Cam Timing
- Thread starter TROUBLE4U
- Start date
brainbypass mod
always bet on black
two, one for the intake lobe, one for the exhaust lobe
You can get by with one, you just have to move it when checking exhaust event timing. If you pick up some light weight springs from comp or local hardware store, you may be able to get good results without the solid lifters. Have not tried it myself, but know some do on cam in block motors so should work here. Think Comp sells a kit with magnetic base, travel indicator indicator, lite springs (diameter probably too big, thus hardware store) and degree wheel.
I have copied my PM for the benefit of anyone else that might want the info. Also added some more hints and experience to this note.
As I said, I have not used the FMS kit. It is part number M-6266-D46 and Lists for $158.99. Frankly this is very expensive for what you get.
I used a 0-1" travel indicator with magnetic base, a 3" or 4" extension for the indicator, and 11" degree wheel. If you buy the right size degree wheel, large center hole diameter, do not have diameter available at the moment, you can use the degree wheel mount/socket for a V-6 chevy to hold degree wheel and turn motor.
If you do not have this tool, you will need to turn motor by the flywheel or crank bolts. With degree wheel on the front of crank, you have no place to turn motor over without the degree wheel moving on the crank. Further you must turn crank both directions to locate TDC, this does not work with degree wheel on the crank. A strategically bent piece of coat hanger will work for a pointer.
You will also need a piston stop for locating TDC. If you have spark plug inserts in your heads, you can buy one from Comp Cams pretty cheap. If you have pre-2003 heads, you will need to fab a stop. You can do so by breaking the pocellin out of a spark plug and threading the shell for a length of threaded rod. Bought a strip of drilled metal from hardware store and attached it along top row of valve cover bolts for the magnetic base to stick to. The long indicator extension allows the indicator tip to reach top of the spring retainer. Mount indicator so shaft is traveling same axis as valve, just offset to top edge of retainer. Left ball tip of extension so it rode more steadily on top of retainer.
The place I got my solid lifters from is no longer iappears in business, web site gone, so not sure where you can get one outside the FMS kit. Thought a bit more on using lite spring instead of a solid lifter, but that will not work either since valve train is not adjustible.
Be very careful when doing this work, if you allow the cam or crank to turn very far independent of the other(timing chain off) , you can bend a valve or two, although we have a lot more valve clearance than the N/A motors, especially the 4.6 motors.
Make sure you keep some drag on the timing chain when turning the motor since the timing chain tensioners may have lost some oil and thus let slack get in the tension side of the chain, this will cause occasional errors in timing due to erratic to/fro moment due to valve springs pushing cam ahead of the crank. Crower cams are more difficult to time since the lobes are assymmetrical, you must set valve clearance to zero and check opening and closing events at 0.050". Since you will be checking these events at the valve instead of at the cam, you must make sure the timing events you are using are at valve, not at the cam. Crower used to list only at the cam and you can not check it at the valve. If you are a bit off on valve clearance setting, the timing events and total duration may not be exact. If the IO is 2 degree early and IC is 2 degree late, the clearance is tight, but timing correct. If the IO is 4 deg early and correct at IC, cam is advanced 2 deg. With Comp or Patriot cams, this job is easier, they use symmetrical lobes. , You can measure 0.050" each direction from maximim lift point to find lobe center and compare to cam card.
While you can time cam with intake numbers alone, you must check both intake and exhaust to insure the cam is ground correctly. If after you get intake timing adjusted correctly, the exhaust should be within about a degree. If it is much further off than this, either the degree wheel hasmoved, you made a mistake, or cam is ground incorrectly.
As I said, I have not used the FMS kit. It is part number M-6266-D46 and Lists for $158.99. Frankly this is very expensive for what you get.
I used a 0-1" travel indicator with magnetic base, a 3" or 4" extension for the indicator, and 11" degree wheel. If you buy the right size degree wheel, large center hole diameter, do not have diameter available at the moment, you can use the degree wheel mount/socket for a V-6 chevy to hold degree wheel and turn motor.
If you do not have this tool, you will need to turn motor by the flywheel or crank bolts. With degree wheel on the front of crank, you have no place to turn motor over without the degree wheel moving on the crank. Further you must turn crank both directions to locate TDC, this does not work with degree wheel on the crank. A strategically bent piece of coat hanger will work for a pointer.
You will also need a piston stop for locating TDC. If you have spark plug inserts in your heads, you can buy one from Comp Cams pretty cheap. If you have pre-2003 heads, you will need to fab a stop. You can do so by breaking the pocellin out of a spark plug and threading the shell for a length of threaded rod. Bought a strip of drilled metal from hardware store and attached it along top row of valve cover bolts for the magnetic base to stick to. The long indicator extension allows the indicator tip to reach top of the spring retainer. Mount indicator so shaft is traveling same axis as valve, just offset to top edge of retainer. Left ball tip of extension so it rode more steadily on top of retainer.
The place I got my solid lifters from is no longer iappears in business, web site gone, so not sure where you can get one outside the FMS kit. Thought a bit more on using lite spring instead of a solid lifter, but that will not work either since valve train is not adjustible.
Be very careful when doing this work, if you allow the cam or crank to turn very far independent of the other(timing chain off) , you can bend a valve or two, although we have a lot more valve clearance than the N/A motors, especially the 4.6 motors.
Make sure you keep some drag on the timing chain when turning the motor since the timing chain tensioners may have lost some oil and thus let slack get in the tension side of the chain, this will cause occasional errors in timing due to erratic to/fro moment due to valve springs pushing cam ahead of the crank. Crower cams are more difficult to time since the lobes are assymmetrical, you must set valve clearance to zero and check opening and closing events at 0.050". Since you will be checking these events at the valve instead of at the cam, you must make sure the timing events you are using are at valve, not at the cam. Crower used to list only at the cam and you can not check it at the valve. If you are a bit off on valve clearance setting, the timing events and total duration may not be exact. If the IO is 2 degree early and IC is 2 degree late, the clearance is tight, but timing correct. If the IO is 4 deg early and correct at IC, cam is advanced 2 deg. With Comp or Patriot cams, this job is easier, they use symmetrical lobes. , You can measure 0.050" each direction from maximim lift point to find lobe center and compare to cam card.
While you can time cam with intake numbers alone, you must check both intake and exhaust to insure the cam is ground correctly. If after you get intake timing adjusted correctly, the exhaust should be within about a degree. If it is much further off than this, either the degree wheel hasmoved, you made a mistake, or cam is ground incorrectly.