Having trouble with Pedestal rocker installation

[5.0calypso93lx]

Combo is 1.7 pedestal rockers and an F cam.

See this thread for a little background of an issue I ran into when trying to measure pushrod length:

http://www.stangbangerz.com/forums/showthread.php?t=79203

So I got the pushrod length measured by using two stock lifters made "solid", having the number 1 cyl TDC so the lifters are on the base circle of the cam, and an adjustable pushrod.

This is the result I got with the adjustable pushrod at 6.375":

http://i446.photobucket.com/albums/qq188/bad306lx/538103_10150628550306847_736166846_9748119_3715401 15_n.jpg

Since they don't make off the shelf pushrods in the 6.375" I decided on a shorter 6.350" pushrod.

I used these instructions to install the rockers:

http://www.cranecams.com/uploads/instructions/453e.pdf

The part I'm not getting the right results on is when I'm actually tightening the rockers. I did what the instructions say by starting on cylinder 1 TDC which should have the lifters on the base circle of the cam. It then says to hand tighten the rocker down until the pushrod won't turn by hand / the rocker will no longer tilt back and forth. It then says to torque the bolt to 18-20lb ft slowly.

Now I only have my big Craftsman torque wrench but it does go down to 20lbs. I set the torque to 20lbs and began tightening very slowly. The instructions say that you should only be able to turn a 1/4 to a full turn. By the time I get the torque wrench to "click" i'm damn near 3 full turns of the bolt and the valve spring is starting to compress.

What am I doing wrong here?

[03z06vette]

So, sounds like the lifter isnt compressing. The lifter (after being soaked in oil) is the same highth as the make shift solid? From there, when you tighten the rocker can u see the lifter compressing? If not, just torque them down and turn the motor 1/4 turn each direction BY HAND!!!! that will vent some of the oil. Then, Back to TDC loosten and retorque to see if your lifter cooperates with the spring. If the spring still compresses id say you need rocker shims or srings are week!

[5.0calypso93lx]

So, sounds like the lifter isnt compressing. The lifter (after being soaked in oil) is the same highth as the make shift solid? From there, when you tighten the rocker can u see the lifter compressing? If not, just torque them down and turn the motor 1/4 turn each direction BY HAND!!!! that will vent some of the oil. Then, Back to TDC loosten and retorque to see if your lifter cooperates with the spring. If the spring still compresses id say you need rocker shims or srings are week!

The lifters and pushrods were both sitting in oil overnight before I installed them, so yes they were soaked in oil. The lifters I used to measure PTV and pushrod length are stock hydraulic roller lifters with the inside gutted and washers stacked to make them solid.

I will give that a try Tom. I am not sure if the lifter is compressing when I torque the rocker arm down, that is something I will check and report back with. I always turn the motor over by hand by using a socket on the balancer bolt.

[03z06vette]

did you measure both lifters to make sure they are perfectly the same? Dont turn the engine all the way untill this is figured out. you may hit a valve if this is not the fix.

[5.0calypso93lx]

I will measure those as well tonight.

I also found out that the highest and lowest torque settings on a torque wrench can be fairly inaccurate. If I measure everything and find everything to be the same I may start looking at finding a smaller torque wrench.

[Gearhead]

The intake manifold is torqued down already ?? If not, you should be able to see if the plunger in the lifter is compressing or not when you tighten down the rocker arm.

[5.0calypso93lx]

The intake manifold is torqued down already ?? If not, you should be able to see if the plunger in the lifter is compressing or not when you tighten down the rocker arm.

Scott, I thought I had what I needed as far as measurements go so I went and ahead and torqued it down. BAD idea LOL.


I'm thinking I have other issues than my torque wrench at this point. I bought a shim kit that contains 16 of the .030" shims and 16 of the .060" shims. On the intake valve the .060" shim worked great and I was able to torque the rocker down to 18lb/ft at about 3/4 turn. The exhaust valve however, would never torque down before the rocker would eventually pushed the valve spring down and open that valve. This continued onto the next cylinder, 3, so I stopped there.

After calling Jason, I found multiple problems with the process I was using to do all the valvetrain. The first mistake I made was only measuring the intake valve when I was checking for pushrod length. The second mistake is that I was using Crane Cams instructions and was torquing both rockers down at what I thought was TDC cylinder 1 and working my way around per the firing order.

The third mistake is I was using the method of putting my finger over the spark plug hole and when I felt it just start to push is where I determind TDC to be.

I now understand why what I thought was TDC is probably not even that close to TDC and even if I was at true TDC on the cylinder I was torquing the rocker at, that doesn't even necessarily mean I'm on the base circle of the camshaft, which is where I should be torquing the rockers.

I'm going to pull the intake back off so I can see exactly what the lifters are doing and am going to remeasure both intake and exhaust pushrod lengths.

One question I did have is when should I actually be torquing the intake and exhaust rockers? I don't think that being on TDC on that particular cylinder I'm working on is good enough. I know it's something along the lines of as soon as you see x valve open/close tighten x rocker, etc.

