I've been running a set of Edelbrock BBC heads for 40K miles and finally bothered to check the specs on the springs that came with them. Turns out they are hydraulic flat tappet springs and I'm running a roller. Ooops!

So I'm changing the springs over to something beefier and I notice this star pattern on the valve stems, where the rocker's roller pushes on it, indicating the valves have rotated. I've heard this means the valves have floated. Also noticed it much more on intakes than exhaust. Only one exhaust valve had it and it looked like it turned 30 dgr once and then stopped (only two wear lines). All intakes have all kinds of patterns.

So is the star pattern a sure sign of float?

WoW, good question. I have never heard that one before, but I am curious to hear what comes of it.:confused:

I think valves are supposed to rotate some!!

Trucks have rotators on them to help even out the seat pattern wear if not mistaken, but they aren't very good in a hi-po motor so they are discarded and .300" thick seat shims are used instead.

But the valves still rotate some regardless..

pdq67

I've been running a set of Edelbrock BBC heads for 40K miles and finally bothered to check the specs on the springs that came with them. Turns out they are hydraulic flat tappet springs and I'm running a roller. Ooops!

So I'm changing the springs over to something beefier and I notice this star pattern on the valve stems, where the rocker's roller pushes on it, indicating the valves have rotated. I've heard this means the valves have floated. Also noticed it much more on intakes than exhaust. Only one exhaust valve had it and it looked like it turned 30 dgr once and then stopped (only two wear lines). All intakes have all kinds of patterns.

So is the star pattern a sure sign of float?
=
It is a pretty fair indication.
You will sometimes find more than one pattern on some tips with roller rockers as sometimes they do not hit the valve square & will tend to rotate the valves some but when you find that "star" lookin pattern this is not a real good sign.
The intake will almost always show signs of float first especially in a Rat due to weight.
If you see this it is time to look real close at the bottoms of the retainers & the shims to see if they are getting beat up.
Also look real close at the keepers both at the valve & where they sit in the retainer.
The valve stems should not look like the keepers are moving on the valve above & below the groove.

I posted about this over a year ago.
I found the * info on the Manley sight.
Not that Mike doesn't know his stuff

Also, with about 10 min on fresh valves, you can see the sweep pattern of the rockers and see just how close you got your pushrod length. Or if any thing is different in the valve train. I found out that my cheap Proform rockers have the tips at least at different heights and distances from the pivot.

Zwede,

I recently ran into this on my 445 SBC on the dyno (6 pulls and two warm-ups). Power was down and the peak RPM occured about 500 RPM lower than expected (672 HP @ 6300 RPM). No audible valve float was ever noticed.

I contacted a noted cam guru after I got the engine home to discuss a new cam. He modeled my cam (very aggressive) and valvetrain setup in his software (NASCAR) and it indicated that I was having valve control issues. He felt like I should pick up 30-40 HP and 500-700 RPM with just more spring, which would keep the valve under control. He suggested that I pull the engine down and inspect the valves and lifters.

I contacted the cam/valvetrain manufacturer. (I'm running their cam, springs, retainers, locks, and lifters.) Before I told them of the problem, I asked again what spring I should be running and emphasized that I'm running a valve that is likely heavier than what is normally used (I'm using a 2.15 diameter x 5.29" long stainless steel intake valve). He recommended a spring with 235 psi seat/580 psi open. I'm running 235 psi seat/560 psi open (measured and verified). He said that should be fine. I then told him about the low dyno numbers/RPM. He felt like there was no issue with the cam and springs and that it was just because the heads are too small for the engine.

When I pulled the rockers and springs, I saw just what you are seeing as well as what Mike indicated. Definite indicators of valve float. I haven't gotten back with cam manufacturer to discuss any further.

A new cam and springs are in the works. So far ~$700 down the toilet (and counting) on the original stuff. I haven't pulled the lifters yet to see if there is any damage there. If there is the cam manufacturer is going to hear about it and then some.

