Recently (apparently within the last week or so), my wife's 70 SS has developed a slight knocking/ticking sound when the engine is running. The sound increases as the RPMs do. I'm not exactly sure where it is coming from. At first, I thought maybe out of the HEI itself. But it could be from the passenger-side of the engine -- possibly under the valve cover?

In any case, I'm not sure how to even start diagnosing this. Here is what I have done so far to check the HEI...

I removed all of the spark plug wires and the top cover. I then turned the engine over a few times so that the distributor would spin around -- and couldn't hear the sound. I put the cover back on and did it again -- still no sound. I then put the plug wires back on and started it up -- sound is there. So, I thought it sounded like it might be coming from the HEI -- but that doesn't appear to be the case.

Any hints on where to go next? I've never even removed the valve covers before -- should that be my next step? What is involved in doing that? Do I need to drain the engine of oil first? Do I need to buy new gaskets to have on hand to be able to put it back together?

Thanks much!

- John...

John
Take a 3 foot piece of garden hose and stick one end in your ear. It makes a great tool for chasing sounds and it's long enough so if you hit something you won't get hurt.
If the sound is a ticking around/inside the HEI cap it's a good chance that you have a bad wire. Sounds like something is hitting something else inside the cap.

Ok -- I'll give the hose a try.

So -- are you saying that having a bad spark plug wire could cause this? Maybe the ticking is an electrical noise? In any case, I'll see if I can better find the sound with the hose. Thanks.

- John...

Yeah, only heard it one time. Swore it was something like the rotor hitting the cap because it sounds almost mechanical. Not really what I would have expected arcing to sound like. The sound should be coming from inside the distributor.
Didn't mess around trying to figure out which wire it was. Just changed them all.

Agree with John. First time I heard this I could have sworn it was a lifter. HEI has enough energy jump large gaps. If the plug wire is bad enough it can't jump across and will jump inside the distributor cap and makes a sound similar to a metallic tap. Replace the wires.

I didn't have a chance to listen last night -- got home too late and didn't want to wake the neighbors. smile.gif

If I do end up changing the wires -- any comments on "wire quality" and such that I should be aware of? I'm more of a Home Theater guy -- and know, for example, that paying 3x as much for specific brands is not necessarily the better purchase! Anything special I should look for in wiresets? Specific brands to try/avoid?

Also -- I see places selling cheap (i.e. $1) "electrical lubricant" to use when putting on new wires. Good idea? Or garbage?

Thanks!

- John...

P.S. I'll let you know what I hear after I do the hose tonight...

Yes, buy the dielectric grease but I seem to pay more than a dollar for it. A little inside the boots makes them go on and off a whole lot easier.
I'll leave wire question alone 'cause not everyone likes the same ones. Just one note though. Some of the better ones you will have to install the boots on them.

Ok -- so -- I did the hose testing tonight and, unfortunately, I could not isolate the sound. It does not appear to be coming from the HEI. But, at this point, I can't really tell WHERE it is coming from.

I did learn that, once the engine warms up, the sound appears to go away -- or, at least, drop from a couple times a second to once every 20-30 seconds. That is why I couldn't really locate it -- it just got less and less frequent. I'll try some more "hosing" later this week.

On a side note, I finally found the source of another sound that has been bothering me. I've always felt like there was an extra "buzz" -- almost a static-like electrical sound. Whatever it is, it is coming directly from where the hose connects from the carb to the valve cover. I have to admit I have little idea what this is -- I assume a hose for oil to flow?

Here's a pic:

http://dcg.com/jgoggan/chevelle/24Aug2004/Valve_Cover.jpg

I'm talking about the connection in the lower-left of the image. Can you tell me more about what that is? When I put the hose near there, it is obvious that this "scratchy/static" sound is coming directly from there. Maybe it is just "normal" and is the sound of fluid flowing through it? To me, it doesn't sound like fluid -- but my wife thought it might be.

I guess I don't see how that part could sound "electical" though -- so, again, maybe I'm wrong. Feel free to fill me in!

Thanks!

- John...

Note: THAT sound is a constant, all-the-time-exactly-the-same sound -- unlike the ticking/knocking that I'm still trying to track down. Just FYI.

- John...

Originally posted by jgoggan:

On a side note, I finally found the source of another sound that has been bothering me. I've always felt like there was an extra "buzz" -- almost a static-like electrical sound. Whatever it is, it is coming directly from where the hose connects from the carb to the valve cover. I have to admit I have little idea what this is -- I assume a hose for oil to flow?

- John... Thats the PCV hose. It is NOT for oil flow and it makes noise. It reduces crankcase pressure and emissions through what is basically a controlled vacuum leak.

Maybe you have a sticky lifter. Put some Seafoam in the oil and see if that takes care of it.

Is Seafoam something I should put in, run, and then drain and replace? Or is it safe to add some and just run it that way until the nxt planned change? I just changed the oil (and had run a cleaner through as recommended by someone here) a couple hundred miles ago -- so, hopefully, I can just add some Seafoam and leave it in?

