Weird metal on magnetic drain plug..what do you think it is??

[Carlaisle]

Don't mind me. I clearly failed reading comprehension. lol

 

[Pinger]

Not necessarily. As long as the lifter roller trunnion is intact and rolling across the lobe,it may not make noise. .

What maintains correct orientation? Does the lifter have some kind of peg and groove arrangement that stops it rotating?

And while I'm asking about valve train - on a 350 Vortec, is there any possibility that in the event of a valve being open other than by cam lobe, that the pushrod (or anything else) can lose engagement with its follower or rocker?
(The 'event' I have in mind is an inlet valve being forced open by an inlet back fire).

 

[SAATR]

What maintains correct orientation? Does the lifter have some kind of peg and groove arrangement that stops it rotating?

And while I'm asking about valve train - on a 350 Vortec, is there any possibility that in the event of a valve being open other than by cam lobe, that the pushrod (or anything else) can lose engagement with its follower or rocker?
(The 'event' I have in mind is an inlet valve being forced open by an inlet back fire).

LS engines use plastic lifter "trays" to maintain correct orientation with the cam lobe. Most recommend replacing them any time you are far enough into the engine to access them, as their failure means, at best, a wiped cam lobe.

For your second scenario, the answer is emphatically yes. The pushrod, without valve spring tension forcing it into the cup on rocker or lifter, can fall out of the lifter or rotate the rocker completely off the valve stem, which can cause all kinds of mechanical interference and damage.

 

[Pinger]

LS engines use plastic lifter "trays" to maintain correct orientation with the cam lobe. Most recommend replacing them any time you are far enough into the engine to access them, as their failure means, at best, a wiped cam lobe.

Is the above applicable to 350 Vortecs also?

For your second scenario, the answer is emphatically yes. The pushrod, without valve spring tension forcing it into the cup on rocker or lifter, can fall out of the lifter or rotate the rocker completely off the valve stem, which can cause all kinds of mechanical interference and damage.

Thanks - for confirming my suspicions. All the more reason to get my LPG calibrated so no inlet back-fires can occur. (The possibility of opening an inlet valve would probably never have occurred to me but for a guy who supercharged Yamaha R1 engines telling me that the two limiting factor as standard for how much boost could be applied were float chambers collapsing - and inlet valves being pushed open. Funny where we pick up our snippets of info from that have relevance elsewhere).

 

[SAATR]

Is the above applicable to 350 Vortecs also?

No. The Vortec 350 uses "dogbones" which link each cylinder's lifters together combined with a spring plate, called a "spider", to hold downward tension on each of the dogbones and by proxy, the lifters.

 

[August76]

No. The Vortec 350 uses "dogbones" which link each cylinder's lifters together combined with a spring plate, called a "spider", to hold downward tension on each of the dogbones and by proxy, the lifters.

ford used something like this on there roller cam 302.
Probably a much better design than the plastic crap. So i wonder if my plastic trays are bad? Hmm. Where am i going to order them from

 

[August76]

It does sound a little clacky like a vw diesel. But it probably always did and i never noticed.

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[SAATR]

ford used something like this on there roller cam 302.
Probably a much better design than the plastic crap. So i wonder if my plastic trays are bad? Hmm. Where am i going to order them from

Texas Speed, Summit, Jegs, GMPartsDirect, Scoggin Dickey, take your pick. $10ish dollars each, you need 4. Some sell all 4 with LS7 or LS9 lifters as a kit. I wouldn't reuse the 200k mile stockers, even if they aren't bad.

Edit: OE GM trays only. Not a place to cheap out, believe me.

 

[August76]

Texas Speed, Summit, Jegs, GMPartsDirect, Scoggin Dickey, take your pick. $10ish dollars each, you need 4. Some sell all 4 with LS7 or LS9 lifters as a kit. I wouldn't reuse the 200k mile stockers, even if they aren't bad.

Edit: OE GM trays only. Not a place to cheap out, believe me.

I wont. Do you think one of them might be the cause?
I had to pick up some tools to remove the balancer so ill start on it tomorrow probably. I was hoping she would say get rid of the pos.

 

[SAATR]

I wont. Do you think one of them might be the cause?
I had to pick up some tools to remove the balancer so ill start on it tomorrow probably. I was hoping she would say get rid of the pos.

No, I doubt it. Tray failure would allow the lifter to rotate in the bore , which tends to rapidly destroy the lifter and cam.