Setting Tension on Roller Rockers

I just broke in my fresh 440. It has Harland Sharpe roller rockers. It's really noisy with clatter. The builder said he likes to set them up "loose" and I may want to tighten them down once I get the engine broken in. I've heard other mopar guys complain about this builder doing the same to them on their RB engine.

Can one of you engine builders give me the 411 on how to properly set the tension on them so that I don't go deaf under the hood?

I always go tighter that the recommended lash and have never had a problem. My Isky solid roller calls for .028 hot and I set em at .014 cold w/alum. heads and end up around .020 hot......you can also tighten up the side clearances to quiet em up a bit...........

Which heads, aluminum or iron and what is the suggested hot valve lash for your cam?
Looser than stock is not the way I would break in a new cam or motor

Hydraulic or solid cam?

"loose" just means the cam is beating the crap out of the lifter and the rocker is slamming it to the valve tip.

Lash is something I'll admit I never understood. In my mind, you should have ZERO lash (or maybe only a couple thou to make sure the valve seats) at normal operating temperatures. More lash just increases the chance of damage - particularly where rollers of any sort are involved.

True: needles don't tolerate crash landing very well.

What cam do you have? I would get it lashed per manufacturer specifications and go from there. As I understand, the ramp of the lobe plays into the lash setting and the manufacturer should know best what that setting is based on the cam profile.

Cab, The heads are cast iron closed chamber. The cam is a Comp Cams XE274H hydraulic.
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=709&sb=2

Should be zero lash with maybe a 1/4 or 1/2 turn more for lifter preloading. Hydraulic cams were made to be quiet. There should be no tappet noise coming from the engine.

Here's what I found on the web. Is it correct?

Most auto repair manuals will list procedures for adjusting two valves at a time while following the firing order. And while adjustments can be made that way, for performance cams COMP Cams advises a more precise method.

When the exhaust valve just begins to open on the number 1 cylinder, adjust the number 1 intake valve. Loosen the adjusting nut slightly until lash can be felt in the rocker arm. While spinning the pushrod with your fingers tighten the adjusting nut—when a slight resistance is felt the valve is at zero lash, or the point where all the slack is removed. Turn the adjusting nut an additional 1/4 to 3/4 of a turn past this point (depending on the cam manufacturer’s specs) to achieve optimal preload on the lifter. Follow this procedure to adjust each intake valve according to the firing order.


To adjust the exhaust valves a similar procedure is used. Turn the engine over until the intake pushrod moves all the way up. Rotate just past maximum lift, where the intake will begin to close. The lifter is now at the base circle, and the exhaust valve can be adjusted. Do not go too far down (over halfway) past the point of maximum lift. If you go too far, you will be in the overlap cycle—where intake valve lash is being taken up as the exhaust valve begins to open. Then follow the same steps of spinning the pushrods and tightening the adjustment nuts.

it's been 3 years but I do believe that the builder said that he sets them at zero lash and that if it's too noisy, to crank them down 3/4 turn. This may explain things. I am not about to just popping the covers and cranking them down. I want them absolutely right.

This and the stocker motors I worked on at Pettis would set em at zero..........

This is correct! Remove the valve covers, bump the engine over and do just like the procedure says. It's easy and will be a good learning experience for you.

I'll give it a go. not afraid to try anything, but always want to go in with the right info!

Thats right but you can forget about the
overlap part of it.. its still closed so it
can be adjusted to the right spec

I call BS on that second part. After the end of the intake cycle comes the compression and power cycles. Overlap is after the exhaust cycle. I take the intake to near closed and adjust the exhaust. This produces repeatable results. If you don't adjust at the same crank position every time the loading of the valve springs will cause the numbers to change making for more work as they'll all seem off a little.
The hard part about hydraulics is that lifters can bleed down varying amounts, totally screwing with your 'feel' when you try to find zero lash. I've never had an adjustable hydraulic but have seen some near catastrophic results from others who didn't get it right.

You are very close, only thing I would add is spin the pushrod with your finger tips (thumb and finger) until you feel it starting to tugg then give the adjuster a 1/4 to 1/2 turn.

I always use the following:

Exhaust starts to open adjust the intake.

