Clicking,tapping noise after shutdown
 

Hopefully someone will know what this is...:eek:

I put a new set of heads on my 502's..One engine is making a clicking, tapping sound for 20 seconds after i shut it off and its coming from under the valve cover area. When it runs its smooth and has no valve train noise..It happens cold or hot..I adjusted the valves several times and set them differently to see if it made a change..Zero lash with a 1/4 turn, then i tried zero lash with a 1/2 turn, zero lash with a 3/4 turn.. I even cut up an old set of valve covers and adjusted them running .. With the valve cover and engine off i touched one of the rockers and you can feel the click..almost like something is moving still..It only lasts 10-20 seconds after shut down...
see video
Please help ??

The only thing I can think off is lifter bleed-off of oil pressure on the valves that are on the ramp of the camshaft. You could try using a oil priming tool to create pressure, the listen when you stop priming. Possibly the inner spring is contacting something or check for clearance under the rocker arm to the retainer. Is the rocker arm contact point centered on the valve tip?

Thanks..
Here's the video

http://www.youtube.com/watch?v=Lr6O4HYfEzA

I was told i didn't have to put the rocker arms and push rods back in the same spot they came from..The rockers are stock stamped steel.. Is it possible there is a wear spot and they are not sitting flush and are at an angle of some sort causing that sound after shutdown ??

Replaced the heads with exactly what was there..781 's GM Heads..The rockers have been there also nothing was changed..Your wrong about torqing the rockers..These are Gen 4 engines, not gen 5 or 6..The MPI's later models had torque down rockers and some of the HP500's. Mercruiser came out with a valve kit to change them over to adjustable rockers. The tapping/clicking happens when engine is cold or hot. It only lasts 10-20 seconds after shutdown. If it was expansion heat etc wouldn't it last longer.

Wow, thats an unusual noise. I cant say I have ever come across it before. While I dont know what it is, my opinion is that it is not a lifter bleeding down. I cant see that happening so quickly after shut down. Besides, a lifter will only bleed down when the engine is shut down while that lifter is on the lift of the cam. If this noise happens everytime you shut down, what are the chances of that being the case?
Being that a metal engine conducts sound so well, tracking down a noise like that will not be easy. I agree with you on the heat and expansion issue , it would take longer than that for things to start to cool.
I am sure you looked carefully, but maybe take a better look at the springs on that valve in question. Maybe the dampener is moving around? I am sure it would be a difficult job, but maybe you can air up that cylinder and use an overhead vlave spring compressor to remove that spring and take a close look?
Good luck with this one, I feel for you.

Vinnie, Thanks for your response...This whole situation is very unusual to me.. I have been working on engines cars and boats for over 30 years and I have never heard a noise like this, especially when the engine is off ..LOL..Based on my video..does it sound like something is going to let loose.I haven't gone for a ride this season..A bit cool still.
and I would hate to just let it blow up without researching this more...

That is a very odd noise. I have seen some crazy things but ya got me on that one. Have you been able to pin down a side of the engine? I assume only one engine is doing it. Is it only one particular side of the engine? or both? Can you tell if it is in the front or rear of the engine? Does it seem like it's in the same place every time? Does it seem like the noise is the same intensity and duration each time? Does anything make it better or worse?
Just trying to get some info so maybe we can start eliminating some things. First, lets figure out what it isn't, so then we can hone in on what it is. Good luck.
Eddie

Eddie, Great questions.. Here are some answers..
Right engine (port) did it until I re-adjusted the valves..No more noise.
Left engine adjusted valves still does it.. Noise is constant alternates left side right side..seems to be from cylinder 4 and opposite 3 to cylinder 5 opposite 6.. middle of engine..
same noise each time and same duration. I even held one rocker and felt a click...Hard to explain
Maybe its making this clicking noise all the time when running and i'm not hearing it until shut down,
maybe it doesn't get louder when reving up..like a rod knock etc.

Could this be anything to do with the new heads..The ss valves, springs, retainers were from the old set of heads.. They checked them and everything was ok..

I'm going to remove the rockers and pushrods today and see if anything is worn..