- John...

If you already used a "cleaner", did it change anything? If it was me, Id still put some Seafoam in it as per teh instructions. I THINK its a put it in and then leave it kinda deal for oil. I havent used it in the oil, BUT I have used it in gas. If it CANT free what might be a sticky lifter, then its more than likely a mechanical issue of somekind. The stuff works...One thing is you have to get it at a MOm and Pop parts store (Carquest, maybe).

http://www.seafoamsales.com/motorTuneUpTechGas.htm

Its a quick and easy start to try to isolate teh problem, like the hose trick was. It certainly wont hurt anything.

Originally posted by Buzzbomb:
If you already used a "cleaner", did it change anything?At the time I used the cleaner (couple of months ago -- beginning of summer actually), the main noise wasn't there. So, there was nothing to change.

If it was me, Id still put some Seafoam in it as per teh instructions. I THINK its a put it in and then leave it kinda deal for oil. I havent used it in the oil, BUT I have used it in gas. If it CANT free what might be a sticky lifter, then its more than likely a mechanical issue of somekind. The stuff works...One thing is you have to get it at a MOm and Pop parts store (Carquest, maybe).I grabbed some this morning. Looks like AutoZone carries it, but was out (someone bought four cans yesterday, they said). However, CarQuest had a ton of it.

I'll give it a go later this week.

- John...

Ok -- a few things...

I went to AutoZone and bought a new PCV valve. I put it on and it eliminated the "static-like" sound that I was hearing. So, it was nice to get rid of that.

I also ran about a 1/2 pint of SeaFoam in the oil (just for 20 minutes or so though -- left it in the garage). No noticeable difference with the "ticking."

However, after another long while messing with it, I was finally about to better determine where the sound was coming from using the hose. It was hard to locate because it appears to be coming from the passenger rear of the engine -- so, near cylinder #8 -- back farther than the spark plug (i.e. if I listen at the spark plug, it isn't nearly as loud as when I go back just behind the header there).

In any case, I took some low-quality video of it with my digital camera -- and it includes audio so hopefully it will help for someone else to hear it.

I am wide open for suggestions on what to do. Today, the car ran for quite a while and the sound never went away. At low idle (as it is in the recording), the sound is most audible. As I rev up the engine, the sound gets faster with the engine -- and seems to eventually go away. I'm not sure if it really does go away at higher RPM -- or if it just seems like it because of the increased noise in general...

In any case, the video is here if some people would like to take a look and have a listen -- it shows me moving in on the 8th cylinder and then trying to be just behind it -- where the sound seems loudest. It is just over 1.5MB...

http://dcg.com/jgoggan/chevelle/24Aug2004/Ticking1.mpg

Again, thanks for any tips on where to go from here!

- John...

Exhaust Leak. Cheap Header Gaskets,replace them or get them replaced. By the way,why dont you put in a Big Block since the Car is an Originall Big Block Car?
MIKE

Originally posted by L7870_cortez:
Exhaust Leak. Cheap Header Gaskets,replace them or get them replaced.Interesting. Just had the headers put on 6 weeks ago -- brand new from Summit (came with the gaskets).

However, now that I think about it -- they had trouble with ONE of the bolts because of it being stripped inside -- couldn't fully tighten it -- and now I'm thinking it was that rear bolt! Maybe it has come loose... graemlins/clonk.gif

So, if that's it... Any advice on what to do about that? Assuming the bolt hole is stripped?

By the way,why dont you put in a Big Block since the Car is an Originall Big Block Car?Simply lack of cash. I've got another thread about that somewhere actually -- whether or not to put money toward a BB or many other smaller items (I've got about $2000 to spend this winter toward the car). Pretty much ended up deciding that the BB was the way to go if I could find a way to do everything for the $2000 or so. So, depending on how my luck goes, putting in a 396 or 454 will be this winter's project! smile.gif

- John...

I am taking a good running 1971 396 350 H.P. Motor out of my 70 Chevelle in about a month. Lets just say after I completely Check it out too make sure it is in good condition It could be yours for a $1000.
MIKE

Well, that sounds like what we're probably looking for. If you were closer to Michigan, we'd probably be quite interested... Unfortunately, it probably wouldn't be feasible to ship anything like that... :(

- John...

We could work out the details on the shipping no problem. Since I am semi retired I could probably Deliver it to your Door. If interested send me an E-Mail. It is in my Profile.
MIKE

Jgoggan,

I had a 454 shipped from Ohio to Raleigh NC for about $350.

Sounds like a header leak to me.

There's a possibility that the noise is actually from an exhaust leak, but I would expect that to be more consistent than you describe. If you have headers it wouldn't hurt to check them and tighten them up a notch.

Otherwise, sounds like you might have a lifter sticking until it warms up. Post how the seafoam works out for you.

Interesting re: the HEI, I'll have to store that in my brain somewhere...