Engine ticking / knocking noise

[Gibbo205]

Hi there

The engine in my 1978 Pace Car has always made a ticking / knocking noise that quietens as the car warms up.
Putting in 20-50W with zinc did help make it quieter.

As such with hood down it was not really noticeable however I am now a little worried about it.

My reasoning is that today I change valve cover gaskets to fix an oil weep and when looking around the engine bay with engine running I noticed the tick/knock sound is present and it’s only present on the drivers side. Also if I hold the valve cover I can feel the tapping on the drivers side. On the passenger side I can’t feel anything.

As such I decided to make a short video of the noise:

My phone makes it sound worse then it is but the noise is easy to hear in the video.

To me it sounds like a worn lifter, maybe a stuck lifter or out of adjustment.

What do people here think?
It’s an L82 engine so I think it’s has hydraulic lifters.

Is it worth trying to adjust the valves with engine running, see a lot of videos online of people undoing the nut until it rattles and then tightening until it stops rattle and then re-tightening a further 3/4 turn. Is this valid for my engine and worth trying? Is an additive worth a try?

Or is it time for a set of new lifters?

 

[Oneball]

Did you look inside the valve covers? Could you see if a rocker arm was hitting the cover?

 

[Gibbo205]

Did you look inside the valve covers? Could you see if a rocker arm was hitting the cover?

Not yet I am gonna pull the valve cover on that side and then run the engine to see if the noise remains and if it does I’ll then hood each rocker arm to see if I can feel which one is specifically knocking.
Are they adjustable on the L82?

 

[kentvette]

Our '78 has had a "ticking" sound when cool for years. A friend who had a similar noise found it was a worn camshaft. When he replaced the shaft, the noise went away. Our car runs fine (for a 125k mile car with an engine that hasn't been opened) and I'm not inclined to fiddle!

 

[Oneball]

Not yet I am gonna pull the valve cover on that side and then run the engine to see if the noise remains and if it does I’ll then hood each rocker arm to see if I can feel which one is specifically knocking.
Are they adjustable on the L82?

If you can feel it on the valve cover I’d bet a rocker arm is hitting it. Usually where there’s a baffle, breather tube or the like.

 

[Gibbo205]

If you can feel it on the valve cover I’d bet a rocker arm is hitting it. Usually where there’s a baffle, breather tube or the like.

Will pull it and take a look, at least they are easy to access and remove.

 

[Chuffer]

I have a ticking / light knocking sound that developed on driver side of mine too . That goes away once warmed too . I really can`t quite pin down down exactly where it comes from . I pulled out all the lifters and checked and reset the pre loads but made no difference . In my experience cam shaft wear knock usually doesn`t go quiet when hot but can quieten down at specific revs.

 

[Roscobbc]

Valve gear noises can be difficult to attribute to a specific rocker. Best way to check if you have a hydraulic rocker out of adjustment (and if you are happy to run the engine with the rocker cover off and perhaps have oil splashing about) is to insert a feeler guage (15 thou perhaps) under each rocker tip when the engine is running to identify the 'noisy' rocker/rockers (they'll quieten-up) If you have adjustable rockers - to adust lifter pre-load simply rotate the engine so that the respective valve is in a closed position and gently tighten-up the rocker to take-up clearance - then tighten rocker half a turn and 'lock' it. Depending on whether a stock or aftermarket cam the lifter pre-load can vary from 1/4 turn to 3/4 turn perhaps........

Intake Valve Adjustment: ENGINE OFF!

• with #1 cylinder Intake Valve at full valve lift .... Adjust #6 Intake Valve
• with #8 cylinder Intake Valve at full valve lift .... Adjust #5 Intake Valve
• with #4 cylinder Intake Valve at full valve lift .... Adjust #7 Intake Valve
• with #3 cylinder Intake Valve at full valve lift .... Adjust #2 Intake Valve
• with #6 cylinder Intake Valve at full valve lift .... Adjust #1 Intake Valve
• with #5 cylinder Intake Valve at full valve lift .... Adjust #8 Intake Valve
• with #7 cylinder Intake Valve at full valve lift .... Adjust #4 Intake Valve
• with #2 cylinder Intake Valve at full valve lift .... Adjust #3 Intake Valv

Exhaust Valve Adjustment: ENGINE OFF!
You will notice that this is the same procedure and sequence as the intake valves listed above. Only now you are adjusting ONLY the exhaust valves the same way.

