The Stovebolt Site Forums The Shop Area Engine Shop 216 rocker arms not centered on valve stems

I may have a problem with a '39 version of a 216. Rocker arms are not centered on valve stems. Some of the arms are flush on one side with the stem and others are within about 1/32 inch of flush. The rocker arm casting numbers do not match those shown on the master parts catalog. How critical is it to have the rocker arms centered or near center in hitting the valve stems? This was discovered following a 160 mile cruise. An intermittent squeaking was and had been heard before, but until recently disappeared. In checking the rocker arm assembly the arms were found to be off center. A light tap on the side of one arm resulted in the squeaking to stop. The engine was rebuilt by a previous owner.
Thanks.

I think your rockers have been installed wrong in the shafts.
I would suggest taking all your rockers off the shafts.
Separate the intake rockers from the exhaust in piles.
Lay all the rockers on a bench on their sides.
Compare how close the valve end of the rocker is to the bench. You will be able to tell which are left and which are right hand.
If you look at Fig.16 on this LINK you will be able to reinstall them in the correct position.

Alright you rockers, get off of there and get back in line like you are supposed to.

Just having a little fun, not trying to be mean.

Thanks to all for your ideas!
I suspect that the rockers are the incorrect parts, since their casting numbers do not match the numbers in the master parts catalog. I hadn't considered the possibility the assembly was done wrong, I'll check that too. The squeaking noise is what caused me to look at the source. I too suspect an oiling problem, but with the engine running the oil flow at the one valve stem squeaking appears to be the same as the others. My catalog lists six exhaust rockers with the same casting number (839001). It lists 2 sets of three inlet rockers with casting numbers of 838997 and 838998.
I have a 1940 version of the engine too and it has the three sets of casting numbers listed in the catalog. They show some wear. I am looking into just getting these re-ground and re-bushed; if needed. The shafts may need replacement too, but I won't know that until I get in there more.
I am uncertain I have a serious enough problem with the way these ride off center on the valve stems. Any thoughts? I am trying to keep the truck as stock as possible.
Thanks.

P.S. I think the stems are "off their rockers"!

Show us a picture.

It is normal for engine rocker arms to be offset some. That causes the valve to rotate which is good. A valve that doesn't rotate will prematurely fail.

However, post a picture for us to look at.

A photo of the offset is shown here. http://i886.photobucket.com/albums/...%20Photos/OldBlueengineNov1002010020.jpg

I would think that is definitely not right.

Looking at the above picture, try swapping them around.

Or maybe my eyeballs arent working right...

The eyeballs are seeing the same way mine are.

The rocker arms were intalled wrong and are the wrong ones too. I am picking up a set of correct arms that I had re-surfaced today.

Installed casting number correct re-surfaced rockers yesterday. The previous arms were incorrect of the '37-'39 version of the 216ci. There were four sets of these which may be correct for a post '40 engine. The casting numbers don't match any shown in the master parts catalog '29-'50 edition. They had been installed in their "correct" positions, afterall.

But, now the arms sit higher and the valves cannot be adjusted. Now I wonder if the push rods and/or the valve lifters are also incorrect.

I understand the correct push rods should be 12 and 47/64 inches long.

What should the correct measurements be for the lifters?

Any ideas?

Thanks.

the valves cannot be adjusted

The adjuster is still too long, even backed out all the way?

I suspect you have 235 rocker supports. The shaft to head position is different on these supports than 216s.

Thanks for the replies, guys.

The screws on the end of the rocker arms seem way too short by at least 1/2 inch. I didn't record the exact measurement yesterday, so I could be =/- there. That would be with the screw at or near flush with the top of the locking nuts on the arms. I need to measure the screw lengths on the arms from both assemblies, but they sure seemed to be near the same length.

I wondered if the supports were wrong too. The supports for the rocker arm assemblies on both engines measure the same at 2.982 inches. I compared the supports from '39 engine I'm trying to fix with the '40 version, that had the correct arms and were re-surfaced for use now. The '40 was not a running engine before, but the arms appeared to be in contact with the push rods and valve stem before disassembly.

I measured the valve lifters on the '40 at 2.81 inches long. I haven't pulled the push rod cover on the '39 yet so I can get a measurement on those lifters.

The push rods for '39 engines are 10 and 5/8 inches long and the '40 are 10 and 1/2 inches.
Thanks

Update:
Discovered there is a difference in valve lifters for pre-40 vs post-40 216ci engines. The pre-40 use hollow lifters the post-40 use lifters that have an funnel shaped top the push rod rest inside of and the lifters are about 1/2 inch longer. That is why the push rods are longer for the pre-40 engines.

Since the last update a near disaster.
In removing the valve lifters one broke off inside the engine. With advice and assistance I was able to avoid removing the cam. The oil pan was removed and a 5/15" oak dowel rod was snaked through the bottom and tapped with a hammer to drive the piece out the top. It worked like a charm. A cursory inspection of the cam and the lobe does not indicate any damage other than the expected wear.