HEMI Tech- Rockers, valves, pushrods, springs

Another great topic for Hemis is the awesome valve train they have! Unique for sure and lots to talk about in reference to this subject!

1) Rockers....
- What motors had adjustable rockers and WHY? (seems to be a typical question)
- When should adjustable rockers be used vs. stock non-adjustable?
- Which ones are interchangable?
- Rocker ratios for each make and model Hemi? (I know they're mostly the same, just a good bit of info)
- Roller and billet rockers and WHEN they're needed?
- Who sells them and who restores/remanufactures them?

2) Rocker spindles/shafts...
- What is interchangable?
- What needs to be considered for high performance applications?
- Things to consider when rebuilding?

3) Valves...
- Which years, makes and models had similar valves?
- Special features of Hemi Valves that should be noted?
- Manufacturers to consider for replacement valves and what to look for?
- When should valves be replaced for various applications?
- Keepers, guides and related... what to get?

4) Pushrods... (overlapping a bit from the cam and lifter topic)
- What is interchangable from other makes and models?
- Solid, tubular and adjustable pushrods for what applications?
- When are stock okay to reuse?
- Who makes them and what to look for?

5) Springs and related...
- What springs for what applications?
- When are stock springs sufficient and when should they be replaced?
- Who makes them and where can they be purchased?

 

The book (& probably everyone else here) says you have to use adjustable rockers or push rods on reground cams. One of my buddies has a 354 w 100K miles on it with the stock non adjustable valve train & a reground cam, runs fine. Valve springs the stock springs are dual springs, but both turn the same way, at least a theoretical chance of causing coil bind. There was a thread here a while back talking about duals being good because they cancell harmonic vibration in the springs. On my '55 331 I have a close to stock cam & used Comp Cams dual springs # 988.

 

Link to some DeSoto Hemi info started by De Soto:
http://www.jalopyjournal.com/forum/showthread.php?t=123365

Just realized this hasn't been filled out much. Maybe we can get this Hemi topic going again.

 

I'll get it started once again with some questions that hopefully can be answered soon...someone PM'd me a while back saying there's a Ford valve that is either a drop in replacement or an easily modified replacement for hemi valves at a much cheaper cost than the typical 17 bucks per valve hemi valves, but I lost the PM and need to know what valves they were...

also, I'll be running a hydraulic cam (possibly a solid, if I can get talked into it by anyone who prefers them over hydraulic in a street/strip car)...but anyways, do I have to run adjustable pushrods with the stock non-adjustable rockers? and if so, what are the adjustment specs for valve lash?...

I'm hoping to send my heads out to be rebuilt in the next couple weeks if I get time to deliver them, so it'd be nice to have some part #'s to hand over to the machine shop for those "cheaper" valves...

 

The best thing to do when looking for an affordable modern replacement engine part is to take all of the measurements of the stock piece, and start looking through the size spec catalog. That's how I found out that stock Buick 455 valve springs make for a cheap, high performance spring for 216-235-261 Chevy sixes.

 

Are we talking hyd. cam? The stock answer is...if it's reground, youre supposed to. A buddy of mine is running a regrind with stock non adjustable rockers & push rods. has 100K on it & it runs fine. Might depend on how much change from stock.

 

I'm not running the stock cam, or regrinding the stock cam...I'll be buying an off the shelf grind hopefully from one of the older companies like Clay Smith and Isky (does Howard only do regrinds?)...I haven't fully decided yet, but I'm really leaning towards a solid lifter cam...so I'm guessing the adjustable pushrods are a definite yes...

 

Yeah, adjustable pushrods are somewhat of a pain in the ass to adjust on a hemi, but given the HUGE price difference between them and adjustable rocker arms, I guess I'll just have to swear and take more time with my 331 when the time comes.

 

I got a new Howard's cam through Hot Heads, bit cheaper than direct.

