Camshaft problems..
Race Director
Joined: Apr 2003
Posts: 19,351
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From: Tampa, Florida
OK... #1 or #6
1. Place engine at #1 cylinder piston at TDC
2. Rotate engine
If #1 lifters and pushrods begin to rise as engine rotates your at TDC with #1
If #1 lifters and pushrods begin to fall as engine rotates your at TDC with #6
1. Place engine at #1 cylinder piston at TDC
2. Rotate engine
If #1 lifters and pushrods begin to rise as engine rotates your at TDC with #1
If #1 lifters and pushrods begin to fall as engine rotates your at TDC with #6
Le Mans Master
Joined: Aug 2008
Posts: 5,578
Likes: 61
From: Austin TX
Sounds like your heads have been milled to the point of creating piston to valve clearance problems. Do you know the history of your heads? If they're 40 years old, who knows how many times they've seen a milling machine.
Race Director
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Leave all of that alone. But you need to rotate the engine one full turn to get #1 cylinder to TDC COMPRESSION stroke where both valves are closed. Then you can adjust that cylinder and move on through the sequence.
During adjustment you just need to barely take out the play. With #1 in position as described,,,turn adjuster while lifting up and down on pushrod. Just a light touch. When it just loses play you're at zero lash. Then turn it 1/2-3/4 of a turn more.
Make sure when you're at zero play that the cup in the lifter is not being depressed at all. It should be high and up against the clip. I'm guessing all the oil has been removed from lifters by now with the previous adjustments...so you'll have to pay close attention.
JIM
Race Director
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From: Corsicana, Tx
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Any chance it's got wrong pushrods and rockers are bottoming or something??
JIM
JIM
Safety Car
Joined: Jan 2008
Posts: 3,795
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From: Aarhus, Denmark
Yes...that's CAM timing in relation to the crank/piston etc.
Leave all of that alone. But you need to rotate the engine one full turn to get #1 cylinder to TDC COMPRESSION stroke where both valves are closed. Then you can adjust that cylinder and move on through the sequence.
During adjustment you just need to barely take out the play. With #1 in position as described,,,turn adjuster while lifting up and down on pushrod. Just a light touch. When it just loses play you're at zero lash. Then turn it 1/2-3/4 of a turn more.
Make sure when you're at zero play that the cup in the lifter is not being depressed at all. It should be high and up against the clip. I'm guessing all the oil has been removed from lifters by now with the previous adjustments...so you'll have to pay close attention.
JIM
Leave all of that alone. But you need to rotate the engine one full turn to get #1 cylinder to TDC COMPRESSION stroke where both valves are closed. Then you can adjust that cylinder and move on through the sequence.
During adjustment you just need to barely take out the play. With #1 in position as described,,,turn adjuster while lifting up and down on pushrod. Just a light touch. When it just loses play you're at zero lash. Then turn it 1/2-3/4 of a turn more.
Make sure when you're at zero play that the cup in the lifter is not being depressed at all. It should be high and up against the clip. I'm guessing all the oil has been removed from lifters by now with the previous adjustments...so you'll have to pay close attention.
JIM
Thread Starter
Le Mans Master
Joined: Jun 2003
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From: Umeå Sweden
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Team Owner
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From: altered state
St. Jude Donor '05
Are you rotating it with the plugs in?
Something isnt right there is no way the valves should be coming anywhere near the piston. Tons of room...
are you spinning the pushrods with your fingers or wiggling them up & down til theres no slack then adding your preload? easy to get fooled
Something isnt right there is no way the valves should be coming anywhere near the piston. Tons of room...
are you spinning the pushrods with your fingers or wiggling them up & down til theres no slack then adding your preload? easy to get fooled
Melting Slicks
Joined: Mar 2008
Posts: 2,666
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From: Spring Park MN
Are you sure it's the exhaust valve hitting the piston. Did you replace the stock springs with Comp's recommended springs. Did you check free travel, valve keeper and top collar to seal?
Stock springs could coil bind with this cam and there may not be enough free travel. Either of these would cause it to bind up.
Mike
Stock springs could coil bind with this cam and there may not be enough free travel. Either of these would cause it to bind up.
Mike
Last edited by v2racing; Jul 25, 2017 at 04:37 PM.
Drifting
Joined: Jun 2008
Posts: 1,565
Likes: 111
Are you rotating it with the plugs in?
Something isnt right there is no way the valves should be coming anywhere near the piston. Tons of room...
are you spinning the pushrods with your fingers or wiggling them up & down til theres no slack then adding your preload? easy to get fooled
Something isnt right there is no way the valves should be coming anywhere near the piston. Tons of room...
are you spinning the pushrods with your fingers or wiggling them up & down til theres no slack then adding your preload? easy to get fooled
Race Director
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From: Corsicana, Tx
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Got any pics of valvetrain/pistons/heads?
JIM
JIM
Race Director
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Good. one thing down.
It's got "universal" pistons that have same valve reliefs on all pockets. Meaning they can go in any cylinder vs many that have right bank and left bank. Also eliminates the common mixup on the middle cylinders of getting them in the wrong direction and not having the proper valve pocket line up with the correct valve.
Got any of the rockers at full lift, the pushrods etc?
JIM
It's got "universal" pistons that have same valve reliefs on all pockets. Meaning they can go in any cylinder vs many that have right bank and left bank. Also eliminates the common mixup on the middle cylinders of getting them in the wrong direction and not having the proper valve pocket line up with the correct valve.
Got any of the rockers at full lift, the pushrods etc?
JIM
Safety Car
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From: Aarhus, Denmark