What lifters are you using? Which rockers? This will determine how much preload should be on the lifters when you set the valves.
Could there be any way the pushrods are rubbing on the head and that is the noise when the lifters bleed down? Did you check pushrod clearance in the head?
Eddie

Something on the exhaust system / header, close to the head, getting hot with only a little or restricted flow of coolant/water flow across the hot part, and when shut down, the water gets into the localized heat issue area, and cools the area down?

Crane cam, crane lifters..I did not change anything except the heads.. and I adjusted them running the last final adjustment. The only thing i did not do is put the rockers, pivots, locking nuts and pushrods back in the same original places..As for heat, cooling..it does it when the engine is cold also..engine water temp on garden hose is 125.

The new heads 781's were machined to fit my old SS valves. I don't remember the sizes but it was bigger than stock..The springs were checked, dual spring with damper
new oil seals and they said they set the closed height of the valve springs to specs ?..Cam is 560 lift..236 dur @ .50 and 114 LBA.
Thinking back..When i turned the engine manually to adjust the rockers i did notice a click sound...not positive though

I'm going to pull the plugs and remove the rockers today
turn it over by hand and see if it makes any kind of noises

pics of valves..

When you dig into it today, check the pushrods to be sure none are rubbing the head.
You should be at about 3/4" preload on the rockers. That should translate to .040-.060 of preload.
Eddie

Check pushrod clearance through the cylinder head, check the contact point of the rocker arm on the valve tip, have you verified the pushrod length is correct.

+1

This is what I am leaning towards, but still a guess. Notice how it goes from a fast tick and slows down. Similar to when you pull the car into the garage and shut it down and the exhaust may tick for a few seconds. That's what it sounds like to me. Does it do it when the boat is in the water with possibly better flow into the engines?

I haven't measured them ..I do know that the ss valves are
.100 over stock

Did you keep all the rockers and adj.piviot balls together? Also did you use assy. lube on them?

No. thats the only thing i did not do...They are all mixed/matched..They did not go back to their original places..several people told me it does not matter where they go back on

I am interested in the comp cams steel rocker with the roller tip..also new pushrods.. I do not want to change the height of the rockers due to the ease of removing the valve covers without removing the exhaust.

I would remove the rockers and make sure there is no gaulding on the pivot balls and lube them and see if the problem is still there.

I removed the valve cover and noticed the intake rocker on cylinder #2 was not sitting flush on the valve stem..I removed both intake and exhaust rockers and also noticed the pushrod was not aligned, seems like it was not centered in the pushrod hole . I loosened the rocker studs and moved the guide plates centered them over the pushrod hole and tightened again...Does this make sense?

Makes sense, but you really shouldn't be able to reposition a guide plate. The guide plate mounting holes should be the same size as the rocker stud bottom.

To check for the noise and simulate as if it was running, pull the spark plugs and disconnect the coil and turn the engine over with the starter.

There was some left/right play in the guide plates..not much.. Since i'm taking all this apart AGAIN I might as well order some new rockers

Comp Cams RP1411-16 Steel rockers with roller tip
and high energy pushrods

What do you think ??

I think the roller tip rockers are a good idea. You should measure the pushrod length to ensure the rocker tip is centered on the valve tip. Comp sells adjustable pushrods to measure the correct length, you will need two different lengths for intake and exhaust, or see if anyone has any you can borrow. The stamped rockers build alot of additional heat to the oil, the stamped rollers are a good mid-priced alternative. Centering the guide plates is also very important, yes they will move slightly. Be sure to use blue loctite and torque the studs to 55 ftlbs when they are positioned correctly. Good luck.

Everyone has given you great advice. As I was reading through the post I could not understand why you were still using stamped steel rockers. The crane golds are good, I use the comp pro magnum rockers. I would do the sharpie test and be sure you have the correct length pushrods. Like everyone said I have never heard anything like that before.

Yes everyone here has been very helpful in trying to figure out my problem. As for the steel rockers, this is what was on the motors when i bought the boat..I never had a problem with them and i like the low profile style valve covers that i can remove without removing the exhaust.
This past winter is the first time i had the engines apart.
I changed the heads because a few exhaust ports sprung a water leak.. I have older posts from last year complaining about milky oil under valve covers... This is why...water entering engine. I do know the stainless intake and exhaust valves are 100 over.. Does this mean the pushrods need to be longer? I will measure them. What measurement should they be?