• with #1 cylinder Exhaust Valve at full valve lift .... Adjust #6 Exhaust Valve
• with #8 cylinder Exhaust Valve at full valve lift .... Adjust #5 Exhaust Valve
• with #4 cylinder Exhaust Valve at full valve lift .... Adjust #7 Exhaust Valve
• with #3 cylinder Exhaust Valve at full valve lift .... Adjust #2 Exhaust Valve
• with #6 cylinder Exhaust Valve at full valve lift .... Adjust #1 Exhaust Valve
• with #5 cylinder Exhaust Valve at full valve lift .... Adjust #8 Exhaust Valve
• with #7 cylinder Exhaust Valve at full valve lift .... Adjust #4 Exhaust Valve
• with #2 cylinder Exhaust Valve at full valve lift .... Adjust #3 Exhaust Valve

 

[Mad4slalom]

I have a ticking / light knocking sound that developed on driver side of mine too . That goes away once warmed too . I really can`t quite pin down down exactly where it comes from . I pulled out all the lifters and checked and reset the pre loads but made no difference . In my experience cam shaft wear knock usually doesn`t go quiet when hot but can quieten down at specific revs.

My beach buggy (1600 air cooled vw motor) has had a clack clack noise from cold for years , sometimes there, sometimes not. I have adjusted the valve clearances numerous times. I thought I had found it as could reproduce it , (I thought )when I found some side play on the rocker shaft. I changed both rocker shafts complete with new rocker arms etc and No difference. I just live with it now . Another buggy owner had a noise not as bad as mine and evryone had a suggestion what it could be, he had the whole motor rebuilt and still never found a definitive answer to what the noise was. Just put it down to a little bit of wear all over .
Hope you find your issue.

 

[Chuffer]

Cheers Mad4 . I had the guy who does all the race cars where I store my car listen too it . He had a stethoscope on it and still couldn`t pin point it and pronounced "it was nothing to worry about " as it went quiet once warmed up . Unresolved things just bug me .

 

[antijam]

I once had a sudden and loud ticking from an old Ford Essex 3.0 V6. Over a period of some months it gradually reduced in intensity which was odd - most unexpected engine noises don't tend to improve with age. Several 'experts' confessed to being baffled and after a year I had almost forgotten it was there. Came time for a decoke and with the heads off there was a small screw embedded in the crown of one of the pistons. It had detached itself from part of the Weber carb, sneaked past the inlet valve and got given a serious thump as the piston rose. The noise reduced as the screw got gradually hammered further into the piston. After winkling out the screw and refitting the heads - quiet as a mouse....

 

[Roscobbc]

Want to hear a 'ticking noise'? - no. 2 big end shell was in about 15 pieces with about 30 thou' movement on the big end - listen on headphones to get the real effect!

 

[Chuffer]

I once had a sudden and loud ticking from an old Ford Essex 3.0 V6. Over a period of some months it gradually reduced in intensity which was odd - most unexpected engine noises don't tend to improve with age. Several 'experts' confessed to being baffled and after a year I had almost forgotten it was there. Came time for a decoke and with the heads off there was a small screw embedded in the crown of one of the pistons. It had detached itself from part of the Weber carb, sneaked past the inlet valve and got given a serious thump as the piston rose. The noise reduced as the screw got gradually hammered further into the piston. After winkling out the crew and refitting the heads - quiet as a mouse....

It`s amazing what can go on inside an engine .

 

[Gibbo205]

Hi there

So I did the valve lash, my method was engine running, valve covers off, yeah it got a bit messy.
I loosened the rocker arm nut until it clattered, I then tighten it until it stopped clattering (zero lash) and then added 1/4 of a turn. Many people online state different amounts from 1/4 to one full turn. I spoke to a friend who runs some classic cars and has built engines and he said always one quarter of a turn, it gives maximum power and stops valve float.

After doing this the knock was far less pronounced when warm and only remaining when cold, the engine also felt smoother, could no longer feel it in valve cover and the car also drove smoother and pulled harder. Most of them seem to be tightened 1/2-3/4 turn based on how much it took to get them clattering.

However the knock was still present cold.

So dropped the car off with a mechanic that has a solid reputation with classics, land rovers and cosworths, he had the car a few days as he fitted me some fresh suspension components, new PS pump and also did an alignment on the car.

