How can I tell what cam is in my old 86 4.2?
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Ok, it will be worth popping the cap out to see what this one says.
I might have a sweet motor hiding in my garage....
Mike
c wrote:
>
> Yup it is. Notice there are no bolt holes or locating pins/keys for the
> timing gear.
>
> Chris
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:40AEF4D6.DB14AC3A@sympatico.ca...
> > Cool, that's the back side?
> >
> > Mike
> >
> > "L.W.(ßill) ------ III" wrote:
> > >
> > > http://www.----------.com/IskyRR1000.jpg
> > > God Bless America, ßill O|||||||O
> > > mailto:--------------------
> > >
> > > c wrote:
> > > >
> > > > You can do it and get pretty close Mike. The important numbers are how
> many
> > > > degrees the LIFTER is above .050 lift. This is the industry standard
> for
> > > > measuring camshaft duration. Advertised duration measurement methods
> vary
> > > > between manufacturers, so I would be leery about measuring how many
> degrees
> > > > the lifter is above zero lift. Some cam companies use a small amount
> of the
> > > > lift to act as lifter preload, especially for hydraulic cams.
> > > >
> > > > To measure the cam, it is best to have access to the lifter with a
> dial
> > > > indicator, but you can get close with a hydralic one. You can also do
> the
> > > > lift measurement at the valve, but then you are reling on the rocker
> arm
> > > > ratio being correct, and you are also assuming that there is no part
> > > > deflection anywhere.
> > > >
> > > > Anyway, the recommended way to do this is with a cam degree wheel.
> Basically
> > > > it is the protractor you talked about using, but is calibrated a full
> 360
> > > > degrees. This bolts to the harmonic balancer. If youhaven't ever seen
> a
> > > > degree wheel, this is what it is:
> > > > http://static.summitracing.com/globa...e/mrg-1570.jpg
> > > >
> > > > The pro engine builders use a very large diameter wheel to get their
> > > > camshafts degreed in as close as possible.
> > > >
> > > > Once you have something like this, you can rig up some kind of a
> pointer for
> > > > the wheel. I used to use a piece of a metal coat hanger and bend it to
> > > > shape. For your purposes this will be plenty accurate. Now you need a
> dial
> > > > indicator to measure the lift at the valve or at the lifter. If you do
> it at
> > > > the valve, you need to know the rocker arm ratio for your engine. I
> will
> > > > assume for my explanation that it is 1.5. If you are meauring the
> valve lift
> > > > you will need to turn the engine in its normal rotation and take a
> reading
> > > > on the degree wheel when the valve reaches .075 lift. You could
> crudely do
> > > > this with a dial caliper as well by meauring from the top of the valve
> > > > spring retainer to the valve spring seat on the head.
> > > >
> > > > Record the reading on the wheel. I will use 5 degrees BTDC as an
> example.
> > > > Now turn the engine until the valve is at maximum lift and record
> that.
> > > > (.450 for my example). Rotate the engine until the valve comes down to
> .075
> > > > lift again and record that number (25 ABDC for my example). You can
> now
> > > > determine the intake lobe and where it is reaching peak lift. Take the
> BTDC
> > > > number, add 180, and add the ABDC number to get 220. This is your
> duration
> > > > at .050 tappet lift. To determine the lobe center angle, divide the
> duration
> > > > in half (110) and "add" that to your intake opening point. (5 deg BTDC
> +110
> > > > rotation = 105 deg ATDC) this would mean your cam lobe reaches peak
> lift at
> > > > 105 degrees ATDC. Cam lobe lift is simply valve lift divided by rocker
> > > > ratio, so .450/1.5 = .300 lobe lift.
> > > >
> > > > Repeat the procedure for the exhaust valve. I will use 40 degrees BBDC
> for
> > > > valve opening. Now turn the engine until the valve is at maximum lift
> and
> > > > record that. (.450 for my example). Rotate the engine until the valve
> comes
> > > > down to .075 lift again and record that number (10 ATDC for my
> example). You
> > > > can now determine the intake lobe and where it is reaching peak lift.
> Take
> > > > the BBDC number, add 180, and add the ABDC number to get 230. This is
> your
> > > > duration at .050 tappet lift. To determine the lobe center angle,
> divide the
> > > > duration in half (115) and "add" that to your exhaust opening point.
> (40 deg
> > > > BBDC +115 rotation = 115 deg BTDC) this would mean your cam lobe
> reaches
> > > > peak lift at 115 degrees BTDC.