The Comp Cams rockers fit under stock covers. There is a article in Hot Rod magazine on how to check pushrod length with a sharpie (marker). Do a search for it it should be easy to find. I have the link somewere, RMbuilder turned me onto it when I did a roller cam a couple of years ago. I like the oversize pushrods if you need to get new ones. you would also need bigger guide plates.

Ok, Just say my rockers aren't centered on the valve stem. Wouldn't something bad have happened by now? Last summer no noises..Changed the heads..swapped parts from old to new..now a noise..?

Foutain I had the same problem years ago check your valve to see if they are bent. What mine was doing when the the valve was open and I shut the engine off the rocker arm was out of adjustment. the valve spring was closing the valve real slow (click... tick... etc) replaced bent valve noise went away. Hope this helps.

Bent valves makes alot of sense. I assumed fresh heads meant they were assembled properly. Ass U Me d, new spelling for assumed. Good Luck.

At this point, I'd get the cheapest rocker covers you can find and cut a slot out of them so you can see what's going on in there. That way when you shut it down your can see what is creeping and making that noise.

Thats what i did ..I cut out a old valve cover and the last valve adjustment i did running..No noises, no stuck valves
everything is moving up/down smoothly..Rev the motor no noises...shut it off, put my hand on one rocker i think # 4 intake and i felt a click and on the other valve cover i heard another click, back and fourth for 15 seconds and then STOP. Engine water temp at 125F.

A bent valve, How would it run so smooth

BENT VALVES
Bent or slightly warped valves tend to hang open. A valve that hangs open not only prevents the cylinder from firing, but also is likely to be struck by the piston and bent so that it cannot seat properly. Symptoms of warped or slightly bent valves will usually show up as damage to the surface of the valve head.

Check these out ....New videos on rockers

http://www.youtube.com/watch?v=AvtnKBX6kX8

http://www.youtube.com/watch?v=SR7zFhRba4M

That movment is normal on that type of rocker after the lifter bleeds off.

I am no expert but I agree with lifter "bleed off", (with the rocker arm play), I experienanced the same thing last season. If you would like to check it remove the the distributor and prime the oiling system using a electric drill and an oil pump priming tool. You should notice that the rockers will loose thier play after they are primed and then bleed off again. This might help you isolate the tick, tick noise by priming the oil system with the drill. Good luck and please keep us posted.

Cliff

I ordered 2 sets of comp cams steel roller rockers and pushrods..The roller tip rockers will sit better on top of the valve stem..and they will fit under my stock valve covers...
Possible wear on old rockers at pushrod or valve stem end ?? This way everything will be new and then hopefully no more noise.. I hope ..

Thats good. When you put the new ones on make sure the roller of the rocker arm is centered on the valve tip. Take assembly lube or grease and coat the valve tip, then set the rocker arm in place, set the pre-load, and then remove the rocker arm. You should see a line in the grease on the valve tip, that should be centered. The pushrod length controls where the rocker tip contacts the valve. Roller rockers are sensative to proper valve tip location. Good luck.

Yea, definally check the pushrod length. Here is a article that may help you http://www.popularhotrodding.com/eng...variables.html

Good choice on the rockers, you may even pick up a couple HP and lower oil temps.

Thanks for the info.. I read the article..

The only thing is i'm not building a new motor. The parts in my new heads were parts from my old heads that were in great shape..The only thing that is new is the head castings, new head gaskets,intake etc. The only thing i did not do is keep all pivots, nuts, rockers and pushrods with the same and to the same place. So hopefully that is causing something not to seat properly when running and causing a odd noise during shutdown.

The last video showed excess movement almost like it was wobbling side to side. I realized after the lifter bleeds down you get some extra play..but not like that..It seems like the part that touches the valve stem of the rocker is worn and not sitting flush. I will check the pushrod length and make sure the roller is centered on the stem.


lets see what happens after i install the new rockers and pushrods