His diagnosis was its an exceptionally clean car, he said its had a full paint job at some point in its life and a very good one at that, he confirmed the car has never been in an accident and that the car was in superb condition and the birdcage was rust free.

Now onto the engine, he said the noise is down to the engine been an L82 in forged internals as the noise I am hearing is piston slap, at this point I looked at him worried and he assured me it was nothing to worry about, stating its luck of the draw, saying some are quiet, some are noisy and it will still do 100k even 200k miles without issue on the basis it stays as it is now which is when its cold you can hear it knocking but once warm it goes away or is just a tap. He assures me not to worry and if it does get worse then its time to look more into it but he feels that won't happen.

Now onto the good stuff, the car drives freaking awesome, ride is superb even with the gymkhana suspension, handles superb and the car feels smoother and more responsive, no doubt a result from doing the valve lash, also my car is finally totally leak free. The PS leak was the RAM, which I fixed, it then moved to the pump which the mechanic replace, the oil leak was the valve covers and the new Fel Pro covers I fitted have solved that, so for now were all good until it starts leaking again, haha!

 

[Vetman]

Dodgy car dealers swear by sawdust in the oil.

 

[Gibbo205]

Dodgy car dealers swear by sawdust in the oil.

And I'd laugh in their face, having rebuilt an engine myself and done a lot of the work myself on the Corvette I an not totally clueless but wanted to get a more professional opinion on my car, when I delivered the car he said the engine had no noise and all I was hearing was tappets and thats normal.

When I collected car a few days later is when he informed me I am hearing the forge piston doing piston slap, he said if it was his car he would not worry about it due to his experience with other 350's and some cosworth motors that do the same and never had an issue.

Car runs great, if it ever gets worse he can crack it open and fix it, if it never changes as he suggest then I won't have spent a chunk of money fixing something that never needed fixing.

 

[Chuffer]

Good to hear you have got yourself a sound and solid car Gibbo . Like you , after much research and internetting i stuck with the 1/4 turn method when I did my rockers and had all the push roads out too to check them out . Never did stop the tapping / clicking sound until warmed up though . Interesting theory about piston slap although my motor is a 1985 LB9 305 cu. in. from a Camaro IROC - Z28 , not an L82 . It is a bit tired ( like its owner ) but still runs well enough now its sorted .

 

[Gibbo205]

Good to hear you have got yourself a sound and solid car Gibbo . Like you , after much research and internetting i stuck with the 1/4 turn method when I did my rockers and had all the push roads out too to check them out . Never did stop the tapping / clicking sound until warmed up though . Interesting theory about piston slap although my motor is a 1985 LB9 305 cu. in. from a Camaro IROC - Z28 , not an L82 . It is a bit tired ( like its owner ) but still runs well enough now its sorted .

To be honest I am just glad to found a mechanic who is not only experienced with such cars and engines, but is actually very good. I do most stuff myself but at times you either cannot be arsed to roll around on the floor and getting dirty or have to admit defeat and let someone with more experience and expertise take a look.

I am using my Corvette as much as possible, because I am a firm believer that using a car, keeps a car reliable.

 

[Roscobbc]

And I'd laugh in their face, having rebuilt an engine myself and done a lot of the work myself on the Corvette I an not totally clueless but wanted to get a more professional opinion on my car, when I delivered the car he said the engine had no noise and all I was hearing was tappets and thats normal.

When I collected car a few days later is when he informed me I am hearing the forge piston doing piston slap, he said if it was his car he would not worry about it due to his experience with other 350's and some cosworth motors that do the same and never had an issue.

Car runs great, if it ever gets worse he can crack it open and fix it, if it never changes as he suggest then I won't have spent a chunk of money fixing something that never needed fixing.

Piston 'slap' with forged pistons is generally something that should disappear once the engine has fully warmed-up. Some people may confuse it with 'pinking'. Some hydraulic rockers are always a little noisy - can depend on the cam design, especially if its an aftermarket performance cam.

 

[Daytona Vette]

Piston Slap is because it is an L82 - Duck for the Flying Pig!
Piston Slap is Ok - Duck Duck there is another one!
I could tell you a story about Piston Slap on a just rebuilt 350 I was sold in a car - stripped it to find one odd piston and one with a big piece missing out of the skirt, that of course was not in the sump - Caveat Emptor