Intake opens all the way and starts to close adjust the exhaust.

I do one cylinder at a time that way I don't forget to do one or the other.

A remote start button is a great tool for this.

GOOD LUCK!

I really hate this.
These instructions begin by assuming that the reader has no grasp of the 4-stroke cycle or a V8 firing order.
Simple directions: set both valves when that piston is @ TDC ignition. Do the next cylinder.
Anything else is needless complicated - saves a minute at the expensive of bending something.
If you do not understand this, you should pay someone to do it for you.
If you do, it's as useful as telling you to open your fly before taking a piss.

This is the best procedure to use on race cams, especially race solid roller cams I would add always set the final clearances with the motor warmed up, not cold or lukewarm
Finally, I set one side at a time and run the motor to get it back to running temps before setting the other side, I start at the front and work my back to the last cylinder on that side so I don't skip one
OP, your cam is not real big so I would try setting the preload at 1/4 turn hot and see if you like that and if so try doing it again later with a 1/2 turn preload to see if one way works better than the other on your motor. The only way to find out what YOU like is to test, test and test some more

I agree as you are right. I also adjust the exh valve right when the intake is closed as the power stroke is next and its not in overlap then. Like you said the overlap is when the exh valve is shutting and the intake starts to open. Ron

THIS.........Works every time and is the non "lazy" better way........

Agreed, never had an issue.

Back in my Chevy days, I set the valves on my new hydraulic cam at zero lash. That was the hot trick of the day. They couldn't pump up because they were already as tall as they could get. I ran the engine for about four years and had no problems.

Now the hot trick is zero lash plus 1/4 to 1/2 turn. The thinking on this is that at zero lash, the little piston inside the hydraulic lifter will pound out the wire retainer. I guess it's possible, my old cam was designed 40 years ago. Valve action is a lot more abrupt nowadays. So use the new advice.

R.

No, I think zero is still the hot ticket, just not on Moparts. Better with a Tru-Arc retainer, but I've run a bunch with std wire retainer too.

Alternatively, if you are running a fast rate cam and the lifter cannot keep up, use a short travel lifter and run it 0.005 off the bottom.

That is a shame they were not setup right from the beginning.

I only set the preload on a hydraulic cam once when it is on the engine stand with the intake manifold off so I can see the plungers in the lifters.

One by one set it for zero lash watching that plunger, then a little pre load on that plunger, down a little ways from the snap ring.

That is the last time you ever you should have to touch it because the lifter takes up any extra slack and keeps everything together smoothly with little to no valve train noise when the plunger is in the middle of it's stroke in the lifter when the valve is closed. A hydraulic lifter is self adjusting once it's preload is set.

Like someone said above, why would you want lash/clearance with a hydraulic cam? and beat all your parts together when running. Even on a fast ramp cam of today like the 274 your running.


I have built countless street motors with hydraulic cams of all varieties and they all lived long healthy lives setup this way.

I think doing it blind with the intake manifold on is very risky cause you can't see what your doing and you can not be sure what that plunger is doing or where it's at in the lifter. Make sense?

To me zero lash is how I would set mine if I was racing the car alot. Cant pump up any more and hold a valve open. I remember that my buddy did that years ago in his 350 Chevelle when he was racing me in my 273 Dart. He missed 3rd gear and just as I grabbed 3rd he fell way back and did not come back to his house for about 30 minutes. He had to wait a bit for his lifters to bleed down since he over reved his eng when he missed 3rd gear and his lifters pumped up to much and held the valves open some.
Course zero lash can be a little noisier also and most manufactors of course want the plunger down about 3/4 turn to take up for wear. Ron

This too.

I've had lifters that are very difficult to "feel". And it takes some time to know what to feel. If it has factory heads, you can see and watch the plunger with the intake on.

If your rocker arms have 3/8 inch x 24 adjusters that have 24 threads per inch then one full turn equals .0416 (I round it up to .042) of travel so 1/4 turn is right at .0105. My message is 1.4 turn is near .010 preload, 1/2 turn is .021 and so on
The 7/16 adjusters are .050 per thread so 1/4 turn is .0125, a tiny bit more
Good luck on getting them where you like it