> > > >
> > > > The last thing you need to determine is the lobe separation angle.
> This is
> > > > simply the average of the 2 lobe center angles, so (105 + 115)/2 =
> 110. This
> > > > is the split betwen the lobes. You can also figure out that the cam is
> > > > installed 5 deg advanced by subtracting the lobe separation angle from
> the
> > > > intake lobe centerline, or 110-105.
> > > >
> > > > Now that I typed all of this, I see it may be easier to pop the rear
> cam
> > > > plug out of the block and see if there is a part number there ;-).
> Many of
> > > > the manufacturers put the number on the back, but some put the number
> on the
> > > > face where the timing gear sits, so this is a bit of a crap shoot.
> > > >
> > > > Chris
I might have a sweet motor hiding in my garage....
Mike
c wrote:
>
> Yup it is. Notice there are no bolt holes or locating pins/keys for the
> timing gear.
>
> Chris
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:40AEF4D6.DB14AC3A@sympatico.ca...
> > Cool, that's the back side?
> >
> > Mike
> >
> > "L.W.(ßill) ------ III" wrote:
> > >
> > > http://www.----------.com/IskyRR1000.jpg
> > > God Bless America, ßill O|||||||O
> > > mailto:--------------------
> > >
> > > c wrote:
> > > >
> > > > You can do it and get pretty close Mike. The important numbers are how
> many
> > > > degrees the LIFTER is above .050 lift. This is the industry standard
> for
> > > > measuring camshaft duration. Advertised duration measurement methods
> vary
> > > > between manufacturers, so I would be leery about measuring how many
> degrees
> > > > the lifter is above zero lift. Some cam companies use a small amount
> of the
> > > > lift to act as lifter preload, especially for hydraulic cams.
> > > >
> > > > To measure the cam, it is best to have access to the lifter with a
> dial
> > > > indicator, but you can get close with a hydralic one. You can also do
> the
> > > > lift measurement at the valve, but then you are reling on the rocker
> arm
> > > > ratio being correct, and you are also assuming that there is no part
> > > > deflection anywhere.
> > > >
> > > > Anyway, the recommended way to do this is with a cam degree wheel.
> Basically
> > > > it is the protractor you talked about using, but is calibrated a full
> 360
> > > > degrees. This bolts to the harmonic balancer. If youhaven't ever seen
> a
> > > > degree wheel, this is what it is:
> > > > http://static.summitracing.com/globa...e/mrg-1570.jpg
> > > >
> > > > The pro engine builders use a very large diameter wheel to get their
> > > > camshafts degreed in as close as possible.
> > > >
> > > > Once you have something like this, you can rig up some kind of a
> pointer for
> > > > the wheel. I used to use a piece of a metal coat hanger and bend it to
> > > > shape. For your purposes this will be plenty accurate. Now you need a
> dial
> > > > indicator to measure the lift at the valve or at the lifter. If you do
> it at
> > > > the valve, you need to know the rocker arm ratio for your engine. I
> will
> > > > assume for my explanation that it is 1.5. If you are meauring the
> valve lift
> > > > you will need to turn the engine in its normal rotation and take a
> reading
> > > > on the degree wheel when the valve reaches .075 lift. You could
> crudely do
> > > > this with a dial caliper as well by meauring from the top of the valve
> > > > spring retainer to the valve spring seat on the head.
> > > >
> > > > Record the reading on the wheel. I will use 5 degrees BTDC as an
> example.
> > > > Now turn the engine until the valve is at maximum lift and record
> that.
> > > > (.450 for my example). Rotate the engine until the valve comes down to
> .075
> > > > lift again and record that number (25 ABDC for my example). You can
> now
> > > > determine the intake lobe and where it is reaching peak lift. Take the
> BTDC
> > > > number, add 180, and add the ABDC number to get 220. This is your
> duration
> > > > at .050 tappet lift. To determine the lobe center angle, divide the
> duration
> > > > in half (110) and "add" that to your intake opening point. (5 deg BTDC
> +110
> > > > rotation = 105 deg ATDC) this would mean your cam lobe reaches peak
> lift at
> > > > 105 degrees ATDC. Cam lobe lift is simply valve lift divided by rocker
> > > > ratio, so .450/1.5 = .300 lobe lift.
> > > >
> > > > Repeat the procedure for the exhaust valve. I will use 40 degrees BBDC
> for
> > > > valve opening. Now turn the engine until the valve is at maximum lift
> and
> > > > record that. (.450 for my example). Rotate the engine until the valve
> comes
> > > > down to .075 lift again and record that number (10 ATDC for my
> example). You
> > > > can now determine the intake lobe and where it is reaching peak lift.
