440 pushrod length and lifter preload

[MRB2U]

Sorry if I missed a previous thread showing this...
440, new 1.6 Mancini (H/S) roller rockers, new lifters, trying to get pushrod length (cup/ball) and set preload.
I listened to someone who told me to prefill the lifters, now I read that I should measure and set dry.
Question: if the lifters have been pumped up, can I find my pushrod measurement and set preload properly?

Any help will be appreciated...

 

[lewtot184]

you need a checking push rod to do this. the tappet doesn't need to be pumped up to check push rod length but it's ok if it is. lifters shouldn't be pumped up prior to start up.

 

[MRB2U]

Thank you,
I have the checking pushrod, but it appears that the lifter plunger after being pumped does not spring to the top (retainer) it stays down in the bore a little ways, when new it is at the top, and that is where "I now" understand is the point of measurement. Crane Cam tech told me I have to release all pressure to properly measure and set preload. Was hoping not to do that, and if I do, what is the easiest way?

 

[DWilbur]

I did this about a year ago. I set the number 1 piston at TDC then took 2 lifter apart and shimmed them so they were solid put them back together and used an adjustable push rod to get the length of the intake and exhaust push rods. I was told to add if I remember correctly .30 or .50 to the length. I did this on each cylinder to get the length for intake and exhaust push rods and ordered a set.

 

[lewtot184]

not sure i understand the question, what pressure?

 

[Oldtimer]

Contact tech rep @ Manton Pushrods. They will give you the answers, you ar looking for in getting your valve train setup correctly.
http://mantonpushrods.com/

 

[Meep-Meep]

To establish push rod length you need to watch the rocker through it's entire motion and how it rides on the tip of the valve stem. Obviously the rocker pad or roller will sweep over some portion of the stem and you want to basically have an even amount past center. Also you don't want too much adjuster hanging out so put the push rod cup as far towards the rocker as possible. Ideally, if you draw a line from the pad through the shaft CL it should meet the center of the ball. On iron adjustables I have found a thread or two peeking out of the rocker is about right.

 

[MRB2U]

Thank you, and for your patience with a rookie...
Lifters pumped up, 1 thread showing on adjuster, I show 8 7/8 (avg) OAL. Mancini said 1-3 threads showing when adjusted, crane said 2/3 of a turn preload.
I think I am good there, corrected me if I'm wrong.
But because I pumped up my lifters, do I need to bleed them off before starting, will that cause any excessive pressures in the valvetrain.
Also, I checked roller to stem contact (without pushrods) just tapping roller on stem by hand with black marker and it shows off center to the intake side, is that about where it should contact?

 

[383man]

What you are doing is once the lifter is on the cam base and you have about 2 threads showing on the bottom of the rocker then you adjust the pushrod to take out all play until the pushrod is in the lifter cup at the top and the lifter plunger is not down in the body any. Thats then at zero clearence and then you add about .030 which is how much the lifter plunger will be down in the lifter body. That is the lifter preload which some give it more but most say about .030 to .050 as I like them higher in the lifter body and set mine at .030 when I do a set. That way if you race and over rev the eng they can only pump up .030 and gives less chance of the valve hitting a piston. Actually some racers just set them at zero but it give a little lifter clatter sometimes. Ron

 

[lewtot184]

Thank you, and for your patience with a rookie...
Lifters pumped up, 1 thread showing on adjuster, I show 8 7/8 (avg) OAL. Mancini said 1-3 threads showing when adjusted, crane said 2/3 of a turn preload.
I think I am good there, corrected me if I'm wrong.
But because I pumped up my lifters, do I need to bleed them off before starting, will that cause any excessive pressures in the valvetrain.
Also, I checked roller to stem contact (without pushrods) just tapping roller on stem by hand with black marker and it shows off center to the intake side, is that about where it should contact?

starting the engine with pumped up lifters could cause a piston to valve issue.

- - - Updated - - -

To establish push rod length you need to watch the rocker through it's entire motion and how it rides on the tip of the valve stem. Obviously the rocker pad or roller will sweep over some portion of the stem and you want to basically have an even amount past center. Also you don't want too much adjuster hanging out so put the push rod cup as far towards the rocker as possible. Ideally, if you draw a line from the pad through the shaft CL it should meet the center of the ball. On iron adjustables I have found a thread or two peeking out of the rocker is about right.

above is what i do to check geometry.

this is what i do for push rod length. i have the lifter on the heel of the lobe , valve closed and then use a checking push rod to measure length.

- - - Updated - - -

i don't do the 2-3 thread showing thing anymore because todays's adjusters are not the same as the adjusters when the 2-3 thread showing was recommended. todays adjuster have the ball extended compared to the older versions. this puts the adjuster/push rod geometry in more of a side load as the tappet rises and can break the adjuster (remember all the adjusters breaking a few years back?).

 

[383man]

starting the engine with pumped up lifters could cause a piston to valve issue.

- - - Updated - - -

above is what i do to check geometry.

this is what i do for push rod length. i have the lifter on the heel of the lobe , valve closed and then use a checking push rod to measure length.

- - - Updated - - -

i don't do the 2-3 thread showing thing anymore because todays's adjusters are not the same as the adjusters when the 2-3 thread showing was recommended. todays adjuster have the ball extended compared to the older versions. this puts the adjuster/push rod geometry in more of a side load as the tappet rises and can break the adjuster (remember all the adjusters breaking a few years back?).

One big reason for the 1 to 2 threads is of course for the oiling of the pushrod cup as I have seen some guys burning the pushrod cups. So I would agree if the rocker or adjuster is different then you need to consider the oiling of the cup and as was stated dont want to much below the rocker causing to much angle. But all that has to be considered when checking the pushrod lenth. My Huges rockers worked very good with 1-1/2 to 2 threads showing and I used my adjustable pushrod to get my lenth like that. They dont have any extra hanging under them. I used Manton to make my pushrods and had good service and a quality part. Ron

 

[lewtot184]

if I can get pictures together of the adjusters maybe it would be easier to understand.

- - - Updated - - -

there are four adjusters here. two early, too late. notice how the ball extends further on the two later adjusters.

 

[MRB2U]

Thanks everyone, appreciate all the help!
And yes lewtot184, I do have the longer adjuster ball length.
Thanks again.

 

[383man]

if I can get pictures together of the adjusters maybe it would be easier to understand.

- - - Updated - - -

there are four adjusters here. two early, too late. notice how the ball extends further on the two later adjusters.

I see what you mean. Ron

 

[lewtot184]

the top adjuster is the /6-318 one piece from back in the '60's.

the second from the top is the adjuster used in the '60's up into the late '90's. it has the screw driver slot with a jam nut and the ball really isn't completely circular. i believe this is the "2 thread showing" adjuster that is referred to in the engine books. letting the ball hang down a little made sense. back when this adjuster was first used, probably late '50's early '60's, .500" lift cams were unheard of.

the bottom two are the same and the ball is extended .100" which is equivalent to 2 1/2 threads with a 3/8-24 screw thread. extending the ball further will probably cause geometry and oil problems leading to breakage. pretty sure this is the adjuster everyone had problems with mainly because they were extending the ball too far, running high lobe lifts with high spring pressures. anyhow, i'd shoot for no threads showing with these. these adjusters have obsoleted the short ones. with higher lobe lifts more ball radius is needed.

anyhow, whatever a person does it needs to be cycled thru with checking valve springs and a close eye to make sure there isn't any issues. another note, harland sharp adjusters are different and i don't have any for comparison.