 

Everything works in harmony......Regrind your cam and you LOOSE base circle -which means your pushrod doesn't go as high. A hydraulic lifter has a RANGE of adjustment that MIGHT make up for this, but if you then add in other things like resurfaced rocker arms, decked block, surfaced heads, different valves - etc etc - then sure you can potentially get a combination that let's you get away with running stock pushrods on a reground cam - But!!!!! Unless you do your homework you're playing with fire - safe bet is to get adjustable pushrods and be absolutely sure everything is right. To toss in a reground cam and hope for the best is a risky proposition no matter how good your karma is.

 

Adjusting hydraulic lifter preload with adjustable pushrods.

Start by filling each lifter with a pump oil can up against the oil feed hole (in the groove near the top)

Coat the bottom of the lifter with molybedenumdisulfide grease (cam lube) Coat the cam loves, too.

Drop the lifters into the bores.

Back off ALL of the adjustable pushrods to their minimum length.

Pull the distributor drive gear and shaft out of the block. Substitute a long, large flat blade screwdriver (or Allen wrench if you're running a 318/340 oil pump for the shaft). ....or you can press out the roll pin and remove the cam gear from an old drive shaft.

Use the makeshift drive to pump up oil pressure.

Bring the engine up on TDC (compression) on #1 cylinder.

Pump up oil pressure with a drill spinning your makeshift pump drive.

What you're going to be doing is filling any lifter that's down in the bore low enough to expose the oil feed hole in the lifter bore. Since we're concerned with cylinder #1 at the moment, that's all we'll worry about.

Once you have the lifter pumped full of oil, hold the tip of the rocker arm onto the valve stem and lengthen the pushrod until the tip just touches the rocker arm. Go 3/4 turn after that and snug the lock nut down. Do this for both pushrods on cylinder #1.

Now, rotate the engine 90 degrees to bring up #8 piston. Go through the same procedure with those two pushrods. pump up oil pressure, hold the rocker on the valve stem, adjust out the slack, go 3/4 turn beyond that.

Some pushrods have fine threads, others have a coarser thread. 3/4 or a turn of preload won't over preload the lifter but it might not be quite enough yet. Do your fine adjustment later. (see below)

Do this for all 8 cylinders (1-8-4-3-6-5-7-2)

Put the covers back on and fire up the engine and break in your cam and lifters.

If you hear lifters clicking, you can run your engine at an idle with the covers off and hold your finger on each rocker to try and locate the noisy one(s). Go 1/4 turn on the pushrod to quiet the lifter down. You DON'T want to be doing this right away on a new cam. You want to give it a chance to run in before you let it idle and chase down a clicky lifter.

The important thing is to not get the pushrods so long that they excessively preload the lifter. You're better off to gradually lengthen the pushrod to find that optimum length than you are to guess and make the pushrods too long.

You could have them so long that the valve barely closes. If this is allowed to remain unaltered, you'll prematurely burn a valve seat.

 

The rocker arm shafts get a shot of oil once every two revolutions of the crank for most camshafts or at 2/3 of a revolution on some special cranks. Because there is a large area to be filled, it is important to pre-fill the rocker shafts before you fire the engine, otherwise, you risk galling rocker arms.

The oil is fed to the rocker shafts via the second rocker stanchion from the left (as you're facing the side of the engine) It's the next to the last one on the right side, second from the front on the left side.

Oil flows up through holes in the second and forth cam bearings. Once per revolution a pair of passages in the camshaft align with the holes in the bottom(6 o'clock) and 2 o'clock (left side for the front hole) and 10 o'clock (right side for the rear hole) This alignment occurs once every other revolution of the crank because the camshaft spins at half the speed of the crank.

Some camshafts have three, instead of two passages so the inlet and outlet bores are aligned with the holes in the cam bearings every third of a revolution of the crank. These cams are few and far between. Most cams only have two passages in each of the two cam journals.

