ten degree change in the duration at .050", the power band moves up or down in RPM range by approximately 500 RPM.)
What is the difference in Advertised Duration and Duration at .050" Lifter Rise (Tappet Lift)?
In order for duration to have any merit as a measurement for comparing camshaft size, the method for determining the duration must be the same. There are two key components for measuring duration-- the degrees of crankshaft rotation and at what point of lifter rise the measurements were taken. Advertised durations are not taken at any consistent point of lifter rise, so these numbers can vary greatly. For this reason, advertised duration figures are not good for comparing cams. Duration values expressed at .050" lifter rise state the exact point the measurement was taken. These are the only duration figures that are consistent and can accurately be used to compare camshafts.
How does Valve Lift affect the operation of an engine?
Lift is the distance the valve actually travels. It is created by the cam lobe lift, which is then increased by the rocker arm ratio. The amount of lift you have and the speed at which the valve moves is a key factor in determining the torque the engine will produce.
What is Camshaft Lobe Separation and how does it affect the engine?
Lobe separation is the distance (in camshaft degrees) that the intake and exhaust lobe centerlines (for a given cylinder) are spread apart. Lobe separation is a physical characteristic of the camshaft and cannot be changed without regrinding the lobes.
This separation determines where peak torque will occur within the engine's power range. Tight lobe separations (such as 106°) cause the peak torque to build early in basic RPM range of the cam. The torque will be concentrated, build quickly and peak out. Broader lobe separations (such as 112°) allow the torque to be spread over a broader portion of the basic RPM range and shows better power through the upper RPM.
What are Intake and Exhaust Centerlines?
The centerline of either the intake or exhaust lobe is the theoretical maximum lift point of the lobe in relationship to Top Dead Center in degrees of crankshaft rotation. (They are shown at the bottom of the camshaft specification card as "MAX LIFT.") The centerline of the cam can be moved by installing the camshaft in the engine to an advanced or a retarded position.
How does Advancing or Retarding the camshaft's position in the engine affect performance?
Advancing the cam will shift the basic RPM range downward. Four degrees of advance (from the original position) will cause the power range to start approximately 200 RPM sooner. Retarding it this same amount will move the power upward approximately 200 RPM. This can be helpful for tuning the power range to match your situation. If the correct cam has been selected for a particular application, installing it in the normal "straight up" position (per the opening and closing events at .050" lifter rise on the spec card) is the best starting point.
Why is it necessary to know the Compression Ratio of an engine in order to choose the correct cam?
The compression ratio of the engine is one of three key factors in determining the engine's cylinder pressure. The other two are the duration of the camshaft (at .050" lifter rise) and the position of the cam in the engine (advanced or retarded). The result of how these three factors interact with one another is the amount of cylinder pressure the engine will generate. (This is usually expressed as the "cranking pressure" that can be measured with a gauge installed in the spark plug hole.)
It is important to be sure that the engine's compression ratio matches the recommended ratio for the cam you are selecting. Too little compression ratio (or too much duration) will cause the cylinder pressure to drop. This will lower the power output of the engine.
With too much compression ratio (or too little duration) the cylinder pressure will be too high, causing pre-ignition and detonation. This condition could severely damage engine components.
How does Cylinder Pressure relate to the octane rating of today's unleaded fuel?
In very basic terms, the more cylinder pressure we make the more power the engine will produce. But look out for the fuel! Today's pump gas is too volatile and cannot tolerate high compression ratio (above 10.5:1) and high cylinder pressure (above approximately 165 PSI) without risking detonation. Fuel octane boosters or expensive racing gasoline will be necessary if too much cylinder pressure is generated.
How does an increase in Rocker Arm Ratio improve the engine's performance?
The lobe lift of the cam is increased by the ratio of the rocker arm to produce the final amount of valve lift. A cam with a .320" lobe lift using a 1.50:1 ratio rocker arm will have a .480" valve lift (.320" x 1.50 = .480"). If you install rocker arms with an increased ratio of 1.60:1, with the same cam, the lift would increase to .512" (.320" x 1.60 = .512"). The engine reacts to the movement of the valve. It doesn't know how the increased lift was generated. It responds the same way it would as if a slightly larger lift cam had been installed. In fact, since the speed of the valve is increased with the higher rocker arm ratio, the engine thinks it has also gained 2° to 4° of camshaft duration.
