Timing Help Needed
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Timing Help Needed
okay here is the issue, i am trying to dial in my s2 p1 cams but my cylinder head has been previously resurface. i am not sure how much thousands of an inch was taken off but but it is causing a slack in the belt on the exhaust side.
when i try to tension the belt because of the slack it throws the crank out about 4-5 degrees, so when i make a complete revolution and the cam gear marks line up i am about 4-5 degrees out.
now i am thinking that if i get a adjustable timing belt tensioner it would probably fix the slack but i want to keep my power steering.also the timing belt is new
is there another work around this besides getting as new cylinder head or the adjustable belt tensioner i have a lot of money invested in the cylinder head as it is so i would love to use it.the motor is a 84mm GSR with Skunk2 Pro1 cams
when i try to tension the belt because of the slack it throws the crank out about 4-5 degrees, so when i make a complete revolution and the cam gear marks line up i am about 4-5 degrees out.
now i am thinking that if i get a adjustable timing belt tensioner it would probably fix the slack but i want to keep my power steering.also the timing belt is new
is there another work around this besides getting as new cylinder head or the adjustable belt tensioner i have a lot of money invested in the cylinder head as it is so i would love to use it.the motor is a 84mm GSR with Skunk2 Pro1 cams
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From: North Georgia/Atlanta
Re: Timing Help Needed
you should be able to tension that belt no problem before degreeing. I know we had a head shaved to the damn near maximum and still tightened belt just fine and THEN degreed the gears.
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Re: Timing Help Needed
i do have adjustable cam gears, they are set at zero, but the problem i am having is that when i adjust the tensioner it pulls the crankshaft about 4-5 degrees in order to get the slack out of the belt which throws off the TDC position.
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Re: Timing Help Needed
okay this is what i noticed today while dialing in the cams using cylinder no.1 with vtec locked the lifter that is locked(the one closer to the timing belt), that valve actually starts to go down before the one next to it. also because of the play that it has which is about 2-3mm that valve does not open to the full lift of the cam.
firstly does this affect the efficiency of air flow into/out of the cylinder and secondly is there a way to stop this from happening and allow both valve to have the same lift when vtec is locked.
firstly does this affect the efficiency of air flow into/out of the cylinder and secondly is there a way to stop this from happening and allow both valve to have the same lift when vtec is locked.
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Joined: Mar 2009
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From: WIconsin
Re: Timing Help Needed
i think you could do ignition timing to get all those degrees back, just advance your distributor to your liking... somebody correct me if im wrong... or does he need to dial in the cams...
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From: Baton Rouge,Louisiana
Re: Timing Help Needed
Not very hard to actually do this..
Take the belt off and set the cams to TDC, and @ 0/0. Set the crank to TDC. Now rotate the crank back a tad, not alot.. but maybe 1/2 inches or so. Put the belt on, starting around the crank, then tensioner, then water pump, and finally the intake gear and exhaust gear.
Before you do anything else, make sure the gears are lined up correctly at the time, moving the slack around. My suggest is you need to move all the slack to the front of the motor, you'll understand why , shortly. When the gears are lined up and there's a good enough tension in the middle of the gears, rotate the crank counter-clock wise to remove all the slack from the front. It should line up with the TDC arrow on the oil pump. Then, Take a coat hanger, or hook tool, or flat head and push up on the tensioner lip. Tighten the tensioner, down and this will remove the slack from the back side. Make sure the timing belt is tight, but not loose, you shoudl have a small amount of slack all the way around, this will eventually go away when the motor heats up and expands.
Centerlines stock are 98/103
Skunk2 recommends 98/105
Since you're milled i would START with +1 intake +3 exhaust, depending on the type of gears you are using.
Take the belt off and set the cams to TDC, and @ 0/0. Set the crank to TDC. Now rotate the crank back a tad, not alot.. but maybe 1/2 inches or so. Put the belt on, starting around the crank, then tensioner, then water pump, and finally the intake gear and exhaust gear.
