Rocker/Springs question.

**Brammer** · 05-08-2009

So I know this has been debated into the ground and I have tried to do a little reading on the subject. I know for a fact I need to change my LIM gasket so I figure while I'm at it I might as well change the rockers. The car is an '02 GT and it will most likely never get an aftermarket cam. It may eventually get the SS M90 kit, but for the near future it will be exhaust, intake, PCM type stuff. I was looking at the Yella Terra Roller Rockers. I know the higher the ratio the more power I'd get, I'm fairly confident with change the rockers, but have no idea how to change the springs. Would I be best to get like 1.8's and leave the stock springs or get 1.9's and have a shop change the springs for me? Also for 1.8's and/or 1.9's what would be my best spring choice?

Thanks,
Eric

**tylerbinski** · 05-08-2009

changing the springs is easy... BUT when changing them while the heads are still on you must be careful not to drop a valve into the cylinder!! some slide down rope thru the spark plug hole to keep it up, and others use a special fitting and air compressor to attach to the spark plug hole and pressurize the cylinder as they do this... which keeps the valves up.

IF you take the heads off, you will need to head gaskets which can run you $70 for felpros or $150 for MLS cosmetic... but this would also be a good time for you to do the following (if you wish)

- Port the heads, get a valve job, lap the valves, deck the surface, gasket match the LIM and the heads, remove the casting maks in the oil drain back area of the heads (under the valve covers)

there are 2 types of valve spring compressors, one for use with the heads off and a smaller one that can be used while the heads are still on.

I don't know much about aftermarket rockers, I just put in an XP cam and did head work and new springs , retainers etc...

**Brammer** · 05-08-2009

Well I found this write up :
Valve Spring Change
That is fairly similar and you're right it doesn't seem too bad at all. My next question is do I need/want to replace the valve seals, valve locks and/or the valve spring retainers? If I'm keeping my stock valves, they should all be good correct? Lastly I'm fairly sure I'm going to go with the Yella Terra 1.9's. So what would be me best spring choice, and how do I know if I need to shim it or anything? Also the write up I linked to talks about
adjusting valves Valve Adjustment
and it talks about replacing studs and guideplates?

Do I need to do any of this?

Thanks,

Eric B.

**Brammer** · 05-08-2009

According to Intense's Website they recommend :
LS6 Medium Load Valve Springs For the Yella Terra setup. However it says :

# Maximum lift supported @ 1.720" (stock retainer install height) - .500"
# Maximum lift supported @ 1.800" (Manley retainer install height)- .580"

So would I be okay to keep my stock retainers?

**Scimmia** · 05-08-2009

If you're changing to LSx style springs, you would need LSx style retainers, also. The stock locks would be fine. Seals would be your call, I would do them while I had everything apart.

Unless you're looking at adjustable rockers, you don't have to worry about those adjustments at all, the stock style rockers and most of the aftermarket roller tip rockers aren't adjustable.

For springs, I would go with the L76 springs myself, but Crow 105s would be a good choice also.

**Scimmia** · 05-08-2009

Originally Posted by Brammer

According to Intense's Website they recommend :
LS6 Medium Load Valve Springs For the Yella Terra setup. However it says :

# Maximum lift supported @ 1.720" (stock retainer install height) - .500"
# Maximum lift supported @ 1.800" (Manley retainer install height)- .580"

So would I be okay to keep my stock retainers?

No, this is BAD BAD info, and Intense should be ashamed that it's still on their site.

**Brammer** · 05-08-2009

Originally Posted by Scimmia

If you're changing to LSx style springs, you would need LSx style retainers, also. The stock locks would be fine. Seals would be your call, I would do them while I had everything apart.

Unless you're looking at adjustable rockers, you don't have to worry about those adjustments at all, the stock style rockers and most of the aftermarket roller tip rockers aren't adjustable.

For springs, I would go with the L76 springs myself, but Crow 105s would be a good choice also.

Thanks Scimmia,

Where can I purchase L76 springs and the matching retainers? Also any word on replacing studs and/or guide plates?

Thanks,

Eric B.