> Take
> > > > the BBDC number, add 180, and add the ABDC number to get 230. This is
> your
> > > > duration at .050 tappet lift. To determine the lobe center angle,
> divide the
> > > > duration in half (115) and "add" that to your exhaust opening point.
> (40 deg
> > > > BBDC +115 rotation = 115 deg BTDC) this would mean your cam lobe
> reaches
> > > > peak lift at 115 degrees BTDC.
> > > >
> > > > The last thing you need to determine is the lobe separation angle.
> This is
> > > > simply the average of the 2 lobe center angles, so (105 + 115)/2 =
> 110. This
> > > > is the split betwen the lobes. You can also figure out that the cam is
> > > > installed 5 deg advanced by subtracting the lobe separation angle from
> the
> > > > intake lobe centerline, or 110-105.
> > > >
> > > > Now that I typed all of this, I see it may be easier to pop the rear
> cam
> > > > plug out of the block and see if there is a part number there ;-).
> Many of
> > > > the manufacturers put the number on the back, but some put the number
> on the
> > > > face where the timing gear sits, so this is a bit of a crap shoot.
> > > >
> > > > Chris
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Ok, it will be worth popping the cap out to see what this one says.
I might have a sweet motor hiding in my garage....
Mike
c wrote:
>
> Yup it is. Notice there are no bolt holes or locating pins/keys for the
> timing gear.
>
> Chris
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:40AEF4D6.DB14AC3A@sympatico.ca...
> > Cool, that's the back side?
> >
> > Mike
> >
> > "L.W.(ßill) ------ III" wrote:
> > >
> > > http://www.----------.com/IskyRR1000.jpg
> > > God Bless America, ßill O|||||||O
> > > mailto:--------------------
> > >
> > > c wrote:
> > > >
> > > > You can do it and get pretty close Mike. The important numbers are how
> many
> > > > degrees the LIFTER is above .050 lift. This is the industry standard
> for
> > > > measuring camshaft duration. Advertised duration measurement methods
> vary
> > > > between manufacturers, so I would be leery about measuring how many
> degrees
> > > > the lifter is above zero lift. Some cam companies use a small amount
> of the
> > > > lift to act as lifter preload, especially for hydraulic cams.
> > > >
> > > > To measure the cam, it is best to have access to the lifter with a
> dial
> > > > indicator, but you can get close with a hydralic one. You can also do
> the
> > > > lift measurement at the valve, but then you are reling on the rocker
> arm
> > > > ratio being correct, and you are also assuming that there is no part
> > > > deflection anywhere.
> > > >
> > > > Anyway, the recommended way to do this is with a cam degree wheel.
> Basically
> > > > it is the protractor you talked about using, but is calibrated a full
> 360
> > > > degrees. This bolts to the harmonic balancer. If youhaven't ever seen
> a
> > > > degree wheel, this is what it is:
> > > > http://static.summitracing.com/globa...e/mrg-1570.jpg
> > > >
> > > > The pro engine builders use a very large diameter wheel to get their
> > > > camshafts degreed in as close as possible.
> > > >
> > > > Once you have something like this, you can rig up some kind of a
> pointer for
> > > > the wheel. I used to use a piece of a metal coat hanger and bend it to
> > > > shape. For your purposes this will be plenty accurate. Now you need a
> dial
> > > > indicator to measure the lift at the valve or at the lifter. If you do
> it at
> > > > the valve, you need to know the rocker arm ratio for your engine. I
> will
> > > > assume for my explanation that it is 1.5. If you are meauring the
> valve lift
> > > > you will need to turn the engine in its normal rotation and take a
> reading
> > > > on the degree wheel when the valve reaches .075 lift. You could
> crudely do
> > > > this with a dial caliper as well by meauring from the top of the valve
> > > > spring retainer to the valve spring seat on the head.
> > > >
> > > > Record the reading on the wheel. I will use 5 degrees BTDC as an
> example.
> > > > Now turn the engine until the valve is at maximum lift and record
> that.
