Hey everyone, my motor has been ticking for awhile, hardly noticable at idle, When I'm driving, it's only noticable when cruising at low rpm, but its louder. I've tracked it down to Cylinder 7 using my stethescope, I'm just trying to figure out what it is now. I'm thinking it might be a noisy fuel injector or a stuck lifter. I unplug the injector and I don't hear the noise, but the truck is running like such crap it's hard to tell (runs great with all 8 hooked up of course). I unplug the spark plug and the noise gets louder and more prominent. After the first of the year I'll be pulling my injectors to clean them and replace a broke pintle cap, so If it is a noisy injector, then would be the time to change it. Also if it's a noisy lifter, that would be the time to tackle that problem too.

Anyone have any ideas?

Exhaust leaks have all but been ruled out, when I put the stethescope on the lower intake, right next to the injector I can hear "tink, tink, tink, tink"

 

You can try listening to the injector itself by putting a plastic handled screw driver on the injector(if possible) and put your ear to the handle. Making sure the tip of the driver is making contact with the injector. Has to be a hard plastic handle though not a rubberized.

Also if its a lifter you could try putting some engine additive in like bardhol or some stp. Those products can sometimes help to lower the noise coming from lifters.

 

I put the stethescope I have on the injector and the sound is about the same as being on the lower intake. As far as additives go, I've tried Rislone, MMO, and Seafoam. I use MMO religously every other oil change, so I'm hoping this thing is pretty clean. It only has 76,000 miles on the entire truck too.

 

This is going to sound to simple to be true. Make sure you don't have something metallic laying against the valve spring. I had a 350 in an old C10 that we thought had a lifter ticking only to notice as we put things back together that the collar around the top of the spring had cracked and broken off and slid down the spring.

 

Tomorrow I'm going to pull the valve cover and check it out, I'll take pics for your opinions. I suppose I should be happy that it's the driver side so I don't have to pull the plenum out...and that I have those nice reusable felpro valve cover gaskets.

 

Well I have it apart right now, pulled both pushrods and rocker arms (one at a time so they dont get mixed up) and everything looks fine. Rods are nice and straight and lifters seem nice a firm. I don't know if it passes as a test or anything but when I pushed on the push rods the lifters wouldn't give at all. I did find a vacuum leak, so maybe that has something to do with it.
Pics:

 

Just got it put back together, and it runs pretty close to the same. I'm sure the vacuum leak being fixed helps, but I didn't really notice. It makes the noise when you are going up hill but still in lower rpms, so before it downshifts...If that makes any sense.

 

It almost sounds like this (around :45), mine might be a little quieter. This guy ended up having a bad exhaust gasket, but I've already changed those. I've checked the manifolds when I had them out, and there was no sign of a leak.
[youtube]6kDPzHcC43Q[/youtube]

 

Well today I retightened the exhaust, tighten spark plugs, cleaned the rotor\cap, swapped back to the original coil, and retarded the timing back to 10 degrees. The only difference I noticed was the buzzing from my MSD coil isn't there anymore. I also went nuts with the stethescope listening and unplugging basically everything (to see if there was a difference). The slight ticking I hear at idling is my injectors, for sure; I don't know if they are the same noise I hear when I'm moving or not.

The only other thing I'd like to do is run a compression check, my dad seems to think that I might have a pinhole leak out of the side of my headgasket. Of course, O-reilly doesn't rent that kit here, so I have to buy it, go figure. I'll update this thread whenever I run the check.

 

Since it sounds like an exhaust leak, I'm trying to rule out all exhaust leaks. I'm thinking the crossover tube on the back of the heads might be leaking, so I'd like to pull it off an inspect it. My Haynes doesn't have the procedure on this. I know I can get it off, but I want to make sure I know what to use as a sealant (grease\gasket?), as well as the torque specs on the bolts going into the head. Does anyone have any info on this?