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I've also read posts where guys say they've brought the piston to TDC in the cylinder they're working on, and the valve won't fall so far that it can't be retrieved. No personal experience doing it that way, because I've always used air......
The car 2003 convertible and lam thinking to go with PAC-1218 Drop-In Beehive Valve 600 lift for peace of mind .... But how much PSI l need to keep the valve up and safe ?
I used 100 psi air with cylinder at TDC just in case. I had no problems.
I agree. Sometimes those keepers don't want to break loose, and you need that much pressure. Just hope the OP has that cylinder at exact TDC, because I did make the mistake once (only once, trust me!) of having the piston down maybe an inch, and 100lbs tried to rotate the crank......
I took all the plugs out, since I was changing them anyways, and found TDC on cylinder 1 of compression stroke by rotating the crank at the balancer. When rotating, watch the intake spring open and close. Used a small wooded dowel rod and felt when the piston was at TDC. Then marked the balancer with chalk. Backed it off a little , then inserted a 1/8-3/16" nylon strong in the cylinder and rotated the crank to TDC. The string should;d not pull out at that point and the valves are wedged so they will not move. Changed the springs, then backed it off a little to remove the string and moved to cylinder 8, the next in the firing order and did the same. Makes it mindless and no fear of the compressed air pushing the piston down. Firing order is 1, 8, 7, 2, 6, 5, 4, 3 When your done you should be back to TDC at 1 after a few wrachets. Then you can torque down the certain rockers as in manual. Your chalk mark on the balancer should be where you marked it at the reference point. Then rotate 360* to torque the other rockers. Do not attempt the air method with all your plugs out!
I took all the plugs out, since I was changing them anyways, and found TDC on cylinder 1 of compression stroke by rotating the crank at the balancer. When rotating, watch the intake spring open and close. Used a small wooded dowel rod and felt when the piston was at TDC. Then marked the balancer with chalk. Backed it off a little , then inserted a 1/8-3/16" nylon strong in the cylinder and rotated the crank to TDC. The string should;d not pull out at that point and the valves are wedged so they will not move. Changed the springs, then backed it off a little to remove the string and moved to cylinder 8, the next in the firing order and did the same. Makes it mindless and no fear of the compressed air pushing the piston down. Firing order is 1, 8, 7, 2, 6, 5, 4, 3 When your done you should be back to TDC at 1 after a few wrachets. Then you can torque down the certain rockers as in manual. Your chalk mark on the balancer should be where you marked it at the reference point. Then rotate 360* to torque the other rockers. Do not attempt the air method with all your plugs out!
Not all of us have an air compressor handy… The TDC method is fine, but if you are also changing the seals, the valve will drop a little bit. So the rope goes in the cylinder, crank it lightly back to TDC and the valve will stay in place. Since your pushrods are out it doesn’t matter if it’s in compression or exhaust stroke, as long as the piston is TDC. So you can do two cylinders at a time. For example #1 and #6 are both TDC at the same time.
The top photo is the sequence for changing the springs, and bottom photo is the sequence for torquing the rocker bolts.
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Last edited by vette4fl; Apr 23, 2022 at 01:11 AM.
Not all of us have an air compressor handy… The TDC method is fine, but if you are also changing the seals, the valve will drop a little bit. So the rope goes in the cylinder, crank it lightly back to TDC and the valve will stay in place. Since your pushrods are out it doesn’t matter if it’s in compression or exhaust stroke, as long as the piston is TDC. So you can do two cylinders at a time. For example #1 and #6 are both TDC at the same time.
The top photo is the sequence for changing the springs, and bottom photo is the sequence for torquing the rocker bolts.