> > > > (.450 for my example). Rotate the engine until the valve comes down to
> .075
> > > > lift again and record that number (25 ABDC for my example). You can
> now
> > > > determine the intake lobe and where it is reaching peak lift. Take the
> BTDC
> > > > number, add 180, and add the ABDC number to get 220. This is your
> duration
> > > > at .050 tappet lift. To determine the lobe center angle, divide the
> duration
> > > > in half (110) and "add" that to your intake opening point. (5 deg BTDC
> +110
> > > > rotation = 105 deg ATDC) this would mean your cam lobe reaches peak
> lift at
> > > > 105 degrees ATDC. Cam lobe lift is simply valve lift divided by rocker
> > > > ratio, so .450/1.5 = .300 lobe lift.
> > > >
> > > > Repeat the procedure for the exhaust valve. I will use 40 degrees BBDC
> for
> > > > valve opening. Now turn the engine until the valve is at maximum lift
> and
> > > > record that. (.450 for my example). Rotate the engine until the valve
> comes
> > > > down to .075 lift again and record that number (10 ATDC for my
> example). You
> > > > can now determine the intake lobe and where it is reaching peak lift.
> Take
> > > > the BBDC number, add 180, and add the ABDC number to get 230. This is
> your
> > > > duration at .050 tappet lift. To determine the lobe center angle,
> divide the
> > > > duration in half (115) and "add" that to your exhaust opening point.
> (40 deg
> > > > BBDC +115 rotation = 115 deg BTDC) this would mean your cam lobe
> reaches
> > > > peak lift at 115 degrees BTDC.
> > > >
> > > > The last thing you need to determine is the lobe separation angle.
> This is
> > > > simply the average of the 2 lobe center angles, so (105 + 115)/2 =
> 110. This
> > > > is the split betwen the lobes. You can also figure out that the cam is
> > > > installed 5 deg advanced by subtracting the lobe separation angle from
> the
> > > > intake lobe centerline, or 110-105.
> > > >
> > > > Now that I typed all of this, I see it may be easier to pop the rear
> cam
> > > > plug out of the block and see if there is a part number there ;-).
> Many of
> > > > the manufacturers put the number on the back, but some put the number
> on the
> > > > face where the timing gear sits, so this is a bit of a crap shoot.
> > > >
> > > > Chris
I might have a sweet motor hiding in my garage....
Mike
c wrote:
>
> Yup it is. Notice there are no bolt holes or locating pins/keys for the
> timing gear.
>
> Chris
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:40AEF4D6.DB14AC3A@sympatico.ca...
> > Cool, that's the back side?
> >
> > Mike
> >
> > "L.W.(ßill) ------ III" wrote:
> > >
> > > http://www.----------.com/IskyRR1000.jpg
> > > God Bless America, ßill O|||||||O
> > > mailto:--------------------
> > >
> > > c wrote:
> > > >
> > > > You can do it and get pretty close Mike. The important numbers are how
> many
> > > > degrees the LIFTER is above .050 lift. This is the industry standard
> for
> > > > measuring camshaft duration. Advertised duration measurement methods
> vary
> > > > between manufacturers, so I would be leery about measuring how many
> degrees
> > > > the lifter is above zero lift. Some cam companies use a small amount
> of the
> > > > lift to act as lifter preload, especially for hydraulic cams.
> > > >
> > > > To measure the cam, it is best to have access to the lifter with a
> dial
> > > > indicator, but you can get close with a hydralic one. You can also do
> the
> > > > lift measurement at the valve, but then you are reling on the rocker
> arm
> > > > ratio being correct, and you are also assuming that there is no part
> > > > deflection anywhere.
> > > >
> > > > Anyway, the recommended way to do this is with a cam degree wheel.
> Basically
> > > > it is the protractor you talked about using, but is calibrated a full
> 360
> > > > degrees. This bolts to the harmonic balancer. If youhaven't ever seen
> a
> > > > degree wheel, this is what it is:
> > > > http://static.summitracing.com/globa...e/mrg-1570.jpg
> > > >
> > > > The pro engine builders use a very large diameter wheel to get their
> > > > camshafts degreed in as close as possible.
> > > >
> > > > Once you have something like this, you can rig up some kind of a
> pointer for
> > > > the wheel. I used to use a piece of a metal coat hanger and bend it to
> > > > shape. For your purposes this will be plenty accurate. Now you need a
> dial
> > > > indicator to measure the lift at the valve or at the lifter. If you do
> it at
> > > > the valve, you need to know the rocker arm ratio for your engine. I
> will
> > > > assume for my explanation that it is 1.5. If you are meauring the
> valve lift
> > > > you will need to turn the engine in its normal rotation and take a
> reading
> > > > on the degree wheel when the valve reaches .075 lift. You could
> crudely do
> > > > this with a dial caliper as well by meauring from the top of the valve
> > > > spring retainer to the valve spring seat on the head.
