Whats Valve Chatter? Weird fluttery noise (2 Viewers)

[faalkinaey]

Okay so this is going to be a loong question but hopefully worth a shot, My 87’ Fj60 has this weird intermittent bucking / struggles to run problem. This first actually happened maybe 2 months ago, after 20-30 minutes of driving the truck starts to buck until you let it rest, accompanied with the bucking is this fluttering noise coming from towards the back of the motor I think. It is a prominent fluttery noise almost how a turbo engine flutters, speeds up with rpm and sorta disappears after 2.5k rpm, the bucking, rough running issues only happens when this noise is there which is about 20-30 minutes of driving. So first thing I did was a valve adjustment, it was my first time doing a valve adjustment so can’t say it was perfect, issue went away for a bit then came back, along with the flutter, decided to do another valve adjustment and pretty sure I did it on point this time as well. Boom that pretty much seemed to take care of the problem. I had some other unrelated bucking issues related to fuel that I solved since in the mean time (no flutter noise when those issues arose) fast forward 2 months later this fluttering noise is back along with a harsh bucking and a rough idle until you decide to let the engine cools off. I don’t think this is a temp issue, recent coolant flush and temp gauge never goes above 1/4 or 1/2. Read somewhere that this noise is related to valve chatter, what is that and does adjusting the valves (once again) do the trick? I adjust my valves cold according to the table someone made here on the forums and by going front to back on the lifters (adjusted closest valve to me first and worked back, used the alternator pulley to rotate the engine until I felt the rocker “loose”, then adjust) hopefully somebody has a hint of clue of where/what to look for, obviously gonna do another valve adjustment since that seemed to take care of it the first time, is there anything wrong in my valve adjustment procedure? Have no idea how to adjust otherwise. I would adjust valves according to FSM but not sure exactly how that procedure goes would love a detailed instruction, all the other threads here about valve adjustment do it at TDC. It could obviously be lotta other issues as well, I guess my main question would be can misadjusted valves cause this sorta fluttery noise? Rather than the typical loud tapping? I’ll get a recording of it next time it happens. Thanks to anybody who tries to help, this issue has genuinely been driving me crazy especially since this 60 is my only car (not a wise decision I know but yolo)

 

[Skreddy]

What is your timing set at? Are you sure it’s not spark knock? Especially if it’s occurring then going away above a certain rpm you could just be lugging it a little too much with too much advance.
Desmogged? Both vacuum advances hooked up? Vacuum leaks? Exhaust leaks?

 

[jclark]

Did you do any pre-diagnosis before doing the valve adjustment?

A clogged or failing catalytic converter causing backpressure? EGR valve stuck open (or closed)? Could it be a failing fuel pump, a clogged filter, or vapor lock?
Is your distributor on points? What is the condition of your spark plugs and ignition wires? Could they be causing misfires you are interpreting as the "bucking/struggles to run" problem?

 

[faalkinaey]

Well fuel pump is new OEM along with the filter, less than 1K miles on both, I have most of the fuel lines under the engine bay wrapped in heat wrap, don’t think it’s vapor lock cause I did have similar vapor lock issues but those issues didn’t have that prominent fluttery noise. My distributor is the GM HEI by Man-a-fre, replaced about 4 months ago, I COULD suspect that this is bad, but my only reasoning for it is because it’s not a Toyota part…. replaced my catalytic converter about 6 months ago, EGR valve bypasssd and is constantly shut closed, maybe still leaking? Spark plug and wires are less than 3 months old. I’ve gone and done about almost every tune-up routine there is, replacing all the vacuum hoses is next.

 

[faalkinaey]

What is your timing set at? Are you sure it’s not spark knock? Especially if it’s occurring then going away above a certain rpm you could just be lugging it a little too much with too much advance.
Desmogged? Both vacuum advances hooked up? Vacuum leaks? Exhaust leaks?

Timing set at 7 degrees, bb is on pointer. One vacuum hose hooked up to the HEI dizzy (no high altitude compensation anymore) other is plugged.

 

[faalkinaey]

Had a big exhaust leak at the down pipe flange, covered it with that exhaust cement stuff which seems to do well, still have a bit of air pushing through there so guess gonna run and get more cement to throw in.

 

[OSS]

The Toyota manual recommends checking the valve lash when the engine is hot and idling. Thats how I always did it - countless times over 30 years. It very easy once you've done it before.
But for some odd reason - people here check and adjust them cold. I tried doing the valves cold - and in my opinion it sucks.

One little detail the ism leaves out is that the valves are checked when the engine is hot and idling - but THE VALVES ARE ADJUSTED WHEN THE ENGINE IS OFF.

So, after the engine is hot, - remove that valve cover and re-attach the PCV hose, start the engine to idle, then slip the correct feeler gauge in between the jumping valve tappet and see how it feels while its bouncing up and down. There should be some light drag.

Remember what valves you checked, then TURN OFF THE ENGINE and make small adjustments, then turn the engine back on and check while its running again. It takes several checks & adjustments to get them all right.

 

[faalkinaey]

The Toyota manual recommends checking the valve lash when the engine is hot and idling. Thats how I always did it - countless times over 30 years. It very easy once you've done it before.
But for some odd reason - people here check and adjust them cold. I tried doing the valves cold - and in my opinion it sucks.

One little detail the ism leaves out is that the valves are checked when the engine is hot and idling - but THE VALVES ARE ADJUSTED WHEN THE ENGINE IS OFF.