[bangingears]

once you have determined the proper pushrod length, and the correct amount of preload on the lifters, just tighten then down. It doesnt matter like a adjustable rocker

[5.0calypso93lx]

once you have determined the proper pushrod length, and the correct amount of preload on the lifters, just tighten then down. It doesnt matter like a adjustable rocker

Jason, maybe I misunderstood but how do I go about checking / measuring the preload on the lifters?

[facemelter71]

I watched Maximus tighten the rockers down when we were working on Twisted Twins. Thats the way I had done it on my engine. Lets say its cylinder 1. I waited for exhaust to open fully and tighten the intake down. Then Vise Versa for the exhaust.

[5.0calypso93lx]

I watched Maximus tighten the rockers down when we were working on Twisted Twins. Thats the way I had done it on my engine. Lets say its cylinder 1. I waited for exhaust to open fully and tighten the intake down. Then Vise Versa for the exhaust.

I think that's close except for the exhaust side. I wouldn't think you'd want to adjust the exhaust when the intake is fully open because of possible overlap with the cam. The exhaust valve is always going to open after the intake valve does. Wouldn't you want to adjust the exhaust as soon as the intake starts to open?

[Rick93coupe]

Hey James, in my experience you can't just soak a lifter in oil. I've always submerged the lifter and used a pushrod to push the plunger up and down, after a couple of pumps the lifter will go solid as it fills with oil.

[bangingears]

with adjustable rockers

-when exhaust opens, adjust intake rocker
-when intake almost closes, adjust exhaust rocker

[facemelter71]

with adjustable rockers

-when exhaust opens, adjust intake rocker
-when intake almost closes, adjust exhaust rocker

I was being quick when I typed it out. This guy has just explained it.

[Gearhead]

with adjustable rockers

-when exhaust opens, adjust intake rocker
-when intake almost closes, adjust exhaust rocker

James - you might be overthinking this, especially with pedestal mount rockers.

What Jason says above is correct, however since you have the ped rockers, just torque that individual rocker instead of "adjust". Add or subtract shims as needed.

Or, once you have the intake off, it's pretty easy to tell when you have a partcular lifter on the base circle of the cam. Once you have that lifter/valve on the base circle, then torque it down and add/subract shims if necessary. That particular individual cylinder may or may not be at TDC - which I wouldn't worry about.

Also, I wouldn't be overly concerned with measuring pre-load on the lifter, as long as you're hitting the 18-20 lb/ft somewhere between 1/2-1 turn you should be good. You should then still be able to push down on the pushrod side of the rocker arm with your thumb and see the plunger in the lifter depress even more until it bottoms out.

I thought you said you had 6.35 pushrods if I remember correctly, which I would think would be just about dead on.
The 6.272 pushrods in a stock 5.0 are actually a little bit too short in my opinion.

When I've used pedestal rockers in the past, all I ever did was torque 'em down, made sure I had some preload on the lifter (withhout the valve opening), and I could still push on the pushrod side of the rocker to see the plunger in the lifter move down. Sort of a hack way of doing it though.....

[5.0calypso93lx]

James - you might be overthinking this, especially with pedestal mount rockers.

What Jason says above is correct, however since you have the ped rockers, just torque that individual rocker instead of "adjust". Add or subtract shims as needed.

Or, once you have the intake off, it's pretty easy to tell when you have a partcular lifter on the base circle of the cam. Once you have that lifter/valve on the base circle, then torque it down and add/subract shims if necessary. That particular individual cylinder may or may not be at TDC - which I wouldn't worry about.

Also, I wouldn't be overly concerned with measuring pre-load on the lifter, as long as you're hitting the 18-20 lb/ft somewhere between 1/2-1 turn you should be good. You should then still be able to push down on the pushrod side of the rocker arm with your thumb and see the plunger in the lifter depress even more until it bottoms out.

I thought you said you had 6.35 pushrods if I remember correctly, which I would think would be just about dead on.
The 6.272 pushrods in a stock 5.0 are actually a little bit too short in my opinion.

When I've used pedestal rockers in the past, all I ever did was torque 'em down, made sure I had some preload on the lifter (withhout the valve opening), and I could still push on the pushrod side of the rocker to see the plunger in the lifter move down. Sort of a hack way of doing it though.....

Scott, from my measurements I did come up with 6.350", but that was only measuring the intake valve. I did try and torque them down but I'm getting about 3 turns on the exhaust valve before the valve spring eventually starts compressing. It's like there's no play in the lifter and no I'm not using the solid lifters I used to measure with lol.

[Rick93coupe]

What am I doing wrong here?

Just sat down at my computer and reread this. Here's one thing that's going wrong. When your hand tightening the rocker until the pushrod wont tilt back and forth, they're assuming your lifters are pumped up fully. Here's how I do it.
When I'm tightening a rocker by hand I've got a close eye on the pushrod in the lifters seat. As your tightening it, you'll start to see the plunger depress. If the lifter was fully pumped up, you may actually only get a 1/4 turn. However since your lifters aren't pumped up and full of oil, your able to keep turning the polylock until the lifter bottoms out (which is roughly 3 turns).
Go back and start over, with one hand turn the pushrod with your fingers until you feel some tension, you'll notice the plunger starting to depress. From there a 1/4 turn and locking it down should have you squared up, although I've had better luck with 1/2 a turn myself.

[5.0calypso93lx]

Thanks guys!