Tappers
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Tappers
On the way home I started hearing a loud tapping noise on engine passenger side.. Sounded like an exhaust leak but now I think it is a rocker.. Engine is too hot to remove cover. Years ago I remeber adjusting the rockers by loosening until they knocked and then tighten until they stop and then 3/4 turn more. Is that a valid way to adjust rockers? Could a rocker all of a sudden start tapping loud or am I in for bigger problems.. Noise got louder under strain.. in gear giving gas. Not as noticable, but still there out of gear reving engine. Any words of wisdom?
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Re: Tappers (DollaGreen)
I pulled the passenger valve cover off last night.. Put an old shirt over manifold to catch oil spray and started her up.. No tapping noise? I loosend a rocker to ensure I would hear the tapping noise.. which I did. but it was different. I replaced the cover and I hear tapping louder on the passenger side but I think it's comming from the carb? Can't explain it. I decided to check the timing and it was at 0.. :confused: I advanced the timing and the tapping sound got less.. Still there but no where near as loud. I just had the carb rebuilt.. Has anyone ever heard tapping from the carb?
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Tappers (Koz)
Noises can travel through the engine so you may be hearing a noise coming from somewhere else. I had a rod knock that was very light but could not figure out what it was until it became a banging noise then there wasn't much doubt. :( Keep an eye/ear on it. I am thinking of getting one of those stethescopes for engine use so I can pinpoint any noise I hear that is out of the ordinary.
Racer
Joined: Mar 2002
Posts: 369
Likes: 1
From: Nowhere
Re: Tappers (Koz)
My engine started tapping for no reason on the passenger rear cylinder. I tried to adjust the rockers, but still tapped.
This is the way I was taught to adjust if they were solid lifters.
But I finally had to pull the intake and lifters. Found out I had collasped a lifter on the exhaust side of the back cylinder.
So I rounded up enough money and changed the engine to my current ZZ4 configuration. I saved the engine for a rebuild, in case I wanted to put it back in someday.
Years ago I remeber adjusting the rockers by loosening until they knocked and then tighten until they stop and then 3/4 turn more. Is that a valid way to adjust rockers?
But I finally had to pull the intake and lifters. Found out I had collasped a lifter on the exhaust side of the back cylinder.
So I rounded up enough money and changed the engine to my current ZZ4 configuration. I saved the engine for a rebuild, in case I wanted to put it back in someday.
Melting Slicks
Joined: Aug 2000
Posts: 2,900
Likes: 2
From: Green Cove Springs FL
Re: Tappers (kgraumann)
My engine started tapping for no reason on the passenger rear cylinder. I tried to adjust the rockers, but still tapped.
Years ago I remeber adjusting the rockers by loosening until they knocked and then tighten until they stop and then 3/4 turn more. Is that a valid way to adjust rockers?
This is the way I was taught to adjust if they were solid lifters.
But I finally had to pull the intake and lifters. Found out I had collasped a lifter on the exhaust side of the back cylinder.
So I rounded up enough money and changed the engine to my current ZZ4 configuration. I saved the engine for a rebuild, in case I wanted to put it back in someday.
Years ago I remeber adjusting the rockers by loosening until they knocked and then tighten until they stop and then 3/4 turn more. Is that a valid way to adjust rockers?
This is the way I was taught to adjust if they were solid lifters.
But I finally had to pull the intake and lifters. Found out I had collasped a lifter on the exhaust side of the back cylinder.
So I rounded up enough money and changed the engine to my current ZZ4 configuration. I saved the engine for a rebuild, in case I wanted to put it back in someday.
Guest
Posts: n/a
Re: Tappers (Fevre)
How do I know if I have hydro or solids lifters? I just loosened until I heard tapping and then tightened back the same number of turns. It was more like 1/2 turn after tapping stopped.. Why would it be different with solids?
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Re: Tappers (kgraumann)
So I rounded up enough money and changed the engine to my current ZZ4 configuration. I saved the engine for a rebuild, in case I wanted to put it back in someday.
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Tappers (Koz)
OK now we have reached the end of my knowledge on solid/hydro. I am sure there is a way to tell without tearing the engine down but I don't have the answer. IF you have the original stock engine and know for a fact no mods then its hydro but if you are unsure then check into it. I am sure others will post a way to tell em apart.
Melting Slicks
Joined: Oct 2001
Posts: 2,062
Likes: 1,360
From: Halifax, Nova Scotia, Canada
Re: Tappers (Koz)
How do I know if I have hydro or solids lifters? I just loosened until I heard tapping and then tightened back the same number of turns. It was more like 1/2 turn after tapping stopped.. Why would it be different with solids?
Hydraulic lifters have an outer casing and an inner piston, along with a spring and some valving. When you adjust the lifters and take out the tapping and then turn an additional 1/2 turn, you are really compressing the inner piston.
When people say they have a collasped lifter, it's just the inner piston has become "stuck" in the lifter casing. Usually from dirty oil or from using cheap oil.
The reason for using hydraulic lifters is to provide a quiet trouble free valve system. The inner piston sort of floats in the lifter, using the engine oil pressure.
Solid lifters have no piston to compress. If you tighten a 1/2 turn after clicking, then you will permentantly open that valve. Thats why you need to adjust the gap with a feeler guage.
Barry
Racer
Joined: Mar 2002
Posts: 369
Likes: 1
From: Nowhere
Re: Tappers (Fevre)
Probably why the lifter collapsed, valve hit piston.
Burning Brakes
Joined: Dec 2000
Posts: 1,183
Likes: 2
From: Des Moines Iowa
Re: Tappers (Koz)
Koz:
Are you really certain that your noise isn't a leaking exhaust manifold gasket????? These will make a noise very similar to a loose rocker arm......a ticking like noise that increases with rpm increases, sometimes a crack in exhaust system can do the same, but these usually are worse when engine is cold, and then quiet some after metal gets hot and expands to make the crack smaller. Just a thought.
Are you really certain that your noise isn't a leaking exhaust manifold gasket????? These will make a noise very similar to a loose rocker arm......a ticking like noise that increases with rpm increases, sometimes a crack in exhaust system can do the same, but these usually are worse when engine is cold, and then quiet some after metal gets hot and expands to make the crack smaller. Just a thought.
Guest
Posts: n/a
Re: Tappers (john's '81 mouse)
BINGO!!! I just got back from the mechanic who did the carb work.. Doesn't if figure.. Yesterday there was no choke at first startup, burping at WOT and today she starts like she should, no burping.. I felt bad bringing her in but as I got his shop the tapping got worse.. I said, "You hear that".. He said Yup.. You have exhaust gaskets on your manifold and it's cracked right there.. Here's a 3/4 in piece of gasket missing.. DAMM... I wish I would have found that.. He's a friend so I didn't feel too stupid but he said it was very common.. Said I should just do metal on metal like GM intened it to be.. He also said if she starts acting up and burping to check and see if the choke released the secondaries. Even though she's warm the choke could be sticking.. So, as usual... it's sunny and warm and the vette is cooling in the garage waiting to be worked on.. Oh well.. I still love her.. Thanks to everyone for your help and advise.. :cheers: