Pro Stock John

iTrader: (34)

I have a buddy with a new Z06 who wants to add some 1.8 rockers, which ones do you reccoment to fit under the stock valve covers?

Are the SLP rockers the same design as stock only in a different ratio?

Chicago Z06

and any dyno numbers associated witht his mod?

Wes

LiquidSnake

PSJ i dont know about the SLP ones but i am using the Crane 1.8 s with my 216-220/114 C.Cam with 941s bu t again mine is a 98 a modified the valve cover for the clearing issues(No big mods just a 4-5 minute grinding) i heard that 98< models haves more room .

bparker

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong>I have a buddy with a new Z06 who wants to add some 1.8 rockers, which ones do you reccoment to fit under the stock valve covers?

Are the SLP rockers the same design as stock only in a different ratio?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I used a set when my 02 Z06 had a stock cam and I picked up a few ponies..

Yes - it is ok to use them - but I forgot what the lift equivalated too.. <img border="0" alt="[chug]" title="" src="graemlins/gr_chug.gif" />

SStrokerAce

iTrader: (2)

Use some good springs with that!

.583/.580 lift!

Bret

Nabbs

Is there any advantage to the 1.8s? It also sounds like there is not any consensus that these will fit on 02 Z06 heads with stock valve covers (btw do the Z06s/C5s use the same valve covers as the fcars?).

I'm looking at going the whole 02 LS6 head/cam route on my Hawk, and was curious as to adding 1.8 roller rockers.

Thanks,

-N

ls1290

iTrader: (20)

Does changing from 1.7 to 1.8 also affect the duration of the cam? If so, is ti by the same ratio?

J-Rod

I posted on this forum a long time ago with all the ratios, lift, etc for just such a swap....

Using both the Jesel shaft rockers, and also the SLP 1.8s. I you'd need a degree wheel to figure the exact ammount of duration you would gain for your .050 lift, but it should be around 4 degrees...

J-Rod

Ok, I found a copy of my post on another forum. This one deletes old posts instead of achiving them (whats up with that?)

Anyhow, here it is...
So, lets do the math over again. The stock LS1 cam is .500/.500 198/208. The 2001 Z cam is 0.525/0.525 204/211. The 2002 is even bigger, but I couldn't find the specs right off the bat, So I am just posting the 2001 LS1/LS6 specs

.500 lift @ 1.7 is .294 at the cam. With a 1.8 rocker it is .529 . With a 1.85 .544 and with a 2.0 rocker it is .588

.525 lift @ 1.7 is .308 at the cam. With a 1.8 rocker it is .555 . With a 1.85 .571 and with a 2.0 rocker it is .617

Ok here are the Cam specs on the MTI cams complete with Lift, duration, and lobe separation.

Roger, you should be able to test your model against the actual dyno sheets. Since there are dyno sheets that are avaliable against all these mods on MTI's website. This would be a good way to verify both the model and the dyno numbers seen.

Cam Lift Duration LobeSeparation
Intake Exhaust Intake Exhaust
A1 .532 .558 209 216 114
B1 .558 .558 221 221 114
C1 .566 .566 .222 .222 112
T1 .558 .558 221 221 112
R1* .560 .560 232 237 114

As you can see, a 2001 LS6 camshaft with 1.8 rockers is close to a B1 cam and with 1.85 rockers it is bigger than a R1. Now, you get into an issue of possible coil bind, and piston to valve clearance.

I will have to go back and look, but, on the SAM Camaro, I believe they ran into piston to valve clearnce problems at .615 lift. So, coil bind may be your only issue

As for all the worries about spring coil action etc... I might worry that the stock valvesprings might not be up to the task, which would require good pushrods and a valvespring change. But I would have to look at what the factory springs are set up for. I suspect an upgrade might be in order though.

But as for a cam change being simple. That is simply not the case. You have to drop the entire front suspension to pull the harmonic balancer, plus there is some other "finagling" to get a cam in. Yes, you don't have to pull the lifters, but there is plenty to do.

Rockers, and possible springs and pushrods can be done with only the removal of the valve covers. But roller rockers in many cases also require modifying the baffles on the valve covers.

Like I said, I may look at rockers as an intermediate step before the cam change to see what effeect they have, since I can get close to the cam numbers with just that simple change.

Ok, I found an article which covered the specs of the 2002 camshaft vs the 2001

.525-in. lift to .551-in lift on the intakes
.525-in. lift to .547-in lift on the exhaust

which translates to

.324 intake lift at the cam

Here is what bigger rockers get you
1.8 .583
1.85 .599
1.9 .615
2.0 .648
2.1 .680

.321 exhaust lift at the cam
1.8 .579
1.85 .595
1.9 .611
2.0 .643
2.1 .675

supposedly 116 degree lobe separation

Jesel PN#'s for LS1/LS6
1.7 K2A-3012203
1.9 K2A-3022203
2.0 K2A-3032203

Current Racers net price on the Jesel setup is is 1416.00

Also the increase from 1.7 to 1.8 should give you between 2 and 4 degrees more duration. I am unsure how much you gain with rockers of an even larger nature.

As a side note. On the springs for the 2002 the closed seat loads are the same 90lbs closed on the seat as 2001 - but the open loads increase from 259lbs in 2001 to 294lbs for both springs in 2002.
Here is the SLP kit....
<http://store.yahoo.com/corvetteforum/slprocarmkit.html>

J-Rod

'02 LS6 cam specs: 204/218 .551/.547 117.5lsa

From Paul J. on the 2002 Z06 Spring
They are very similar to the Comp 915 spring in spring rate and seat load. I wouldn't use them with a cam over .530" lift. These are the specs I measured:

Height Load (Lbs)

1.800 90
1.750 105
1.700 120
1.650 138
1.600 155
1.550 173
1.500 190
1.450 208
1.400 225
1.350 250
1.300 272
1.250 298
1.200 328
1.150 Coilbind 1.152"

So, a 1.8 rocker would mean you would need a new spring. Duration should end up between 206 and 208 on the intake and 220 and 222 on the exhaust.

So, with 1.8 rockers you end up with
either a

206/220 .583/.579
or
208/222 .583/.579 both with 117.5 LSA

Compare that with PatrickG's new "Old Man Cam"
214/220, .600/.527, 115 LSA, -2 degrees ground in

<small>[ December 11, 2002, 09:04 AM: Message edited by: J-Rod ]</small>

Pro Stock John

iTrader: (34)

J-rod, thanks for digging up that info. FYI we don't prune threads in the tech forums but we do prune the regional forums and the classifieds.

How about the SLP 1.8 rockers? Aren't they very similar to OE and a lot cheaper than the other aftermarket stuff? IMO stock rocker arm failures are relatively rare sometimes folks lose the needle bearings.

Pro Stock John

iTrader: (34)

Would a 918 be a nice step up from 02 Z06 springs?

bparker

Yep - that would be - but I ran them just fine with stockers.. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong>Would a 918 be a nice step up from 02 Z06 springs?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">

J-Rod

I did a search in the tech section, but my threads only went back just a short while. It may be that I needed to set my "topics" to 365 days or something like that.

Anyhow, the 1.8s look just like stock. The link I posted has a picture of them. most of the stock failures have been due to needle bearing failure.

It you use the 1.8's I would suggest an upgrade to a new spring like the rev dual spring or something like that.

EDIT : Never mind the link I posted was dead. Her eis the page from SLP's site. The Z06 does require different springs.

http://www.slponline.com/view_produc...RTNUMBER=53300

They don't have apicture. But the pic I saw looked just like stock...

<small>[ December 11, 2002, 12:17 PM: Message edited by: J-Rod ]</small>