Hey all just rebuilt a 318 for my belvedere. the motor runs great everything is working the way it should but. I have a small tapping noise that is coming from the passenger side valve train

I am almost certain that it is coming from one of my rocker arms I believe there is a little bit of play between the rocker arm and the top of the valve. it is only one rocker arm that is sounding.

I installed .030 over length pushrods and still have the tapping.

has anyone run into this problem before?

is it possible that one lifter is just not pumping up enough to take out the play?


Just looking for any insight. It doesn't seem to effecting anything mechanically it just bugs the heck out of me.

P.S. Everything is new, lifters, valves, springs, seals, guides, with the exception of the non adjustable rocker arms and shaft.

Thanks Luke

 

Luke -

The most obvious answer is a bad lifter, but it may also be a wrong answer. Without hearing it kinda hard to tell. From my own experience, don't let a small exhaust leak trick you into thinking it's a valve train problem ...

Archer

 

Thanks i was thinking that also it does kinda have that exhaust leak sound. The only place i could think it might be would be at the collector , maybe i will pull it off and try to re set it.

I just swear i think i can hear it coming from under the valve cover i have even run the motor with the covers off and think i can hear it but it is so damn hard to narrow down.

thanks

 

do you have a mechanics stethoscope (probly spelled wrong) if you dont a long screw driver can serve as one as well. put it on the valve cover and listen to it with your ear, then around the exaust,
(pointy end down)

 

Luke -

Could be at the collector, but more likely at the head flange. It doesn't have to be a big leak to sound like a lifter. Drove me nuts for about 6 months many years ago...

Not saying that's it, just a possibility.

Archer

 

well the good new is i don't have any exhaust leak the bad news is that the tapping is still there. I am positive that the rockers are making the noise. i read in the manual that the rockers when they get worn can make a tapping noise because they are not adjustable.

The only thin i can think to do is to buy a new shaft and rockers and see if that takes care of it. I hate just throwing money at it though.

I have a set of 273 adjustable rockers but if i use them i will have to buy custom length pushrods so i have to spend money either way.

any more suggestions are welcomed,

Thanks all

Luke

 

Luke, did you try the stethoscope trick with the screw driver. This was going to be my first suggestion as well, I think it could help you.


Joe.

 

when the car fully warms up after 10-15 minutes of driving, is the noise still there?

 

The noise is still there when the car is warm and running. you can't hear it quite as much on the highway when the RPMs are up but if you mash the pedal you can hear it.

I don't have a stethoscope but I do have a broom stick that i am able to put against mt ear and listen to the different parts of the engine and i think i have it narrowed down to the third set of valves from the front on the passenger side.(#6 intake, exhaust).

Question , can you replace just one lifter at a time? , they are new lifters from the rebuild so what are the odds that one is bad. i pulled all of them and they all had oil in them and were relativley hard to push down.

what do custom length pushrods go for, if i could throw the 273 rockers on and get custom pushrods that might take care of the problem right?

Thanks

Luke

 

I had this problem when I had a motor rebuilt. Since the push rods were longer, the rocker was hitting the inside of the valve cover. Right below the breather was a "shield" I had to trim the shield.
If you remove the valve cover, does it still make the noise?

 

What cam are you running? Some of the flat tappet cams on the market have such a sharp drop off that the valves click shut. I just installed a hydraulic flat tappet cam in mine and I can hear clicking as well. Mine is a Comp cam.

 

mine is a comp cam as well , it is a pretty mild cam though,

it is definatley only on the passenger side,

I had the same thing with the valve cover happen on a 65 barracuda i had, i wish that was the case here. i have tall valve covers so no luck that it is that.

I really think that i have a lifter that is not pumping up all the way and it is giving me a little play in one or two rockers.

I am going to pull the cover tomorrow and rotate the engine over a little and see if i can narrow the loose rocker.

Has any one rebuilt a lifter before is it easy?

Thanks

 

its your fuel pump i bet, the damn things are loud, put a new on on it, and i bet the tapping will change. probably not go away but change, then yul know

 

hyd, lifters are simple to pull apart, and put back together just check for blockage

 

I can hear mine more on the drivers side toward the rear of the engine. When I sit it the car and play with the pedal I can hear it there as well through the headers. My engine runs great as well, it is also a 318 with a 340 grind cam. After researching this what I found is that the comp cams "fall off" so quickly over the nose that it lets the valves snap shut more quickly than a stock cam. There are other cams out there that do the same thing. Everything thing else is normal in regards to lifters and such so that is the only thing I can attribute it to. I'm not saying you have the same problem and it is certainly worth looking into, but I suspect that may be the issue. Mine is not loud but you can hear it with your ear closer to the engine. Keep us posted, I am curious.

 

I will keep you all informed as to what i find out.

it is definitely a more pronounced sound that just a typical valve train noise. i have pinned it down to some either exhaust to intake on the #6 cylinder , i am going to pull out the lifter clean and deconstruct them hopefully and see what i can come up with.

probabley wont get to it until the weekend so it might be a couple of days.

Thanks for all of the advise

 

Maybe a partialy plugged oil passage to the lifter in question

 

hey is your woman sitting next to you when the car is running she could be tapping her fingers on the door or foot on the ground in disgust of how much attention you give your car instead of her. mine will do that some times. lol

 

Well here is what happened, I definately had some play in one of my rocker arms. Si my thinking original rockers, maybe i should replace them with new ones, the new ones will be a fresh maybe make up some of the distance between the rocker and valve.

Soi put the new ones in and the thing begins to run like it is firing on only two cyclinders. after trying every combination of pushrod and rocker configuration i can think of, i put the old stuff back in it runs like a champ again. It stil has the tapping but at least it is running again.

The sealed power rockers i bought definetly did not do me any good.

does anyone know if they make mulitiple ratio rockers for the 318 , because these were definatley not the right ones for my set up , ut then again i have a backyard built mutt motor.

well thats the latest.

Thanks

 

i know this thread is a year old but just an fyi, i had the same issue and had to get 60 over pushrods. noise gone