engine knock after top end rebuild

[cerberusaardvark]

thats from right after i cleaned the lifters and was putting stuff back together.

 

[jd4242]

do you have a Automotive stethoscope or a long screwdriver, piece of metal pipe or something you could use to place against the valve covers and listen to it to narrow down which one is making the most noise?? Then I would just remove the valve covers..i would check to see if you can narrow it down to which one you thought was making the most noise..then take the rockers off and push the pushrods up and down.but this is gonna be very hard to tell because they still might have pressure and not move.. heads will have to come off to replace it tho.

Do you have oil psi? Might wanna check that first.cant belive I didnt ask that long time ago, just assumed you did

 

[cerberusaardvark]

im positive its coming from the lifters on the number one cylinder. it just sounds like someone tapping on the inside of the valve cover. that would make sense too because the number one cylinder is first to fire and thats when i hear the bang.

when i took apart the lifters i made sure that they all moved freely up and down. some were more stubborn that others..

hopefully that would make the smoke clear up because if one of the lifters is stuck then it means that one of the valves isnt opening right?

 

[cerberusaardvark]

also yes i have oil pressure. i know the oil gauge doesnt show the actual pressure and is more of a pass and fail type thing but its reading right in the middle the gauge.

 

[FR-425]

well i tried running it up to 1500 rpms for about 5 minutes and the noise it still there. every time the engine catches theres a hollow knock or bang that worries me.

im going to start removing stuff down to the lower intake manifold. i know i can get at the lifters without taking out the heads. hopefully i can avoid that. is there any way to spot a collapsed lifter upon sight?

When you get the lower, covers, and rockers off you can press the lifters down with the push-rod.

The lifters that are primed will not depress.

The one that is not primed will depress easily.

If the "bad" lifter returns to the top of the stroke the spring is still good.

If the spring is broke the lifter will not return or only partially return to the top. This will leave the check ball unseated.

This would be a collapsed lifter.

If the spring or check ball are fubar the lifter will never prime as the oil will just pass through with no resistance.

The spring in the lifter does not have enough force to open a valve, however at full compression it will still open the valve some. (enough to run)

The spring ensures that the lifter opens when it "falls" off the back of the cam lobe, allowing oil in under the plunger.

The spring also holds prime by holding the check ball closed during the brief moments at start up and shut down when there is no oil pressure to support the plunger, this also keeps them primed when shut down.

This image doesn't show it but there is also a check ball at the inlet hole.

When you soak the lifters you can press this side check ball in with a ball point pen or paper clip to let oil in and air out.

Definitely soak them (it) if it is still good) in 5w-30 motor oil, not ATF

ATF is good for cleaning but not so much for initial start up.

Big question: Can you prime it in place....Well maybe, If you can raise it up out of the bore high enough with the cylinder head still on to get at the inlet hole with a syringe and force oil in,, it may be possible.

The big concern here if the lifter IS ok , Is that the oil galley may be plugged and no oil is getting to that lifter.

Drag you have to do it all again , Hope this helps....

 

[cerberusaardvark]

wow super helpful information. ok, i will look for the suspect lifters. probably wont be till tomorrow until i can get down that far. im assuming its safe to re use the head gaskets? good thing i have a new set of head bolts too.

 

[jd4242]

I wouldnt re-use anything gasket or head bolts.

 

[cerberusaardvark]

i have extra head bolts and an extra set of head gaskets... but they are from titan engines and they dont look at sturdy...

would it be advisable to take off the drivers side head also and inspect the lifters on that side? or should i go straight for the problem noise?

 

[malohnes]

With all that you've done to get to one head, why not check the other and replace both gaskets with good ones. I'd scrutinize everything closely and make sure you haven't missed anything. Doing this top end tear down is a drag and while you are certainly good at it by now, it is still a pain so make the most of it.

Inspect the problem cylinder rocker and pushrod too, not just the lifter. IF you have an oil passage that is not fully plugged, you might be able to get by and clean it up by dumping all your engine oil after you have reassembled the engine and filling with 100% ATF. Run it to warm up and then let it sit for several days Then start it up a second time until warmed up and then shut off and dump the oil and filter. Replace with your brand of proper engine ol and filter, I'd suggest a quality full synthetic and Wick filter and go front here. That procedure worked well for me and it sure made a difference in my on going issues with top end noises while chasing a bad head.

 

[jd4242]

Any updates??

 

[FR-425]

Elbows deep I'm think'n

 

[cerberusaardvark]

ok some updates. just got back down to the block this evening

apart from some crud on the head gaskets, everything looked exactly the way it was when i put it together.

as for the lifters, all were primed and would not depress. i pushed hard on the rocker arms and there wasnt any play in any of them, which is a relief, but also frustrating because i can see anything to fix.

i looked closely at the rocker arm mounting tabs and found no work metal nor any free floating particulates anywhere within the valve cover.

the bottoms of the heads were pretty clean, and the spark plug tips are looking nice and shiny.

the only thing i found that was unusual is that one of the drivers side exhaust bolts from the manifold to the y pipe was pretty loose. i suppose the smoke could have been leaking from there.

no fluid in any of the vacuum lines anywhere.

no leaks that i could see as well.

is it advisable to take the lifters apart and clean them again? or is being all primed and rock hard an indication that they are functional?

all i had done the first time was take off the plastic guide cap and use a brake cleaner straw in the check hole to blow out the top cup. i left the rest of the lifter in there marinating.

none of the gaskets were damaged, scorched, scratched, or unseemly.

the one thing that did bother me was how loosely the lower intake manifold seems to sit on the block. when i took it off the first time it was like pulling teeth. then when i looked at my beads of permatex on the sealing surfaces i could tell they hadnt squished down far. ill get some pics up later

 

[cerberusaardvark]

also, there was not fluid or metal in the cylinder bores. apart from dirty oil , nothing looked out of the ordinary.

are there any regulators or doodads that could fail and produce flucuations in the fluid or vacuum systems? i talking little things like the fuel pressure regulator (which i replaced) egr tube, any of the intake sensors, etc that often go overlooked that are easy to get at with everything off?

 

[jd4242]

You didnt put a cam in did you?you sure you had it at tdc and timing marks aligned?
Very strange, im stumped

 

[cerberusaardvark]

no, same cam. when i took off the timing gear not only did i make sure the cam and the crank were aligned, i realized it was impossible to put the timing gear on wrong because there is an alignment tab on the end of the cam itself to make the gear sit where the old one was. i did make sure to align the tabs of the crank and timing gear before taking the old one off so it should have been good.

i got some good advice on putting the oil in before replacing the lower intake manifold, and slopping it on the cam and lifters, so maybe something was just dried out.

is there a sensor or computer that could be fried thats causing deregulation?

 

[jd4242]

Man I dont know im outa ideas

 

[cerberusaardvark]

jd how do you feel about re cleaning the lifters? or should i let them stay fully primed?

 

[jd4242]

They will bleed down but if they were full when you took them out they should be fine.its when they are collapsed or stuck in the down position that they make noise.re cleaning them wouldnt hurt but probably a waste of time.

 

[cerberusaardvark]

ill just drown them in oil then. is it possible for a lifter to get stuck in the up position? just wondering.

 

[jd4242]

It is possible but not typically in a engine, the springs usually have enough force to push it down.even if it does it should act like a solid lifter.the max spec on the lifter plus the rod should still allow the valve to close.it shouldnt make noise if so, it when they get stuck down and the rocker smacks the valve. One thing maybe to check is that the lifter moves freely in the bore.I have seen them be very tight and will smack the cam after the top of the lobe