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#21
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Thanks to everyone that gave ideas. This Saturday I hope to investigate more. Will report back what I find. Keep your fingers crossed it something simple. This engine has put me through the ringer so far. It makes GREAT power and performs amazing but it's been one issue after another with it. |
The Following 2 Users Say Thank You to slowbird For This Useful Post: | ||
#22
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So the little testing I did tonight is interesting. Pulled all 8 plug wires while running and no change in noise. Listened closely with a screw driver and hear nothing but lifter chatter everywhere EXCEPT front of valley cover where I do here knocking/banging. So lifter hitting valley?????
Tomorrow I will change oil and pull valve covers while it running to see if I can find something. |
#23
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A cracked flex plate can make a hard to locate knocking sound.
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The Following User Says Thank You to tstroud For This Useful Post: | ||
#24
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Thoughts on what caused these marks??
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#25
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Interference with cast valve cover rib?
__________________
Triple Black 1971 GTO |
#26
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IDK when I had interference it was on the pushrod side of the rocker by the bolt hole. That’s not where that would be from.
Slow bird, where is that rocker located? It’s not touching the bottom of the oil cap is it? |
#27
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I can’t say how those scratches got there, but I don’t think that such would the source of a knocking or banging sound.
I would do as you said and first pull each valve cover off one at a time a see if that makes any changes. If no changes take place I would get a length of 3/4” heater hose, take all the belts off the motor and listen on the side of the balancer for the knocking sound. In fact I would be inclined to do this first even before pulling off the valve covers because if you hear anything from down there, then it anit from the valvetrain and you really do not want to run the motor anymore for troubleshooting.
__________________
I do stuff for reasons. |
#28
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I see Murf suggested earlier what I was thinking. If the rocker was straddling the rib formed for the hold down bolt access, it might contact. Odd though that it is behind the axle and the axle sticks out further and shows no witness marks
__________________
Triple Black 1971 GTO |
#29
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Maybe a broken fuel pump spring. They still work but have clearance on the lever.
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The Following User Says Thank You to hobbygto65 For This Useful Post: | ||
#30
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Video shows he is running an electric fuel pump.
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#31
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Sounds like a sticky lifter to me. Is this at operating temp? Did you inspect movement of the rocker arms with the engine running to see if one of them is not moving the same as the others, or at all? The mess that makes is sometimes worth seeing the problem in action.
__________________
1979 Trans Am W72 400/4-Speed WS6 - Starlight Black Hardtop
Last edited by nUcLeArEnVoY; 11-12-2022 at 04:04 PM. |
#32
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Well found the noise issue. But also found other issues. 3/8 pushrod on #3 intake is hit the bottom of the head. Also has almost no oil going through it. We just happened to have a correct length 5/16 pushrod laying around put that in and no more knocking. But we still don't have oil going to oil 😕
https://youtu.be/d6_BIMe0VBk 3/8 pushrod https://youtu.be/F2t7XtTQUKo 5/16 pushrod |
#33
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I appreciate everyone's help. My next steps will be to determine why there's no oil to that rocker. I'm guessing something is messed up in the lifter now.
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#34
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Glad you found it. You need to get that lifter out and inspect it most likely. One thing you could try is to run the engine with that adjuster really loose and see if it will unstick and begin oiling again. Most likely, the lifter is collapsed and oil is not getting through the body, through the plunger and out to the pushrod.
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#35
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May just be sludge or crud buildup in the lifter. While you have the valve cover off, spray some carb or brake cleaner directly down the pushrod oiling orifice and it'll bleed directly into the lifter body. May dissolve that crud and let oil through. If not, it's a fundamental lifter problem and you'll have to remove the valley pan and inspect. May just need to replace the lifter - a collapsed lifter doesn't always mean a wiped cam lobe, in fact most of the time it doesn't, especially if the engine isn't operated in high RPMs very often.
__________________
1979 Trans Am W72 400/4-Speed WS6 - Starlight Black Hardtop
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#36
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What heads are these?
Maybe you floated that valve and the clip holding the plunger in came out.
__________________
I do stuff for reasons. |
#37
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Hopefully over Thanksgiving I can find more time to investigate further. Just one issue after another |
#38
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Worth pulling the intake and valley cover to get hands on the lifter(s); maybe resolve the knockin-contact too.
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#39
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As I recall long ago when I had the plunger clip come out from a over rev condition the tip off I found to that was when I pulled that side valve cover off and started the motor.
I had then saw that I had several times more oil coming out of that rocker then the other 7 on that side.
__________________
I do stuff for reasons. |
#40
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