Is there any prep necessary (engine at normal operating temperature, or recently started to pressure up the hydraulic lifters) prior to adjusting valves? Or can you just pop the valve covers off, rotate the engine over to top dead center (compression stroke), and just starting adjusting anyway?

 

Lar's has a great write up on this. Go under "other" above, click "Tech Tips" C 3. It's there. Explains everything, step by step.

 

To answer your question, no. Your engine does not have to be hot to adjust hydraulic valves...unlike solid lifters whose tolerances are much tighter.

 

I recently had an issue after a valve adjustment.
I actually bent a push rod.

I will from now on pull the valve cover run the engine until I get oil to the top of the push rod.
take the slack out of the adjustment.
Then adjust the lifter. Lunati suggests 1/2 turn with their lifters.

Ralph

 

Warm or cold, I prefer warm

 

So they warm them up and them adjust the valves when they are being made at the factory ?

I don't want to get anyone mad or anything but some things just never go away, personally I should give up but the reason I have been here so long is just to help. Maybe I should go

When adjusting hydraulic valves all you are doing is putting a preload on the spring inside the lifter. There is lots of room for error ( as in half a turn, one full turn etc. ) but you can do it warm or cold, oil in the lifter has no effect on adjustment of a hydraulic lifter

 

Motorhead speaks the truth.

 

Wow, now I'm a little confused. Seems like more votes for cold...doesn't matter. To be on the safe side, i will probably run the engine to get the oil circulated. I will check Lars's post as suggested.

This will be a project for next week

Thanks everyone

Pat

 

I understand what motorhead is saying.

I have adjusted my own valves for 40 years.

Last month I put roller tipped rockers and new +.100 push rods on my 75.

I drove around town for 3 or 4 miles no problem.
I started up the on ramp of the freeway and bent a push rod.

The way I figure it one of two things happened.

1) the lifter pumped up causing the valve to hit the piston. Exhaust valve on number 8.

2) The new hardened push rod bent all by it's self.

Ralph

 

You simply over-tightened that rocker arm, thats all, it has nothing to do with cold/warm adjustments.

Maybe its just easier to do it while ALL the lifters are pumped up with oil, so you can firgure out the zero lash more easily.

I was helping a friend to fire up a newly built 406, I was trying to find the firing TDC so I removed the #1 plug and put my finger so I can feel the pressure while he cranks it with the starter, to my surprise there wasn't any!, I asked him if he is sure he didn't forgot to slide that piston in! , turned out that he over tightened the intake rocker arm while doing so with the engine cold and lifters empty of oil, so the valve is not closing fully and the piston could not pressurize the cylinder, its amazing how a small mistake can cause sometimes a devastating results. Bottom line is that you can do them cold or warm, but you have to be REALLY careful when finding your zero lash.

 

Not a chance.

1st I have a 75. It has dish pistons there is a lot of room between the valve and the piston.

How many turns to many would it take to put the valve to piston close enough to get a 3/8 bow in a push rod.

I was very carefull, trust me.

The lifter had to of " pumped up" for this to happen.

I rolled the push rod back and forth untill it was tight and then added 1/2 turn.
Just like the other 15 valves.

I do have 80# of oil pressure at freeway speed and 60 or so at idle.

 

It's easy to depress the lifter plunger using the "roll" method.
I preferr the "up and down" method with the pushrod on a newly assembled engine. Just make sure you're on the heel of the cam by whatever method you choose. Then I find it a lot easier and faster to adjust them hot and running. Use the number of turns the lifter manufacturer recommends or slightly less.
Spring bind will also bend push rods.

 

Adjust them running. Either pick up the oil stoppers for each rocker or grab an old valve cover. (tin one) cut it so unfolded it catches most of the oil. While running and warm, back them off until they begin to clack and tighten them a half turn. First a quarter turn then the second quarter turn.
Then they will be adjusted in the condition they will be opperating in. That way you won't miss the correct location on the cam lobe.

