Rotating exhaust valves

-
OLFOOL

OLFOOL

OLFOOL
Joined
Jul 27, 2021
Messages
42
Reaction score
30
Location
New South Wales, Australia
Never noticed before but the J heads I have just bought, the exhaust valve once fitted I can rotate the valve when the locks are fitted, is this normal as I am quite new to small blocks. thanks.
 
Sounds like the installed height is off, or the spring pressure might not be up to snuf. If the stock springs with a ''rotator'' removed, that may be the problem.
 
Not original installed height or springs, never seen a seen or heard of 'rotators' before asking the question. I've only worked on a couple of SB heads previously and didn't run into this issue, been advised that it's not a drama if the valves can rotate as they are.
 
Do you mean you can rotate the valves by hand? Are you gripping the stem with pliers to do this?
 
Is the valve closed, with spring pressure holding it closed? If so somethings wrong..

Rotators replaced with standard retainers & the stock spring could cause that...

Mostly Mopar used multi groove locks that allow the exhaust valves to rotate but don't use rotators... But there are some engines with rotators....

Anything the least bit performance oriented rotators get scrapped... On semi serious performance builds multi groove keepers get scrapped...



thumbnail_IMG_8633.jpg
 
Rotators work great but the problem is you have to run a short spring so it limits you to small cams. Mostly used on industrial engines.
 
MoparMike1974 said:
Rotators work great but the problem is you have to run a short spring so it limits you to small cams. Mostly used on industrial engines.
Click to expand...
I've never been convinced they ever really worked at all. As many burned exhaust valves as I've seen through the years that had rotators, you just caint prove it by me.
 
Some damn week valve springs if you can rotate a valve while it's sitting on it's seat!
 
the multi groove locks allow the valve to rotate freely i read this in an article the intake locks grip the valve , the exhaust do do not. take a lock and grip it, then rotate the valve, i've done that, just food for thought
 
perfacar said:
the multi groove locks allow the valve to rotate freely i read this in an article the intake locks grip the valve , the exhaust do do not. take a lock and grip it, then rotate the valve, i've done that, just food for thought
Click to expand...


Yep, multi groove locks touch each other when they are assembled so they don’t totally lock on the valve stem. It makes them rotate.

I know guys use that style lock with solid lifters but every time I’ve seen it done it beats the hell out of the valves and locks in pretty short order.

Hydraulic lifters don’t mind because you don’t have the lash beating on the lock.
 
I thought it was common for valves to rotate during operation.
Did I have that wrong?
 
I've posted it elsewhere, but the 4-groove exh. stem locks are in a rounded-bead form with matching grooves, and as correctly stated above the locks "butt" together before they can grip the stem. This is a simple rotator system, and will allow the valve to turn when open. When I install serious valve springs using these, I grind one side of each lock half until they have a decent gap, and a solid grip on the stem.
C'mon RRR, You've never seen a circular pattern on a valve-stem tip before? I'm not sayin' to bank on it's function, but they DO turn...whether rotators were worth it or not, only engineers & fleet feedback can probably say.
All that said, if those J head valves are turning on the seats, good chance they're 340HP's that need shimmed or replaced. They have a decent rate, but low seat load(~70#) when the height is correct, little tolerance for too much installed ht.
 
Kern Dog said:
I thought it was common for valves to rotate during operation.
Did I have that wrong?
Click to expand...

It depends. It’s been years and years but for OE type lobes and such it’s ok. As the lobes get more aggressive I’ve and/or spring loads go up it’s not good.
 
Newbomb Turk said:
Yep, multi groove locks touch each other when they are assembled so they don’t totally lock on the valve stem. It makes them rotate.

I know guys use that style lock with solid lifters but every time I’ve seen it done it beats the hell out of the valves and locks in pretty short order.

Hydraulic lifters don’t mind because you don’t have the lash beating on the lock.
Click to expand...
I've never seen slant sixes do that and they all came with four groove locks on the exhaust with solid lifter cams up to 1982.
 
Aircraft engines use sodium exhaust valves with with bearing retainers.
 
RustyRatRod said:
I've never seen slant sixes do that and they all came with four groove locks on the exhaust with solid lifter cams up to 1982.
Click to expand...

Now that I posted what I did my foggy brain said all multigroove locks touch so the valves rotate but IIRC the two groove, square locks lock onto the valve and do not rotate.

Of course, I could go out to the shop and verify that by my doc and the warden (my wife) have banned me from the shop until I see the real heart doc.

Someone here should be able to verify that one way or the other so I’m not posting nonsense.
 
Newbomb Turk said:
Now that I posted what I did my foggy brain said all multigroove locks touch so the valves rotate but IIRC the two groove, square locks lock onto the valve and do not rotate.

Of course, I could go out to the shop and verify that by my doc and the warden (my wife) have banned me from the shop until I see the real heart doc.

Someone here should be able to verify that one way or the other so I’m not posting nonsense.
Click to expand...
You always post nonsense. Your wife told me so. lol
 
well learn something new everyday i just went on what i was taught in the engineering applications centre in my collage .....! getting credits for going there rather than the computer centre for programming in fortran 86 seemed like a win to me.

which was all locks should clamp and the 2 parts should not touch. that way the retainer is held on by friction between the lock and the stem caused by the taper in the retainer. therefore grooves/lumps do not carry the load and you wont wear/snap/drop a valve.

based on the posts above i guess that ain't right in all circumstances. !!!
I've been grinding or discarding the little buggers to achieve a space between them when needed, ever since

i'll pay more attention from now on

Dave
 
You must log in or register to reply here.
-

Back
Top