Engine really knocks after leakdown

-
340Duster247

340Duster247

Well-Known Member
Joined
Dec 5, 2012
Messages
833
Reaction score
141
Location
Calgary
Well did leak down test. Put it back together. Now have really bad knock from motor
 
Really need a better discription of the noise and exactly where it's coming from. Did you pull the rockers shafts to close all the valves while testing? If so, maybe something didn't get tightened or go back where it belongs.
 
Sorry guys was outside when I posted that and frustrated.
I did my leak down test on #1,2,3 cylinders today. Made sure piston was on compression stroke all the way to the top.
Did the test and failed because air is coming out of crankcase/dip stick. (time to rebuild)
I always had lifter tick from #1,3. But after I put everything back together the noise got a whole lot worse. Clanky ticking sound. A sound that makes you turn the car off when you hear it.
I took the valve cover off on that side and seems like the rocker arm has way too much play on #3
 
I forgot to mention. While doing the test the motor did rotate backwards a couple times. I was only putting in 80-90 psi and did not expect this to happen. I'm not sure if this plays any roll in the now noisy motor
 
This is a tough one......... So just thinking out loud.......Was the air chuck you used a lot longer then a spark plug? my reasoning on this is, could it have knocked a piece of carbon off the piston top and now it's hanging a valve open a hair, which could also account for the loose rocker. I know it sounds nuts, but i'm kinda at a loss myself as to why the noise happened right after the test. I also don't believe a soft reverse rotation has caused the issue.
 
I'll give it one more shot. With the engine rotating while the engine was off, no oil pressure, and the cam rolling over the high side on the few already weak lifters, it may have pumped oil out of them and opened up too much clearence. When you restarted, did it run long enough to pump them back up and get them stabilized? Like i said, just thinking outloud.
 
Thanks oldmanrick. That is what I'm leaning towards. I ran it for around 2-3 mins I didn't wanna do anymore damage to the motor so I turned it off.
It's very bizarre that is to so much louder. I have to do a rebuild now anyways do to the results of the leak down test. ( air coming from crank case).
 
340Duster247 said:
Thanks oldmanrick. That is what I'm leaning towards. I ran it for around 2-3 mins I didn't wanna do anymore damage to the motor so I turned it off.
It's very bizarre that is to so much louder. I have to do a rebuild now anyways do to the results of the leak down test. ( air coming from crank case).
Click to expand...

You're welcome.... I don't think you did anything wrong, and if i heard the noise i would have done the same thing and shut it off....lol. Hopefully that's all it is, lifter/rocker noise. Sorry that the leakdown didn't go well. But the rings will eventually give up on all engines sooner or later.
 
Agree with OldmanRick. Backward movement of engine by hand should not harm.... Faulty - Weak lifters drained....after yourleak down. Check your oil level. Flash up the engine tell she warms up or to the sound of your orginal engine sound. Lifters should refill and be stiff. Turn off, and do a lifter check to see how fast they empty by doing a push test between the valve and the rocker using a screw-driver.
 
Maybe u bent a push rod, maybe the plunger just took a **** after u let the cup come all the way up...
Stethoscope it and listen around the lifters, also simply push on the rockers 'push rod side' to see if you can easily depress the lifter, thatll clear it right up.
 
[ame]http://i1273.photobucket.com/albums/y403/arejay642/5582919F-73B9-445C-8F36-B4972611044C-7028-0000051DBEC3BAFA_zps2c9388fa.mp4[/ame]

Here's a video of the noise. Hopefully it works.
 
The engine should not "kick-back" when you apply air. That cylinder was not at a true tdc. in that video I didn't see any indication of oil good pressure. Did you take the rocker shaft off to do the test? Is the shaft on correctly?? This wouldn't cause lifter tick but no oil pressure will. You can narrow it down to which valve it is by just touching each rocker. It'll let you know which one is sick.
 
My oil pressure gauge inside says I have great oil pressure. I explained how I did the test above in previous comments.
This sound came AFTER the leak down test.
 
You must log in or register to reply here.
-

Back
Top