Adjustable rockers

ofb383

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Your thoughts guys, on a budget and want to go over to adjustable rockers for my top end build, I've seen these over on Summit https://www.summitracing.com/parts/sdm-1-261-026/overview/make/chrysler
Has anyone experience of them ?
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Top end build, are you doin a cam swap with it? Does the cam required to have adjustable's, or do you just want to change to change them without a cam swap? How worn are the old rockers & shaft?
If it ain't broke, why fix it? Good Luck
 
Top end build, are you doin a cam swap with it? Does the cam required to have adjustable's, or do you just want to change to change them without a cam swap? How worn are the old rockers & shaft?
If it ain't broke, why fix it? Good Luck
Yes, cam, lifters, valve springs, cam chain set. I feel happier setting pre load on the lifters in the traditional way, I'm use to the Chevy set up.
If I do nothing to the valves other than lap them in, does it mean I could drop the rocker shaft assembly back in how it came out even though I have heavy duty valve springs going in ?
 
Yes, cam, lifters, valve springs, cam chain set. I feel happier setting pre load on the lifters in the traditional way, I'm use to the Chevy set up.
If I do nothing to the valves other than lap them in, does it mean I could drop the rocker shaft assembly back in how it came out even though I have heavy duty valve springs going in ?

Mopar lifters will work with either type valve springs as long as you are not installing a high lift cam that requires a manual adjustment of the rocker set. Look at the specs that came with your new cam shaft. It will state clearly if the cam needs manual adjusters.

Dave
 
Mopar lifters will work with either type valve springs as long as you are not installing a high lift cam that requires a manual adjustment of the rocker set. Look at the specs that came with your new cam shaft. It will state clearly if the cam needs manual adjusters.

Dave
I never saw where he said he had a hi-lift cam? As said, check to see if adjustable rockers are required with that cam, if you don't need them, go get your money back! Good Luck
If I do nothing to the valves other than lap them in, does it mean I could drop the rocker shaft assembly back in how it came out even though I have heavy duty valve springs going in ?

Again, Does the cam require you to have adjustable rockers, yes or no? This isn't rocket science!
 
First, I would not recommend aluminum rockers for street engines. Aluminum is subject to metal fatigue and eventual failure.

Cams for hydraulic lifters do not REQUIRE the use of adjustable rockers, but they do make installation easier. (Please show me a cam card that says manual adjusters are REQUIRED for this cam.) Even with adjustable rockers, you need to determine the correct length of pushrod, and only use the rocker adjustments to make setup the preload. This is what Comp Cams website has to say about adjustable rockers:

Rocker Arm Adjustment/Lifter Preload
All but a few Chrysler engines were equipped at the factory with non-adjustable rocker arms. Anytime a solid lifter camshaft (either roller or flat tappet) is used, you must also use the adjustable rocker arms and appropriate pushrods.

When installing any high performance hydraulic camshaft, the lifter preload is something which must be considered. Too little preload will result in a noisy valve train, and too much preload will result in tight valves and a poor running engine. Either condition can result in less than expected performance or engine failure. After the cam, lifters and rocker arms are installed and prior to installing the intake manifold, you must check the plunger depression in the lifter. With the cam on the base circle (valve closed) the plunger in the lifter should be depressed .040”-.060”. With nonadjustable rocker arms, you must change pushrod lengths to obtain proper lifter preload. This is a delicate and time consuming process, so if you have any questions, contact the CAM HELP® line at 1-800-999-0853.
 
Throw some spark plug washers under the shaft if you want to reduce preload, and that is only if your planning on going over 6000 rpm. My 400 sees almost 6200 in second through the traps, cast pistons, stamped rockers, hydraulic cam.
K.I.S.S.
 
Point taken guys, nothing says in black and white that I must use one or the other.
 
First, I would not recommend aluminum rockers for street engines. Aluminum is subject to metal fatigue and eventual failure.

Cams for hydraulic lifters do not REQUIRE the use of adjustable rockers, but they do make installation easier. (Please show me a cam card that says manual adjusters are REQUIRED for this cam.) Even with adjustable rockers, you need to determine the correct length of pushrod, and only use the rocker adjustments to make setup the preload. This is what Comp Cams website has to say about adjustable rockers:

I never saw anywhere saying he's using a Comp cam? The Hughes cam I'm runnin says to use adjustable's. They have changed things on their site now so that even the wimpiest of cams they say to use adjustable's, anything to make a buck I guess? But at the bottom of this page at stage #3 mentions that true rollers be used, so those are adjustable. Good Luck
Hughes Engines
 
I never saw anywhere saying he's using a Comp cam? The Hughes cam I'm runnin says to use adjustable's. They have changed things on their site now so that even the wimpiest of cams they say to use adjustable's, anything to make a buck I guess? But at the bottom of this page at stage #3 mentions that true rollers be used, so those are adjustable. Good Luck
Hughes Engines
Nobody said he is using a Comp cam. That happened to be the website that I got the information from, and it's general advice, not just applicable to Comp cams. If YOU read the heading of the column you directed me to on the Hughes page, it says "Suggested (not required) Upgrades". Learn to read before you post, because you're not helping your argument at all.
 
