Need help with weird ticking noise and rough idle

[NoCashValue]

Hey Guys, 

 

Trying to work out a few ticks on my 02 before I get it ready to sell. I have a 76, with a Weber 32/36 and vacuum advance distributor (with pertronix). It has always had a rough idle since I received it (had been sitting for years) and I wanted to tackle the idle issues before I get ready to sell it. CA car, all smog equipment removed. I recently pulled the head thinking the head gasket may have failed but found it intact, but noticed the cooling channels in the head were clogged up with what I assume was radiator leak stop? Well, I cleaned out all the cooling passages and installed a new head gasket. Started it up and it still idles rough. Pictures of the head (without gasket) just after it was removed are below as well as the block with the head gasket just after removal. The scratch on cyl 4 piston is from me. 

I pulled and cleaned the carb and reinstalled, adjusted the idle mixture screws to 1.5 turns out and started it up to let it warm up. It has no issues starting, but once it is running I noticed a weird tick. Almost like a tapping but it almost sounds like a cracking noise? Very hard to describe so I recorded a video. Still seems to have the rough idle I am trying to diagnose. 

 

https://photos.app.goo.gl/rxEYXPO7DJ5xLOA63

 

I also pulled the radiator cap and tried to watch to see if the coolant drops when the throttle is advanced and couldn't see any movement. I checked this because I was concerned after seeing how much stuff had been clogged in the head. 

 

Any one have an ideas on what the noise could be? I really dont want to drive it until I know this is all sorted out. 

 

Thanks, 

 

Eric  

[Mike Self]

While this isn't gonna directly affect the idle and ticking sound...With as much crud in the head as you pictured, I hope you also cleaned out the block and radiator.  If not, you really should flush out the block thoroughly and--were it my car--remove the radiator and try back-flushing it yourself.  If that isn't successful, have a radiator shop do it.  

 

There's a drain in the block, inconveniently placed under the exhaust manifold--a (IIRC) 17 (or perhaps 19) mm bolt.  With the radiator out, pull the hoses connected with the thermostat and run a garden hose into the top radiator hose and let it flush out the block.  Hopefully your heater isn't too badly clogged--although you probably don't have that much need for it in Phoenix.  To flush the radiator, turn it upside down and poke the garden hose in the lower hose nipple and let the water run backwards through the radiator.  Bet you'll get a lot of crud out of both the block and the radiator.  

Could the ticking be a mis-adjusted valve?  You did readjust the valves after replacing the head gasket, didn't you?  You'll need to re-torque the head in 500-1000 miles--and readjust the valves--so check valve adjustments again.  

 

As for the rough idle--Weber 32/36's have a rep for rough idles--mine isn't nearly as smooth as the idle on my 1 bbl Solex that's on my '69.  

 

Have you checked for vacuum leaks?  Carb base, dizzy vacuum advance, vacuum ports on the manifold, intake manifold-to-head gaskets etc?  Even the brake booster hose.  Squirt a little carb cleaner around each of these joints--if you're rewarded with an momentary increase in idle speed, you've found your leak.   Pull the dizzy vacuum hose off at the carb end and suck on it.  If you feel no resistance, then the vacuum capsule on your dizzy is bad, and is a vacuum leak.  That can also affect idle speed and smoothness as it's messing with your ignition advance.

 

Check this stuff out and let us know whatcha find...

 

mike

[NoCashValue]

Hey Mike, 

 

I agree that with what was found, the rest of the cooling system needed attention and I did flush the block and check all the other hoses. I found a ton more in the diverter that comes off the head and feeds the intake manifold. That hose was completely packed solid. 

 

I actually didn't set or check the valve timing when I replaced the head gasket. I just pulled the head, inspected the gasket, cleaned the cooling passages and reinstalled. That is on my list but has not been done so I need to read up on it and take a look. I also have gone over everything looking for vacuum leaks. All the vacuum lines are new and I used a vacuum pump and gauge to check the dizzy. 

 

Your comments about the Weber carbs having a rep for rough idles makes me think I may be alright, just need to re-jet. After writing this all up I went and started to play with the idle mixture screw and found that adjusting it out ~2.5 to 3 turns would cause the ticking to completely go away (or the temp change made a difference as the engine had completely warmed up). The instructions say anything over 1.5 turns out needs a larger idle jet and is likely running lean. My primary idle jet is a 60 at the moment. Do you think I may just need to re-jet this thing?

 

Thanks,

 

Eric

[Hans]

It doesn't sound like a valve, or timing chain slap. Too random i think. It sounds familiar but damned if I can think of what it is. hard to think of something that would be changed by mixture screw.

[Simeon]

Broken ring? (He says guessing without listening to the video)

[andyleonard]

I think the idle screw adjustment is just changing the vibration rpm. Get 2-3' of 1/2-3/4" hose and stick one end in your ear and put the other end everywhere. Fuel pump push rod? Exhaust gasket leak? Alternator bushing rotten? Heat shield loose? There are a million choices.

 

Find where the tick lives and we'll figure out what it is.

 

I've heard a loose rocker pad do that. I've heard a loose valve seat do a bigger version of that.

[Simeon]

I had an annoying tick once and the I realised it was the hood bouncing and making the noise. You only heard it with the hood up. 

[Dudeland]

Being around a lot of pumps in my life. it sounds like you are pumping gravel. It may be a chunk that keeps going around in the impeller. Whatever was in it is loose and now getting ground up in the pump. 

 

It isn't metallic in my opinion. It is random things flying off the impeller. 

 

[Dudeland]

The only other pump is the fuel pump. It may be grenading.  That may also explain your rough idle. Pull it out and inspect it for wear.  You can even start it without it attached (briefly) and see if that makes any difference to the noise. 

 

I would bet it is one or the other. 

 

 

[2002Scoob]

Wow! That's an insane amount of crud in your coolant passages. 

 

My favorite suggestion is Dudeland's above that you dislodged some gravel or gunk and it's getting thwapped around by the water pump. 

 

Any change in sound dependent upon revs?

[Hans]

Fuel pump push rod. That fits the noise better than valves, etc.. Maybe the end of the rod in the pump needs some grease. 

[artbo]

Are you still running the plastic/Bakelite plug wire connectors? If so check them for carbon traces, cracks or missing hunks. The ticking could be the spark arcing to the head. This also causes a dead miss to the affected plug or plugs hence rough idle.

[Hans]

May be my speakers, but I'm hearing more of a random squeak...

['76mintgrün'02]

Take a short length of hose and hold it up to your ear, as you listen around to find the source of the sound.

Cheap-O stethoscopes are not worth buying, imho... at least the NAPA piece of crappa that I regret spending $8 on....

 

I have heard a similar sounding 'gravelly' sound come from the throats of my carburetor... so stick the hose in there as well : )