The Stovebolt Site Forums The Shop Area Engine Shop Valve spring caps on a 216

I am assembling a 216 head and I have two different types of caps to hold the springs in place. The picture in the manual shows what looks like one is for intake, one for exhaust. The intakes look to have a slightly raised center section and the exhausts look to be flatter and squared off.

Is this correct ?

Some engines had rotators on the exhaust valve to keep carbon from building up.

What year 216 engine ?

Do your valve spring caps look anything like these ?

@photobucket

http://i669.photobucket.com/albums/vv57/glp0329/valve%20spring%20caps/new-2_zps9wsmlt31.jpg

&

http://i669.photobucket.com/albums/...Carlisle%20Spring%202010_zpseoftokra.jpg

The head is a 52. I just assembled it after studying the pictures in my manual. From the pictures you sent, I got the intakes right so the others had to be right as well. Then I found a set of the rotator caps in my collection os parts. So I may be switching them out and use the rotators.

Thanks for the help all.

OK - be warned - I know little about this.

The rotator caps (used on exhaust valves on some stovebolt engines) were also used with longer springs (and, the caps were thicker than normal caps). This resulted in greater valve spring "pressure". In engines that used the rotator caps, the valve spring "pressure" was significantly greater. The higher spring pressure was used due to the higher lift of the 261 cam (a cam used in 1954/55 Corvette 235s and in all 235s in later years).

This higher spring pressure presumably resulted in better heat transfer (cooling) at the contact surface, and I guess, lower possibility of "valve float" (especially at high RPM). On some engines (maybe not stovebolts?), valve float might result in a valve hitting a piston.

On stovebolts, different composition valves were used with the rotators (Silchrome XCR).

Exhaust valve rotators were first used on heavy-duty stovebolt engines (in 1954, I think); but, by the end of the 235 "run", I think they were used on all 235s & 261s.

This just got harder! Everything you said makes perfect sense. I "think" I took them off a 216 head that had hairline cracks in the vicinity of the valve seats. No ideas if they are related, cracks and rotators.

I know just the place for these, my friends 261 head, I think he will be glad to have them!

Thanks

Stove bolt engines as well as other Chevy engines used in trucks and heavy industrial applications used rotating valve spring retainers on the exhaust valves to increase the life of the valve. The installed spring height of the valve springs on a stovebolt is the same no mater which retainer is used.
The valve springs listed for all 1962 235&261 engines are the same part # therefore they are the same spring.
Putting thicker i.e. heavier retainers on a performance engine is asking for valve float. In fact the opposite is true. The higher the RPM the less weight you want on top of the valves ergo titanium retainers.
A quick aside, V8 international truck engines used exhaust valve rotators but they were placed under the valve spring. The exhaust springs were shorter than the intake springs to keep the installed height of the springs the same. Hope this helps.
Hot rod Lincoln you wanna weigh in on this?

Tim,

Your comments are all well-taken.

However, your general comments regarding 235/261 springs and compressed spring-heights being the same is only correct in later years (as I posted), but the springs and spring heights were not the same in earlier years of the 261.

And, yes, GM indicated in 1954 that the rotators were used/introduced on/in the 261 (only in/on the 261 in 1954 for a few years) to increase valve life/durability.

According to Engine tech and Sealed power the exhaust and intake springs for 1954 to 1962 261 engines are the same part#. Engine Tech ERV709 and Sealed power VS434. I did discover that 235 engines of these same years used a different valve spring # than the 261, but still only 1 spring for intake and exhaust.
Also the free height (uninstalled height ) of the springs is different. 261= 2.250 235= 2.160 according to sealed power.
I wasn't born 21, so, obviously I don't know everything.

Respectfully

I thought I knew everything when I was in the eighth grade. I didn't turn 21 until a couple of years later.
Carl

I thought I knew everything when I was in the eighth grade. I didn't turn 21 until a couple of years later.
Carl[/quote]

You must understand that the toughest 3 years of my life were 4th grade.
I'm not a fast mechanic. I'm only half fast.