> > > >
> > > > Record the reading on the wheel. I will use 5 degrees BTDC as an
> example.
> > > > Now turn the engine until the valve is at maximum lift and record
> that.
> > > > (.450 for my example). Rotate the engine until the valve comes down to
> .075
> > > > lift again and record that number (25 ABDC for my example). You can
> now
> > > > determine the intake lobe and where it is reaching peak lift. Take the
> BTDC
> > > > number, add 180, and add the ABDC number to get 220. This is your
> duration
> > > > at .050 tappet lift. To determine the lobe center angle, divide the
> duration
> > > > in half (110) and "add" that to your intake opening point. (5 deg BTDC
> +110
> > > > rotation = 105 deg ATDC) this would mean your cam lobe reaches peak
> lift at
> > > > 105 degrees ATDC. Cam lobe lift is simply valve lift divided by rocker
> > > > ratio, so .450/1.5 = .300 lobe lift.
> > > >
> > > > Repeat the procedure for the exhaust valve. I will use 40 degrees BBDC
> for
> > > > valve opening. Now turn the engine until the valve is at maximum lift
> and
> > > > record that. (.450 for my example). Rotate the engine until the valve
> comes
> > > > down to .075 lift again and record that number (10 ATDC for my
> example). You
> > > > can now determine the intake lobe and where it is reaching peak lift.
> Take
> > > > the BBDC number, add 180, and add the ABDC number to get 230. This is
> your
> > > > duration at .050 tappet lift. To determine the lobe center angle,
> divide the
> > > > duration in half (115) and "add" that to your exhaust opening point.
> (40 deg
> > > > BBDC +115 rotation = 115 deg BTDC) this would mean your cam lobe
> reaches
> > > > peak lift at 115 degrees BTDC.
> > > >
> > > > The last thing you need to determine is the lobe separation angle.
> This is
> > > > simply the average of the 2 lobe center angles, so (105 + 115)/2 =
> 110. This
> > > > is the split betwen the lobes. You can also figure out that the cam is
> > > > installed 5 deg advanced by subtracting the lobe separation angle from
> the
> > > > intake lobe centerline, or 110-105.
> > > >
> > > > Now that I typed all of this, I see it may be easier to pop the rear
> cam
> > > > plug out of the block and see if there is a part number there ;-).
> Many of
> > > > the manufacturers put the number on the back, but some put the number
> on the
> > > > face where the timing gear sits, so this is a bit of a crap shoot.
> > > >
> > > > Chris
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Ok, it will be worth popping the cap out to see what this one says.
I might have a sweet motor hiding in my garage....
Mike
c wrote:
>
> Yup it is. Notice there are no bolt holes or locating pins/keys for the
> timing gear.
>
> Chris
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:40AEF4D6.DB14AC3A@sympatico.ca...
> > Cool, that's the back side?
> >
> > Mike
> >
> > "L.W.(ßill) ------ III" wrote:
> > >
> > > http://www.----------.com/IskyRR1000.jpg
> > > God Bless America, ßill O|||||||O
> > > mailto:--------------------
> > >
> > > c wrote:
> > > >
> > > > You can do it and get pretty close Mike. The important numbers are how
> many
> > > > degrees the LIFTER is above .050 lift. This is the industry standard
> for
> > > > measuring camshaft duration. Advertised duration measurement methods
> vary
> > > > between manufacturers, so I would be leery about measuring how many
> degrees
> > > > the lifter is above zero lift. Some cam companies use a small amount
> of the
> > > > lift to act as lifter preload, especially for hydraulic cams.
> > > >
> > > > To measure the cam, it is best to have access to the lifter with a
> dial
> > > > indicator, but you can get close with a hydralic one. You can also do
> the
> > > > lift measurement at the valve, but then you are reling on the rocker
> arm
> > > > ratio being correct, and you are also assuming that there is no part
> > > > deflection anywhere.
> > > >
> > > > Anyway, the recommended way to do this is with a cam degree wheel.
> Basically
> > > > it is the protractor you talked about using, but is calibrated a full
> 360
> > > > degrees. This bolts to the harmonic balancer. If youhaven't ever seen
> a
> > > > degree wheel, this is what it is:
> > > > http://static.summitracing.com/globa...e/mrg-1570.jpg
> > > >
> > > > The pro engine builders use a very large diameter wheel to get their
> > > > camshafts degreed in as close as possible.
