Technical Tapping noise is driving me nuts !!

I've been building this truck for the last 3-4 years, driving it for 2 years with open lakes headers. I recently had a complete exhaust system installed and now I am hearing a lifter tapping noise.
SBC 383 with Babe Erson cam and hydraulic lifters. I've readjusted the lifters, lash + 3/4, no difference. I was wanting to post a video so you could hear it but I don't see how. Anyway it runs Great !!
Any ideas ?????????????

 

could be a fuel pump rod if you have a mechanical pump.

 

Just thinking. Might have a exhaust leak? Check all your fasteners


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Turn up the radio.

 

exhaust rattle.

You would be surprised what sounds like engine noise. My pal had some wheels in the trunk and they would get into a cadence at certain rpm. He thought he had a rod knock!

 

like the others said.... check for exhaust leak where the headers join the head. Sounds exactly like lifter noise. If it's bad you can just move your hand around the header flanges and feel air pumping out and past. I have been battling it myself with a shitty set of hooker headers that never sealed up right. Probably warped. Finally gave up and just used copper high temp RTV with a new gasket. So far so good.

 

Had a friend chase a tapping noise for a long time. Turned out to be a torque convertor bolt had loosened up!
Hope you find it soon.
KK

 

Cracked flexplate?

 

REAL LOUD !!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

use a few feet of garden or heater hose as a stethoscope, to see if you can figure out where it's coming from.

 

Fuel pump

 

I fought a lifter noise on my model A (blown SBC) for about 6 months had it nailed down to # 4 or 6 I had readjusted the valves numerous times swapped all the roller rocker from the left bank to the right. You name it I tried it. figured it was a bad lifter.
So I picked up another set of heads (better) and had them at the machine shop just driving it and ignoring it,
I figure when I replaced the heads I would replace the lifter and inspect the cam. Driving home from work It let go the valve stem seal came off the worn out exhaust guide that was the noise.
Since the heads did not have 2000 miles on the since the overhaul I took them to my machinist and said wtf?
Got the run around from him but he fixed it for free. There was no smoke from the exhaust until that seal pulled off ! When it did oh boy!!!

Loose guide sounds just like a lifter. Andy

 

might be that 1/2 inch wrench lost in the valley like in a friend of mines car

 

Great suggestion. I always use this trick to find a noise I can't figure out.

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A cracked flexplate can make an infuriatingly difficult sound to trace.

I have known people who have discovered this, when pulling the engine to replace it, thinking that they had an incurable knock.

It starts as a tick, but gets worse over time.

 

just hope its not a pair of channel locks like my uncle found twisted up around a 409 crank

 

Here is a picture of my '29 pickup that's making the tapping noise ! I have a good video that you can hear the tapping very well but I don't know how to post it.

 

Most likely the fuel pump. Check it with the hose or get a cheap Stethoscope.
I chased the same problem for 2 days until someone told me to check the fuel pump and it was the problem.
Turns out the pump arm gets loose on the pivot over time and clicks when the arm moves back and forth.

 

upload the video to youtube, then post the link to the video here.

 

I had a counter weight come loose from a vented rotor and hit against the caliper drove me nuts trying to find it.

 

Lash +3/4 turn is too much preload. Most people use lash +1/2 turn. A lot of people use lash +1/4 turn. I know the chiltons books say 3/4, they're wrong.

 

....and Chilton got the 3/4 turn number from the original Chevy service manual. It works just fine.

 

Been there - done that. Mine was cracked flex plate. Very difficult to diagnose. Apparently the crack allowed the flex plate to deform just enough to touch the housing. Clearances in there must be very close. One I got it all apart I could see where the housing had been "tapped". My engine is a 400 and I was told that the 400 engines are much more susceptible to this kind of failure. Don't know why.

 

I don't know much about chevys knocking, but I've been hearing an odd squeaking noise, then the doctor took an x-ray. Crap, now what!

 

I'm surprised that you can hear anything at all after driving that long with open lakes headers.

The saving grace for your hearing was that you likely didn't do a lot of hours or miles in the truck during that time.

Not sure what the tapping might be but you have been given some good ideas of where to look.

 

I'm still learning how to link stuff but this is the youtube link if you would like to use and hear my pickup !!
http://Tappingnoisedrives menuts!:http://youtube

 

Link does not work. Load your YouTube video, and while it's playing, highlight and copy the web address.
Paste that into your post and it will work.
Like this :


To me that sounds like an exhaust leak.

 

Tapping noise is a understatement!

I was going to say exhaust but after hearing the video that is a loud knock! HRP

 

Thanks Blue One for doing that!! I'm trying to learn how to do this stuff from a smart phone. Anyway what you say makes alot of sense. I know the guy that built my exhaust system had the headers off several times. The down pipes are welded to the headers to hide them and don't come apart until the mufflers. You would think being an exhaust specialist he would have caught a leak!
The thing is though that when you listen with a stethoscope the tapping sounds like it's coming from above the valve cover on the left side about the 3rd cylinder back. I did check the rocker clearance to the value cover.

 

If you have the Lisle or a similar stethoscope, take the rod attachment off and just use the tube to listen around the header connections. Start from a ways away because it could hurt your ears.