I have a 68 240 six in my F100 and recently installed a new cam, springs and lifters. After adjusting the valves according to my original factory manual that says to place cylinder at TDC then tighten nut until no pushrod can no longer be turned to eliminate clearence then tighten 1additional turn. After doing this the motor would not start, so I backed off adjustment 1/4 turn and it started right up but had some valve clatter. Someone told me to adjust them while the motor is running by loosening the nut until tapping is heard then tighten 1/4 additonal turn. I did this but there is still some clatter and after the motor has been left to sit overnight the rockers have a lot of play in them when they are on their base circle. I also noticed when I added an aditional 1/2 turn to all the nuts following the correct sequence, by the time I was done most of the lifters had bled down enough that I could pump the pushrod up and down about a 1/2 centimeter, but some of the lifters could not be pumped up and down so what gives? I placed each lifter on the cam base circle but some could be pumped and others could not. All valves were adjusted in the same way and given the same number of turns, but I still hear some clatter. I thought I read somewhere that the plunger in the lifter should be 1/2 way down and I know that with only 3/4 turn down after contact it would not place the plunger 1/2 way down. So what is the correct way to do this?

 

The way I remember adjusting hyd lifters is to tighten the rocker nuts until the pushrods stop spinning between your fingers then add a 1/2 turn more. Remember that your new lifters and cam maybe more finiky then the 60's technology. Just a thought at least.

 

[updated:LAST EDITED ON 05-Apr-02 AT 11:18 AM (EST)]I've allways thought you tighten the nut as you turn the pushrod between you're fingers.When you feel resistance you tighten a 1/4 of a turn.If you tightend em until they stopped spinning and then another turn that's too tight.You may have bent a pushrod,thats why you're getting noise now.Spin them between you're fingers with the nuts loose and look for wobble.If you went with a different cam or springs or had your heads or block milled you're pushrod length maybe wrong.You could have a collapsed lifter,that's not pumping up.

Billy

 

OK Did you pump up your lifters before you installed them ??

 

Yes, after installing the lifters I primed them all using my drill and hex drive till oil flowed out of all the pushrods turning the crank several times while doing that. I pulled the #6cyl. pushrods where the tapping seems to be coming from and they were straight. When I run the engine and place a finger on the retainers I can feel no stinging or sharp tapping only hear it. All the rockers seem to to be moving the same and I tried to put a thin feeler gauge to see if there was any gap but could not get any thickness in.

 

 

LOL, sure glad I found this thread NOW. I'm rebuilding my 240 and have the bottome end together and getting ready to put the head on. This is some handy info to have.
Thanks Guys!

 

LOL, sure glad I found this thread NOW. I'm rebuilding my 240 and have the bottom end together and getting ready to put the head on. This is some handy info to have.
Thanks Guys!

(I hate it when I double post- Sorry)

 

Sounds like you bent a push rod. Take them all back out and roll them on flat surface to check. Once you find and fix the bent ones (buy new ones), the sequence for adjusting is :

This is cylinder by cylinder looking at the lifter or rocker
With the intake opening fully and returning 1/2 way adjust the exhaust valve
To do so rotate pushrod and lift up and down while tightning nut until all lash is gone this is right before the lifter cup depresses. Once at zero lash tighten additional amount cam and lifter manufacturer recommend. If none given 1/4 to 1/2 should be sufficient.

For the intake, rotate crank till exhaust valve fully opens, and repeat lash and tightning sequence as you did for the exhaust valve.

Repeat procedure for remaining cylinders. This is meant to be done cold with lifters fullly primed first. If your drill will not pump them you can use an old oil squirt can with some motor oil in it and manually pump oil into the hole on the side of the lifter until all air bubbles stop.

This is the procedure I used on all marine and automotive engines I've built. Never have had to pull a valve cover to readjust vavles afterward. Reason I do them cold is on marine engines it is to much of a pain to have too pull exhaust manifolds to get to the valve covers to do a hot lash.

P.S. Make sure you are using the correct lifters with the cam ie. hydralic flat tappet lifter with a hydralic flat tappet cam not a hydralic roller or solid cam. This will also cause the issues of rapid clearance degradation like you speak if the pushrods are not bent