> > > >
> > > > Once you have something like this, you can rig up some kind of a
> pointer for
> > > > the wheel. I used to use a piece of a metal coat hanger and bend it to
> > > > shape. For your purposes this will be plenty accurate. Now you need a
> dial
> > > > indicator to measure the lift at the valve or at the lifter. If you do
> it at
> > > > the valve, you need to know the rocker arm ratio for your engine. I
> will
> > > > assume for my explanation that it is 1.5. If you are meauring the
> valve lift
> > > > you will need to turn the engine in its normal rotation and take a
> reading
> > > > on the degree wheel when the valve reaches .075 lift. You could
> crudely do
> > > > this with a dial caliper as well by meauring from the top of the valve
> > > > spring retainer to the valve spring seat on the head.
> > > >
> > > > Record the reading on the wheel. I will use 5 degrees BTDC as an
> example.
> > > > Now turn the engine until the valve is at maximum lift and record
> that.
> > > > (.450 for my example). Rotate the engine until the valve comes down to
> .075
> > > > lift again and record that number (25 ABDC for my example). You can
> now
> > > > determine the intake lobe and where it is reaching peak lift. Take the
> BTDC
> > > > number, add 180, and add the ABDC number to get 220. This is your
> duration
> > > > at .050 tappet lift. To determine the lobe center angle, divide the
> duration
> > > > in half (110) and "add" that to your intake opening point. (5 deg BTDC
> +110
> > > > rotation = 105 deg ATDC) this would mean your cam lobe reaches peak
> lift at
> > > > 105 degrees ATDC. Cam lobe lift is simply valve lift divided by rocker
> > > > ratio, so .450/1.5 = .300 lobe lift.
> > > >
> > > > Repeat the procedure for the exhaust valve. I will use 40 degrees BBDC
> for
> > > > valve opening. Now turn the engine until the valve is at maximum lift
> and
> > > > record that. (.450 for my example). Rotate the engine until the valve
> comes
> > > > down to .075 lift again and record that number (10 ATDC for my
> example). You
> > > > can now determine the intake lobe and where it is reaching peak lift.
> Take
> > > > the BBDC number, add 180, and add the ABDC number to get 230. This is
> your
> > > > duration at .050 tappet lift. To determine the lobe center angle,
> divide the
> > > > duration in half (115) and "add" that to your exhaust opening point.
> (40 deg
> > > > BBDC +115 rotation = 115 deg BTDC) this would mean your cam lobe
> reaches
> > > > peak lift at 115 degrees BTDC.
> > > >
> > > > The last thing you need to determine is the lobe separation angle.
> This is
> > > > simply the average of the 2 lobe center angles, so (105 + 115)/2 =
> 110. This
> > > > is the split betwen the lobes. You can also figure out that the cam is
> > > > installed 5 deg advanced by subtracting the lobe separation angle from
> the
> > > > intake lobe centerline, or 110-105.
> > > >
> > > > Now that I typed all of this, I see it may be easier to pop the rear
> cam
> > > > plug out of the block and see if there is a part number there ;-).
> Many of
> > > > the manufacturers put the number on the back, but some put the number
> on the
> > > > face where the timing gear sits, so this is a bit of a crap shoot.
> > > >
> > > > Chris
I might have a sweet motor hiding in my garage....
Mike
c wrote:
>
> Yup it is. Notice there are no bolt holes or locating pins/keys for the
> timing gear.
>
> Chris
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:40AEF4D6.DB14AC3A@sympatico.ca...
> > Cool, that's the back side?
> >
> > Mike
> >
> > "L.W.(ßill) ------ III" wrote:
> > >
> > > http://www.----------.com/IskyRR1000.jpg
> > > God Bless America, ßill O|||||||O
> > > mailto:--------------------
> > >
> > > c wrote:
> > > >
> > > > You can do it and get pretty close Mike. The important numbers are how
> many
> > > > degrees the LIFTER is above .050 lift. This is the industry standard
> for
> > > > measuring camshaft duration. Advertised duration measurement methods
> vary
> > > > between manufacturers, so I would be leery about measuring how many
> degrees
> > > > the lifter is above zero lift. Some cam companies use a small amount
> of the
> > > > lift to act as lifter preload, especially for hydraulic cams.
> > > >
> > > > To measure the cam, it is best to have access to the lifter with a
> dial
> > > > indicator, but you can get close with a hydralic one. You can also do
> the
> > > > lift measurement at the valve, but then you are reling on the rocker
> arm
> > > > ratio being correct, and you are also assuming that there is no part
> > > > deflection anywhere.