Lay the rocker assemblies on a bench and, using a pump oil can, fill the shafts via the oil hole in the oddball looking rocker shaft (2nd or 4th, depending on which way you're looking at it). Keep pumping until oil starts to ooze out around the rockers or out through the pushrod lube holes. Oil won't come out the pushrod holes unless the rocker arm is aligned with the feed hole in the shaft.

If you want to determine where the rocker should be positioned on the shaft to align the oil passages, slip a piece of welding rod down the hole in the end of the rocker (above the valve end) and gently push it while you slowly rotate the rocker on the shaft. Don't push too hard or you'll score the rocker shaft. When you find the hole in the shaft, the welding rod will fall deeper into the rocker. This is the ideal position to have your rocker arms resting when you fill them as it allows trapped air to easily escape.

As you start to see oil come out through the holes in the rockers, rotate each oozing rocker a bit to close off the oil flow until you have them all filled.

now, SQUIRT IN A DAB OF CHASSIS GREASE TO "PLUG" THE HOLE. The chassis grease will be easily displaced by the oil pressure once the engine fires up but it will also prevent the oil from draining out when you flip the rocker assemblies over to install them on your heads.

 

You ARE the man for posting all that info! Serious applause to you for taking the time to do that! Thank you!

 

For sake of Scooters thread all add in a lil, But i dont understand all the Yaa Hoo i hear guys griping about just cus its a Hemi...

Its still just VALVE TRAIN !

I looked & priced lotsa stuff, Scoured old parts availability & did some home work.

My first Race DeSoto, which was built in 1960 & set a record at Freemont drag strip in '62 ran adjustable push rods.. No Problem !!

Except as HEATHEN said... THEY ARE A PAIN IN THE ASS TO ADJUST !

I ordered mine from CLAY SMITH CAMS, Worked out Perfect.. 3/8 tube, 3/8 Bottom ball & 5/16 top tip.

I used Stock rockers cus DeSoto adjustable rockers are hard to find, The 3/8 bottom ball was to fit in Standard 440 MoPaR Solid lifters.

Clay Smith also re~ground my old Isky cam to spec of an old Clay Smith grind that works out well.

Valves were another part i did research on, Stock Hemi valves are 2 PIECE, Meaning the head are SPIN WELDED on.. Ask me how i know .. One broke off in my 291 & wiped out a Head & 1 11.5~1 Jahns STD bore piston !!

I checked Hot Heads & they want to rape you, Found a company called MAD DOG RACING, Purchased a set of STAINLESS STEEL valves & had them professionally inspected for defects.. Machine shop says they are the same S/S Valves as everyone else is selling & are a good quality valve... FOR 1/2 WHAT HOT HEADS SELLS THEM FOR !

Had the heads done at WILLAIMS MACHINE, Yup.. Same place that the now famous WILLIAMS BROS. land speed '29 Roadster came from... They set BONNIVILLE RECODS in 1954 with a Dodge Hemi.

They used some Valve Guids they had in the back room, I think they were MICKEY THOMPSN parts & P/C seal.

All in all, its not rocket science.. But ya do need to research before you just jump in.

 

Thanks DE SOTO! We need more DeSoto tech around here! Good to see you back and thanks for contributing as always!

 

Thanks desoto. This info has helped me out a whole bunch. -Kevin-

 

When I start building my DeSoto Hemi I'm gonna have alot of reading to do thanks to all these threads from scootermcrad

 

I just got a good news/ bad news call from my machine shop reguarding valves for my 392. upon inspection fo my valves, it turnes out I have Donovan engineering valves. YEA!!! The bad part is one of the exhaust valves is bent. BOOOO!!!!! The real bad part is Donovan doesnt make valves any more and these are not a standard size. So what im getting at is I need a valve of the folowing dimentions. 1.875 dia, .295 tip, .340 stem, and 5.195 over all lenght. I guess I could just buy a new set of exhaust valves of a similar size, but it seems like a waste for just one bad valve. Can anyone help me out?