20 years ago, using Speedmaster or 440 source shitty rockers was more of a gamble. The Chinese stuff has evolved to a better quality. The issue with those rockers is that, if you have a 1 out of 16 failure, you are going to risk spreading needle bearings into your engine.
With that said, I know a couple guys that beat their cars with both and had no problems.

If you can find a used set of the old Crane/Isky ductile rockers, those things are bullet proof.
I have a set of used Crane ductiles I may sell.

I use these 1.6 Harlan Sharp copies from Mancini, they see 7k rpm regularly. 670 lift, 225/430 over the nose.
Mancini Racing Aluminum Roller Rocker Arm Kit

These are probably as good as anything for mid level lift
COMP Cams Pro Magnum Shaft Mount Roller Rocker Arms 1621-16
 
Chrysler is NOT the only OEM to not use non-adjustable valve trains.

I can understand the desire to perceive that as "Chevy" might do it, then we all should follow them in this area. BUT that does not mean that it will make any real difference in things. Chevy is also famous for doing things "simply" and they work just fine (even better than some of the more expensive ways to do things, as things seem to work out, by observation).

Back when the small block Chevy was designed, hydraulic lifters tended to "pump up" against their valve springs, which limited upper rpms of the motor. Adjusting them "up" toward the top of the lifter's plunger travel minimized this situation, so it became common to adjust them with little preload (just enough to keep them quiet) so they'd then rev past 6000rpm with ease. Without having to have a solid lifter cam.

If you desire to want the lifter plungers positioned toward the top of their travel (rather than be centered, as is usually the case), then get some custom length pushrods and use the OEM-style Chrysler valve rocker shaft items. Best of both worlds?

It was common for the Olds engine builders to shim their rocker shaft brackets with washers, which was a "cut and fit" situation. Once done, no more high-rpm capability issues. There was a HOT ROD magazine engine article on Olds engines, which mentioned doing this and gave dimensions of what they ended up with.

NO issues with trying to make things "better than stock", BUT sometimes "stock" is already pretty good as it is. An observation over the years. IF you're going to spend money, ensure that you'll get more horsepower from that particular change, otherwise, it becomes a "learning experience".

The only REAL issue with a camshaft change is to use THEIR recommended valve lifters so they'll cover the cam warranty (provided "installation" was done as recommended!). Past that, any other recommendations of equipment could well be oriented toward what other stuff they might sell themselves. An awareness issue where individual judgment might come into play.

CBODY67
 
Thanks for the reply guys. Just for the record, wrongly or rightly I have gone with a complete Comp Cams kit.
Where I may struggle:rolleyes: is upon reading some of the info with it, I wasn't quite prepared for the complexity of the job, an honest statement by me. It's going to be a learning curve and hopefully not a expensive one due to issues.
Was thinking just pull it all apart, remove one and put all the new parts in:D
 
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Learn to read before you post, because you're not helping your argument at all.

Well, excuse me for living! I don't see you helping much either!
Thanks for the reply guys. Just for the record, wrongly or rightly I have gone with a complete Comp Cams kit.
Where I my struggle:rolleyes: is upon reading some of the info with it, I wasn't quite prepared for the complexity of the job, an honest statement by me. It's going to be a learning curve and hopefully not a expensive one due to issues.
Was thinking just pull it all apart, remove one and put all the new parts in:D
When you start throwing aftermarket parts on a car, it's not as easy as just putting them on! The cam and valve train is a complicated system, the bigger the cam gets, the more you need to change things to make them work as a whole. Good Luck!
 
Ya know with this post and many other cam, valve train related posts I have never seen anyone refer to the FSM about valve stem height, or "Valve stem length".
When I foolishly did my 440 6bbl heads I got 'Chevy'fied' by the machine shop and as a result suffered the "during high speed driving" aspect.

383-440.Valve.Stem.Length.001.jpg

383-440.Valve.Stem.Length.002.jpg


Live & Learn...
 
Ya know with this post and many other cam, valve train related posts I have never seen anyone refer to the FSM about valve stem height, or "Valve stem length".
When I foolishly did my 440 6bbl heads I got 'Chevy'fied' by the machine shop and as a result suffered the "during high speed driving" aspect.

View attachment 335703
View attachment 335704

Live & Learn...
Your shop did you no favors.
 
Your shop did you no favors.

Naa he was alright, just not a Mopar guy, did me right on many things like free light grind on new drums while I waited just in case it got dropped in shipping/handling.
1 man shop in the back of the local NAPA store, he did a lot of Antique engine work back then in the 60/70's, well known for that. I have many fond memories going back into the shop after asking the parts counter guy if my stuff was ready, I remember now it was a two brother owned NAPA, one ran the parts and the other did the machine work and I had to get the invoice from the brother in the shop. Stuff was always done when he said it would be an usually a one day turn around and the norm for brake drums would be if you got it in the shop by 9/10am they would be ready by 3pm. Saved me from getting a brake lathe ($$$$).

When I went in the shop I politely waited for him to notice me as not to bother what he was doing at the time. Plenty of done Flathead Fords engines, think I saw my first straight 8 at that shop, an other weird antique stuff to look at while I waited plus I may get the story from him about some of them, learning experience when your a teenager ya'kno.
I believe he owned a Model T and would drive it in the town parades IIRC.
 
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