Name this knock
10-14-2018, 06:34 PM
#1
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Thread Starter
Name this knock
Car was overheating previously, got it back running and now it has a knock. Don’t know the cam or lifters that are in it but it didn’t previously tick so I don’t believe it’s solid. Not sure if it bent a pushrod or if a lifter is bad. Let me know what you think and the easiest way to diagnose it.
10-14-2018, 07:13 PM
#2
Re: Name this knock
Pull the valve covers and check for mushy lifters. It's perimeter bolt so probably hydraulic. Sounds like a fairly rowdy camshaft though so could be solid lifter? If you don't know you better check.....
if you find nothing then cut open the oil filter and check for metal. Going to be loose valve train or rod bearing I should think.
GD
if you find nothing then cut open the oil filter and check for metal. Going to be loose valve train or rod bearing I should think.
GD
10-14-2018, 07:58 PM
#3
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Re: Name this knock
Thanks for the reply, not very knowledgeable on engine internals so I’m learning as I go... I do have play between some rockers and pushrods. How do I check for “mushy lifters”? Is there a way to identify what I have without pulling everything out? Thanks again
10-14-2018, 08:22 PM
#4
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Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Name this knock
There is something missing from your picture - OIL.
Did you wipe the heads clean before that picture?
I can't believe your heads would drain that clean on their own.
If you are not getting a decent amount of oil while running, then you already have bigger problems than a tick / knock.
Did you wipe the heads clean before that picture?
I can't believe your heads would drain that clean on their own.
If you are not getting a decent amount of oil while running, then you already have bigger problems than a tick / knock.
10-14-2018, 08:41 PM
#5
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Re: Name this knock
Pic was taken with motor cold and not run in a couple days. Oil change was just done and I’m running about 80psi cold and about 30 once warm and at idle. I could run it with the valve cover off but haven’t for fear of getting oil everywhere.
10-14-2018, 08:44 PM
#6
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Re: Name this knock
Just installed new breather and pcv because it didn’t previously have one and old breathers were oil saturated and smoking/spitting. Pretty sure oil is circulating but I’m willing to inspect anything.
10-14-2018, 09:21 PM
#7
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Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Name this knock
Use a piece of cardboard to lessen the oil going everywhere with the valve cover off.
Stick one end of a piece of vacuum hose 18-24" long in your ear and move the other end along the valvetrain with the engine running at idle.
If there is a tick, you will be able to isolate it.
Stick one end of a piece of vacuum hose 18-24" long in your ear and move the other end along the valvetrain with the engine running at idle.
If there is a tick, you will be able to isolate it.
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10-14-2018, 10:51 PM
#8
Re: Name this knock
Well a solid lifter valve train would have a little play. But we're talking about .010" give or take 50% of that.
Someone that knows the difference could tell by pulling a pushrod and looking at the lifters with a bore scope or even a penlight. I'm concerned that you may not be able to do that though.
If you can push down on the pushrod side of the rockers - they should have very little play. If you can move them significantly by hand then the lifter is deflated. Which it should not be.... and that would be a likely candidate for your noise.
Given the series of events and how dry it is under those valve covers.... I would sacrifice the oil filter anyway and check for metal.
Someone that knows the difference could tell by pulling a pushrod and looking at the lifters with a bore scope or even a penlight. I'm concerned that you may not be able to do that though.
If you can push down on the pushrod side of the rockers - they should have very little play. If you can move them significantly by hand then the lifter is deflated. Which it should not be.... and that would be a likely candidate for your noise.
Given the series of events and how dry it is under those valve covers.... I would sacrifice the oil filter anyway and check for metal.
10-15-2018, 07:04 AM
#9
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Thread Starter
Re: Name this knock
I just did an oil change and had no metal on the magnetic drain plug and no visible metallic sheen in the oil. I did not set tdc or anything but had play in some but not all rockers. Is this something I can just attempt to reset preload on? Or should I just be pulling stuff at this point?
10-15-2018, 09:48 AM
#10
Re: Name this knock
Bearing material would not be magnetic. It's good that it didn't appear metallic though. Still I would cut the filter. They are cheap.