Before you do anything else, make sure the gears are lined up correctly at the time, moving the slack around. My suggest is you need to move all the slack to the front of the motor, you'll understand why , shortly. When the gears are lined up and there's a good enough tension in the middle of the gears, rotate the crank counter-clock wise to remove all the slack from the front. It should line up with the TDC arrow on the oil pump. Then, Take a coat hanger, or hook tool, or flat head and push up on the tensioner lip. Tighten the tensioner, down and this will remove the slack from the back side. Make sure the timing belt is tight, but not loose, you shoudl have a small amount of slack all the way around, this will eventually go away when the motor heats up and expands.
Centerlines stock are 98/103
Skunk2 recommends 98/105
Since you're milled i would START with +1 intake +3 exhaust, depending on the type of gears you are using.
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Re: Timing Help Needed
I always put the belt on in this order. crank, exhaust cam gear, intake gear, water pump, tensioner. Maybe the OP is doing it the other way and has excess belt slop between the crank and exhaust gear, then when he preloads the tensioner, the slack on the exhaust side throws the crank out. Maybe try doing the way I stated above. Hopefully that helps.
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From: WIconsin
Re: Timing Help Needed
i have a different way of doing it.
i put the crank onto 16 btdc which is the mark on the oil pump.
using a 14in ranch, i adjust my cam gears to meet there marks.
put the belt on from crank, to exhaust, to intake, and than the waterpump, than the tension last. (Like H2.4 does)
but before putting the belt onto the exhaust cam, i move it toward the front of the car(radiator) a little, like a teeth to catch onto the belt and use the 14 ranch to move it towards the intake cam to tighten the slack.
and than i do the same to the exhaust cam gear. making sure that the marks meet at the same spot. (first try isn't always the charm, takes me a couple to get it right on, or close enough like 1/4 teeth away.)
than with all the slack on the water pump and the tension, i use a cloths hanger to hook onto the tension hole where the spring hooks up and ask a buddy to pull the tension as hard as he can and i tighten it.
and than rotate the crank CC wise to see if everything is fine.
when everything seems fine and I have enough faith in it, than I start the car and set ignition time too 16 btdc or I won't even have to move the dizzy at all.
there you go. easy if your just swapping out cams and not have to take everything off.
I know that i don't follow the helms or any other manual.
my way is different, but i haven't had anything gone wrong with it so far with my cars and my buddies turbo d16 and gsr swap hatch. 2 yrs and still going.
i put the crank onto 16 btdc which is the mark on the oil pump.
using a 14in ranch, i adjust my cam gears to meet there marks.
put the belt on from crank, to exhaust, to intake, and than the waterpump, than the tension last. (Like H2.4 does)
but before putting the belt onto the exhaust cam, i move it toward the front of the car(radiator) a little, like a teeth to catch onto the belt and use the 14 ranch to move it towards the intake cam to tighten the slack.
and than i do the same to the exhaust cam gear. making sure that the marks meet at the same spot. (first try isn't always the charm, takes me a couple to get it right on, or close enough like 1/4 teeth away.)
than with all the slack on the water pump and the tension, i use a cloths hanger to hook onto the tension hole where the spring hooks up and ask a buddy to pull the tension as hard as he can and i tighten it.
and than rotate the crank CC wise to see if everything is fine.
when everything seems fine and I have enough faith in it, than I start the car and set ignition time too 16 btdc or I won't even have to move the dizzy at all.
there you go. easy if your just swapping out cams and not have to take everything off.
I know that i don't follow the helms or any other manual.
my way is different, but i haven't had anything gone wrong with it so far with my cars and my buddies turbo d16 and gsr swap hatch. 2 yrs and still going.
Last edited by dk=gsr; Dec 17, 2011 at 08:19 PM.
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From: Riversides Finest, America
Re: Timing Help Needed
Off our Website on how to degree in cams if you needed help (www.webcamshafts.com) :
FINDING TRUE TOP DEAD CENTER ( TDC )
DISCONNECT THE BATTERY! Do not use the starter to perform any of these steps.
To find Top Dead Center use a piston stop, to stop the piston in the same position on either side of TDC and take readings from the degree wheel. You will then split the difference in these readings and move the pointer this amount, making it the true TDC point.
First mount the degree wheel on the end of the crankshaft, and rotate the engine to approximate TDC
Mount the pointer and line it up at zero on the degree wheel.
