Im down to the last bit on my 03 Z06. I got the shim kit from Shane at Thunder Racing last year, with the custom manton 7.625" pushrods. So here goes.. Im installing the rockers pushrods, doing the EO IO method. It just seems that when I get to 22lbft on the rocker bolt it seems too tight. The odd rocker I can move a bit side to side with great hand pressure and the other one same cylinder cant move at all. I have checked and rechecked. Even used another brand new torque wrench with the same results. I have the shims under the aluminum rocker pedastals. Heres the weird thing. Those little tabs I believe there are 4 per rocker pedastal. Well as i get to the number 1 exhaust and the number 7 and 8 rear rockers the torquing will snap these littel tabs off as well. Since these tabs are right at those valves. I dont know why this is happening or if maybe the pushrod is too long, springs arent shimmed correctly maybe? I have the .650 springs and cam in sig. I have no clue. Hoping Shane from Thunder or anyone with a similar setup will chime in with something knowledgable for me. There must be 100's of these exact setups with no problems. Come on guys help me please!!

Thanks to anyone. I have to have this rectified since Im flatdecking my Z06 to my tuner in 5 days and didnt expect these issues!

 

I have also used blue loctite and done no thread sealer as well. Zero difference..my 2003 shop manuals call for no lubricants on the rocker bolt threads. No one here has a similar setup with the Thunder Racing shims and trickflow heads with stock rockers?? Would new rocker bolts make a difference maybe?? Using LS7 lifters.

 

You need to grind the tabs off the rocker pedestals. I just set up my power metal tea tfs 245(65cc) with stock rockers and didn't use a shim kit. (7.45 pushrods)Tea advised me not to!! Wrong wipe pattern. The valvetrain is actually pretty quiet. Good luck with shims!

 

Oh yeah gasket maker on intake bolt and blue lock tight on exhaust bolt

 

Any shim kit will eventially kill a tfs head from the rocker being offset on the valve tip... I run tfs 225's with powder metal guides, shaved the tabs off the rocker stands and are using the trunion upgraded stockers.... No problems here

 

Stock rockers should never be used on any heads that have bronze guides. It doesn't matter if they're OEM heads, AFR heads, Dart heads, or TFS heads. Long term guide wear will occur.

Rocker shim kits with stock rockers should never be used on anything other than a track only car.

Stock 15 degree rockers scrub after .550"-.600" lift and this scrubbing action causes two problems. #1 it causes guide wear and #2 it causes valve tip damage. Guide wear is minimized when OEM powdered metal guides are used, and valve tip damage is minimized if the correct open spring pressure is used.

The more stock rocker arms are shimmed, the sooner in the lift cycle the scrubbing occurs, and the more severe the damage will be to the valve tips and guides.

I've seen LS6 heads with bronze guides using stock rockers and the guides had severe wear after 10K miles.

Just a couple of months ago I had a pair of 317 castings that had the shim kit and the valve tips were killed. They had grooves cut in them from the tip end of the rocker digging into them. These particular heads also had springs with 450 lbs of open pressure which also aggravates the valve tip damage caused by using stock rockers.

A couple of months before that I had some bone stock 243 heads off a C6 Corvette that had springs with 450 lb open pressure and a cam with about .630" lift and all of the valve tips were damaged. This was without a shim kit.

The only way to run stock rockers on TFS heads is to:
#1 Use special powdered metal guides that are available through TEA or myself.
#2 Use springs with less than 400 lbs of open pressure. I have the best springs available for that application.

The standard TFS springs are 450 lbs open pressure and are designed for roller rocker arms.

TEA has received several heads back with stock rockers using these shim kits that had the valve tips worn down to the valve locks.

If you have bronze guides my best advice is to find some roller rocker arms. They can be shimmed, but the wipe pattern should still be checked.

I hope this helps.

 

Thanks Brian and everyone else. So why is Thunder Racing selling these shim and pushrod kits for TFS heads saying they work and provide correct valvetrain geometry with stock rockers??. I would like Shane to respond here, since I gave them a fair amount of business. $$

 

My heads came with the extreme gold .650 springs. Can I still use these springs on a 234/236 XER cam .598/.602 ?? On a 59 cc TFS head with stock GM MLS gaskets, what length pushrod should work? Yella Terras ok for rockers? Brian can I do this without shimming with the new parts? Thanks.

 

The only way to correctly set the wipe on an non-adjustable rocker (non stud mounted) is to raise/lower the pivot point. With a dial indicator and check springs, this can be done with the heads on the car. When I finished setting up mine, the wipe width was 0.045" centered on the valve stem.

 

Who assembled the heads with Extreme Gold springs? Do you have pictures of the springs that are installed? Are they Gold on the outer spring and polished silver on the inner spring?

Standard TFS 7.500" length should work on the heads, depending on whether or not you shim the roller rockers. The Yella Terra tend to work better with some shimming and you may need as long as 7.550" pushrods.

Brian

 

Brian, thanks for the replies. The springs are gold on the outside and gold on the inner spring too. So what springs are these? I bought them from a ls1tech forum member but they were brand new never installed. manufactured in 2010. Im thinking to buying the YT6645 roller rockers and a pushrod length checker and go from there. With LS7 lifters, 59.5 cc chambers, stock gm MLS gaskets, I should be between 7.500 to 7.550.

 

Those sound like the standard Gold springs which are about 360 lbs open pressure.

Do you still have the original TFS springs that came with the heads? Are the inner springs taller than the outer springs? If so those springs are about 450 lbs open and are what you need to run with the roller rocker arms.

 

Brian. These are the only springs they came with. They came completely assembled. The guy I bought them off of said that the springs are the .660 ones. Whats the pressure on these? Can I use these for my XER 234/236 cam and yella terras?? Can I snap a photo of the springs on the heads. Would that help you identifying them maybe? Thanks

Derek

 

Go here and click on the closeup pic of each of these springs.
http://www.briantooleyracing.com/650...l-springs.html
http://www.briantooleyracing.com/660...l-springs.html

The standard high lift TFS springs should look like my Max Pressure. The "Gold" and "Xtreme" outer springs are very shiny gold, they're polished and plated. As opposed to standard spring color.

 

Brian. They are the max pressure springs. Dull bronze color, inner and outer. Can I use these for my application still with that cam and yella terras? Thanks soo much for your help.

Derek

 

Yes sir, those springs and roller rockers work well together.

Some 3/8" pushrods would be a nice benefit too, and should drop right in there. The higher open pressure springs combined with the heavier rockers makes the 5/16" pushrods start to pole vault, so the bigger diameter pushrods work better. You won't see a difference in power, but you will see a difference in durability.

 

One last thing Brian please. So with the XER 234/236 cam, those max pressure spring yella terras, LS7 lifters and the correct length 3/8 pushrod I should be a go? I found the flow chart from my heads from April 2010. These heads were originally bought from Vengeance. So my heads will clear a 3/8 pushrod no problem Brian? Thanks again very much.

Derek

Off to hunt for lowest price yella terras and a pushrod checker.