 

So I just got my first Hemi, a 52 331 Extended bell....See thread here about the it...

http://www.jalopyjournal.com/forum/showthread.php?t=347784

Anyway it came with rebuilt heads...YEAH!! and I was mocking up the heads and valve train and found that my rocker arms would not seat into the heads.

Here are some pics of my problem...

The seats on the rockers are basicly the same size as the opening in the heads, mic'd at .755 +/- .003, so the rockers will not seat.





Now I have read through as much as the Hemi tech I could find on the HAMB and have not come across this issue.

So do I have the wrong rocker assemblies, or do you just crank them down with the head bolts and they will force seat themselves??

Thanks guys!

 

Never heard of this. That's really weird! To the best of my knowledge, I wasn't aware that there were any differences. So both mic'd out at 0.755"? Strange. Maybe one of the "older" guys will have some input.

I'll go take a couple measurements on mine real quick...

 

Okay, just for comparison sake, I randomly grabbed one of my rocker sets and took some measurements. Take a look at what I found...

From left to right...

 

I liked you idea there Scooter so I went out and did the same thing, here's what I found.

Rockers....









As you can see they are all within the .757 to .760 range.

 

And then I did my heads...they are Cast # 1323333-1









Again the size is almost the exact same as the rockers, .757 to .760

So they won't fit..at least in my way of thinking.

 

Got an emty freezer?...

 

Took me a few seconds to figure out what you were getting at.....freeze the rockers then install them in the nice warm heads....This would work but should I have to do this?? But cool idea!!...pun intended..

Pretty sure the factory would not have gone to this amount of trouble to assemble the rocker assemblies on these motors. I think I might have rockers from a later 354/392 hemi?? Anyway to identify rocker assemblies??

 

Wow! That is really crazy! I couldn't get to my heads to measure them, but I'll see what I can come up with this weekend.

Well, you definitely have first generation heads. Round ports. Were these the stock rockers or were they replaced somewhere in time with the previous owner?

Anyone else seen this before? My rockers drop right on all the different heads I've mocked them up on.

Now, on the flip side, do those bosses slide out? Maybe their are different sizes? If they come out you could have them stepped and they would drop right on, right?

This is a good one. Hopefully someone will have some input on this.

 

I have no idea if these are the matched original heads and rockers? The guy told me the farmer sent the heads off to be rebuilt, so who knows if they actually rebuilt the originals or just pulled a set off the shelf and sent those back.

Was going to do just that Scooter, see if the bosses come out, then I could get a new set machined up to fit, or have the originals turned down a bit. But would like to know what I have or what's going on regardless.

I await your measurments...

 

I was just looking at the pics of our rocker assemblies and I noticed a big difference in them. My rockers are a lot beefier then yours Scooter. It also looks like they have a different ratio with the length of the arms.

What are your rocker assemblies off of??

 

Chrysler rockers are all interchangeable. You just need to slide the rocker stanchions sideways until they line up. It's a VERY common problem. They won't settle down right until you have all five stanchions perfectly aligned with the holes in the head then they'll drop in.

If you have the heads on the motor and the pushrods are in place putting tension on any rocker that's trying to open a valve, you have to be VERY careful to align the rocker stanchions or you'll break one or more trying to force them down with the head bolts.

If the rockers don't slide easily, the assembly was never taken apart and cleaned.

Take the assemblies apart and clean them thoroughly to remove the thin coating of sludge.

PULL THE CORE PLUGS OUT AND CLEAN THE SLUDGE OUT OF THE INSIDE OF THE SHAFTS, TOO. They're common 5/8" Welch plugs.

 

You know... I was thinking the same thing! Those do look a little than mine. Maybe they're not Chrysler? Maybe one of the Desoto guys can jump in and have a closer look. The biggest difference I see is on the rocker arms themselves also the area around oil inlet hole has a different shape to the casting.

I have three sets of rockers and they're all identical with the exception of the amount of filth on them. If it helps, my rocker shafts measure 19-1/4" from end to end, including the end rocker stands.

Are you saying my rockers are "whimpy"??