Now rotate the engine to move the piston down into the cylinder. Install your positive stop device into the spark plug hole and extend the bolt.
Turn the engine by hand, rotating it until the piston comes up and stops against the piston stop bolt.
Look at the degree wheel and write down the number of degrees shown by the pointer.
Turn the engine by hand in the opposite direction until the piston comes up and stops on the piston stop bolt again.
Go back to the degree wheel and write down the degrees it now reads.
Add these two readings together and divide the answer by two.
Now either move your pointer by this many degrees, or carefully loosen the degree wheel (without disturbing the position of the crankshaft) and move the wheel this required amount.
Retighten the bolts, and rotate the engine again making sure that the readings on each side of TDC are equal degrees away from zero. If they are, the zero on the degree wheel will now be the true TDC point.
Remove the positive stop device from the spark plug hole.
You're now done finding true TDC.
FINDING INTAKE LOBE CENTER LINE
Remove all valve lash (clearance). Place your dial indicator on the valve spring retainer, or tappet. If you are degreeing in a pushrod engine we recommend placing the indicator on the valve retainer. Please be sure the angle of your indicator travels at the same angle that your valve travels. Zero the dial indicator, then turn the engine until you reach full lift and record how far the valve traveled off its fully seated position. This will be the actual valve lift of your desired cam profile. Note: Rocker arm engines can vary. At this point make sure there is additional clearance with your dial indicator to verify plenty of travel for our next step.
Rotate the engine until you are back to Top Dead Center (TDC). Zero your dial indicator. Next you will start turning the engine until you are .050 off the seated position of the valve (It is very important to turn the engine it’s normal way of rotation). Look at the degree wheel and determine how many degrees the valve opened. If we are working on the intake valve this will normally occur Before Top Dead Center (BTDC). Record that number in degrees. NOTE: Some low overlap engines may open After Top Dead Center (ATDC). Record that number in degrees for further calculations.
Look at your inner dial on the dial indicator and record that number to help achieve our next step, however some dial indicators do not have this feature and is not needed to proceed. See WEB CAM camshaft degree kit part #95-144. Proceed to rotate the engine until your inner dial is back on the number it left from. You will notice your big dial is almost back to .050. Slightly move it until it is exactly reads at .050. If you pass it back way up and come at it again. You are now .050 from closing on the opposite side to achieve your next number on the degree wheel, which is normally After Bottom Dead center (ABDC). Now you will use the following steps to properly calculate what actual lobe centers are on the opening valve timing events.
If the valve opened Before Top Dead Center (BTDC) do the following calculation:
Take the open number plus the closing number plus 180°, which will be the duration at .050. Next divide the duration into 2. Subtract the open from that number, which will equals the centerline of the intake cam.
Example:
+10° Opening Before Top Dead Center (BTDC)
+39° Closing After Bottom Dead Center (ABDC)
+180° Distance from Top Dead Center (TDC) to Bottom Dead Center (BDC)
=229° Total Duration @ .050 inches of lift
229°/2 = 114.5°
114.5° - 10° = 104.5° Lobe Center
If the valve opened After Top Dead Center (ATDC) subtract the open from the close plus 180°, which will be your duration at .050. Next divide the duration into 2. Add back the open number, which will equal the centerline of the intake side.
Example:
-10° Opening After Top Dead Center (ATDC)
+39° Closing After Bottom Dead Center (ABDC)
+180° Distance from Top Dead Center (TDC) to Bottom Dead Center (BDC)
=209° Total Duration @ .050 inches of lift
209°/2 = 104.5°
104.5° +10° = 114.5° Lobe Center
If you have adjustable gears move them at this time and redo above procedure.
FINDING EXHAUST LOBE CENTER LINE
Next step is to set up your dial indicator and repeat the above procedure. The exhaust valve normally opens Before Bottom Dead Center (BBDC), and the closing will occur After Top Dead Center (ATDC). On some low overlap cam profiles the exhaust valve may close Before Top Dead Center (BTDC) however, record for further calculations. Once you have achieved your opening and closing events we can precede to the following calculations.
