Stupid question, back to basics
Thread Starter
On The Tree
Joined: Sep 2009
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Stupid question, back to basics So I am just really curious about what prevents the lifters from falling down on to the cam off lobe. So the trays prevent them from turning, so that means they are not supposed to come out of the trays.
It seems it would be easy for one of the lifters to come out of the tray and spin since there is plenty of room if the cam isn't opening that particular valve.
I know it's probably a dumb question, just having a hard time figuring it out in my head.
Thanks
It seems it would be easy for one of the lifters to come out of the tray and spin since there is plenty of room if the cam isn't opening that particular valve.
I know it's probably a dumb question, just having a hard time figuring it out in my head.
Thanks
I'm not sure what you are asking, The roller on the lifter follows the cam lobe and the pressure of the valve spring holds the pushrod on the top of the lifter... so as long as the spring is strong enough the roller on the lifter will never leave the lobe of the cam. The cam will only allow the lifter to raise and lower a set distance, That distance is less than the distance it would take for the lifter to come out of it's bore to the point that it will rotate. If you break a valve spring, or bend/break a pushrod then yes the lifter can be pushed out of the bore.
Actually, there isn't. If assembled properly, there's no way for the lifter to drop down far enough to come out the bottom of the tray.
Thread Starter
On The Tree
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I guess my question is whats keeping the lifter from turning and coming down out of the tray when the valve is not open. It doesn't seem like the trays are a wear item so it seems strange to me that the lifters have the ability to move up and down in the tray.
I don't know if I'm reading this right but the pushrod always has some pressure on the lifter (keeping it on the cam lobe) whether the valve is open or not. Comes from the combination of the spring and rocker. The only way they will fall out of the bottom is when the cam is out and the trays don't hold them up. Never seen one come out the top. U could if u had some serious engine failure lol. They can spin (sideways say bye to the camshaft maybe more) inside the trays which is why I went to link bar lifters. No more trays for me.
How does the posi in a Plymouth work? It just does. But if I read this right also you ask what prevents the lifter from falling? But like said the lifter rolls on the cam at all time. Unless something castrophic happens then it sandwich between the cam and pushrod.
OP, I think you're asking what keeps the lifters up away from the cam when the rocker arms & pushrods are removed?
If this is your question, the lifter trays have a little squeeze on the lifters. Pull the rockers & push rods and rotate the crank twice (camshaft once) and all the lifters will be held far enough to allow removal of the camshaft-without removing the heads and completely removing the lifters.
If this is your question, the lifter trays have a little squeeze on the lifters. Pull the rockers & push rods and rotate the crank twice (camshaft once) and all the lifters will be held far enough to allow removal of the camshaft-without removing the heads and completely removing the lifters.
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From: indiana
ive always been leary of the trays holding the lifters up when changing the cam they do make a tool to hold them up too
has anyone ever had one fall out of the tray into the engine its basically a your screwed kinda situation isnt it ?
has anyone ever had one fall out of the tray into the engine its basically a your screwed kinda situation isnt it ?
Thread Starter
On The Tree
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The lifters are constantly moving in and out of those plastic guides. This seems impossible without that plastic wearing out and causing the lifter to turn.
What am I still missing>!>!>!
TECH Fanatic
Joined: Aug 2011
Posts: 1,324
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From: Marengo, Ia
This makes sense for a sbc or sbf. On the LS the lifters being held by the plastic guides makes my head spin.
The lifters are constantly moving in and out of those plastic guides. This seems impossible without that plastic wearing out and causing the lifter to turn.
What am I still missing>!>!>!
The lifters are constantly moving in and out of those plastic guides. This seems impossible without that plastic wearing out and causing the lifter to turn.
What am I still missing>!>!>!
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
This makes sense for a sbc or sbf. On the LS the lifters being held by the plastic guides makes my head spin.
The lifters are constantly moving in and out of those plastic guides. This seems impossible without that plastic wearing out and causing the lifter to turn.
What am I still missing>!>!>!
The lifters are constantly moving in and out of those plastic guides. This seems impossible without that plastic wearing out and causing the lifter to turn.
What am I still missing>!>!>!