**Scimmia** · 05-08-2009

The L76 springs can be had from your dealer, or any of the online parts places, like gmpartsdirect or paceperformance. I posted a part number around here somewhere, I can look it up later if you need it. Retainers can be any LSx retainer, from Manley, Comp Cams, stock, etc. They can be had anywhere.

We have bolts, which will need replaced since they're TTY, not studs. Studs and adjustable guide plates are generally used for adjustable rockers, and as I said, ours aren't.

**Sabrewings** · 05-08-2009

For a non supercharged car, get ZZP's ER rockers.

**Scimmia** · 05-08-2009

Originally Posted by Sabrewings

For a non supercharged car, get ZZP's ER rockers.

I know ER ratio rockers are better for the NA 3800 than the modded 1.9s, but I've never seen them compared to roller tip 1.9s. Would the gains from the roller tips offset the difference?

**Sabrewings** · 05-08-2009

Originally Posted by Scimmia

I know ER ratio rockers are better for the NA 3800 than the modded 1.9s, but I've never seen them compared to roller tip 1.9s. Would the gains from the roller tips offset the difference?

First, let me ask you this. What gains from roller tips? I know the theory, but has anyone actually dyno'd a car with normal 1.9s and roller 1.9s? I bet you'd be hard pressed to find any difference at all. There just isn't a need for roller rockers in our engines.

**Scimmia** · 05-08-2009

No, I have never seen an A/B dyno, but how can less friction, deflection, and moving mass NOT be a good thing? Are you saying that all of the big guys running 1.6 ratio RRs are just wasting their money?

**Sabrewings** · 05-08-2009

I'm applying the logic that is used from LSx mods (which I have more experience with), which is still valid on our engines. RRs don't do hardly anything except allow stupid high RPMs on a pushrod setup. Never once have I seen a dyno of the same ratio rockers between stamped and rollers show improvements outside the dyno's margin for error. Saying on an LSx forum that RRs of the same ratio give you more performance will get you flamed pretty quick.

Are they wasting their money? If they're about the same price I wouldn't say that. Just that in his case RRs are not going to be worth not going to ER rockers since on a N/A motor the extra pull at the high RPMs will be well worth it. The L36 falls on its face in the top end due to its cam and the intake insert. ER rockers and the HV3 insert is all it really needs as far as top end mods go.

**Brammer** · 05-08-2009

Originally Posted by Sabrewings

For a non supercharged car, get ZZP's ER rockers.

Like I said long term goal is M90 kit. Still think I oughta do the ER Rockers? Not trying to be sarcastic, being serious? Also hate to sound n00bish but what does TTY mean?

**Sabrewings** · 05-08-2009

Originally Posted by Brammer

Like I said long term goal is M90 kit. Still think I oughta do the ER Rockers? Not trying to be sarcastic, being serious?

QwikGT put down impressive numbers when he had ER rockers on his SSM90 setup. It's up to you. Your car.

Originally Posted by Brammer

Also hate to sound n00bish but what does TTY mean?

Torque to yield.

**99prixgt** · 05-08-2009

Honestly i bought the yella terras for the name and lifetime warranty.

**Brammer** · 05-08-2009

So If I did modified rockers. Would I better to go with :

Modified 1.9 Rockers

Or the :

ER Rockers.

And really.....what's the difference?

**Sabrewings** · 05-08-2009

ER rockers are split ratio (different between exhaust to intake). Also, their ratio was fine tuned to a perfect ratio (not just a round number like 1.8 or 1.9) so they give the most power for the widest range on a N/A setup. ER means extended range.

**Bio248** · 05-08-2009

ER rockers are dumb on a blown setup.

if youre planning on the SSM90 kit i would shoot for a cam right away.

**Brammer** · 05-08-2009

Originally Posted by Bio248

ER rockers are dumb on a blown setup.

if youre planning on the SSM90 kit i would shoot for a cam right away.

Well I'm def not thinking about a cam at all. So I just gotta figure out which Rockers would be best. I like the idea of roller rockers, but the price is more. I know Sabre said that one person has had substantial results with the ER rockers and the SS M90 setup. So I'm guessing the cheaper 1.9 rockers by ZZP are just not split ratio. So they should be good for N/A setup and then eventually a boosted setup. Will the L67 springs still work on either ZZP rocker sets?