If the exhaust closed After Top Dead Center (ATDC) add the exhaust opening figure to the exhaust closing figure plus 180°, which will equal the duration at .050. Divide the duration by 2. Subtract the closing number, which will equal the centerline of the exhaust side.
Example:
+39° Opening Before Bottom Dead Center (BBDC)
+10° Closing After Top Dead Center (ATDC)
+180° Distance from Bottom Dead Center (BDC) to Top Dead Center (TDC)
=229° Total Duration @ .050 inches of lift
229°/2 = 114.5°
114.5° - 10° = 104.5° Lobe Center
If the exhaust closed Before Top Dead Center (BTDC) subtract the exhaust closing from the opening figure plus 180°, which will equal the duration at .050. Divide the duration by 2. Add back the closing number, which will equal the centerline of the exhaust side.
Example:
+39° Opening Before Bottom Dead Center (BBDC)
-10° Closing Before Top Dead Center (BTDC)
+180° Distance from Bottom Dead Center (BDC) to Top Dead Center (TDC)
=209° Total Duration @ .050 inches of lift
209°/2 = 104.5°
104.5° + 10° = 114.5° Lobe Center
If you have adjustable gears move them at this time and redo above procedure.
ALWAYS CHECK SEVERAL TIMES FOR ACCURACY
CALCULATE LOBE CENTER SEPARATION
Add your intake lobe center line to the exhaust lobe center line, and divide by 2.
( 108° + 110° ) / 2 = 109°
ADJUSTING LOBE CENTER SEPARATION
You may move the cam to the desired lobe center and check again. If you move the lobe centers closer together ( Smaller Number ), it would normally give you more low to mid range. If you move the lobe centers apart ( Larger Number ), it would normally give you more mid to top range. Not all engines can handle tight lobe centers. Certain applications require wider lobe centers, such as stock fuel injected engines or blown applications. For our best recommendation, please call us directly.
FINDING TRUE TOP DEAD CENTER ( TDC )
DISCONNECT THE BATTERY! Do not use the starter to perform any of these steps.
To find Top Dead Center use a piston stop, to stop the piston in the same position on either side of TDC and take readings from the degree wheel. You will then split the difference in these readings and move the pointer this amount, making it the true TDC point.
First mount the degree wheel on the end of the crankshaft, and rotate the engine to approximate TDC
Mount the pointer and line it up at zero on the degree wheel.
Now rotate the engine to move the piston down into the cylinder. Install your positive stop device into the spark plug hole and extend the bolt.
Turn the engine by hand, rotating it until the piston comes up and stops against the piston stop bolt.
Look at the degree wheel and write down the number of degrees shown by the pointer.
Turn the engine by hand in the opposite direction until the piston comes up and stops on the piston stop bolt again.
Go back to the degree wheel and write down the degrees it now reads.
Add these two readings together and divide the answer by two.
Now either move your pointer by this many degrees, or carefully loosen the degree wheel (without disturbing the position of the crankshaft) and move the wheel this required amount.
Retighten the bolts, and rotate the engine again making sure that the readings on each side of TDC are equal degrees away from zero. If they are, the zero on the degree wheel will now be the true TDC point.
Remove the positive stop device from the spark plug hole.
You're now done finding true TDC.
FINDING INTAKE LOBE CENTER LINE
Remove all valve lash (clearance). Place your dial indicator on the valve spring retainer, or tappet. If you are degreeing in a pushrod engine we recommend placing the indicator on the valve retainer. Please be sure the angle of your indicator travels at the same angle that your valve travels. Zero the dial indicator, then turn the engine until you reach full lift and record how far the valve traveled off its fully seated position. This will be the actual valve lift of your desired cam profile. Note: Rocker arm engines can vary. At this point make sure there is additional clearance with your dial indicator to verify plenty of travel for our next step.
Rotate the engine until you are back to Top Dead Center (TDC). Zero your dial indicator. Next you will start turning the engine until you are .050 off the seated position of the valve (It is very important to turn the engine it’s normal way of rotation). Look at the degree wheel and determine how many degrees the valve opened. If we are working on the intake valve this will normally occur Before Top Dead Center (BTDC). Record that number in degrees. NOTE: Some low overlap engines may open After Top Dead Center (ATDC). Record that number in degrees for further calculations.