The end result is an easy and quick way to improve the performance of the existing cam without having to install a new one. See the Buyers Guide section for availability of increased ratio rocker arms. Remember, whenever you increase the valve lift, with either a bigger cam or larger rocker arm ratio, you must check for valve spring coil bind and for other mechanical interference. Please review the previous sections concerning these matters.
Must new (Standard Design) lifters always be installed on a new camshaft?
YES! All new standard hydraulic and mechanical camshafts must have new lifters installed. The face of these lifters have a slight crown, and the mating lobe surface they ride on has been ground with a slight taper. The purpose of this is to create a "spinning" of the lifter as it rides on the lobe. This is necessary to prevent premature wear of the lifter and lobe.
Therefore, these parts will be mated to one another during the initial break-in period. Used lifters will not mate properly, causing the lobe to fail. If you are rebuilding an engine and plan to re-use the existing cam and lifters (in the same block) it can be done, as long as the lifter goes back on the same lobe it is mated to. To keep your components in order, a Crane Cams "Organizer Tray" part number 99015-1 would be helpful. If the lifters get mixed up, they cannot be used, and a new set will be required. The new lifters would also have to go through the break-in procedure to mate to the old cam.
Can used Roller Lifters be installed on a new camshaft?
YES. "Roller" lifters are the only ones that can be re-used. This design lifter has a wheel (supported by needle bearings) attached to the bottom of it. The lobe the roller lifter rides on does not have any taper. This is a very low friction design and does not require the lifter to mate to the cam. As long as the wheel shows no wear, and the needle bearings are in good condition, the "hydraulic roller" or "mechanical roller" lifter can be re-used.
What Engine Oil and Lubricants should I use?
Crane Cams does not recommend the use of synthetic oils during the initial break-in period for a new camshaft. Use a good quality grade of naturally formulated motor oil during this period. If you choose to use synthetic oil after the engine has been broken in, change the oil filter and follow the oil manufacturer's instructions.
When using either regular oil or synthetic it is important to pick the weight oil that best matches your engine bearing clearances, the engine's operating temperature, and the climate the vehicle will be operating in. Use the oil manufacturer's recommendation to satisfy these conditions. Crane Cams offers lubricants to aid during the critical break-in procedure, and to prolong the engine's life.
Should I use "Oil Restrictors" in my engine?
No, Crane Cams does not recommend the use of oil restrictors. The oil is the life blood of the engine, not only lubricating but cooling the engine components as well. For example, a valve spring builds in temperature as it compresses and relaxes. This increase of temperature affects the characteristics of the spring material, and if excessive, will shorten the life of the spring. Oil is the only means the spring has for cooling.
How do I prime the engine's oiling system?
It is critical that the engine's oiling system be primed before starting the newly built, or rebuilt, engine for the first time. This must be done by turning the oil pump with a drill motor to supply oil throughout the engine. If this is done with the valve covers off, you will be able to see that the oil is being delivered to the top of the engine and to all the valve train components.
What is the Most Important thing to remember?
Reading and following the instructions supplied to you is most important. If there is something you don't understand, contact the people who supplied you the parts, or call one of the Crane Cams Technical Consultants. Get answers to your questions before proceeding. Any non-roller camshaft and lifters must be pre-lubricated before installation. Use Crane Cams Assembly Lube, part number 99002-1, and Crane Cams Super-Lube, part number 99003-1.
What is Valve Spring Installed Height?
Installed height is the dimension measured from the bottom of the valve spring retainer, where the outer valve spring locates, to the spring pocket in the cylinder head, when the valve is closed.
How Does Installed Height Affect the Spring Tension?
