Looking for knocking noise driver side

[wahya]

I recently installed a new carb and while I was running the motor, a noise, like a knocking, but a bit of a lighter pitch. It kind of sounded like the same sound when I tapped on one of the pipes on my headers. The only other thing I did recently was change my oil. I had been running Valvolene 20w50 racing oil with zinc. I found out that my local store had straight 30 weight Valvolene. I'm running solid lifters.
BTW, I am using my old 318, now ported with larger valves, heads. The motor was built about ten years or so ago.
I decided to pull the driver side valve cover and while looking at the rocker arms, I noticed that by moving a few of the arms, without pressure on them, from side to side made about the same sound. I don't know if the running engine would cause this sideways motion, but, it looks like these arms are going to need attention, as I think I have found a crack in one of them.

 

[pnora]

You are not running solid lifters with those rocker arms.

 

[eldubb440]

id disconnect one plug at a time and rule out a header leak

I also once had an exhaust leak at the cross over

 

[wahya]

You are not running solid lifters with those rocker arms.

So, living on borrowed time here, or the guy told me wrong? He said he was building it with flat tappet cam and solid lifters and he told me that I would have to use zinc additive or I wouldn't get far. Would having these non adjustable arms cause some of these arms to appear to be shaped differently. I have not taken these covers off before.

 

[Bird 426]

Yeah, you are not running solid lifters with those rocker arms. As for the noise, usually if one of the pictured rocker arms fail, a pushrod blows through the cup. Are you sure that something didn't get dropped in the intake when changing the carb? All fasteners accounted for? Those should be stamping marks on the rockers that look like cracks. Yes, they can probably move side to side if unloaded. The rockers are left and right accordingly.

 

[wahya]

id disconnect one plug at a time and rule out a header leak

I also once had an exhaust leak at the cross over

I've got new gaskets coming today. I tried just spinning motor without starting it and started to make a mess.

 

[wahya]

Yeah, you are not running solid lifters with those rocker arms. As for the noise, usually if one of the pictured rocker arms fail, a pushrod blows through the cup. Are you sure that something didn't get dropped in the intake when changing the carb? All fasteners accounted for? Those should be stamping marks on the rockers that look like cracks. Yes, they can probably move side to side if unloaded. The rockers are left and right accordingly.

Pretty careful with covering intake after carb removal. Never say never though.

 

[pnora]

So, living on borrowed time here, or the guy told me wrong? He said he was building it with flat tappet cam and solid lifters and he told me that I would have to use zinc additive or I wouldn't get far. Would having these non adjustable arms cause some of these arms to appear to be shaped differently. I have not taken these covers off before.

If you had solid lifters with that valve train it most likely would not run. Valves would be severely out of wack and either be hanging open or rattling like hell.

 

[coloradodave]

You are not running solid lifters with those rocker arms.

You are a sharp guy! Good call...

 

[dadsbee]

Drain the oil and switch back to what you were using.. noise gone?

 

[wahya]

Maybe so.

 

[Geoff 2]

The mark in post #1 is most likely a forging mark.....not a crack. These rockers are much stronger than many people give them credit for, & I doubt the rockers are causing the problem. As long adjustable prods are used to adjust lash, there is NO problem using those rockers.

I suspect you might have the dreaded lobe/lifter failure. Check the lash on each rocker & look for excessive lash.

 

[1 Wild R/T]

When you pulled the carb did you exchange it? Put the same one back on? What kind of carb was it? Any chance one of the screws securing the base plate to the carb body had come loose & is now missing? Twice in my years working on cars I've removed a carb & one of the base plate screws fell down the intake as the carb was being removed... If you're not aware it's easy to miss & if you miss it soon after starting the engine you are gonna had a knocking noise....

 

[wahya]

When you pulled the carb did you exchange it? Put the same one back on? What kind of carb was it? Any chance one of the screws securing the base plate to the carb body had come loose & is now missing? Twice in my years working on cars I've removed a carb & one of the base plate screws fell down the intake as the carb was being removed... If you're not aware it's easy to miss & if you miss it soon after starting the engine you are gonna had a knocking noise....

I finally took off my leaky TQ and installed a Street demon. I don’t think anything dropped. Changed around a couple screws and carefully put masking tape on first. Wife’s picking up my gaskets today and I may get after it this afternoon after taking the kids fishing.

 

[1 Wild R/T]

I finally took off my leaky TQ and installed a Street demon. I don’t think anything dropped. Changed around a couple screws and carefully put masking tape on first. Wife’s picking up my gaskets today and I may get after it this afternoon after taking the kids fishing.

Take a look at the bottom of the thermoquad, so if any screws are missing

 

[Don selleck]

oil, IMO. I did the thinner oil thing in the 90's in a well used 340, sounded like it was coming apart, put some royal purple 50w range I believe, quieted it right down.

 

[wahya]

I put some marvel mystery oil in my 318 years ago and it really loosened things up. Drained it out and put my regular oil back in and I do believe it ran a lot better.
About checking the bottom of the tq. I checked that and no missing parts, but I did not see the small bolt for the spring choke. I went back to the motor make sure it wasn’t down in the hole and found something else. I’m going to wait until I get my valve cover back on and start it before I’m confident that I found the problem.

 

[Geoff 2]

All the screws holding the TQ together are top down. None in the base.

 

[wahya]

Update:
So, when I put my hand near the intake, I happened to brush a hose from the breather to the air cleaner and there was a sound just like what I was hearing. The metal connector to the cleaner base was loose, apparently from when we were working on the carb. I put everything back together and no noise, that is until the motor warmed up a bit. Noise back again, oh no! I took my wrench and started probing at different places and then, when I touched one of the header pipes, I thought I felt it. I kind of jammed the wrench between where the pipes come together and noise gone. The bolts are tight. I don’t know, maybe a bad weld. Guess I have to get car on a lift. Appreciate all the help and I found out a few things. I was about to start digging into what kind of lifters I have for sure, but decided no, I will just take the word of experienced people here and leave it alone.

 

[RemCharger]

id disconnect one plug at a time and rule out a header leak

I also once had an exhaust leak at the cross over

Sounds like we possibly have a winner. People need to read the replies to their questions.