baxsom

I've been trying to read all I can about swapping the OEM rockers in my ls3 for 1.8s. I understand it's good for decent HP bump and since I've had two corvettes prior that both lost needle bearings I'm definitely doing something on my newest car before it happens again. Is there a proven combo that works easily. I'm seeing pac 1219 springs and new pushrods are common with this swap but what brand rocker is easiest to install? Any install like stock or are they all the poly lock adjustable style?

Turbo6TA

Installs just like stock ... I have a set on my supercharged LS3

Using the PAC 1218 'drop-in' beehive springs.


Attachment 48331316



Attachment 48331317

baxsom

Those are the main ones I've been looking at. Did you need valve cover spacers or new pushrods?

Turbo6TA

I am almost certain you will need either valve cover spacers or taller valve covers.

In my case, I used the Holley LS 'tall' covers ... don't get the standard size Holley covers since they are no taller than your OEM covers.

Pushrods ... You can use your stock 7.4" length pushrods.


Attachment 48331311

baxsom

I'm reading that the scorpion ls3 1.8 rockers do not require a taller valve cover. Any insight into their quality?

grocerygetter

on your Holley tall valve covers I see the bracket to push that first coil pack back out of way of alt. Where did you get those? Come with the VC?

Turbo6TA

That #1 coil bracket came with the Holley 'tall' LS valve covers ... no need to buy separately.

NYC6

looks good, my car is SC’d as well and interested in doing rollers. Did you retune after install and did you see an increase in power? Thanks

Turbo6TA

If you don't plan on replacing your stock cam with something bigger, changing to 1.8 ratio rocker arms will increase your stock cams lift .030"

No dyno sheet to prove anything, but that increase in lift is much noticeable.

No retune needed if all your doing is installing 1.8 ratio rocker arms.

Turbo6TA

Stock LS3 cam Lift with 1.7 ratio rocker arms: . . .551” / .525”

Stock LS3 cam Lift with 1.8 ratio rocker arms: . . .583" / .556"

http://www.wallaceracing.com/rockercalc.php

baxsom

Do the comp rockers need any type of shim for wipe pattern adjustments? I am reading shims under the springs are necessary if they don't torque to 22 ftlbs after zero lash in half a turn or less. Trying to find install instructions

Turbo6TA

No shims ... Just replace your OEM LS3 rocker arms with the Comp Cams 1.8 ratio fully roller rocker arms.

Tighten the rocker arm bolts to 22 Ft/Lb just like you would do with the OEM rocker arms.

simple- stupid
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You can use your stock LS3 valve springs, but I would suggest you use a set PAC-1218 springs ... They are a drop-in replacement for your stock LS3 springs and can 'safely' accept a .600" valve lift. (with more closing valve pressure and slightly better fully open valve pressure).

Will rev to 6,500 rpm without a single problem.

Kocmeister

I can confirm. I have got the mentioned Comp Cam 1678-16 rockers with PAC1218 springs and billet valve cover spacer. Stock 7.4 pushods. Everything works perfectly. The only downside is that if you want to replace the cam with a bigger one in the future, you will be limited in lift. Which is exactly what I'm dealing with right now. If I had known, I would have taken stronger springs, perhaps PAC1219.

old motorhead

Cam Motion can grind you a custom cam with just about any lift with any duration you want.

baxsom

How thick of spacer did you use? I am seeing 3/8, 1/2, 3/4 inch spacers.

Kocmeister

I used 3/8 inch ICT Billet spacer.

baxsom

Damn well I guess it's all over but spending the money
Comp rockers
Pac1218 or 1219 springs
ict spacers
I've got arh headers on the way to jet hot for coating and an intake headed to gwatney for the rod mod so perfect time to do the rockers

Kocmeister

I read somewhere, maybe in the reviews about the 1.8 rockers on the Summit site or something like that, that someone didn't use a spacer and it was ok, but I can't confirm. I haven't tried without it.

baxsom

I've read on a few places where people are just grinding where it's hitting. I'd rather do the spacers. I'd go with holleys covers but I put those on my old 07 and never could figure out the pcv system hookups

Turbo6TA

If you have the Holley LS valve covers (and are not supercharged or turbocharged and are not using a catch can), you leave your stock PCV system alone ... don't do anything different ... just change out the valve covers and plumb any tubes attached to the new valve covers the same as they were attached to the stock valve covers (there is one tube on each valve cover that's part of the PCV system)

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