I was having a little leakage around the valve covers so I decided to remove covers and install new gaskets. Engine is a 1963 327/300. Question is: if I'm able, between my thumb and fore finger, to turn the push rods do they need to be tighten. At times when the engine is running it sounds like I hear tappet noise but with the magnaflow muffers it's hard to tell. I'm assuming the tappets are hydraulic and not solid. None of the stems are that loose.
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Re: Do my valve lifters need to be adjusted
Chester,
NO! Don't tighten! If you hear a clicking have someone that has adjusted hydraulic lifters before help you. Just tightening them will yield a burned valve in short time.
Please consult a mechanic or friend that has experience in adjusting valves.
JR -
Re: Do my valve lifters need to be adjusted
Chester, just replacing the valve cover gasket does not require the lifters to be readjusted. What you have sound normal. Some push rods will be loose enough to turn with your fingers.Comment
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Re: Do my valve lifters need to be adjusted
Agree with Joe, hydraulic lifters are adjusted hot and pumped up. (That s why you don't just tighten them if you think they are loose.) When they are at this state the pushrod will not turn. If they have cooled down and the fluid has run out of lifter then you might be able to turn a few. You can "Google" this procedure and get a better idea of what I'm talking about, but again do what Joe suggested and get a knowledgeable mechanic to show you how. It is not rocket science but if done wrong can be very costly! Don't know how long you have had the car, but if it has been a while it would be a good time to have this done to insure proper adjustment.
TerryComment
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Re: Do my valve lifters need to be adjusted
Chester -
The hot valve adjustment procedure for hydraulic lifters is described on page 6-6 of your 1963 Corvette Shop Manual; if you haven't done it before, follow the process to the letter or have someone help you who is familiar with the procedure. Doing it improperly can result in serious engine damage. You'll need a set of rocker arm clips to deflect the hot oil back into the rocker arms.
RockerArmClips.JPGComment
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Re: Do my valve lifters need to be adjusted
Yes - I use the oil deflector clips on my '63 250hp hydraulics. One note to add to what the manual says -- when you are backing off the adjustment to listen for the 'clatter' before tightening to the adjustment specs let off on the pressure of the socket on the nut or you may not hear the clatter. Its easy to sort of 'lay' on the nut enough so the sound is not pronounced enough to note the clatter....Comment
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Re: Do my valve lifters need to be adjusted
Oil deflector clips attach at the pushrod end of the rocker, they just clip on sorta like a paper clip, and keep the oil from hitting you in the face!Comment
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Re: Do my valve lifters need to be adjusted
I always adjust mine when the engine is off. In the 63 shop manual the valves to be adjusted are listed in each position of #1 cylinder at TDC.Comment
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Re: Do my valve lifters need to be adjusted
Tim,
I agree totally! On page 6-14 and page 6-15 of the 63 Corvette Shop Manual it describes how to adjust half the valves on the Number 1 Firing Position and then adjust the other half on the Number 6 Firing Position.
I have adjusted well over 100 small blocks and big blocks with this procedure long before they were ever fired up for the first time and every one of them was perfect. It's an old tale that the engine has to be hot and adjusted running because the lifters must be pumped up.
Who wants hot oil running all over the engine, the floor and themselves?????? If anyone believes the engine must be hot just explain how they were adjusted at Flint. And they were not adjusted when running on natural gas!
JRComment
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Re: Do my valve lifters need to be adjusted
The beauty of hydraulic lifters: they are very forgiving. There are a variety of ways to adjust them. You can adjust them cold but a lot of the methods for adjusting while the engine is not running tend to put the lifter plunger and push rod cup in the upper portion of the bore, and really, that's OK. The main reason for adjusting them hot with deflectors is that you allow the lifter plunger and cup to pump up while the engine is running and has oil pressure to the lifter body. By backing off on the rocker nut you can hear when the plunger and cup have no pressure on them from the valve assembly and are at the top of their travel in the lifter body. Turning the nut down until the clicking just disappears gets you very close to zero lash with a hydraulic lifter. Next, shut down the engine and give each nut no more than an 1/8th of a turn. This method will keep the lifter plunger at the top of the bore and tends to help keep the valves from floating at high RPM's because of the lifter pumping up. That anyway, is the theory. This whole business is probably only useful to someone planning on racing, their engine has a hydraulic cam, and they intend to see high RPM's. The methods of adjusting valves based on having the lifter on the base circle works fine for most engines because they won't see extreme RPM's. I've used both methods with no problems, and quite honestly, I couldn't tell the difference. If you are building an engine, you don't have much choice anyway, until after it's been run in.
SteveComment
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Re: Do my valve lifters need to be adjusted
I agree with Mr. Barbieri. I haven't adjusted solid or hydraulic lifters with the engine running in probably 40 years.
Steve, get off the computer and get out to your shop to replace those u-joints.
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Re: Do my valve lifters need to be adjusted
This procedure is usually called "zero lashing". It won't increase valvetrain limiting speed, but it will reduce the amount of time it takes the engine to recover from a lifter pump up event, which occurs when inertia forces can no longer be controlled by the valve spring, so the plunger travels to the top of the lifter bore filling the entire chamber with oil, and the valves hang open until the lifters bleed down.
Careful setup of the OE valve springs will allow at least 6500 with OE cams before lifter pump up occurs, but even a L-79 or L-46 will be wheezing at this speed unless the heads are massaged for more flow.
The service manual recommended 3/4-1 turn down from zero lash will provide sufficient margin for any reasonable amount of wear over the life of the engine, so the valves will likely never need to be adjusted until the next overhaul, but it will be slower to recover from lifter pump up, which few owners will ever experience.
The easiest way to adjust is per the service manuals - the 8 specified at TDC #1 and the 8 specified at TDC #6. Wiggle the pushrod up and down while loosening the nut until you just begin to feel clearance, then turn the nut down 1/2 to 1 turn. So where should you be withing this range? How about splitting the difference at 3/4. It's not something to obsess over if you don't plan on regularly exceeding the tach redline.
If you have massaged heads, and the engine will make useable power to at least 6500 then the "zero lash" procedure (0 to 1/8 turn down) is optional, but the valves should probably be relashed every 30K miles.
DukeComment
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Re: Do my valve lifters need to be adjusted
I adjusted mine when I had a 65 300 HP and my other hydraulic lifter cars at 0 lash and some at 1/8 turn and they ran great, no noise and no pump up.
DomComment
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