Installed height is the determining factor of what the valve spring “Closed Tension” will be. The camshaft specification card, and the spring section of the catalog both show what the approximate tension a particular valve spring will exert if installed at a specific height. For example, spring part no. 99848 shows 105# @ 1.700”. This means that if this spring is installed at a height of 1.700” it should exert 105 pounds of tension with the valve closed.
How Do You Change Installed Height, and What Effect Does it Have?
The easiest way to lessen installed height is to insert a shim in the spring pocket below the valve spring. Another method is to use a different design valve spring retainer. Retainers with a deeper dish will have more installed height; with a shallower dish, less installed height. You can also use a valve lock that is designed to change the location where the retainer is positioned on the valve stem. Longer length valves can also be used.
The shorter the installed height, the higher the valve spring tension will be, and the less distance the spring can travel before reaching coil bind.
The taller the installed height, the less the valve spring tension and the further the spring can travel before coil bind occurs.
What is Valve Spring Coil Bind and How Does it Relate to Spring Travel and Valve Lift?
When the valve spring is compressed until its coils touch one another and can travel no further, it is said to be in coil bind. To measure this you must install the retainer in the valve spring, then compress the spring until it coil binds. Now measure from the bottom side of the retainer to the bottom of the spring. This measurement is the coil bind height. This can be done on the cylinder head with a spring compression tool (part number 99417-1), in a bench vise, or in a professional valve spring tester.
Using Figure 5, subtract the coil bind height “B” from the valve spring installed height “A”. The difference “C” is the maximum spring travel. The spring travel must always be at least .060” greater than the full lift of the valve. This safety margin of .060” (or more) is necessary to avoid the dangers of coil bind and over-stressing the spring.
If coil bind occurs, the resulting mechanical interference will severely damage the camshaft and valve train components.
How Do You Increase the Spring Travel?
The valve spring must have sufficient travel (plus .060” safety margin) to accommodate the amount of valve lift created by the camshaft and/or an increase in rocker arm ratio. To increase spring travel you can either raise the installed height (but this will lessen the spring tension), or change to a spring with additional travel. If there is not a standard diameter spring available with enough travel, then the cylinder heads will have to be machined and a larger spring installed.
Crane Cams offers some special valve springs in standard diameters which saves you from having to machine the cylinder heads. For example, a small block Chevrolet engine can use spring kit part no. 11309-1 to handle .550” to .600” valve lift. The 85-95 302 Ford hydraulic roller engines can use spring kit part no. 44308-1 to handle .550” lift.
Besides Coil Bind, What Other Types of Mechanical Interference Should You Look Out For?
When you increase the valve lift with a bigger cam or increased rocker arm ratio you must be sure that there is no interference between any of the moving parts. Some of the components that must be inspected for clearance are:
1. The distance from the bottom of the valve spring retainer and the top of the valve stem guide, or the top of the valve stem seal must be equal to the net valve lift of the valve plus at least .060” more for clearance.
2. When using rocker arms mounted on a stud, the length of the slot in the rocker arm body must be inspected to be sure it is long enough to avoid binding on the stud. The ends of the slot must be at least .060” away from the stud when the rocker is at full valve lift and when the valve is closed. – Crane Cams offers steel long slot and extra long slot rocker arms to relieve this interference problem. Aluminum roller rocker arms may be required to provide sufficient travel on larger lift camshafts.
3. The underside of the rocker arm body cannot touch the valve spring retainer. You will need at least .040” clearance to the retainer throughout the full movement of the rocker arm. If necessary, a different shape retainer or rocker arm design will be required. In some cases, installing a lash cap on the tip of the valve stem can provide the clearance required.
4. Valve to piston clearance must be checked to be sure there is sufficient clearance. The intake valve must have at least .100” clearance to the piston and at least .120” clearance on the exhaust valve.
What is a Quick Way to Check Valve to Piston Clearance on an Assembled Engine?
Low tension checking springs, Part Number 99881-2, must be used (instead of your normal spring) to mock up your valve train and to check the piston to valve clearance on the engine. Assemble the valve train and verify correct lifter preload or valve lash. By mounting a dial indicator on the cylinder head with the plunger’s tip on the valve spring retainer, you can quickly check the clearance.
