Trunuion upgrade complication
Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 1
From: Piqua, OH
Trunuion upgrade complication
So I take one of the rockers off and as I lift it up the pushrod and lifter come up and when I go to put it back on the lifter must not of dropped back down. As I tighten it up I notice the valve is opening way more than the lift of the cam. Any ideas as to what's happened here? This is a 60000 mile stock 98 ls1. Thanks
Could the lifter of rotated? Aren't there tie bars or something to prevent that? Could the roller of dropped out and wedged? Guess I should of just left it alone. It was running great.
Could the lifter of rotated? Aren't there tie bars or something to prevent that? Could the roller of dropped out and wedged? Guess I should of just left it alone. It was running great.
Last edited by southman; Jun 30, 2021 at 03:08 PM.
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,670
So I take one of the rockers off and as I lift it up the pushrod and lifter come up and when I go to put it back on the lifter must not of dropped back down. As I tighten it up I notice the valve is opening way more than the lift of the cam. Any ideas as to what's happened here? This is a 60000 mile stock 98 ls1. Thanks
Could the lifter of rotated? Aren't there tie bars or something to prevent that? Could the roller of dropped out and wedged? Guess I should of just left it alone. It was running great.
Could the lifter of rotated? Aren't there tie bars or something to prevent that? Could the roller of dropped out and wedged? Guess I should of just left it alone. It was running great.
Le Mans Master
Joined: Jul 2010
Posts: 6,039
Likes: 732
So I take one of the rockers off and as I lift it up the pushrod and lifter come up and when I go to put it back on the lifter must not of dropped back down. As I tighten it up I notice the valve is opening way more than the lift of the cam. Any ideas as to what's happened here? This is a 60000 mile stock 98 ls1. Thanks
Could the lifter of rotated? Aren't there tie bars or something to prevent that? Could the roller of dropped out and wedged? Guess I should of just left it alone. It was running great.
Could the lifter of rotated? Aren't there tie bars or something to prevent that? Could the roller of dropped out and wedged? Guess I should of just left it alone. It was running great.
Le Mans Master
Joined: Jul 2010
Posts: 6,039
Likes: 732
But u problem go to the golf range and try to hit a hole in one at 200yrs
Last edited by helga203; Jul 1, 2021 at 11:32 AM.
Drifting
Joined: May 2007
Posts: 1,548
Likes: 210
From: Huntersville, NC
The lifters are roller/hydraulic. If the car ran fine when you shut down, then it is unlikely the tray failed and the lifter rotated. These lifters pre-load about 1/16 inch, so it is possible that the lifter won’t compress. What I suggest is to get a pushrod length check tool and see how this particular valve compares with a nearby valve.
If you live near me, I can loan you mine and show you how to use it. At least this way you will know where you are mechanically.
If you live near me, I can loan you mine and show you how to use it. At least this way you will know where you are mechanically.
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Thread Starter
Cruising
Joined: Jun 2010
Posts: 12
Likes: 1
From: Piqua, OH
[QUOTE]These lifters pre-load about 1/16 inch, so it is possible that the lifter won’t compress. /[QUOTE]
For some reason that lifter compressed very slowly. I was just tightening with a ratchet and when I saw what looked like coil bind I backed off immediately. I was certain there was something wrong, cause thats my luck. So tightening a little and then waiting and then tightening did the trick. Thank you for keeping me from tearing it all apart. It is back together and running just as before.
For some reason that lifter compressed very slowly. I was just tightening with a ratchet and when I saw what looked like coil bind I backed off immediately. I was certain there was something wrong, cause thats my luck. So tightening a little and then waiting and then tightening did the trick. Thank you for keeping me from tearing it all apart. It is back together and running just as before.
Le Mans Master
Joined: Jul 2010
Posts: 6,039
Likes: 732
[QUOTE=southman;1603688620][QUOTE]These lifters pre-load about 1/16 inch, so it is possible that the lifter won’t compress. /
For some reason that lifter compressed very slowly. I was just tightening with a ratchet and when I saw what looked like coil bind I backed off immediately. I was certain there was something wrong, cause thats my luck. So tightening a little and then waiting and then tightening did the trick. Thank you for keeping me from tearing it all apart. It is back together and running just as before.
Nice
For some reason that lifter compressed very slowly. I was just tightening with a ratchet and when I saw what looked like coil bind I backed off immediately. I was certain there was something wrong, cause thats my luck. So tightening a little and then waiting and then tightening did the trick. Thank you for keeping me from tearing it all apart. It is back together and running just as before.
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,670
[QUOTE=southman;1603688620][QUOTE]These lifters pre-load about 1/16 inch, so it is possible that the lifter won’t compress. /
For some reason that lifter compressed very slowly. I was just tightening with a ratchet and when I saw what looked like coil bind I backed off immediately. I was certain there was something wrong, cause thats my luck. So tightening a little and then waiting and then tightening did the trick. Thank you for keeping me from tearing it all apart. It is back together and running just as before.
Great!! We're glad to hear it. The lifter collapses/compresses slowly. I remember on the original SBC that when you tightened the adjustable rockers, the engine stumbled slightly until the lifter bled down, and proper preload was attained........
For some reason that lifter compressed very slowly. I was just tightening with a ratchet and when I saw what looked like coil bind I backed off immediately. I was certain there was something wrong, cause thats my luck. So tightening a little and then waiting and then tightening did the trick. Thank you for keeping me from tearing it all apart. It is back together and running just as before.