HEMI Tech- Rockers, valves, pushrods, springs

.100 on the valves. The shafts are lifted and spread .100

 

Bingo not stock rocker stands thanks.

 

Tubman if its running good why do you want to put a rev kit on. The extra friction and tension only robs hp. Remember these kits were designed at a time when valve spring technology was very primitive. Today's springs are so much better that rev kits are no longer needed. We use Manley springs in everything.

 

Can some room be gained with a slightly shorter valve guide (within reasonable limits)? I’m looking at custom made bronze guide, set up for the Chevy type Teflon stem seals. Anyone have a particular recommendation for beehive springs? My brother (a mechanical engineer) tells me beehives also help reduce harmonics. I’m looking at trying to wring out a few more rpm’s. I read that Gene Adams spun his junior ruler up to 9000rpm! So the Milodon type rev-kit springs sound like a plus to me. I read on another thread about someone that was looking at reproducing those. Was that you, 73RR? I’m also exploring options to do roller tip rockers. That would help reduce side forces, and help a shorter guide live. Does anyone make those for the DeSoto? If not, I’ll start looking for someone that can do investment castings based on a model I’m playing with.

 

Should read “junior fueler”.

 

"racer-x" - The reason I asked is that after reading some of the previous posts, it seems there might be an accelerated wear problem with the push rods and at least the intake rockers that might be alleviated with a "Rev Kit". As I said earlier, I don't have enough experience with this particular segment of the valve train to have any idea. The valve springs that are on the engine now were purchased and installed about 25 years ago. Does this qualify them as "non-primitive"? As I said, I don't run this engine that hard (mainly exhibitions) and would like to do what I can to ensure it has a long life.

 

The best way to learn about the springs you have is to test them. The easy way is to do it on the head with the correct tool. Lsm makes the correct tool. The harder way is to disassemble the heads and check them on a bench mounted tester. Springs loose pressure as they are used. knowing the installed height and pressure you have now can be given to a spring manufacturer to get a recomendation on the spring to use or to tell you if you have enough spring pressure for what you are doing. The racing industry changes rapidly. I would say 25 year old springs are not as good as today's. I'm not saying that won't work just not as good as today's designs. You need a starting point installed height plus a pressure reading is where to begin. Set up correctly a solid lifter engine should have 1-2 threads showing with the lash set. The only thing i have found that reduces wear is the manton brand tool steel screws and push rod cups. Putting the screw out do to short push rods creates a problem with oiling. See the little hole in the rocker arm. The oil comes out here. If the screw is too long the oil can't get to the cup. The cup is too low and no longer in line with the hole. The oil doesn't shoot out of the hole. Too short of push rods with high lift cams will cause a bind as the screw and push rod get close to a 90 degree angle. The result is bent push rods. Good oil and clean rocker shafts are key. They cant be clogged with crusty old oil. The adjuster should look like this or with another thread showing. The rev kit is a band aide for the wrong spring.

 

The height of the guide is not the issue. It's the space between the bottom of the retainer and the head. The spring coil binds. This really limits the cam lift a engine can use. It also limits the amount of pressure that can be run. The stock head can't be machined because it's thin in that area with water right below. We have machined hot heads .050 with sucess. So if you cant go down to get more room you go up. Longer valves and special locks move the retainer up providing extra room. Choosing the correct parts can correct the geometry problems these engines have had since day one. Stock the hemis get lots of miles on them before it's time for a rebuild. Depending on what's modified in a performance engine the geometry can get all screwed up creating unnecessary wear.

 

Don't worry about seals on the exhaust side.

 

Thanks. Wasn’t planning on them, but appreciate the input.

 

When modifying the stands to raise the shaft for long valves, you must also move the shaft toward the valve centerline to keep the rocker arm length in check.
This is not a DIY project.

While some may argue the value of a rev-kit I think it has merit in order to keep valve spring pressure down. Too much spring on top usually cause wear on parts and can break rocker arms. Think about welding a rib to the back of the long rocker to stiffen it up.
The other issue, in a non-modified rocker assembly, is at high lift the retainer can/will contact the underside of the rocker arm.
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A rev kit on top of roller lifters keeps the roller in contact. Less hamering on rollers.

 

I had decided to leave well enough alone until you posted this!

 

Just a re-cap for the casual reader.
No, I do not consider myself an expert on the subject of valve train design but I have observed and learned a few things over the last few decades so hopefully can offer some help.
On these EarlyHemi engines the original design was, as Skip mentions in several posts, a ball pushrod into a cup rocker for the hydraulic lifter assembly. When the factory used solid lifters they changed to cup pushrods and ball adjusters. This arrangement was also used on the A engines as they all had solid lifters. The larger ball offers greater bearing surface and a slightly different oiling pattern.
Now, alot of folks just want to use adjustable pushrods with solid lifters due to the cost of adjustable rockers but the same ball pushrod design is maintained. This is where the problems start and if you add in some big valve springs rates then it gets worse.
We sell alot of rocker arm conversions, mainly for hydraulic lifters, and we use ball adjusters when we know it is for a hydraulic lifter. If we know it will be for solid lifters we use a cup adjuster. Obviously, new pushrods are required for either due to the change in OAL. All of this gets expensive so what do many folks do? back to the adjustable pushrods and the wear cycle continues.
The entire wear issue centers around the lash required for solid lifters. This creates a 'slapping' effect, either at the rocker tip to valve or at the rocker tip to pushrod or at the pushrod to lifter. Additionally, inertia can also cause a heavy lifter to loose contact with the lobe, and this pounds on the face of the lifter or roller.
With a spring set-up like the one Skip has, constant pressure can be applied to everything except for the rocker to valve interface where the lash should be and then the ball pushrods will not be beating into the rocker arm cup.
A rev-kit can also be helpful but it functions in a bit different manner. It is most useful for roller cam/lifters that are subjected to more rpm than a flat tappet might see. When mounted inside of the valley, it places a spring load ('x' pounds) either onto the roller lifter or onto the pushrod to keep the roller on the cam. Current roller lifter technology has made for some fairly light weight solid lifters as opposed to some heavy weights of years past but the hydraulic rollers today are still not-light. A rev-kit does not negate the need for proper pushrod/rocker arm interface but does help in offering more lifter control at elevated rpm. Some will argue that valve train harmonics also benefit from the rev-kit design.
Hope this helps someone.