Hand rotate the engine through a complete cycle (two rotations of the crankshaft), stopping at several points before and after Top Dead Center (T.D.C.) to check the valve clearance. The least amount of clearance will usually occur between 15 degrees before T.D.C. and 15 degrees after T.D.C. This also provides a graphic illustration that gross valve lift does not determine piston to valve clearance, as the piston is fairly far down in the cylinder when maximum valve lift is reached.
By pushing the rocker arm down with your finger, the valve will contact the piston. The amount of movement shown on the dial indicator is the valve clearance at that point of engine rotation. Rotate the crankshaft a few degrees and re-check the clearance. As the piston moves through this area, the dial indicator reading will lessen, then become larger as you rotate the engine past the critical point. The shortest reading you get is the actual valve to piston clearance.
What is the Critical Point of Crankshaft Rotation for Checking Valve to Piston Clearance?
The critical point for both valves is the “Overlap Period” as the exhaust cycle is ending and the intake cycle is beginning. You must start checking the clearance before and continue after T.D.C. on both the intake and exhaust to be sure you have the correct readings through the overlap period.
You can find all the tools required for checking valve to piston clearance (as well as degreeing a cam) in Crane Cams’ Tune-A-Cam Kit, Part Number 99030-1.
Mark W
Yep, I really don't really care that much I guess.
Basically the 3FE specs show that the timing of the cam has been advanced 5 degrees. In general this will increase lower rpm effeciency at some loss of top end effeciency. It is related to intake manaifold design. At higher rpm you can actually pack more air fuel mixture into the cylinder by utilizing the inertia odf the moving charge in the intake runners. This inertia causes the air to pileup against the back of the intake valve when it closes. At higher rpm a valve that opens earlier can take advantage of this "rebound" effect before it dissipates.
A longer duration cam does the same, as well as letting the moving air fuel charge pile up against the climbing piston at the end of the intake stroke. The valve actually stays open as the piston reaches the bottom and starts up. The momentum of the charge keeps it moving into the cylinder even without the suction of the piston moving downward.
The key here is to close the intake valve before the compression of the upward moving piston overpowers the momentum of the air/fuel.
When the valve needs to close to do this depends on the speed of the intake charge and the weight of the charge. The weight depends on the length of the intake tract. The speed depends on the rpm of the engine, the shape of the intake passage, the texture of the walls and a variety of other smaller factors.
This stuff also effects the stacking of the charge against the intake valve after it closes.
Short answer is that the 5 degree advance moves the powerband down a bit.
Mark...
A longer duration cam does the same, as well as letting the moving air fuel charge pile up against the climbing piston at the end of the intake stroke. The valve actually stays open as the piston reaches the bottom and starts up. The momentum of the charge keeps it moving into the cylinder even without the suction of the piston moving downward.
The key here is to close the intake valve before the compression of the upward moving piston overpowers the momentum of the air/fuel.
When the valve needs to close to do this depends on the speed of the intake charge and the weight of the charge. The weight depends on the length of the intake tract. The speed depends on the rpm of the engine, the shape of the intake passage, the texture of the walls and a variety of other smaller factors.
This stuff also effects the stacking of the charge against the intake valve after it closes.
Short answer is that the 5 degree advance moves the powerband down a bit.
Mark...
PabloCruise
SILVER Star
O-k, so if I were considering a 2F block + 3FE head combo, it sounds like the 2F cam would be a good one to keep, as I will keep the 2F stroke, but up the compression a little w/ 3FE head.
Will the 3FE head and intake breath well enough to use that extra stroke, esp when combined with a header?
Will the 3FE head and intake breath well enough to use that extra stroke, esp when combined with a header?
Mark W
Yep, I really don't really care that much I guess.
If you keep the stock 2 or 3 F cam, you'll be passing up the opportunity for significant power gains available with an aftermarket.
