Peter Olson

My engine is experiencing a ticking noise that I am including a video link to.
I am fairly new to engine work but decided to rebuild an engine. I have a 1985 IROC that had a 305. I took a used 350 had it inspected and cleaned, I replaced all the internals, put summit racing heads, cam, and intake on and a edelbrock carb. I replaced the distributor with a vac advance distributor. It starts right up, but I get a ticking sound that varies with RPM that I am having trouble diagnosing. I checked the tightness on the rockers and the ignition timing. All cylinders have decent compression at about 170#. My thoughts right now are bad lifter, but if that's what it is how do you determine which one is bad? Any suggestions are welcome. Thanks.

midias

Have you adjusted all rockers with the engine running?

NoEmissions84TA

iTrader: (1)

If you are really lucky, an exhaust leak can sound just like a lifter tick.
Put one end of a 3 foot length of vacuum line in your ear and probe around with the other end.
You won't believe how this can isolate sounds / noises.
Be careful of rotating and hot parts when doing this!

Peter Olson

@midias No not while running, I watched a lot of videos of different ways to do it, and decided to just adjust them the way it tells you to in the service manual by rotating the engine and doing each valve separately. I took rockers back off and checked pushrods and retightened rockers, noise stayed in the same spot, so I think its probably something else but don't want to rule out anything.

Peter Olson

@NoEmissions84TA , I'll give that a try. after reading some threads here I'm hoping its just a loose exhaust manifold.

midias

Because things tend to loosen up when hot I like to do the rotate method and then after do a hot adjustment were you back it off a little bit till it starts making noise and tighten it back down again

Peter Olson

I've checked all the bolts tight on the exhaust manifold, noting loose and noise still present. I ordered a batch of hydraulic lifters to replace the passenger side ones, so Ill update the thread when those get in.

NoEmissions84TA

iTrader: (1)

Your chances of that working are very slim unless your camshaft is a roller. If it's a flat tappet, you will end up creating 8 lathes, each cutting down the lobes where you put the new lifters. And all of that shrapnel is going to circulate throughout the engine - destroying everything else.
Look at the pic below - ZERO rotation. This is what happens with a new lifter on a used camshaft lobe. No rotation equals rounded cam lobes.

NoEmissions84TA

iTrader: (1)

Peter Olson

Ok, I did the hot adjustment while running that was recommended, and found the noise was coming from the exhaust on #6. When i tightened it down the noise went away. I went back and readjusted all the valves with the engine running, giving them an extra 1/2-3/4 turn when the noise stopped as discussed in many youtube videos. After turning engine off and turning back on again, i get the ticking again from the same spot, so I readjust that one again and it goes away. I took the car for a drive today and It sounds great except periodically during the drive I got the ticking again from the same cylinder. Do you guys think I should just give the full one turn on the rocker arm nut after zero lash or does this sound like I have another issue? Thanks for all the help and advice.

TransamGTA350

iTrader: (2)

Could be a press in rocker arm stud pulling out.

NoEmissions84TA

iTrader: (1)

Add some Marvel Mystery Oil to your crankcase. It might free up the pumping mechanism inside the lifter.
DO NOT adjust to 1 turn down.
An exhaust leak can sound EXACTLY like a ticking lifter.
You can easily isolate and pinpoint the sound by shoving one end of a 2-3 foot piece of vacuum line in your ear and probing around with the other end. You will be amazed. Be careful of rotating and hot parts.