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I have been running hemis on the street and track for years. I have never had any damage due to " pounding" in the valve train. Can anyone post some pics of their damaged parts?

 

73RR-
If the time comes you can get progress on that “in-the-valley” rev kit, I would be interested. In the interim, if you have any of the mousetrap spring set-ups, I would be interested in those. Do you do the conversion of rockers to adjustable, or is that from someone else? While I don’t expect to wind to 9000 like Gene Adams did with his 305 c.i. Junior Fueler, I do think I will be making excursions well over the 5500 rpm “safe range”. Anything I can do to stabilize the valvetrain would be a plus.

 

How do you know your valve train is not stable now?

 

I don’t. Just know with increased lift, duration, rpm and substantially higher spring pressures that it has a much greater risk of being unstable. Would rather work for prevention now, instead of having to replace a lot of hard-to-find pieces later.

 

I have custom valve guides made for my setups and are best quality. They are shorter than stock ones, which will help gain a few cfm. I'm willing to sell the guides if you need some. They are currently setup for 5/16 stem but can be opened up to 8mm or 11/32. These have a common .531 PC Seal top on them and work with all of my CNC Port Programs. I wrote a technical article about a beehive setup I did. Has been raced at the Ohio Mile and Bonneville to 6800 RPM to date on a hydraulic flat tappet cam with no issues.

https://www.jalopyjournal.com/forum/threads/heinz-57-street-hemi-heads.984943/#post-11091605

There is no need to run a REV Kit of any kind, valvetrain technology has come a long way since then. I have developed other setups that work very well with a mere 1.800 Installed Height. Also running .600+ lift on the street for the Hot Setups. I also offer a offset stand kit to get even better rocker geometry for this same setup, it uses the stock shafts and rockers - everything else supplied in the kit. In the article above it is pushing the geometry to absolute MAX, particularly the intake side. You can find pictures on my website of the stand kits, super nice pieces! Feel free to contact me as I have what you are looking for.

 

Just put beehive springs on and are good for a 560 lift cam.we are currently running a similar set up on a LA small block in stock class. This is going in a Hot Rod 39 Plymouth coupe .

 

The only reason you'd want to run a Milodon style rev kit is if you were running a solid lifter cam as the Milodon-style kit keeps tension on the pushrod-rocker junction to prevent wearing the pushrod tip into the oil hole in the rocker.

 

I believe a rev kit would help a solid roller cam by keeping the roller lifters from pounding the needle bearings.

 

There is clearance for a reason. Taking away the gap on the rocker tip puts all of this so called pounding on the push rod tip and adjuster then. I would still like to see some one post pictures of there pounded up parts. Anyone? Well there you have it then. Making up problems when there really isn't one.

 

The Milodon rev kit puts the clearance it the junction of the rocker arm and the valve stem where it belongs.

When the clearance occurs at the end of the pushrod, the pushrod erodes itself into the oil hole in the rocker arm.
I'll have to dig around and see if I can find any ruined push rod ends but I think I threw them all away whenever I ran into one (when a rev kit spring broke) over the past 50 years.

In close to 300,000 miles, I've had my share of broken rev kit springs and ruined pushrod ends. I'd put the number around 50 at least but I never save them. What's the use? They're junk.

Yes, I run a solid lifter roller tappet cam and have been running it since 1965.

 

#8 intake rev kit spring is broken. #6 is still intact.
The spring lifts the rocker up off the valve stem and tensions the rest of the valve train. The end
of the #8 intake pushrod was a point sticking up into the rocker arm.

This happened on the way home from the NSRA Nationals in Louisville in 2015 and I probably threw the ruined end away because it wasn't serviceable anymore.

 

If you used manton pushrods they could have changed the cup end for six dollars each. The only time i have seen damaged parts it was due to a lack of oil.

 

Me too. Lack of oil is exactly why the push rod end gets destroyed. The point worn onto the end of the pushrod when a rev kit spring breaks plugs the squirt hole and the wear process accelerates rapidly.

In over 50 years the only time I've lost pushrod ends is when a rev kit spring or chrome-moly ring (the ring attaches the spring to the rocker end) breaks and the lash at the pushrod end starts the pushrod wear issue. As long as the rev kit is intact the wear is non existent just as if I were running a hydraulic cam.

The other "lack of oil" issue occurred when the cover bolt backed out of the new Hot Heads oil pump. That one cost me an engine.

Looking at your avatar, is this car regularly driven on the street or is it primarily a drag car? Mine gets in a 1,000 mile-a-day workout every year when I drive it home from the Nats.

 

this is the head with beehive springs with rockers

 

Above 392 with factory adjustable rockers.

 

My car is both regularly street driven and raced. I will be doing 1200 miles in one weeks time starting Sept 9th. That's the start of drag week. Follow my build on the rebuilding after the crash thread. Lots of early hemi tech there.