Mystery engine noise, hyd. lifters? Help guys...
 

Hi, factory 402BB/400TH, headers, 1970 CST/400

I posted this about a year ago and have some follow up. STILL a mystery to me, hoping someone can help please.

I am hearing a "ticking" noise in my engine compartment that I'd say sounds just like a sticky lifter. We've all heard this ticking before with hydraulic lifters... However, I recently replaced all my lifters and found a bad one (did a happy dance thinking I had it licked!) I did not change the cam. Valve adjustment done many times, timed well and sounds great. Runs great. STILL ticking. Ugh!! So annoying.
Here are some details:
1. quiet with covers off, adjusted fine, all 16 valves. quite with covers on.
2. increase ticking on acceleration, decrease on deceleration.
3. lifters new, exh. manifold gaskets new, header to muffler gasket new
4. sometimes makes no noise at all
5. hot or cold same symptoms

See pic, I've been told the low profile valve covers sometimes have clearence problems? Don't think it's speedo cable... Any ideas?

Thanks guys!!

Re: Mystery engine noise, hyd. lifters? Help guys...
 

I am subscribing to this thread. My 402 is also making a deep ticking noise. You can only hear it when the hood is up (too quiet otherwise. The motor runs great and idles smooth. I have only had it for a couple of weeks so I have not started changing out parts to diagnose but am interested in possible causes.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Mechanical fuel pump?

My antique brain sez we chased a tick over a couple of weeks (back when I was a kid) and finally discovered there was excessive clearance between the op-rod and the pump arm. As I recall, Dad had a machine-shop turn one for him that was just a little longer (or maybe he welded a button on the end and ground it to suit...I can't remember exactly). However, the tick went away.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Are you sure it is not an exhaust leak with those headers. I had the same problem with mine and put on manifolds and a new exhaust. Quiet ever since

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Fuel pump new.

Could be a rod, I did check them all too. Clearance could be an issue...

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Fuel pumps can make a hard pecki g sound just like a lifter. Exhaust leak real possibility too.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Taken a stethoscope to it? Much easier to track down odd noises with one. I was taught to use an extra-long screwdriver as a stethoscope...then I bought a special one for doing engine diagnostics when I was an A&P mechanic. Long gone...need to buy a new one. On sale this week @ Harbor Freight for $3.99!

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Do you have a mini-starter on it? I know that me and another board member had the same problem with the gear being to close to the flywheel.
It only made noise on acceleration and declaration.
It sounded like a ticking noise too.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Fuel pump was replaced, and I also think the sound is coming from the left bank. Or... maybe I am just closer to that side. I have no interior carpet, bare metal, sound travels easier from engine compartment.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

I think it is a standard starter. What's a mini? Is that the induction starter? Interesting...

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Just the aftermarket hi torque starter. I suppose any starter could do this, but I've never heard of a stock one doing it.
It was a real head scratcher for me. I was so relieved when that's all it was. I would have sworn the sound was coming from the rear of the truck. Just goes to show that sound travels and you can't ever be sure where it's coming from.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

So in your case, the starter/flywheel issue would make noise while moving? Even in neutral, theoretically?

I am rarely surprised at the "what" or "causes" of issues. Many head scratchers out there. That's why we have this site. :-)

Thanks!

Re: Mystery engine noise, hyd. lifters? Help guys...
 

A way to make sure it's not the fuel pump rod is start the motor then shut it off. While fuel lines are still hooked up, remove the fuel pump from the block, the rod will slide down. Then start the motor to see if you can still hear the ticking (it will run for a short time with the fuel that's left in the carb). At least this way you can eliminate the pump rod...:chevy:

Re: Mystery engine noise, hyd. lifters? Help guys...
 

I have seen a bunch of threads on big blocks with a "ticking" noise that's been resolved to timing issues. The ticking being heard was actually pinging.

Paul

Check and double check your header gaskets at the cylinder head. Mine is "ticking" as we speak and I just installed them.
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Re: Mystery engine noise, hyd. lifters? Help guys...
 

Agree with others, most of the time a ticking noise on a big block is from header gasket leaks. I never use those mr gaskets paper type gaskets. I only use metal gaskets nowadays.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Even though I bought some custom, thick gaskets, I am leaning towards headers being warped. This is making the most sense right now. All of these suggestions are great! My Rochester Carb leaks out gas overnight, I am thinking of going electric. That might take care of the pump situation once and for all.

Thanks.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

You've got Headers on that truck! Headers are notorious for leaks. A very small exhaust leak can, and often does, sound just like a lifter ticking. If you don't have a long (14-16 inch) screwdriver get a length of 1/4 in iron rod. Use it as a stethoscope at each header tube right at the flange, if one is louder, you just found your "tick".

Re: Mystery engine noise, hyd. lifters? Help guys...
 

No, mine only did it under load. Check out post #12 in this link. It's a video where you can hear the ticking noise I'm talking about.

http://67-72chevytrucks.com/vboard/s....php?p=5935966

Re: Mystery engine noise, hyd. lifters? Help guys...
 

For sure you need to check this, and rule it out. Also, check your pulleys, fan, and weird things that increase speed with engine rpm. Fuel pump, or rod could be the cause still since you never changed the cam. Best of luck.

Re: Mystery engine noise, hyd. lifters? Help guys...
 

Did you ever find that noise?

Re: Mystery engine noise, hyd. lifters? Help guys...
 

I'd get a set of the dead soft aluminium or copper exhaust gaskets can b pricy at 30-50dollars but they work better than anything else on the market