I've had a small tapping sound for a few years that I've been told is a valve. I looked into adjusting them and am willing to give it a try. Planning to do it while the engine is running, but I'm worried oil will spray. It idles at about 700rpms and jumps to 1,000 sometimes.. Is there any specific rpm range where it would start spraying oil? I'm not even sure if this relates to one another? Also, my issue seems to hopefully be on the 1,3,5,7 side, so would I be able to just adjust this side instead of having to deal with the nightmare on the passenger side to get to the valve cover?

 

There is really no point in adjusting only one side. It is part of the regular tuning procedures on a small block Chevy. That is like only replacing half the spark plugs.

Oil can be shooting out of the pushrod/rocker arm right at idle, hitting hood and fender areas.. Mostly, they just dribble. Still very messy.

A remote starter button can make the job so much easier. One of the best tools I ever bought. You only have to remember to adjust the valves when they are closed, or the lifter is on the heel side of the cam lobe. I use the starter button to click each cylinder to near top dead center, then adjust both valves on that cylinder. To find TDC, I have the spark plugs out and just click the engine over with my finger over that cylinder's spark plug hole. When air pushes out of the cylinder past your finger, you know it is on the compression stroke and both valves are closed. Adjusting from there is just a matter of loosening the adjusting nut on the rocker stud until you have slop between the rocker arm, pushrod, and lifter. That is where the pushrod can move up and down between the rocker and lifter. Zero lash happens as soon as that slop removed by slowly tightening the adjusting nut. You can also feel this by feel and spinning the pushrod with your fingers while tighening the nut until there is a slight drag.

If you really prefer to perform the valve adjustment, , or lifter preload, when the engine is running. Just use a pair of old stock valve covers with a slot cut down the top above where the rocker stud location. There are also rocker arm clips to prevent oil spraying, but I have never had any luck with them staying on.

When I am resorting to adjusting the valve while the engine is running, I use a bunch of rags or old T shirts in order to try to keep the mess down. It helps, but I always end up with a mess. Just remember that rags lying on top of the exhaust manifolds can catch on fire. So, keep them off the manifolds as best as possible. I keep the hose nearby just in case I need to yank a smoldering rag off the engine and douse it with water on the ground. Don't hose down your open engine with the hose. I like to do 4 valves at a time on each side, then cover up the rest as best as possible.

Adjusting the valves is easy enough when the engine is running. Just loosen the adjusting nut until you hear a distinct clattering sound, then retighten it until it just goes away. Go slowly doing this. Right when it goes quiet is zero lash. Then go 1/2 turn farther.

WD40 or PB Blaster work great for cleaning up oil that gets on stuff under the hood without damaging anything.

Scott Liggett
BluePrint Engines
Product Specialist
800-483-4263
info@blueprintengines.com
www.blueprintengines.com

 

Thanks for the information! I understand it makes more sense to adjust all the valves if you adjust any, but I really don't trust myself removing everything on the passenger side to get to the valve cover. There's not actually anything that is noticeably wrong performance wise, so if it wasn't for the annoying tapping sound I would never be doing this anyway. Even currently with the tapping sound people tell me to leave it alone since it runs fine. If just adjusting the valve that's currently tapping and not messing with the others doesn't hurt anything than I'd prefer to just do that. I'm not sure if it's okay to just adjust one valve without adjusting others?

 

Yes, it's OK to adjust only the noisy rocker, but you'll probably have to go through all of them on that side of the engine anyway to find the noisy one.

That said, a method that sometimes works to find one noisy one is to fold a shop rag over onto itself until it's about the size of the heel of your hand, and with the engine running, press it (the rag/heel of your hand) on one rocker at a time and see if you can determine which one is noisy by a change in the noise.

Without a hogged-out old valve cover and a set of rocker arm clips, this is, indeed, a messy job. While static adjustment (engine not running) of lifters is OK, if you're dealing with a stuck/dirty/otherwise defective lifter, you'll never find it without the engine running.

 

I understand where you are coming from, removing all that stuff. I have a 89 Caprice with a TBI 305 in my fleet that needs the valve cover gaskets replaced. I have been avoiding doing the job because of the mess on the passenger side.

It may be hard to find the exact valve that is making the noise unless it is completely loose. I doubt that it is because you have not lost performance.

One other thing to consider: A small exhaust leak is often mistaken for a lifter tapping. An easy way to check for an exhaust leak, without burning yourself, is to use a 3 ft section of vacuum line like a stethoscope. Put one end in your ear, then run the other end all around the exhaust manifold. If there is a leak, you will find it, and it be able to narrow down the location to the square inch.

Scott Liggett
BluePrint Engines
Product Specialist
800-483-4263
info@blueprintengines.com
www.blueprintengines.com

 

The car 100% has exhaust leaks I just didn't think this would cause such a sound especially from where it seems to be coming from. I guess my best bet is to just wait until after I have an entire new exhaust system put on and then see if the sound still is present.

 

I am old school and use a lot of old school hacks to find noises. Find a big screwdriver, use it like a stethoscope. Put the handle against your ear hard enough to close the ear opening. Then rest the pointy end along the valve cover. If there is a tapping sound under the valve cover that you can kind of locate by moving to different spots along valve cover, then you may have a rocker out of adjustment. Do this on the other side of the engine to see if they sound the same.

Scott Liggett
BluePrint Engines
Product Specialist
800-483-4263
info@blueprintengines.com
www.blueprintengines.com

 

Definitely can tell a difference in sound by cylinder 1. I am not sure if this is just the engine vibrating or the valve underneath the valve cover though. Hopefully one of the valves, so that I at least know what's causing the tapping.