Longer pushrods, or can I use lash caps?

Tried that. They are .650 longer, I only need .060 extra.

 

Ok, unconfuse me. I've only worked with solids an clevelands in last so years.

You are only getting proper rocker valve alignment right now with your pushrods, right?

You have a hydraulic roller (right?) so if you get proper contact on valve with rocker in lift travel, you'll have right pushrod and just have to adjust valves with rocker adjustment.

Am I on the right track of what you doing here? Pushrods can be bought in .050 or .060 different lengths.

Also, did you talk to Comp tech?

 

Scooper, you need to check for proper pushrod/rocker geometry first. THEN add the .060" of preload to the length you determine and that will be what you should order. Remember, that 8 of one length and 8 of another. If you order all 16 to the longer length, you could shim the pedistals with a .060" shim to get the preload right on all the lifters. Make sense? Hope this helps. Ben

 

Rocker arms bottom out before I get a chance to set preload. And then still have a .060 gap/slop. When I get the rockers tightened down, I can never get the wiggle to go away on the rocker arm (cannot get to 0 preload). I need a longer pushrod by .060 to get me to a point where I can get my rocker zeroed, then preloaded.

And only on exhaust valves.

Yeah, ben, makes sense. still $15 per rod...

I will give comp a call and see what they have to offer.

 

Comp guy said best bet is to buy .100 longer rod, then shim my rocker up the .040 or so that I need to meet my .060 difference.

He said that cam may likely have a different base circle because of the much higher exhaust lift.

 

You need to use the tie bars accross/ between the rockers of each cylinder.
The pre-load on the lifters is speced between .020 and .060" lifter plunger travel.
The only way to absolutly know what pre-load you have, is to use a dial indicator and understand how to use it.
I set all mine up using this method and corrected for misaligned rocker roller tip position on the some cylinder valve stems.
Some heads are not machined with the rocker stand holes in perfect alignment and can misalign the roller tip to stem position.
If you have to do large girations such as stem caps, something is wrong.
Also the push rod lengths are different between roller setup and non roller set up even with pedistal rockers.
Aftermarket cams can indeed have a difference in base circle making the rocker set up a slieight hassle, so you must accept what you have to work with and make the changes needed to get the geomertry correct.
And don't mix roller cams with non roller lifters etc.
Sometimes you need shims, other times a little bit has to be machined off the rocker stand if not quite enough preload is ontained.
But this is all done within less than .050" to still have the rocker tip travel on the valve stem tip on the correct center area or you begin to look at different length push-rods..
It's all no different than work done in a machine shop of any kind where precision is the only way to get a proper job done.

 

Hmmm....machine down the pedestal mounting bumps on the heads...

That would work.

I think I will spend the $100 on the 8 longer pushrods. Considering I have a custom ground fairly big roller cam, roller lifters, dogbones and spider bar for free, I cannot complain about spending $100 on a couple of pushrods...

 

You did't see me say that. {machine the head bump.}
I did say the bottoms of the stands, not the head pads.
Unless you do some precision measuements, don't do anything like that.

 

No, I am done messing with heads. If I was going to do that I would do it to the ported heads I have. I want to leave these stock.

You didn't say anything about machining those bumps down, but while I was reading your post, it gave me that idea...

Now, when I cratered that last lifter, I was trying to pick up lost space by grinding down the pedestal stands. It made some improvement, but I had to overcome something close to .200". You think I could grind away .060 and get by like that?

 

I know this will cost you more than a 100 beans since you will have to go to a normal roller rocker as opposed to the pedestal type but:Have you thought about changing to regular rocker studs and guide plates??? the stuff is available to retro fit pedestal heads to rocker studs and guide plates.Makes valve train geometry problems easier to solve and less likely in some instances.Just a thought.I know you are trying to spend less not more.

 

You need to get the Geometry rite first,Comp sells a adjustable pushrod that you can use to measure with,( about 20 bucks last account i had) it is strong enough to actually roll the motor thru( to see where your rocker is traveling) If you grind on the pedestal im afraid you will surly ( don't call me Shirley) mess up the geometry.

 

Well, good thing is I have two complete sets of the little pedestal inserts, that sit on top of the shims. I may mess with one, see how it fits, run the motor over and see how the roller tip rides on the valvestem. It just MIGHT work...

Might start with the one I started griding down after i lost the lifter.

Cannot hurt anything, and easy to swap back to a fresh one.

And since the motor is not running and I'm still broke, may as well mess with free stuff that will not permanently screw up parts.

Again, I want to thank you all for working through this with me. Can't help but accidentally learn something along the way

 

The rocker stand has to be chucked into a lathe for precision bottom facing. No hand filing unless your good at it like a gunsmith or it could end up at an angle and cause more problems with valve stem contact.
The hold down bolt would no longer be concentric with the stand hole if the stand sets at an angle.

 

All credit goes to "Benny C" (although I knew what the problem was all along. I just wanted Scott to sweat a little of that vino off for his own good. ). Glad to hear the cause has been identified.

'You're right Scott - a lot of us are learning from the spillage of your blood, sweat and tears over this project.

 

Scott, you will need a solid lifter to check pushrod length accurately. No problem of cost you can make one for free out of an old hyd roler lifter, if you have one laying around or go to the junkyard and get one. Just mark it good so you don't get it mixed in with the good ones.

Just remove the spring clip out of the top, take out the pushrod cup and plunger and spring. Turn the plunger upsidedown and reinstall. re-assemble the pushrod cup and spring clip. Thats it---solid lifter that is the proper length.

Make an adjustable pushrod for checking the length from an old pushrod. Cut it about 1 inch from either end. Remove enough material so it will be about 1/2 inch shorter than what you need to fill in between the above mentioned solid lifter and rocker. Now tap the inside of both pieces of pushrod with a 1/4" tap and insert a length of 1/4" allthread with a jam nut. Make sure you tap enough so that the allthread is in the pushrod quite a ways for strength. Then when you establish the proper geomentry, just measure the pushrod, add .030"-.040" for the preload and order. Order 16 of the LONGER pushrods needed, and shim the pedistalls on the 8 intake pedistalls to match the preload on the 8 exhaust.

Almost free tools that are invaluable. Everyone building an engine other than stock should have these in thier toolbox.

Double, triple check everything, before firing the motor. Not hard or expensive at all, just a PITA. Thats why I try to always do fully adjustable rocker studs instead of pedistals. Hope this helps. BenC