should valves rotate ?

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RustyRatRod said:
Both of your provided links clearly show and talk about using valve rotators. Valve rotators are not used in performance builds, so valve rotation is not supposed to occur. If it does, something is wrong.
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Lack of rotator does not indicate that rotation should not, and does not occur. A key or pin would.

Read it again: The cdx link I posted goes so far as to state, "some engines EVEN use positive rotators."

Op should be concerned for the fifteen not rotating, Not the one that does. This is not a function of cam type, or even valve actuation design. It's inherent in the function of the poppet valve. Paint the stems, run the engine, talk to your head builder.
 
A body said:
....and I'm still curious. Are you running lash caps on the exhaust valves? I know a lot of people do on these builds including both of mine. Not sure what or if any difference it makes, but it might....
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No lash caps on either.
If I ran a lot more lift or rocker ratio , I might consider it......but the sweep is well centered on the valves and nowhere near the edges.
I won't get out to the garage till this week end , so I will have plenty of time to ponder this.
And I have gotten some solid advice on what to look for , so I should be able to sort it out.
I just hope I can do it without pulling the head.
 
My engine builder told me that, if the valve is rotating it could be a sign of detonation. Some of the valves in my 408 had multiple ware marks on the valves indicating it was rotating. Also the head gasket blew in a cylinder that had the marks on the valve tip.
 
jos51700 said:
How about a source? I don't generally consider it wise to take technical advice from someone with something to sell. Especially when they hint that normal operation might require more and more expensive race engine parts rather that a simple pin, as suggested in the first link below.

Link makes it look like a Manley valve brochure.

I maintain my position: http://www.cdxetextbook.com/engines/comp/vlves/valverotation.html
https://books.google.com/books?id=D...onepage&q=valve rotation in an engine&f=false
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Your links refer to engines with rotation designed into the valve train. They have no relevance to Tubtars engine. Some engine need valve rotation some don't. Apples to oranges.

You are right those pics are from a Manley tech page. The information is quite valid for engines with non rotational valve train such as virtually any race motor. Just because they sell parts doesn't make the information any less true. If they really wanted to sell parts they wouldn't put this info out there, and would sell more parts due people's increased engine parts failures.
 
Unless you're using springs that are not made by winding into coils, the valves are going to rotate to some extent over time. It's not a sign of loss of valvetrain control, but a sign that as a coil is compressed and released a rotary motion is induced in it. Sometimes (over some rpm range for each possibility I'd imagine) the retainer will allow the spring to slip, sometimes the shim at the base of the spring, sometimes the locks will rotate around the valve, and sometimes the valve will turn. The beehive spring would help eliminate this to some extent because of the differing frequencies occuring along it's length. one might cancel out another. By design or not - valves may rotate and there's not a damn thing you can do about it.
 
Ok fellas.

Why is this the first time in twenty five years of dicking with cars that I've heard the term "non rotational valve train?

If every valve guide on the head is tight, guess what.... No rotate.

Op: your head builder fucked up and left the anti rotation key off one valve.....;-)

Please please please find a technical document (NOTa sales document, sorry) that covers non rotational poppet valve. I wanna see it.
 
some things will not change, valve rotation is one of them.
valves will rotate to some degree.
 
My 714 casting heads came with exhaust valves the had rotators installed. SO why go thru the effort to design and manufacture these different parts if
All valves rotate? Just saying... MT
 
all valves will move some at times. in the ? 1973 + era when we went to unleaded gas rotating retainers began being used on exh valves cuz it was thought to help longevity. a rotating retainer is heavy and not used or needed in a hi po engine. 15 valve guides on the heads are not too tight, and mopar w heads do not have anti rotation keys
 
A body said:
any updates?
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I got the LSM on head spring tester and they were all between 210-220 lbs. on the seat.
I was looking for consistency , rather than an actual value.......they are supposed to be 240 on the seat , so I will see about testing the tester now. It is easy to get a different reading using this tool , so I tried to get the same position on the rocker and the same pull when I checked them.
The guy who set the heads up said he used the retainers for each valve when he set installed height and we kicked it around a bit.
My best guess is that I probably floated them while doing a little spirited driving around the house.
I have not been able to get the car to hook on the street and that led to some monstrous burnouts........not much better than revving the engine in neutral.
I didn't spin the motor that hard.....I am fairly certain it hasn't been north of 8000 , but with no load to speak of , it will behave differently.
The valve in question was .004 looser than the rest.
I re-installed the rocker arms and shot for .024 clearance ( was .026 before ).....using .006 for growth left me spot on last year.
I have a test day on the 16th and I will take another look after that.
For now , the consensus is drive it and keep an eye on things.
 
I didn't set my LSM up when we did the build so it's a little "off", but as you, I just look for consistency, matter of fact... I should put the car in the garage and run them all and log the results. Whopping 18 passes on it now :)
 
A body said:
I didn't set my LSM up when we did the build so it's a little "off", but as you, I just look for consistency, matter of fact... I should put the car in the garage and run them all and log the results. Whopping 18 passes on it now :)
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Nice.
Next Saturday is a test day at the local 1/8th mile track and I am hoping to get some results there.
If it hooks , it will take a week to wipe the grin off my face. lol
 
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