The 5 degree difference in the two cams (with everything else identical BTW) amounts to very little difference. In fact, the dealer sells the 3FE cam as the replacement for 2Fs if you go looking for one from them.
As to whther the 3FE head and intake are up to the extra size of the 2F... it's only a 5% difference in volume. Again, insignificant.
Mark...
The 5 degree difference in the two cams (with everything else identical BTW) amounts to very little difference. In fact, the dealer sells the 3FE cam as the replacement for 2Fs if you go looking for one from them.
As to whther the 3FE head and intake are up to the extra size of the 2F... it's only a 5% difference in volume. Again, insignificant.
Mark...
Nothing off the shelf that I am aware of. Custom...well that is always a question of how deep your pockets are.
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RUSH55 said:
The latest news is that I blew a head gasket because my block heater (used to live in Alaska) came out and therefore all my coolant came out.
I am trying to get the data from Downey on the cam so I can get the valve train adjusted correctly.
Besides the blown head gasket, the engine was performing very well. I have yet to get it off road but on the street it seemed to have a lot more torgue and better throttle response. More to follow....
John
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The last aftermarket cam I bought I got from Mark W, and it worked out quite nicely....
PabloCruise
SILVER Star
Chef said:
Thanks Chef, can you elaborate?
Engine, rig, what you liked about the cam...
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The engine was a rebuild of what was in my '83 FJ60. Stock bore, new bearings and rings, milled .080 off the head, sor header, one dynomax muffler, stock aisin carb, stock ignition (pretty hard to beat carb and ignition)...got the cam and lifters from Mark. In typical 2F fashion it will idle down to pretty much nothing, and it makes nice big torque from idle to 4,000, tho I typically never spin it harder than 3500. Can't compare to before the rebuild as the truck had a rod knock when I bought it: I never ran it stock. It makes a great street motor. I typically wheel my 40, tho I have had the 60 out a few times. It seems to do well in both environs.
PabloCruise
SILVER Star
I may have a chance to pick up a 3FE.
It needs freshening, so I thought this might be an ideal time to mod the 3FE.
My question:
Will the computer be able to manage fuel delivery with a Mark W cam in there?
I was thinking of a cam and headers... Would this just mess with the computers mind???
It needs freshening, so I thought this might be an ideal time to mod the 3FE.
My question:
Will the computer be able to manage fuel delivery with a Mark W cam in there?
I was thinking of a cam and headers... Would this just mess with the computers mind???
matt.mcinnes
2F-ETI
My Cam specs are as follows
Camshaft specification duration 220deg @.050". Valve lift 0.43" Final decision yet to be made, will post up later once ordered
Camshaft specification duration 220deg @.050". Valve lift 0.43" Final decision yet to be made, will post up later once ordered
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Mark W
Yep, I really don't really care that much I guess.
Since this thread has been dredged up, I figured I'd answer this question.
Yes.
Mark...
So what was the verdict, Downey's Torquer or MAF, for not loosing the low down grunt, in the process?
matt.mcinnes
2F-ETI
Cam was ordered at these specs
Duration 220 @ 0.050" Lift 0.43" Center line 112 Degrees.
The 3FE head is fitted with larger flat faced Ferrea Valves and Crows heavy duty valve springs.
Ferrea exhaust valve 1.6
Ferrea intake valve 1.9
Valve springs by Crow Part No 4832
Ported and polished 3FE head, the flow rates look like this after testing.
These gains would be pretty much the same for 2F & 3F heads, the only real difference between them and the 3FE is the intake ports which are shaped to accommodate the injectors.
Intake
Exhaust
Duration 220 @ 0.050" Lift 0.43" Center line 112 Degrees.
The 3FE head is fitted with larger flat faced Ferrea Valves and Crows heavy duty valve springs.
Ferrea exhaust valve 1.6
Ferrea intake valve 1.9
Valve springs by Crow Part No 4832
Ported and polished 3FE head, the flow rates look like this after testing.
These gains would be pretty much the same for 2F & 3F heads, the only real difference between them and the 3FE is the intake ports which are shaped to accommodate the injectors.
Intake
Exhaust
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