Valvetrain geometry setup problems and questions

[Killercanary]

RANT- I HATE PEDESTAL MOUNT HEADS!!!

OK, so I'm trying to get my engine put together and I worked on setting up the valvetrain tonight. Its been almost 5yrs since I last did this and I forgot how much I hated it. I have a problem, I'm using a pushrod length checker to determine what length I need for proper pre-load. I think I have the length I need but I have two problems:

1. I need a shim under the intake pedestal to get obtain the proper preload. Without the shim I'm getting a hair over a 1/2 turn preload on the exhaust lifter. To get the same on the intake I needed the thinnest shim from my pack with the same length pushrod. I had to run this same setup on my old combo with my AFR 165's. The preload is the same on the intake and exhaust, but the pushrods show different wear patterns. Does this wear pattern tell anyone anything? My gut tells me that it shouldn't be different, but the preload is similar. I assume its a geometry issue, but I'm not sure. Here's a pic:

The pushrod on the right is the one from the exhaust, the pushrod on the left is the intake that has the shimmed pedestal. You can see that the entire end of the exhaust pushrod is shiny (on the right) and only a little part of the intake(on the left) is.

2. Second problem is that with these 185's, with the pushrod length adjusted so that I get 1/2 turn of preload the roller rocker roller tip is sitting on the back side of the valve tip. The only way I can think to get the proper geometry is to put thicker shims under the pedestal. I haven't had a chance to rotate the engine to see the total valve tip travel of the rocker, but I think its too far towards the lifter valley. What do you think? If I need to move the tip more towards the center of the valve tip how do i accomplish this with pedestal mount heads? I'm thinking I need to run shims under the pedestals and run longer pushrods, is that correct? The roller tip is not running off of the valve tip JFYI.

Here's some pics:

 

[gmkillr]

Those look like 2 different style pushrods there, maybe their lies the problem??
The tips look different and so do the oil passages. I dont know very much about valvetrain setup so my opinion could be off. Sorry I couldnt be more help. Good luck!

 

[Killercanary]

Rob, they are the same exact pushrod, but it does sort of look like they are different in the pics. The entire end of the one on the right is worn and shiny, the one on the left only has a thin shiny ring. Thanks though!

 

[eagleautosports]

Looks like you definately need longer rods. That roller tip needs to be in the middle of the valve before, during, and after you rotate the engine over. Mark the top with a marker and look at the wear pattern.

 

[Killercanary]

Here's a crude pic that shows the pushrod wear:

 

[Killercanary]

Looks like you definately need longer rods. That roller tip needs to be in the middle of the valve before, during, and after you rotate the engine over. Mark the top with a marker and look at the wear pattern.

Thanks for the reply. That's what I thought I'd have to do. I was all excited when I got the proper preload and then I looked at the roller tip. I can't find my old shim pack so I guess I'll have to buy a new one to get the rocker up higher and then go back to the drawing board on pushrod length.


Does the wear pattern tell anyone anything? There has to be a reason why it looks like it does, but I don't what that is. When installed on my old combo, the rocker tip visually looked to be in the same location on both the exhaust and intake valve tip and preload was virtually the same.

 

[blksn955.o]

I just went threw this over the winter.

I took the approch that the rocker needs to be setup properly with the shims. I went from no shim to .030 to .060 to .090 and depending on what rocker (crane factory cobra 1.7's that had to have a lash cap to clear the springs or the factory ones) I used I found what shim I needed for proper rocker geo. first.

Once I got the rocker setup to the correct travel and mid lift setup I then took the adj. rocker and adj. until there was drag and trqd. the rocker.

If your close on the PR remember on stock lifters there is like a .060 or something toll. in how far you can go preload. The important thing that I have seen/heard is that the travel of the rocker is correct.

The rocker tip should be dead center at mid lift of the cam and as narrow of a mark as possible. I used greese on the valve head and the line will get narrower with the correct shim without turning over the valvetrain. It has to do with the angle of the tip...the correct setup has the narrowest line as its the most effic. use of the leverage.

 

[eagleautosports]

Are you sure that valve was getting the proper amount of oil? It looks like it was definately not getting lubrication and eating itself. Use that pushrod length checker and extend it until it reaches the proper position. You can shim pedestal rockers only so much before you have to go to stud mount.

 

[gmkillr]

Paul, Id try posting this on Hardcore 5.0 in the smallblock ford engine section.

 

[final5-0]

Paul

Thoughts more than help here but ...........

I'm no expert at setting up vt's but it does look like you need to get the pivot farther up to scoot the tip closer to the center.

IIRC, even though the optimum is for roller travel to be centered

I seem to remember a split like 60/40 is OK

I like the idea of getting the hardcore boys thoughts as well

If you don't mind ... Let us know what you decide to do

Grady

 

[Black95GTS]

As far as wear goes, I can't tell you.

Far as the rocker... I would "de-shim" it till its too far off, then shim again till its too far over, and take the middle, using that shim. Sort of like finding true top dead center but with pushrods. I'm not so good at explanations so please yell at me if you need me to explain better.

coughstudmountsandshaftrockerscough

Excuse me.

Adam

 

[blksn955.o]

Dont guess,

get a mag base and a dial and on the lifter go to the mid lift. To get the number you need to see on the dial for mid lift take your cam lift (if given with 1.6 or 1.7) and divide the rocker from the lift. So with a .500 lift cam that uses 1.6rr divide .500/1.6=3.125. Then for mid lift divide again by 2 so you get 1.5625 at the lobe. Rotate the motor until you see this number from the dial. Then take some greese and lightly coat (realy realy lightly) the valve head. Mount the rocker making sure to keep it still and not moving. trq down and remove you will see how far off from center it is if it is not shimmed correctly. As it gets closer to center it also will leave a narrower mark in the greese.

It may take a few times to get it down but dont guess. Your spending the time and it is ALOT easier to do on a stand than in the car (I sucked doing it this winter in the garage bent over).

with it not centerd' you run the change of putting too much stress on the valve/springs/retainer and you will wear out those parts due to the added stress and run a higher rate of dropping a valve, breaking a spring, ect.

 

[yellow1995Cobra]

How come you bought pedistal mount heads again paul? I recall you complaining about setting the 165's up.

 

[WhiteDevil]

I wish i could help but i only know how to do stud mount heads. I just check my geometry and this is the wear pattern you are lookin for.