I somewhat recently heard a story from a noted engine builder (mostly drag racing) about something similar. A customer had contacted the company about building one of their proven combinations for a boat application. The customer wanted to upgrade to Manley Nextek springs over what they normally used (very similar in pressures). The company had used the Manley spring in drag applications with good success so it was agreed upon. The engine was dynoed and made the expected power that they usually see with this type of engine and the engine was delivered to the customer. When the customer installed the engine in the boat it ran well except for a band within the operating range that severe valve float was heard (To the point the engine was breaking up.) After the customer chased the issue for some time the engine builder recommended switching back to their normal valve spring. Problem solved. Although the two springs were like pressures and the Nextek springs were used before by the engine builder in drag car applications where the engine pulls quickly through the RPM range a harmonic showed up in a boat application where the RPMs climb much more slowly. This is not a knock on the Manley spring as it is a VERY good spring. It just didn't work in this particular application due to a harmonic issue.

It just goes to show you though, that just because you are running the "recommended" spring or one "similar" doesn't necessarily mean it is correct and all is good for your combination/application. Valve weight and RPM come into play as well as spring harmonics (more an issue with endurance or boat stuff as mentioned above). The only way to know for sure is to Spintron YOUR combination, which is not an option for most anyone here. In short of that, we have to rely on experience of what is proven. Stick to what you or your engine builder knows works for your application.

Sorry for the long post, but hopefully it can be of use and save some of you some grief and $$.

Thanks for all the great replies! I think the engine is yelling "VALVE FLOAT" at me. I should have known better. The Edelbrock springs were only 120/330 and I'm running a hydraulic roller with all the weight that entails. Plus the springs have 30-40K miles on them so they are probably barely above 100 lbs now! Susrpised the thing even idles. :)

New springs are 155/368 so that should work much better. I plan on a 6100-6200 redline. Cam is small.

Here's a pic trying to show the star pattern. It doesn't show up as clear in the picture as in reality. You can see two lines clearly and a faint third line. There's also a 4th line that didn't show in the picture.

On the bright side the lines are centered so my valvetrain geometry is spot-on.

http://temp.corvetteforum.net/c3/zwede//staging/float.jpg

[QUOTE=zwede]Here's a pic trying to show the star pattern. It doesn't show up as clear in the picture as in reality. You can see two lines clearly and a faint third line. There's also a 4th line that didn't show in the picture.
On the bright side the lines are centered so my valvetrain geometry is spot-on.
QUOTE]
Hi Zwede, be very careful what you "read" into that pattern. Some years back we had a little "to do" with K.C. down at Manley. They ended up giving us some valves "on-the-house". It had a little something to do with some special-made valves for pre-assembled "Dart" heads coming from "Summit". They had the "Manley" name etched on the top. I'd be really curious as to the brand AND level of quality in the pictured valves? Thanks, Gary in N.Y.
P.S. I'm not saying it couldn't be a "float" condition, I'm just saying be cautious. What you see there was VERY common years ago with "PEP" (shin-ichi) valves, coming out of China and shipped through California. We paid some $4.00 each for the first few we tested. These were considered their top valves at the time. I would have hated to see their "stock" replacements. Needless to say, there was no deal put together. This whole scenario stopped us from ordering ANY pre-assembled heads from that point forward.
http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/th_P1010608.jpg (http://i16.photobucket.com/albums/b28/GOSFAST/PES%20Engines/P1010608.jpg)

Hi Gary, The valves are whatever comes with Edelbrock aluminum heads cirka 4-5 years ago. I don't think there's a quality problem with the valves as they have 40K miles on them and there is only a pattern, no valley.

The picture you posted is interesting. How long did it take for the wear? Looks like they are made of low grade steel (what a surprise, low grade steel out of China!)

Zwede, those ARE "Manleys" in my photo, as I said we had "words" with them at the time. They were "special" made for the Dart heads that were being mass produced back in that era. And in the photo it's tough to see but it's a distinct, very clear pattern from the roller. What appears to be other "marks" on the valves is only in the photo not on the valves. We knew this issue wasn't from "float" because we put some new valves in with the same springs and the car ran for years. We had the customer check it from time to time directly after the repair. But there was no further issues. Thanks, Gary in N.Y.
P.S. The Chinese "Shin-ichi's" never got into as much as one unit from here, although we did test some units, on the dyno, for our own purposes. I don't know what Edelbrock used for valves back when you got the heads, but if they can "save" a buck, I'd imagine they would also. I have some issues right now with their "marine" BB heads. They don't want hear about it, "it's the exhaust manifolds' mfr's. problem. Same old story!

