Knocking but not bent valves
#1
Knocking but not bent valves
Bumping the engine with the starter to line crank up with cam sprocket and bent two valves slightly.
Sounded like loose valves, but no matter how I adjusted them the sound did not change. Took the truck to two pro mechanics before we figured it out.
Question is, should I just drive it; or park and fix asap?
One mechanic said drive it. The other said it might break and fubar the head.
Any experience in this problem out there?
It runs Great!
Sounded like loose valves, but no matter how I adjusted them the sound did not change. Took the truck to two pro mechanics before we figured it out.
Question is, should I just drive it; or park and fix asap?
One mechanic said drive it. The other said it might break and fubar the head.
Any experience in this problem out there?
It runs Great!
#2
What? No way!
For one thing I don't care who you took it to, you cannot diagnose a bent valve stem without removing it from the engine. Unless you're Superman and have x-ray vision. Not too mention the fact that it's so extremely unlikely to have happened to any valve in any circumstance. Let alone cold valves in a cold engine. There's just no way in hell, to put it bluntly. If anything the guides were slightly damaged somehow. But I'm not believing that either.
If all you're going by is an unfamiliar sound, forget about it. You're hearing things that aren't probably even related to the valves. Even if they are, the sounds are probably what you would normally expect to hear from that particular motor. Which I'm gonna assume is that clickity-clacking 22RE right?
If that's the case then there's nothing to worry about IMO. If it's running fine, drive it.
For one thing I don't care who you took it to, you cannot diagnose a bent valve stem without removing it from the engine. Unless you're Superman and have x-ray vision. Not too mention the fact that it's so extremely unlikely to have happened to any valve in any circumstance. Let alone cold valves in a cold engine. There's just no way in hell, to put it bluntly. If anything the guides were slightly damaged somehow. But I'm not believing that either.
If all you're going by is an unfamiliar sound, forget about it. You're hearing things that aren't probably even related to the valves. Even if they are, the sounds are probably what you would normally expect to hear from that particular motor. Which I'm gonna assume is that clickity-clacking 22RE right?
If that's the case then there's nothing to worry about IMO. If it's running fine, drive it.
#4
Contributing Member
So I take it the timing chain was off?
Have you checked compression? If it were me, I'd fix it. I don't think you're going to damage anything you haven't already if you drive it, but you should notice a loss in performance if you've really got bent valves.
I bought my FJ40 with a bent valve and the thing ran like poop! Once I took the head off and got it replaced, it was a huge difference in power.
Have you checked compression? If it were me, I'd fix it. I don't think you're going to damage anything you haven't already if you drive it, but you should notice a loss in performance if you've really got bent valves.
I bought my FJ40 with a bent valve and the thing ran like poop! Once I took the head off and got it replaced, it was a huge difference in power.
#5
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check the compression; you should do that, well, anyway.
If you bent a valve your emissions will be in the tank; you might not care, but some of the rest of us do.
My understanding is that all 2nd gen pickups have a non-interference engine. Turning the crank in an Accord with a broken timing belt will bend the open valves, but not in our trucks. So I'm not sure I could figure out how you could have bent a valve anyway.
If you bent a valve your emissions will be in the tank; you might not care, but some of the rest of us do.
My understanding is that all 2nd gen pickups have a non-interference engine. Turning the crank in an Accord with a broken timing belt will bend the open valves, but not in our trucks. So I'm not sure I could figure out how you could have bent a valve anyway.
#6
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#8
Registered User
but it's closer to an non-interference engine. Lots of things have to go wrong for those valves to really hit the pistons. I don't know if the tall deck motors were easier to hit than the shorter ones though. No one really mentions it.
#9
Contributing Member
All that matters is the 22-RE is an interference engine, it's degree of interference is unimportant. If the OP has a 22-RE, it's possible he bent a valve when he cranked the motor over if a valve was open. If he has a 3VZ-E, it's impossible.
#10
Registered User
there was a thread on here a while ago, explaining how hard it is to actually hit those valves and the fact it is extremely rare, what it comes down to is how he and these "mechanics" came to the conclusion he has bent valves. Did they do a compression check, did they do a leak down check, etc etc.
In technical terms the 22r's are interference but because of the physical length of the valves and the fact the head's cyl chambers are not flat, added to the fact the flat top pistons have valve reliefs in them it is extremely difficult to get the valves to hit the pistons unless the head and/or blocks are drastically shaved down.
In technical terms the 22r's are interference but because of the physical length of the valves and the fact the head's cyl chambers are not flat, added to the fact the flat top pistons have valve reliefs in them it is extremely difficult to get the valves to hit the pistons unless the head and/or blocks are drastically shaved down.
Last edited by xxxtreme22r; 11-10-2010 at 10:47 AM.
#11
Possible he bent a valve? Possibly I suppose. But not any more likely than damaging a piston, rod bearing, rocker arm(or any combination of which)in the process too, or instead of, though. Considering the valve is going to be constructed of the hardest, least bendable, material in comparison to any of those(if they were stock), then I'd say it's less likely. If so then the likelyhood of the engine running "great" afterwards is diminishing quickly. So I still highly doubt it.
"mechanics" indeed! Better yet "pro mechanics"!
Last edited by MudHippy; 11-10-2010 at 04:55 PM.
#13
Knock knock!
22re 1990
I have a knock that I can plainly hear when I am driving. It sounds just like a loose valve only a bit louder. It increases in frequency with rpms. It is not a bent valve and it is not a rod bearing. It is much higher pitched than a rod bearing. I have adjusted the valves at least 8 times and it makes no difference. With a stethoscope the sound is loudest at the exhaust manifold. I searched for a leak there and all down the exhaust and can find nothing. I can't hear it with the scope at the valve cover because the valve noise drowns it out. I can barely hear it from the bottom of the block. Other than that the truck runs great.
The noise seems loudest at 1500 rpms. I believe it increases in frequency above that so that it just blends in with sound of the motor. At idle it is noticeable but just barely.
As I said, the knock is the most noticeable when behind the wheel. If I turn on the air or heater, I cannot hear it. It's harder to hear when outside the car. Makes no difference if the truck is in gear.
Any ideas? Wrist pin?
I have a knock that I can plainly hear when I am driving. It sounds just like a loose valve only a bit louder. It increases in frequency with rpms. It is not a bent valve and it is not a rod bearing. It is much higher pitched than a rod bearing. I have adjusted the valves at least 8 times and it makes no difference. With a stethoscope the sound is loudest at the exhaust manifold. I searched for a leak there and all down the exhaust and can find nothing. I can't hear it with the scope at the valve cover because the valve noise drowns it out. I can barely hear it from the bottom of the block. Other than that the truck runs great.
The noise seems loudest at 1500 rpms. I believe it increases in frequency above that so that it just blends in with sound of the motor. At idle it is noticeable but just barely.
As I said, the knock is the most noticeable when behind the wheel. If I turn on the air or heater, I cannot hear it. It's harder to hear when outside the car. Makes no difference if the truck is in gear.
Any ideas? Wrist pin?
#16
Registered User
I have said this at least once on here and I will say it again, How can we diagnose a sound accurately on here without no sound? Get yourself a video of this. And put it up.
#17
Sounds like what I just went threw turned out I had a spun bearing and my crank journals were worn out. Someone tried to fix it by replacing a rod cap without pulling motor.....bad idea!!!
#19
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Knocking engine
I am having the same problem with my truck. Do you lose speed going up hills? I would also like to know how to solve this problem before I go getting work done or buying a newer engine.
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