ZZP Head And GT1 Cam - Valve Issue

[ibuansary]

Hi guys,

Hoping someone can shed light on an issue im having with the ZZP Stage 2 Head and GT1 Cam install. When im trying to install this on my 1997 Chevy Camaro 3800 - the valves remain open all the time leading to no compression in the cylinder.

Stock Lifters and push rods.

Whats wrong ? why are the valves not closing when installed on the engine ?
My mechanic reckons the valves are too long (tall) for the application.
Here are the valve specs -

Stock Intake Valve -
Height : 120mm = 4.72"
Dia : 46mm = 1.81"

New Intake Valve -
Height : 123mm = 4.84"
Dia : 48mm = 1.89"



Stock Exhaust Valve -
Height : 119.5mm = 4.70"
Dia : 38.5mm = 1.52"

New Exhaust Valve -
Height : 124.5mm = 4.90"
Dia : 39.5mm = 1.55"



Would appreciate if anyone could help.

Thanks !

[techsan23]

Re: ZZP Head And GT1 Cam - Valve Issue

What length pushrods are you running? Which lifters and rocker arms do you have? Have you contacted Zoomer yet?

[ibuansary]

Re: ZZP Head And GT1 Cam - Valve Issue

Using Stock everything - Lifters / Pushrods / Rockers

Iv mailed ZZP but with no reply as of yet.
However I did come across this little piece of info on their website -


" Important note: These valves are based on LS1 blanks and are .100 taller than 3800 valves. They require raising the rocker pedistal or running shorter pushrods. We recommend using 3800 retainers to maintain 1.80 install height on the springs, in addition you may need ZZP head rocker shims. "

The Head Rocker Shims are 40$ and i'v placed an order for em.
Wondering what else should I change up to make it work.
Shorter Push rods ? Part # or link would have been nice.
Already have the 3800 Retainers on it so thats off the list.

Any input will be appreciated.

[ibuansary]

Re: ZZP Head And GT1 Cam - Valve Issue

For those looking for a solution -
This might be it :

ZZP recommends using their ZZP Head Rocker Shims : Part # ZZ-RSHIM on their website along with 3800 Retainers : Item # COMP-774-12 and Comp Shorter Pushrod : Item # COMP-7935-12.

Stock Pushrods are 7.05" whereas the comp ones above can be ordered with a height of 6.95"

Have ordered these -
Will update once they are installed on the car.

[htmabe]

Re: ZZP Head And GT1 Cam - Valve Issue

.010" is not that much difference in rod length really it's just getting the all to important valve train geometry back on track. Be careful not to bend those new valves on domed pistons or what ever your set up is. The rockers will need to shim up to compensate for those longer valve stems but sounds like your on the right track with that already. Been a long time since I've ran a stock valve train but the math seems about right. Setting valve spring install height requires a special tool that wraps around the valve then goes up and down on a dial which you read. You're going to want to get your install height nailed,dead on with that shim kit, some of them are .001" but it makes a difference on longevity. Then there's another tool to check your geometry with those shorter 6.95" pushrods to make sure there not to short or long. Hope that doesn't sound too complicated. The short n simple is the math adds up I just triple check everything, and I mean everything.

[ibuansary]

Re: ZZP Head And GT1 Cam - Valve Issue

Hey Htmabe,

Thanks for the input.
Im not doing the install myself - have a workshop doing it for me.
Just dont have the right tools or know how to mess with valvetrain.

I will however instruct them based on ur input - if they didnt know it already.

Parts taking awfully long to get here.
Hopefully I can have her back next week.

Been 2 months since I drove her - **** hit the fan with a blown head gasket.
Landed up with a cam and head install as well.

Haha..