Roller rocker arms will provide zero performance benefit and most of the time they tend to make more noise than stock non roller rocker arms. The side to side motion is normal and it won't make the valvetrain noisy because there is no loading or motion in that direction.

 

I drained the tank & refilled with non-ethanol fuel + octane boost & seafoam. Changed oil filters & cut open the old one - no trace of any type of metal shavings anywhere, so I'm guessing the cam is ok. Fired it up & it's running kind of rough - shaking the whole truck - at low rpm's. Once it's revved up a little, it smooths out. I noticed a drip out of the accelerator pump whenever I blip the throttle, so I'm going to pull the carb to replace the diaphragm and/or gasket. Might as well take it apart & give it a thorough cleaning while I'm at it. Will report back...

 

Didn't you check the lifter preload when you had the valve covers off ?

 

I did not yet. Had to do some research; found this in another thread:

Alternate method for measuring preload:

On valve in question, rotate to backside of lobe with valve train assembled and torqued. Lay a quality straight edge along the top of the head surface where the valve cover mates. Mark (do not scribe) a line with a fine line Sharpie brand pen. (on a dry clean push rod, of course.) Relax rocker arm nut until pushrod no longer moves upward. Scribe a second line. Measure this distance with your dial caliper from edge to edge. This assumes, of course you have some pre-load to begin with, which is normally the case, as after a valve jobe the valves have receded deeper into the head. I have yet to need a longer pushrod on a re-build, but this may not be the case for you. Yes, is is a pain, but do it twice once you have the lines drawn and verify they hit the same. It is a snap other that to bring them into range. Check them again after the adjustment.

Does this sound accurate? I don't have any fancy machinist's tools, so this would be about the best I could do in the garage. If I'm understanding correctly, adjusting preload would require shims(to decrease) or longer pushrods(to increase)? What is the correct spec for preload?

 

I attempted this method above while doing my 400 build. All I'll say is its very difficult way of going about it.

I put a piece of masking tape on the pushrod and a long breakaway flat razor blade laying on the top of the head... With engine on a stand I want to say its almost impossible to get an accurate reading.

Id make my marks then remove the pushrod and need to shine a bright light, close one eye and try to read between the marks with dial calipers....yea right.

It will give you an idea if you have some preload or not. But not an accurate reading will need to be taken with a dial indicator.

If still in truck the master/booster will make some drivers side impossible to check with dial indicator.

I had to swap lifters on new build due to a slightly noisy lifter on startup in the truck. For the ones I could not get the tool on my way to.measure them was to verify on one I could check exactly how many degrees the bolt needed to rotate from 0 lash/ 0 preload to torqued with .030 preload.

Once verified that amount was (lets say 270degree or 3/4 full rotation) from 0 lash/preload to full torque spec
**if memory is correct .030 preload was about 3/4 turn)


So if you go from 0 lash to torqued in a 90degree or 1/4 turn its not enough preload

if it takes 2 full rotations to get torqued from.0 lash its too much.

Dial indicators can be found for $50 or so if you shop around

For what its worth I think as long as they have a little preload they should pump up and do their thing. Id think it would quiet down with rpm as oil pressure builds pumping up the lifter. Not sure if the lifter is gona be the bad guy.

 

I think that as long as the lifters have just about any preload at all they will run quietly if everything else is ok. It just isn't very critical and the lifter has a lot of travel. With that said another thing to possibly look at is aeration of the oil. The smallest amount of air will make an otherwise perfectly good lifter become spongy. I've seen this before when running an engine on the dyno. The one I'm thinking about was a Mopar 440 that was mostly stock and getting revved to about 5500rpm. Oil pressure on the gauge would look fine but after a pull it with it idling there would be a few lifters go tick, tick.... Tick, tick tick. Then be quiet again. We fixed it by modifying a factory windage tray to keep the crank from whipping the oil so much.

 

Finally got around to messing with this 400 again. I went ahead & replaced all the rockers, mostly because it was cheap & easy. Still have a wicked clatter. Some additional observations: 1)It's MUCH worse when the engine is up to operating temp - 190+ 2) oil pressure doesn't seem to affect it at all 3)Only hear it when the engine is under a load - idles perfectly fine.
Here's a quick video I shot just to get an audio clip:
Should I try replacing springs next, pull and inspect/replace lifters, or just pull the heads & completely go through them?

 

Detonation?

 

Was piston to valve and piston to head checked ? I've never used TMI pistons but I've heard they can sit pretty high in the bore.

 

That sounds to be timing very far advanced or wrist pin slap, with the bet on wrist pin.

 

Again, assuming it was, as the engine was built & assembled by a reputable machine shop that's been in business 50+ years.

 

Wrist pin would require completely tearing down the engine to diagnose, right? I have the ProForm HEI distributor from Summit & thought I had the timing set correctly, but I will check it again. After doing additional research on it, it's not exactly a top-shelf part, so I guess it could be causing issues as well.

 

Before setting the timing, bring the #1 piston to top dead center, verified through the spark plug hole with a wooden dowel, or something, and make sure the timing pointer is pointed at zero. Your balancer could be off.

 

That's a possibility, as I reused the original after the rebuild. I will certainly check it.

 

Well, the TDC mark on the balancer lines up exactly with #1 TDC, so that checks out. Guess I'll be buying a timing light & vacuum gauge & checking the timing. I had a local mechanic who supposedly specialized in custom cars check it & he said everything looked good, but guess I'll just have to learn to do it myself.