 

Valve adjustment and finding #1 TDC discussions are pretty popular and mysterious topics.
Pat,they can be adjusted cold like the factory does or like more experienced car guys do OR warm. Cold or warm will work but for the novice there is less room for error when the lifter is pumped up (warm).Warm and lifter pumped up makes feeling 0 easier for the novice.
Understanding the plunger travel in the lifter is a must.
Briefly-the plunger has a travel top to bottom of aprox. .140 , when your doing the touchy adjustment of "0" the plunger must be at the top( this the most important adjustment),when you do your 1/2 , 3/4 or 1 turn down your positioning the plunger down somewhere in the .140 travel.Factory likes it close to the middle,down .070 or 1 turn with stock rockers. This allows .070 up and .070 down.
Getting a lifter in hand and feeling the light spring under the plunger might help,once the lifter is warm or pumped up the plunger is very hard to push down.
You need to develop the " 0 touch".
Hope this helps a little.

 

Don't leave,you know this can be a very confusing adjustment for a novice. I'm sure you have run into things during your builds that was confusing until AFTER you had done them successfully. I'm betting you did some things over and over making sure it was done right.

I think some of the confusion and room for error is in the terms ,cold ,warm, hot , pumped up , primed.
Just guessing but I doubt the factory adjusted the lifters oil-less or not pumped up. Wouldn't they have already spun the motor and primed it ,so the lifters would have been pumped up ? I think "pumped up" could be thought of the same as warm.

Finding #1 TDC is part of this process and is another confusing thing for the novice.

 

One other thought and I'll shut-up. I think a door would open up if a novice could view an engine with the intake off so they could see the plunger while turning down the rocker nut.
With the intake off its easy to do the 0 adjustment even with a dry lifter (no oil,not pumped up).

 

If your engine is together then sure, run it if you like or adjust them running if you can deal with the mess.

However, it is not necessary. I just did a cam change for example. Running the engine first is not an option. It IS possible to correctly and accurately adjust the valves with a cold engine, no oil in it, lifters right out of the box. I adjusted them once, broke the cam in and a week later took the car to a dyno for a few 5k rpm pulls. I did have the benefit of having the intake removed.

With the intake in place, I can see there being a bit more of a challenge to get to 0 lash. Mark your balancer in quarters and take your time.

Best regards,

john

 

Years ago a friend of mine had a '72 C20 truck that was running crappy; his know-it-all 'mechanic' had 'adjusted' his valves. Since he knew I was a novice gearhead, he then condescended to ask me to take a shot at it. Mind you, I had never done this before; but I did know cylinder 1 from cylinder 8 so I opened up a Chilton's (which spelled out the procedure verbatim) and adjusted the valves, COLD, just like the book said, something like "get subject pushrod/rocker on cam base circle, loosen rocker till sloppy, then slowly tighten rocker nut while twiddling pushrod gently and sensitively back and forth like a giant booger. When pushrod just begins to drag, you be at zero lash. Add a half turn. Repeat 15 times." I did that, and lo and behold, when he turned the key that baby fired right up and purred...
I have also adjusted valves on old motors where the lifter springs were so flaccid that you could barely tell where zero lash was; you'd have to go back and forth with the rocker nut several times to get it right. It does take some sensitivity. I have also built a number of brand-new engines with brand-new cam and lifters; on every one I set the lash once, COLD, when new and never touched them again. I prefer doing them cold because the low temperature puts just a little more tension in the plunger springs and makes it easier to 'find zero'.
Curiously, Ford engineered a system on their later hydraulic lifter-equipped engines where the correct lash was literally machined into the rocker pedestals. As long as you were using all OEM pieces you just threw all the parts in there, bolted the rockers down tight, and you were done. I wonder why they did that??
One of the greatest things about this forum and others like it is the wealth of information available...it can also be one of the worst, since most noobs are repeatedly confronted with many conflicting opinions that often have little basis in sound logic. Love to all!

 

And they also had different length push rods available for proper lash setting. What a PITA
Pontiac, Buick and Olds also used non adjustables.

 

Sorry but I would have to disagree on the last sentence statement, 1964 Bonneville 389 were adjustable fwiw Ed