> > > >
> > > > Anyway, the recommended way to do this is with a cam degree wheel.
> Basically
> > > > it is the protractor you talked about using, but is calibrated a full
> 360
> > > > degrees. This bolts to the harmonic balancer. If youhaven't ever seen
> a
> > > > degree wheel, this is what it is:
> > > > http://static.summitracing.com/globa...e/mrg-1570.jpg
> > > >
> > > > The pro engine builders use a very large diameter wheel to get their
> > > > camshafts degreed in as close as possible.
> > > >
> > > > Once you have something like this, you can rig up some kind of a
> pointer for
> > > > the wheel. I used to use a piece of a metal coat hanger and bend it to
> > > > shape. For your purposes this will be plenty accurate. Now you need a
> dial
> > > > indicator to measure the lift at the valve or at the lifter. If you do
> it at
> > > > the valve, you need to know the rocker arm ratio for your engine. I
> will
> > > > assume for my explanation that it is 1.5. If you are meauring the
> valve lift
> > > > you will need to turn the engine in its normal rotation and take a
> reading
> > > > on the degree wheel when the valve reaches .075 lift. You could
> crudely do
> > > > this with a dial caliper as well by meauring from the top of the valve
> > > > spring retainer to the valve spring seat on the head.
> > > >
> > > > Record the reading on the wheel. I will use 5 degrees BTDC as an
> example.
> > > > Now turn the engine until the valve is at maximum lift and record
> that.
> > > > (.450 for my example). Rotate the engine until the valve comes down to
> .075
> > > > lift again and record that number (25 ABDC for my example). You can
> now
> > > > determine the intake lobe and where it is reaching peak lift. Take the
> BTDC
> > > > number, add 180, and add the ABDC number to get 220. This is your
> duration
> > > > at .050 tappet lift. To determine the lobe center angle, divide the
> duration
> > > > in half (110) and "add" that to your intake opening point. (5 deg BTDC
> +110
> > > > rotation = 105 deg ATDC) this would mean your cam lobe reaches peak
> lift at
> > > > 105 degrees ATDC. Cam lobe lift is simply valve lift divided by rocker
> > > > ratio, so .450/1.5 = .300 lobe lift.
> > > >
> > > > Repeat the procedure for the exhaust valve. I will use 40 degrees BBDC
> for
> > > > valve opening. Now turn the engine until the valve is at maximum lift
> and
> > > > record that. (.450 for my example). Rotate the engine until the valve
> comes
> > > > down to .075 lift again and record that number (10 ATDC for my
> example). You
> > > > can now determine the intake lobe and where it is reaching peak lift.
> Take
> > > > the BBDC number, add 180, and add the ABDC number to get 230. This is
> your
> > > > duration at .050 tappet lift. To determine the lobe center angle,
> divide the
> > > > duration in half (115) and "add" that to your exhaust opening point.
> (40 deg
> > > > BBDC +115 rotation = 115 deg BTDC) this would mean your cam lobe
> reaches
> > > > peak lift at 115 degrees BTDC.
> > > >
> > > > The last thing you need to determine is the lobe separation angle.
> This is
> > > > simply the average of the 2 lobe center angles, so (105 + 115)/2 =
> 110. This
> > > > is the split betwen the lobes. You can also figure out that the cam is
> > > > installed 5 deg advanced by subtracting the lobe separation angle from
> the
> > > > intake lobe centerline, or 110-105.
> > > >
> > > > Now that I typed all of this, I see it may be easier to pop the rear
> cam
> > > > plug out of the block and see if there is a part number there ;-).
> Many of
> > > > the manufacturers put the number on the back, but some put the number
> on the
> > > > face where the timing gear sits, so this is a bit of a crap shoot.
> > > >
> > > > Chris
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Hi Mike,
You'll be wasting your time, unless you have the cam code book for
whoever made of ground that cam. Like the "R" on my Isky stands for
roller.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> Ok, it will be worth popping the cap out to see what this one says.
>
> I might have a sweet motor hiding in my garage....
>
> Mike
You'll be wasting your time, unless you have the cam code book for
whoever made of ground that cam. Like the "R" on my Isky stands for
roller.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> Ok, it will be worth popping the cap out to see what this one says.
>
> I might have a sweet motor hiding in my garage....
>
> Mike
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Hi Mike,
You'll be wasting your time, unless you have the cam code book for
whoever made of ground that cam. Like the "R" on my Isky stands for
roller.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> Ok, it will be worth popping the cap out to see what this one says.
