Probably about time-rocker adjustment

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gtgto

gtgto

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I'm almost embarrassed to say but I've had my car for about 5 years and I have never felt the need to adjust the rockers. It has adjustable rockers for some reason....Not sure if it has a solid lifter setup. The rockers look to be from maybe a 273 with adjustable rockers. The car runs good but it seems to be noisier while driving it and maybe even a little down on power. I have done valve cover gaskets in the past but never felt the need to really inspect and look things over. I like to drive my car whenever possible. I have a small oil leak coming from the pressure gauge setup on the block so I have that to fix and I figured I would remove at least the valve covers and take a look. Spinning pushrods are evidence of adjustment needed . What else should I be looking out for? Engine is a 70-340
 
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Do all of the push rods spin all the time?

'Cause....if it is a solid lifter cam......those ol' push rods better spin some of the time.

Time to decide if'n it is a solid or hydraulic camshaft.
 
Video of the rocker arms with the cover off while running warmed up of course. Get as close as safely possible
 
IQ52 said:
Do all of the push rods spin all the time?

'Cause....if it is a solid lifter cam......those ol' push rods better spin some of the time.

Time to decide if'n it is a solid or hydraulic camshaft.
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Removed both valve covers and 5 of the 8 on the drivers side spin freely and 7 of the 8 on the passenger side spin freely. Without removing the intake and physically holding a lifter in my hand is there any way to tell for sure if they are solid or hydraulic? The valve springs look to be stock with the dampener built into them but they are not doubled up
 
69FBCuda said:
Video of the rocker arms with the cover off while running warmed up of course. Get as close as safely possible
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I would rather not make a huge mess of my engine bay but if it comes to that I will do it. Just not gonna be able to do it tonight since I am headin out now to get my son to hockey practice. I can spin the pushrods on 12 of the 16 valves with the engine cold. The previous reply I got said they all should spin if they are solid lifters. So does this mean most of my valves are out of adjustment?
 
gtgto said:
I would rather not make a huge mess of my engine bay but if it comes to that I will do it. Just not gonna be able to do it tonight since I am headin out now to get my son to hockey practice. I can spin the pushrods on 12 of the 16 valves with the engine cold. The previous reply I got said they all should spin if they are solid lifters. So does this mean most of my valves are out of adjustment?
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If solid they each should spin when on the cam lobe base circle and should be tight when on the cam lobe ramps.

On a stock engine you should be able to remove a lifter up through the cylinder head with a magnet or a lifter pulling tool.
 
69FBCuda said:
Typical adjustment would with lifter on the bottom of the cam lobe 1/4 turn past a slightly resisting while spinning pushrod. You can follow factory lash specs but I think you will end up close anyway. Warm engine.
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Not confusing at all?

Eh....1/4 turn on what?

I assume you mean the rocker arm adjusting screw. Which would be one method of setting a hydraulic lifter's pre-load.

Then as an alternative to that process you want him to follow the factory lash setting specs? Would that not be for a solid lifter cam?

If he follows your first suggestion, and it is a solid lifter cam, the valves would be open all the time.

Does he have a hydraulic or solid lifter cam????????

Don't think anybody knows for sure yet.
 
uh, spinning pushrods is a good thing. It means the lifters are spinning, which they should do, also. The lifters have a slightly crowned surface on their bottoms and the cam lobes have a very slight taper across their faces, so the lifters contact near the edge of the lobe, thus spinning them. This action limits the friction & wear on these things. Therefore the lifter/cam lobe don't grind themselves down. If you don't know this, and you don't know if you have an hydraulic or solid lifter cam, maybe you should seek some hands-on help, locally.
 
remove the valve cover and then remove the rocker shafts (loosen each bolt a turn them move to next one starting from the center and moving out, unti they are all out. You dont want to loosen them all and have one end still holding tight as it could damage the shaft) and then remove the pushrods (keep in order). Look down into the lifter with a flashlight. If it has a circlip or a wire retainer at the pushrod cup, its 95% chance a hydraulic lifter. If it has no clip whatsoever, its a solid. Solids need lash when the valve is UP, and it can only be measured when the lifter is on the base circle of the cam lobe. Hydros need to be sunk into the lifter about .060 at same cam base circle position. you do that with the adjuster. It will be fighting a spring in the lifter so you may or may not be able to spin the pushrods when they are under hydraulic preload. You can also tap the rocker with motor turned off and at rest for at least 10 minutes with a mallet under load and if it gives a little, that could point to a hydraulic. If the pushrods are turning while the motor is idling, that is a good thing as the rockers are doing what they were designed to do, rotate with the crown of the lobe tip. That keeps wear to a minimum. Solid and a hydro, note the retainer clip on hydro
SolidLifter.png
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Spinning the push rod is not the proper way to adjust a hydraulic lifter. Get the lifter on the base circle. Loosen the rocker while lifting the pushrod up and down. When u feel clearance start tightening the adjuster till u take out the play. Then tighten the additional 1/4, 1/2, 3/4 or 1 full turn. Some may 2 turns. I have only ever needed no more that 1/2 turn. In fact when I measure the preload I adjust it to .006 thou. Kim
 