You should check that each push rod spins freely when the valve is unloaded - if not they may be bent. The pre-load should already be set unless the locks backed off the rockers. The bigger question if not is why did the lifters deflate? You can try setting the lash with it running. It looks dry in there as we previously noted - seems too dry for an engine that has run. The oil doesn't really drain from the outer edges of the heads - usually there is some pooling. Makes me think enough oil isn't getting to the lifters.
You should check that each push rod spins freely when the valve is unloaded - if not they may be bent. The pre-load should already be set unless the locks backed off the rockers. The bigger question if not is why did the lifters deflate? You can try setting the lash with it running. It looks dry in there as we previously noted - seems too dry for an engine that has run. The oil doesn't really drain from the outer edges of the heads - usually there is some pooling. Makes me think enough oil isn't getting to the lifters.
10-15-2018, 10:46 AM
#11
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Thread Starter
Re: Name this knock
I’ll run it with the valve cover off at the next chance I get and make a video. The lock nuts on the rockers seemed tight and set on inspection. It did have play in unloaded rockers and the pushrods spun freely. If the oil isn’t making it up top correctly what’s the next thing to look at? Thanks for the responses
10-15-2018, 12:52 PM
#12
Re: Name this knock
I’ll run it with the valve cover off at the next chance I get and make a video. The lock nuts on the rockers seemed tight and set on inspection. It did have play in unloaded rockers and the pushrods spun freely. If the oil isn’t making it up top correctly what’s the next thing to look at? Thanks for the responses
GD
10-15-2018, 07:00 PM
#13
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Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Name this knock
If you do get to the point of having to remove a lifter to see if it is a HYD or SOLID, I can tell you how to do it
WITHOUT REMOVING THE INTAKE MANIFOLD.
In either case, you should have oil filling each and every rocker arm within 30 seconds of starting the engine.
WITHOUT REMOVING THE INTAKE MANIFOLD.
In either case, you should have oil filling each and every rocker arm within 30 seconds of starting the engine.
10-16-2018, 08:32 AM
#14
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Thread Starter
Re: Name this knock
Video showing the play in the rockers
running to check for oil
is it possible the overheating bent a bunch of pushrods? Let me know what y’all see and think. Thanks again
running to check for oil
is it possible the overheating bent a bunch of pushrods? Let me know what y’all see and think. Thanks again
10-16-2018, 05:32 PM
#18
Re: Name this knock
Crank, Cam - doesn't matter much at that point. The engine has to be torn completely down and hot-tanked to get all that out of it and the source will be quite obviously when you find it. Likely it's a rod bearing based on the noise, and the metallic bits are either bearing insert backing material, rod material, or crank material. It probably goes without saying, but don't run it anymore - it will just cause further damage.
I guess you could pull the pan and check the rod caps, or pull the intake and check out the lifters. Could be a camshaft going flat also.....
IMHO though you don't have a choice but to pull it and completely rebuild it. With that much metal - it would be a total gamble and probably a complete waste of time to take any short cuts. Or just throw a crate motor in there.
GD
I guess you could pull the pan and check the rod caps, or pull the intake and check out the lifters. Could be a camshaft going flat also.....
IMHO though you don't have a choice but to pull it and completely rebuild it. With that much metal - it would be a total gamble and probably a complete waste of time to take any short cuts. Or just throw a crate motor in there.
GD
Last edited by GeneralDisorder; 10-16-2018 at 05:44 PM.
10-16-2018, 05:56 PM
#19
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Car: 1991 Pontiac Firebird Trans Am
Engine: 5.7L TPI
Transmission: 4 speed 4L60/700R4
Re: Name this knock
Me being straight to the point for once.......that really SUCKS!!!! While I'm running essentially a completely stock motor, I'm getting tons of perceived knock also. I hope to God I don't end up with the same problem you have. Good luck.......
10-16-2018, 06:54 PM
#20
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Re: Name this knock
Thanks for all the info guys, this car has been a nightmare since I got it... I’ll hopefully get it torn down soon and probably won’t buy parts and rebuild till after the holidays. Again thanks for the help
10-17-2018, 01:33 AM
#22
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Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Name this knock
Teardown. Sorry man. 
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