>
> I might have a sweet motor hiding in my garage....
>
> Mike
You'll be wasting your time, unless you have the cam code book for
whoever made of ground that cam. Like the "R" on my Isky stands for
roller.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> Ok, it will be worth popping the cap out to see what this one says.
>
> I might have a sweet motor hiding in my garage....
>
> Mike
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Hi Mike,
You'll be wasting your time, unless you have the cam code book for
whoever made of ground that cam. Like the "R" on my Isky stands for
roller.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> Ok, it will be worth popping the cap out to see what this one says.
>
> I might have a sweet motor hiding in my garage....
>
> Mike
You'll be wasting your time, unless you have the cam code book for
whoever made of ground that cam. Like the "R" on my Isky stands for
roller.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> Ok, it will be worth popping the cap out to see what this one says.
>
> I might have a sweet motor hiding in my garage....
>
> Mike
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
Hi Mike,
You'll be wasting your time, unless you have the cam code book for
whoever made of ground that cam. Like the "R" on my Isky stands for
roller.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> Ok, it will be worth popping the cap out to see what this one says.
>
> I might have a sweet motor hiding in my garage....
>
> Mike
You'll be wasting your time, unless you have the cam code book for
whoever made of ground that cam. Like the "R" on my Isky stands for
roller.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Mike Romain wrote:
>
> Ok, it will be worth popping the cap out to see what this one says.
>
> I might have a sweet motor hiding in my garage....
>
> Mike
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
I can decode many of the numbers Bill. If he posts them here, I will see
what I can do.
Chris
"L.W. (ßill) ------ III" <----------@***.net> wrote in message
news:40AFB073.469957DA@***.net...
> Hi Mike,
> You'll be wasting your time, unless you have the cam code book for
> whoever made of ground that cam. Like the "R" on my Isky stands for
> roller.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > Ok, it will be worth popping the cap out to see what this one says.
> >
> > I might have a sweet motor hiding in my garage....
> >
> > Mike
what I can do.
Chris
"L.W. (ßill) ------ III" <----------@***.net> wrote in message
news:40AFB073.469957DA@***.net...
> Hi Mike,
> You'll be wasting your time, unless you have the cam code book for
> whoever made of ground that cam. Like the "R" on my Isky stands for
> roller.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > Ok, it will be worth popping the cap out to see what this one says.
> >
> > I might have a sweet motor hiding in my garage....
> >
> > Mike
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
I can decode many of the numbers Bill. If he posts them here, I will see
what I can do.
Chris
"L.W. (ßill) ------ III" <----------@***.net> wrote in message
news:40AFB073.469957DA@***.net...
> Hi Mike,
> You'll be wasting your time, unless you have the cam code book for
> whoever made of ground that cam. Like the "R" on my Isky stands for
> roller.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > Ok, it will be worth popping the cap out to see what this one says.
> >
> > I might have a sweet motor hiding in my garage....
> >
> > Mike
what I can do.
Chris
"L.W. (ßill) ------ III" <----------@***.net> wrote in message
news:40AFB073.469957DA@***.net...
> Hi Mike,
> You'll be wasting your time, unless you have the cam code book for
> whoever made of ground that cam. Like the "R" on my Isky stands for
> roller.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > Ok, it will be worth popping the cap out to see what this one says.
> >
> > I might have a sweet motor hiding in my garage....
> >
> > Mike
Guest
Posts: n/a
Re: How can I tell what cam is in my old 86 4.2?
I can decode many of the numbers Bill. If he posts them here, I will see
what I can do.
Chris
"L.W. (ßill) ------ III" <----------@***.net> wrote in message
news:40AFB073.469957DA@***.net...
> Hi Mike,
> You'll be wasting your time, unless you have the cam code book for
> whoever made of ground that cam. Like the "R" on my Isky stands for
> roller.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > Ok, it will be worth popping the cap out to see what this one says.
> >
> > I might have a sweet motor hiding in my garage....
> >
> > Mike
what I can do.
Chris
"L.W. (ßill) ------ III" <----------@***.net> wrote in message
news:40AFB073.469957DA@***.net...
> Hi Mike,
> You'll be wasting your time, unless you have the cam code book for
> whoever made of ground that cam. Like the "R" on my Isky stands for
> roller.
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> Mike Romain wrote:
> >
> > Ok, it will be worth popping the cap out to see what this one says.
> >
> > I might have a sweet motor hiding in my garage....
> >
> > Mike