Look at your inner dial on the dial indicator and record that number to help achieve our next step, however some dial indicators do not have this feature and is not needed to proceed. See WEB CAM camshaft degree kit part #95-144. Proceed to rotate the engine until your inner dial is back on the number it left from. You will notice your big dial is almost back to .050. Slightly move it until it is exactly reads at .050. If you pass it back way up and come at it again. You are now .050 from closing on the opposite side to achieve your next number on the degree wheel, which is normally After Bottom Dead center (ABDC). Now you will use the following steps to properly calculate what actual lobe centers are on the opening valve timing events.
If the valve opened Before Top Dead Center (BTDC) do the following calculation:
Take the open number plus the closing number plus 180°, which will be the duration at .050. Next divide the duration into 2. Subtract the open from that number, which will equals the centerline of the intake cam.
Example:
+10° Opening Before Top Dead Center (BTDC)
+39° Closing After Bottom Dead Center (ABDC)
+180° Distance from Top Dead Center (TDC) to Bottom Dead Center (BDC)
=229° Total Duration @ .050 inches of lift
229°/2 = 114.5°
114.5° - 10° = 104.5° Lobe Center
If the valve opened After Top Dead Center (ATDC) subtract the open from the close plus 180°, which will be your duration at .050. Next divide the duration into 2. Add back the open number, which will equal the centerline of the intake side.
Example:
-10° Opening After Top Dead Center (ATDC)
+39° Closing After Bottom Dead Center (ABDC)
+180° Distance from Top Dead Center (TDC) to Bottom Dead Center (BDC)
=209° Total Duration @ .050 inches of lift
209°/2 = 104.5°
104.5° +10° = 114.5° Lobe Center
If you have adjustable gears move them at this time and redo above procedure.
FINDING EXHAUST LOBE CENTER LINE
Next step is to set up your dial indicator and repeat the above procedure. The exhaust valve normally opens Before Bottom Dead Center (BBDC), and the closing will occur After Top Dead Center (ATDC). On some low overlap cam profiles the exhaust valve may close Before Top Dead Center (BTDC) however, record for further calculations. Once you have achieved your opening and closing events we can precede to the following calculations.
If the exhaust closed After Top Dead Center (ATDC) add the exhaust opening figure to the exhaust closing figure plus 180°, which will equal the duration at .050. Divide the duration by 2. Subtract the closing number, which will equal the centerline of the exhaust side.
Example:
+39° Opening Before Bottom Dead Center (BBDC)
+10° Closing After Top Dead Center (ATDC)
+180° Distance from Bottom Dead Center (BDC) to Top Dead Center (TDC)
=229° Total Duration @ .050 inches of lift
229°/2 = 114.5°
114.5° - 10° = 104.5° Lobe Center
If the exhaust closed Before Top Dead Center (BTDC) subtract the exhaust closing from the opening figure plus 180°, which will equal the duration at .050. Divide the duration by 2. Add back the closing number, which will equal the centerline of the exhaust side.
Example:
+39° Opening Before Bottom Dead Center (BBDC)
-10° Closing Before Top Dead Center (BTDC)
+180° Distance from Bottom Dead Center (BDC) to Top Dead Center (TDC)
=209° Total Duration @ .050 inches of lift
209°/2 = 104.5°
104.5° + 10° = 114.5° Lobe Center
If you have adjustable gears move them at this time and redo above procedure.
ALWAYS CHECK SEVERAL TIMES FOR ACCURACY
CALCULATE LOBE CENTER SEPARATION
Add your intake lobe center line to the exhaust lobe center line, and divide by 2.
( 108° + 110° ) / 2 = 109°
ADJUSTING LOBE CENTER SEPARATION
You may move the cam to the desired lobe center and check again. If you move the lobe centers closer together ( Smaller Number ), it would normally give you more low to mid range. If you move the lobe centers apart ( Larger Number ), it would normally give you more mid to top range. Not all engines can handle tight lobe centers. Certain applications require wider lobe centers, such as stock fuel injected engines or blown applications. For our best recommendation, please call us directly.
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