So, after the engine is hot, - remove that valve cover and re-attach the PCV hose, start the engine to idle, then slip the correct feeler gauge in between the jumping valve tappet and see how it feels while its bouncing up and down. There should be some light drag.

Remember what valves you checked, then TURN OFF THE ENGINE and make small adjustments, then turn the engine back on and check while its running again. It takes several checks & adjustments to get them all right.

I’m going to try and adjust the valves the same way you do. Is there certain valves I should check first? Or no order at all? From what I understood I could basically check first 6 valves, turn off, adjust, recheck, adjust if needed, then move on to the other valves? No other steps?

 

[cps432]

The Toyota manual recommends checking the valve lash when the engine is hot and idling. Thats how I always did it - countless times over 30 years. It very easy once you've done it before.
But for some odd reason - people here check and adjust them cold. I tried doing the valves cold - and in my opinion it sucks.

One little detail the ism leaves out is that the valves are checked when the engine is hot and idling - but THE VALVES ARE ADJUSTED WHEN THE ENGINE IS OFF.

So, after the engine is hot, - remove that valve cover and re-attach the PCV hose, start the engine to idle, then slip the correct feeler gauge in between the jumping valve tappet and see how it feels while its bouncing up and down. There should be some light drag.

Remember what valves you checked, then TURN OFF THE ENGINE and make small adjustments, then turn the engine back on and check while its running again. It takes several checks & adjustments to get them all right.

When I tried to do it like that it hammered my feeler gauges to death. It also felt like I was near breaking a finger or getting pinched severely. I wish there was a video with one of you guys who do it hot and running so we could see how you do it with our own eyes.

 

[OSS]

I’m going to try and adjust the valves the same way you do. Is there certain valves I should check first? Or no order at all? From what I understood I could basically check first 6 valves, turn off, adjust, recheck, adjust if needed, then move on to the other valves? No other steps?

The way that was easiest for me, was to check the Exhaust valves first, and try to remember which ones were loose and which were tight after I shut down the engine, then adjust them and check again etc until all the exhaust valves were good, then do all the intake valves.
That way you're dealing with only one size feeler gauge at a time.
You'll need a rag handy to wipe off the feeler when you pull it out each time.

The best part about doing the valves hot & running is you can hear when the gap is too big because the valve clicks - and the clicking goes away when you slide a feeler in it.
Also you can tell when a valve is too tight because the engine doesn't idle as smooth.
And when you're all done with all the valves adjusted, you know with absolute certainty that they're all good to go.

 

[OSS]

When I tried to do it like that it hammered my feeler gauges to death. It also felt like I was near breaking a finger or getting pinched severely. I wish there was a video with one of you guys who do it hot and running so we could see how you do it with our own eyes.

Ive heard other people mention that about smashing the feeler gauge - but I never experienced that. And I was using a generic set from an autocrats store. Nothing fancy.
In fact. I used the same feeler gauge set for 20 years with countless adjustments and the two feelers (.008" and .014") were just a little bent but definitely not smashed.
I was curious about this - after reading people's comments, so I flipped the feeler over to virgin metal and then used both ends back & forth between a running valve and I couldn't feel any difference. So after 20 years of regular use- my feelers weren't worn out at all.
Maybe they were super feelers!

As for a video -
I learned how to do it before there was the internet. Its not hard. Just try it out. You'll figure it out quickly.

All you're doing is sliding a feeler gauge under the bouncing tappet and noting how the drag feels. If the feeler doesn't fit in , its too tight. If the feeler is sloppy, its too loose.

There isn't any risk to smashing a finger. The fingers are far away from the valve train

 

[DrRock]

The Toyota manual recommends checking the valve lash when the engine is hot and idling. Thats how I always did it - countless times over 30 years. It very easy once you've done it before.
But for some odd reason - people here check and adjust them cold. I tried doing the valves cold - and in my opinion it sucks.

One little detail the ism leaves out is that the valves are checked when the engine is hot and idling - but THE VALVES ARE ADJUSTED WHEN THE ENGINE IS OFF.

So, after the engine is hot, - remove that valve cover and re-attach the PCV hose, start the engine to idle, then slip the correct feeler gauge in between the jumping valve tappet and see how it feels while its bouncing up and down. There should be some light drag.

Remember what valves you checked, then TURN OFF THE ENGINE and make small adjustments, then turn the engine back on and check while it’s running again. It takes several checks & adjustments to get them all right.

This^^ So much easier to get the correct gap and saves the faff of finding TDC etc. I like to do the exhausts first, then intakes. I take a scrap piece of paper and draw this out, one diagram for exhaust, one for intake. Then I run the engine, identify the tight or loose ones by putting a “T” or “L” next to the correct valve on my diagrams, then adjust and recheck.

 

[cps432]

I wonder if feeler gauge metallurgy has taken a tumble in the past decade like many other tools of the sort.

I can visualize what you’re describing and I’ve tried it before. I ruined a set of feelers doing it so I figured it must be understanding the FSM wrong. Maybe it’s just crummy tools?

As for the danger to fingers: In my factory job we do a machine guarding audit from time to time where we ask ourselves how easy is it for someone to override the fool proofing? We have a set of criteria we check off to determine the risk factor for injury on a certain tool. I would put the risk factor for hurting yourself checking valve lash on a running engine at about an 7 out of 10. Mainly because there is no guarding what so ever and the possibility for someone to do something dumb is fairly high.

But that’s why mechanics school exists.

Edit: I meant to tag you @OSS