" I plan on a 6100-6200 redline. Cam is small."

Allright,,,,we gotta get this story straight. Is it a "small cam" , a "healthy cam", a "neat cam" or what??? he he he..........


I haven't seen Nicks after the teardown...do his look the same?

Are you going back with the Beehives?

Isn't it time to change cams yet? Voodoo's are out, right???




JIM

I've always said the cam is small, Jim. You're the one who called it healthy! :D

Yeah, I remember seeing a star pattern on Nicks also.

Beehives are in. Putting it back together now.

http://temp.corvetteforum.net/c3/zwede//staging/beehives.jpg

Zwede, those ARE "Manleys" in my photo, as I said we had "words" with them at the time. They were "special" made for the Dart heads that were being mass produced back in that era.

Sorry, I misunderstood. I thought you were saying Manley sourced in Chinese valves and rebranded them as Manley. So those were still made by Manley but with low quality material?

Isn't it time to change cams yet? Voodoo's are out, right???


<Charlton Heston>
NEVER!!!! You'll get this cam from my dead, coooold hands.
</Charlton Heston>

Nah, I'm quite happy with it. I was tempted by the Voodoos but the way Holley treated Harold turned me off. I'll see what he comes up with next.

Now THAT's what I like.....a "Zwede" quoting a good ole American gun toter like Charlie! You HAVE been in TX long enough for us to have an affect on you!!

Does my heart good!

With you on Harold...not sure he fit the corporate mold....they should have let him do what he does best.....lock him back in a dyno room and design cams like I'm sure he would have liked!

Doesn't mean we can't go visit Doug again though does it? We need to work on our Cruise In week. I'm thinking another day in Memphis would be fun?

JIM

I think that was the problem, They did and THEN cut him loose!!

BUT all in all, he did get a pay-check for the work he performed...

Hope everything works out for him in the end..

pdq67

Jim, I'm sure we can visit Doug again. He's a good guy and no way he had anything to do with how the suits treated Harold. Besides, Doug promised me a software upgrade!

As for the cruise in, I think you need to get on Nick's case. All he does is piddle on that black truck. <where's the smiley shaking his head?>

From what I've gathered...he has a LONG way to go on the Vette.

If we manage to get dyno time this week, are you going to make it down?

Has he got engine back together?


JIM

BTW- did you tell 'em you'd be willing to race at BG this year? Looks like we get track to ourselves this year!


JIM

Damn, the hamsters ate my reply!

Let's try again... Yup, I'll go down to Houston with Nick. I figure he can use the moral support. Hey, we can pick out your EFI setup while I'm down there!

The engine is supposedly ready to go. He popped the isky springs on it.

I'll do a few passes @ BG. If it breaks, will you have a Ryder truck show up? :D

I haven't talked to him today. If you do first....the 2nd dyno shop hasn't answered phone since last week. Hopefully tomorrow. If not I'll go back to begging the 1st one!

Hey, we never leave a stranded brother behind...we got Joe home remember?

If not I'll bring a tow strap....you don't mind being towed 1000 miles at 75 mph do you with a strap? Might get a little "ripe" in there though being that close to exhaust pipes!


JIM

JIM

See you boys at the track this year!

Markus,
From what I have seen, look at what Mike said, the wear on the locks and retainers where they meet and the shims below to get a good indication if float occurred.

Doug: I don't see anything funky on the locks/retainers. The shims look like there is some wear but I don't know what is normal after 40K miles though.

In any case, I'm not replacing the springs because of the star pattern, I'm replacing them because they are the wrong spec for my setup and in addition they are getting old.

I hope you'll be at the track with Jim and me this time Doug. Maybe seeing your Nova will get Jim to go to the dark side and EFI it.

Tell Jim I'll run him heads-up! Just he has to run his street tires and I can run my slicks!! Should be a close race except he'll have 15 mph on my trap speed! :)