first put #1 piston on the compression stroke then check for up and down movement in pushrod if it goes up/down you have a solid lifter but if its a tight spin without up/down its hyd. let engine sit for 30 min. after putting on #1 tdc to allow for lifter to self adjust.
 
teringer said:
first put #1 piston on the compression stroke then check for up and down movement in pushrod if it goes up/down you have a solid lifter but if its a tight spin without up/down its hyd. let engine sit for 30 min. after putting on #1 tdc to allow for lifter to self adjust.
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Havent had a hyd. cam in a long time , biut if urs is a hyd. , let it set for a couple of days , and push real hard on the rocker arm to see if the pushrod collapses the lifter any, if none do , more than likely its a solid-----------------
 
69FBCuda said:
Typical adjustment would with lifter on the bottom of the cam lobe 1/4 turn past a slightly resisting while spinning pushrod. You can follow factory lash specs but I think you will end up close anyway. Warm engine.
Click to expand...


That's dangerous information if you don't know for sure if it's a solid or hydraulic cam. We don't know and neither does the original poster here.
 
Perfect time to find out if solid or hydraulic. Adjusting valves is a standard maintenance check. Part of the learning curve. Interested to what you find, your 340 sounds like a same build to mine with 273 adjustable rockers.
Good luck:thumbsup:
 
toolmanmike said:
That's dangerous information if you don't know for sure if it's a solid or hydraulic cam. We don't know and neither does the original poster here.
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I am hoping to find out later today. I am planning on removing the rocker shaft and then the pushrods and visually inspect what I have.
 
Well I took the drivers side rockers off and it looks like I have solid lifters. I only removed 3 pushrods and one of them is bent. Oh boy. I got a knot in my stomach now. Can I just order correct length pushrods, and adjust the valves and be done?
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Best to remove all pushrods(number them) and check for straightness on a piece of glass.
Show pics of pushrods with measurements.
 
bent pushrod? how was that one rotating?
I strongly suggest you consult a FSM, to determine/confirm the rocker shafts are oriented properly, AND while you're at it, also confirm the soft plugs are in place at both ends of both shafts
 
Good points. I believe notch on shaft faces down and to your left when hanging over the fender. So drivers side would be down and front, passenger side would be down and to firewall. Check the adjusters to see if any have loosened up. They are an interference fit and tight to the rocker. Unless they have been modified with upgraded adjusters and locknut.
Side note ....I just checked my adjustable rockers and shafts for my 340 build....bo notches? Sorry for the hijack.
rustycowll69 said:
bent pushrod? how was that one rotating?
I strongly suggest you consult a FSM, to determine/confirm the rocker shafts are oriented properly, AND while you're at it, also confirm the soft plugs are in place at both ends of both shafts
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Bent pushrod, don't know if solids or hyd...... pull the intake so you can work on it easier and check the lifters, potential cam damage, and check for correct pushrod length for sure.

If in good shape, order pushrods, install a timing tape on the damper and use the Direct Connection crank rotation method to adjust rockers.
 
Outsder said:
Bent pushrod, don't know if solids or hyd...... pull the intake so you can work on it easier and check the lifters, potential cam damage, and check for correct pushrod length for sure.

If in good shape, order pushrods, install a timing tape on the damper and use the Direct Connection crank rotation method to adjust rockers.
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Definitely solid lifters. Removed them all and only found the 1 exhaust valve pushrod on #1 cylinder being bent. Planning on ordering a new set of pushrods and learning how to adjust the valves myself. Can add this to my list of firsts since I've owned my car 5 plus years.
 
4spdragtop said:
Good points. I believe notch on shaft faces down and to your left when hanging over the fender. So drivers side would be down and front, passenger side would be down and to firewall. Check the adjusters to see if any have loosened up. They are an interference fit and tight to the rocker. Unless they have been modified with upgraded adjusters and locknut.
Side note ....I just checked my adjustable rockers and shafts for my 340 build....bo notches? Sorry for the hijack.


View attachment 1715746239

View attachment 1715746240
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on top pic(of two) it has a ground "flat" spot instead of a milled notch.
 
Before installing the new prod, I would be finding out why the original one bent...
 
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