I havea 69 360 and when it is idling there is a tapping noise. I know it is not a rod knock because that is much louder and I don't think that it is a rocker arm because when I rev the engine the sound goes away and with loose rockers the tapping usualy just goes faster when the engine is reved right? What does a bad lifter sound like? Its hard to tell where exactly the sound is coming from and it actually sounds like it may just be from the fan or the pulley. Its not really that loud and there is only one thing tapping not multiple things.

Also when replacing all of the intake manifold gaskets should I use any sealant. Does anyone know the torque specs for the manifold bolts.
thanks
brad

 

>I havea 69 360 and when it is idling there is a tapping
>noise. I know it is not a rod knock because that is much
>louder and I don't think that it is a rocker arm because
>when I rev the engine the sound goes away and with loose
>rockers the tapping usualy just goes faster when the engine
>is reved right? What does a bad lifter sound like? Its hard
>to tell where exactly the sound is coming from and it
>actually sounds like it may just be from the fan or the
>pulley. Its not really that loud and there is only one thing
>tapping not multiple things.
>
>Also when replacing all of the intake manifold gaskets
>should I use any sealant. Does anyone know the torque specs
>for the manifold bolts.
>thanks
>brad

Hey Brad- 32-35 ft. lbs. on the torque for the intake manifold. As far as sealant, I use high temp silicone- I find it to be the best on anything that is not in direct contact with fuel. As far as sealing the intake, I always circle the coolant ports, dob some in the corners, and place a solid bead in the front and the back about 1/2" thick. I don't use those gaskets because they always leak a couple hundred miles down the road.

As far as the tick, without hearing it for myself, I'll almost bet you it's an exhaust leak. If it is faint, but noticable and goes away or gets quieter at higher RPM's, it's an exhaust leak. If it's loud like a lifter tap but goes away at higher RPM's, it may be a lifter bleeding down.

To check for an exhaust leak, use a piece of vacuum hose long enough to place one end in your ear and move the other end along the exhaust manifold gaskets (at the block and the donut gasket) and I garantee you will hear it when you find it. Don't worry- it won't hurt your ear, but there won't be any doubt.

Good luck!

Joe

 

So you suggest that when I reinstall my manifold that I not use any gaskets only sealant? I do have some exhaust leaks but they make their own noise. This tapping is a little louder than the exhaust leaks and if I remember correctly the tapping started either after I replaced the alternator or when I pulled the front cover so that is why I was leaning toward the possibility of it being the fan or pulley or something. But I can't see anywhere that metal is contacting metal within the fan belt system. I just found it odd that the tapping goes away when I give it gas. If it is a noisey lifter will it be as loud as a rod knock and should I be sure to replace it or is it not too big of a deal.
thanks for your response
brad

 

Use the two gaskets running across the ports on the heads, but don't use the small ones across the front and rear of the valley. Just make sure the bead of silicone is tall enough to make up for the gap.

I've heard exhaust leaks that were louder than lifters (and they did tick, too)- it's easier to check for an exhaust leak that it is to check for a bad lifter. Cheaper and easier to fix, too. If a lifter is noisy, you have to diagnose why it's noisy: bent rod, worn rocker, lifter itself, or flat cam. Worn valve guides can also give you a tick.

The only thing I can think of on the front of the engine is the cam button on the inside of the cover. Did it fall out when you pulled the cover? Did you make sure the spring wasn't broken? A stock fan with rivets holding the blades on may be coming abart at the rivets. Those are some other things to check. Cracked brackets can make a ticking sound, also, due to vibration.

Can be overwhelming sometimes- best thing to do is just tackle it using the process of ellimination. Just one step at a time.

Good Luck-

Joe

 

I just went outside and messed with the truck. I discovered that when cold the ticking will go up with the rpm but after being driven and warmed up the ticking does not get louder with the rpm going up but its still there at idle. I also removed the belt and started the engine. the ticking was still there. Maybe the exhaust ticks have gotten louder. I can see where the previouse owner tried to patch the exhaust manifold with some stuff. What should I use to to repatch the manifolds? And on those gaskets again when I put on the head to manifold gaskets should I put them on without sealant?
thanks again
brad

 

If you have an exhaust manifold that's cracked or cracking, it's best to replace it. I've heard of people having good luck having someone use some cast iron welding rod to seal it up, but that all depends on how far gone your manifolds are. If the sealing surface is rounded out due to leakage, I've had luck with using 2 gaskets on each manifold with silicone in between all the surfaces.

>>And on those gaskets again when I put on the head to manifold gaskets should I put them on without sealant?<<

I use sealant around the coolant passages only. If you use it around the intake and exhaust passages, the silicone that squeezes out will create a restriction in airflow through these passages.

Good luck-

Joe