Have you checked to see if you have a spark plug boot not on he plug. I had one make a ticking noise and when I pushed it on it went away. If your headers are new, remove them and take a big file and file them flat, use a long straight edge to check for high and low areas, you'd be surprised how bad most header flanged are. Pull the headers, the gastes really show where your leaks are.
I am having the same issue 66flaresid execpt I got about 40 miles on my rebuild. Mine sounds more like a knock and I'm afraid that it is a bad rod. You don't know how bad I would like this to be a lifter problem and I will be watching this thread. I am changing jobs so I have no place yet to work on it.
I actually did replace the header gasket today, are you are right, you could see exactly where the leak waqs by the black marks. Which is why I got so excited thinking a new gasket would fix it. After replacing it, it sounded the same. I think the leaks where from when I had a few during break in.Which I fixed by loosening all bolts and tightening them from the inside two sets and working my way out. Than all leaks were quiet. Untill this. Today I also stuck a feeler gauge between the rocker and valve of the suspicious sound and It did not change a bit. I also am afraid It might be something more serious than just a valve train issue or an exhaust leak. I am going to probably pull off the rocker shaft and clean it out, hoping that there is a clog. I cleaned them before I installed them, but never blew them out with air. I just soaked the entire assembly in solvent, and cleaned under the rocker by sliding it over on the shaft. So I'm hoping that will fix it and it's just an oiling problem. However, I don't really think it will, givin just how loud it is. So we'll see on monday when I get back in town and go from there. Thanks to everyone who chimed in. I once again got alot of good info. I will post again on monday evening.
It is really hard to tell. It sounds like it's coming from a rocker on that same #3 cylinder. I noticed that same rocker is not getting as much oil and the push rod is not spinning. could that be it?
I would not use MMO in a new engine. You should also still be using some type of oil with high Zinc content, or one of the aftermarket oil additives for older engines. Rotella is not what it used to be for Zinc content.
II think before you remove the rocker shafts, put each lifter on the base circle of the cam them rock the rocker, you should have a little springing feeling, if its really loose, like you could almost remove the push rod, then you likely have a bad lifter, rocker, or wrong pushrods.
Were your heads and/or block milled during the rebuild process? If so you might need to shim up your rocker stands.
I would be careful putting shims under the rocker and valve tip, this could over preload the lifter and wipe out the cam lobe.
My 340 in my dart made a tapping noise and the #1 intake lifter was wiped out, the motor has less than 10 miles on it. Even though we broke it in properly, the rocker was just too tight. But I have adjustable rockers.
One note, if your heads were rebuilt and/or you put a larger cam in it, you could have a situation were the valve spring retainer is hitting the guide. Check for bent pushrods. If you do as suggested on walking though and checking for bad lifter, look at how much clearance you have between the retainer and guide. Could have one jut too long.
I don't have any slop in the lifter when that cylinder is at tdc. Thats a good idea about thru the distributor hole. If I can get it out, could I put a new one right in without damaging the cam? If I can than I will try that tomorrow and report back
The fact that the pushrod is not rotating is telling. That particular lifter is not sitting at an angle to the lobe, or the lobe is not canted or there is no clearance. The pushrods rotate because the lifters rotate. The lifters rotate because they sit askance the cam lobes. If this lifter had too much preload, as in there was no clearance internal to the lifter when on the heel of the cam, it would not rotate. Other than that, the lobe or cam are not angled correctly.
If the lifer face is bad then the cam lobe is bad. If the lifter is not spinning in the bore, there is an issue with it being over preloaded. One thing, what carb are you running? I've seen situations were too big or over fueling on break in washes the prelube and will eat a cam.
I am running a 600 cfm vaccum seconday carb. the plugs look great.
I don't know if the heads were milled during rebuild. but it's all about the #3 cylinder. everything else sounds nice and quite.
o'k, so I was able (after some cursing) to fish out both lifters from the #3 cylinder. The exhaust side was the side that was not rotating, buy the way. And that exhaust lifter definatly had wear marks on it that indicated it had NEVER spun. the wear marks were in a straight line, from front to back, where as the intake lifter was evenly worn all around the base of the lifter. So i'm thinking cool. I check the pushrods for straightness, even compare the length to neighboring pushrods and all looks well. I replace the two lifters, fire it up and SAME!
SAME exact sound. which is still quieter at idle, and then very loud as soon as the rpms go up. And it seems less loud when under load. but when you just rev up the rpms with it in neutral, it is very loud. And the worse part is, that I slid under it just to check the header gaskets, and it is much louder under the truck, than it is on top of. this can't be good.
can a wiped cam lobe cause this much racket in the bottom of the engine?
how do I just for a bad rod bearing or wrist pin! I'm starting to think bad thoughts........