As you may remember, I've been experiencing high rpm problems that were very much like valve float. Hard to believe it was valve float because I was running badass Crane 99893 double springs (145 seat/375 open). At 6300-6400, the revs would stop climbing and it would hit a wall. I could not pull my measly 6600 rpm rev limiter...NEVER.

I changed everything. Changed springs. Took the inner springs out thinking it might be too much spring pressure. Only got worse. Replaced lifters. Nothing. Got fresh springs (again) Nothing. Swapped out pcms. Nothing. Adjusted lifter preload with shims. Nothing. Swapped out my Lunati 221/224 113 LSA cam for a TR 224/224 112 LSA cam. Still nothing. This problem absolutely has kicked my ***. What was really crazy was this exact motor was in Judson's black Camaro and it would pull 7000 rpms with no problem. WTF? How could it rpm in one car and not the other?

Things really got bad when I tried really hard to find the rpm problem and slammed every 2.055 intake valve into the pistons below. Bent 4 of them pretty good. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> Time to get serious and find out the problem.

Thanks to an e-mail from Vince Moore in Florida (vmoore LS1Tech.com), he helped solved my problem. He too, was running the same Crane springs and had the same high rpm valve float. He told me on his car, the underside of stock rockers were coming into contact with the wide 1.460 OD spring retainers. I had checked the clearance in the past, and while tight, they didn't appear to be hitting. Boy was I wrong. The underside of the rockers were worn and the tops of the titanium retainers had gouges in them.

Thanks to Judson Massingill over at the School of Automotive Machinsists, he put chief instructor Casey Snider on the task. Casey installed new Ferrea valves (2.055/1.60), new Comp Ti retainers (much shallower), he unshrouded the cc, freshened up the valve job and port work, and reinstalled the same Crane 99893 springs (since they all checked within 1 lb of each other). The biggest key of all (thanks to Vince) was the SAM crew clearanced the underside of the stock rockers to allow about .040-.050" of clearance between the rocker and spring retainer.

Upon first startup, I immediately noticed the valvetrain was much quieter. Good sign. Took the SS out on the Beltway and was pleased to find I could easily bang my 6600 rpm rev limiter with ease. Problem solved.

Apparently, when the valves would close, the retainers would come into contact with the bottom of the rockers which would slightly open the valve back up, bleeding off all my cylinder pressure. The reason why it stumped Judson and me was why it would run so well in the black car and not mine. Judson said his guys had clearanced the rockers a long time ago. After talking with some of the SAM students, we found out that the clearanced rockers had been robbed off my motor after it was taken out of the black car and they were put on a 375 all bore motor. Stock unclearanced rockers (from another LS1) were put on my motor before it was installed. Nobody ever knew.

Now I can start fine tuning my combination. I am going to get some wide band dyno tuning and LS1 Edit programming at Thunder Racing on Saturday. My A/F has been 14.2 to 1 at WOT, my timing is sitting around 24-26 degrees, my rev limiter is at a wimpy 6600 and my shift points are a lowly 6000. Looks like I'm going to be going a lot faster very soon.

 

you never noticed the gouges in the retainers when the springs were swapped? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

 

Great question Fireball. Yes, I noticed the gouges, but months ago I had a problem with some old valves who's tips had mushroomed and allowed the rockers to come into contact with the retainers. The retainers looked pretty ugly after that, but we reused them since the gouges were only cosmetic.

When we changed springs, I noticed the gouges. When I aked Joe Huneycutt what the deal was, he said the gouges were from the earlier damage when the valve tips mushroomed. Guess it was hard to tell if it was old damage or new damage. The whole deal was a huge cluster. Very expensive. <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" />

 

Chris and Vince,

The SAM crew clearanced the rockers around .040-.050". A good guideline to use is to torque down the rockers to 22 ft lbs, then see if you can pass a coat hanger between the rocker and the spring retainer. A coat hanger is about .050" and it bends enough to get in these tight quarters. Unfortunately I did not get a chance to snap photos before the job was done. I'm so happy right now, all I want to do is go out and blast around in the car. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

I stopped counting all the $ spent after I passed the thousand dollar mark (which was months ago) <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> Probably spent twice that.

I forgot to mention this, but while the heads were off, I also had the pistons fly cut. I'll now be able to run a bigger cam if I ever decide to get really stupid!

 

Glad to see everything is working well Patrick! <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" /> I know how much of a struggle it has been. I can't wait to see what kind of numbers it puts out now.

That was a good idea to flycut the pistons when the heads were off. Now, you can go crazy with the cam this summer. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

See you Saturday.

Jason

 

I want my pistons flycut. Jason you are suppose to be emailing me...

 

Jason I called Geoff and we discussed my options and he gave me his advice. I will email you later.. Now I cant wait for my car to be fixed... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

I'm glad to hear that things are back together and running strong. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Hey, Vince. Keep me posted. Still wondering how that's going to work out.

'Los

 

I will.. I am real anxious to see what my car can really do.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Patrick,

In addition to jmX's previous post on how we clearanced the rockers, is there a chance you could get a pic of the gouged retainers as well as the newly clearanced rockers from SAM? Im beginning to wonder if we clearanced to rockers *enough*. Recall jmX's "valve float" issue and my ability to destroy valves. We clearanced the rockers, but I dont know if it was enough.

\chris

 

I am happy to hear this Patrick.. You just do not know how happy I am.. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> My car will be at Norris Motorsports soon. They cant take it until Friday. Jmx we clearanced mine b4 and when I got my heads back it was still hitting. I do not want to touch it again. I want a professional to do it.. It has already cost me too much money as well. <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> I could have purchased a 12bolt by now with the money I have dumped in trying to fix this problem. I am so happy....

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Patrick G:
<strong>I am going to get some wide band dyno tuning and LS1 Edit programming at Thunder Racing on Saturday. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Wait,,,,,,,,, the infamous Patrick G is gonna be in BR Sat???
I may have to stop the carnage on the wifes car long enough to see this!!! LOL
Maybe I'll have her car back together by then and drive IT up there. Seeing how she is doggin' my car while hers is under surgery.

Tim

 

Tim C, what's up! Yes, I've got a tuning session starting at 12 noon and I'll be there 'til it's done. Come on by.

Patrick

 

Man, what a nightmare! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> Glad to hear it's over. <img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" />

 

Good luck with the car!

I hope whoever did not look at the rockers last time takes care of you.

 

Patrick,

Glad you have that problem fixed. That was one hell of a lot of work you went through..

BR ? HMMMMM, I am sure you will get the red carpet treatment over there..Since you are a special guest.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

NOw its time to get that roll bar fixed and get LEGAL.. Parts are ready to be sized .. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Cool deal Brooke!

I'll see you at your shop next week to check out the "bars". Let's hope the tuning session goes well in BR. I'm pumped!

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 99RedHawk:
<strong>BR ? HMMMMM, I am sure you will get the red carpet treatment over there..Since you are a special guest.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yeah, there are SOME people from Houston we don't mind seeing here in BR.

Tim